fix default value in interactiveshell.ask_yes_no

was True, should be None

closes  #1026

IPython/core/interactiveshell.py

@@ -1,2710 +1,2710 b''
 # -*- coding: utf-8 -*-
 """Main IPython class."""
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2001 Janko Hauser <[e-mail]>
 #  Copyright (C) 2001-2007 Fernando Perez. <[e-mail]>
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from __future__ import with_statement
 from __future__ import absolute_import
 
 import __builtin__ as builtin_mod
 import __future__
 import abc
 import ast
 import atexit
 import codeop
 import inspect
 import os
 import re
 import sys
 import tempfile
 import types
 try:
     from contextlib import nested
 except:
     from IPython.utils.nested_context import nested
 
 from IPython.config.configurable import SingletonConfigurable
 from IPython.core import debugger, oinspect
 from IPython.core import history as ipcorehist
 from IPython.core import page
 from IPython.core import prefilter
 from IPython.core import shadowns
 from IPython.core import ultratb
 from IPython.core.alias import AliasManager, AliasError
 from IPython.core.autocall import ExitAutocall
 from IPython.core.builtin_trap import BuiltinTrap
 from IPython.core.compilerop import CachingCompiler
 from IPython.core.display_trap import DisplayTrap
 from IPython.core.displayhook import DisplayHook
 from IPython.core.displaypub import DisplayPublisher
 from IPython.core.error import TryNext, UsageError
 from IPython.core.extensions import ExtensionManager
 from IPython.core.fakemodule import FakeModule, init_fakemod_dict
 from IPython.core.formatters import DisplayFormatter
 from IPython.core.history import HistoryManager
 from IPython.core.inputsplitter import IPythonInputSplitter
 from IPython.core.logger import Logger
 from IPython.core.macro import Macro
 from IPython.core.magic import Magic
 from IPython.core.payload import PayloadManager
 from IPython.core.plugin import PluginManager
 from IPython.core.prefilter import PrefilterManager, ESC_MAGIC
 from IPython.core.profiledir import ProfileDir
 from IPython.external.Itpl import ItplNS
 from IPython.utils import PyColorize
 from IPython.utils import io
 from IPython.utils import py3compat
 from IPython.utils.doctestreload import doctest_reload
 from IPython.utils.io import ask_yes_no, rprint
 from IPython.utils.ipstruct import Struct
 from IPython.utils.path import get_home_dir, get_ipython_dir, HomeDirError
 from IPython.utils.pickleshare import PickleShareDB
 from IPython.utils.process import system, getoutput
 from IPython.utils.strdispatch import StrDispatch
 from IPython.utils.syspathcontext import prepended_to_syspath
 from IPython.utils.text import (num_ini_spaces, format_screen, LSString, SList,
                                 DollarFormatter)
 from IPython.utils.traitlets import (Integer, CBool, CaselessStrEnum, Enum,
                                      List, Unicode, Instance, Type)
 from IPython.utils.warn import warn, error, fatal
 import IPython.core.hooks
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 # compiled regexps for autoindent management
 dedent_re = re.compile(r'^\s+raise|^\s+return|^\s+pass')
 
 #-----------------------------------------------------------------------------
 # Utilities
 #-----------------------------------------------------------------------------
 
 def softspace(file, newvalue):
     """Copied from code.py, to remove the dependency"""
 
     oldvalue = 0
     try:
         oldvalue = file.softspace
     except AttributeError:
         pass
     try:
         file.softspace = newvalue
     except (AttributeError, TypeError):
         # "attribute-less object" or "read-only attributes"
         pass
     return oldvalue
 
 
 def no_op(*a, **kw): pass
 
 class NoOpContext(object):
     def __enter__(self): pass
     def __exit__(self, type, value, traceback): pass
 no_op_context = NoOpContext()
 
 class SpaceInInput(Exception): pass
 
 class Bunch: pass
 
 
 def get_default_colors():
     if sys.platform=='darwin':
         return "LightBG"
     elif os.name=='nt':
         return 'Linux'
     else:
         return 'Linux'
 
 
 class SeparateUnicode(Unicode):
     """A Unicode subclass to validate separate_in, separate_out, etc.
 
     This is a Unicode based trait that converts '0'->'' and '\\n'->'\n'.
     """
 
     def validate(self, obj, value):
         if value == '0': value = ''
         value = value.replace('\\n','\n')
         return super(SeparateUnicode, self).validate(obj, value)
 
 
 class ReadlineNoRecord(object):
     """Context manager to execute some code, then reload readline history
     so that interactive input to the code doesn't appear when pressing up."""
     def __init__(self, shell):
         self.shell = shell
         self._nested_level = 0
 
     def __enter__(self):
         if self._nested_level == 0:
             try:
                 self.orig_length = self.current_length()
                 self.readline_tail = self.get_readline_tail()
             except (AttributeError, IndexError):   # Can fail with pyreadline
                 self.orig_length, self.readline_tail = 999999, []
         self._nested_level += 1
 
     def __exit__(self, type, value, traceback):
         self._nested_level -= 1
         if self._nested_level == 0:
             # Try clipping the end if it's got longer
             try:
                 e = self.current_length() - self.orig_length
                 if e > 0:
                     for _ in range(e):
                         self.shell.readline.remove_history_item(self.orig_length)
 
                 # If it still doesn't match, just reload readline history.
                 if self.current_length() != self.orig_length \
                     or self.get_readline_tail() != self.readline_tail:
                     self.shell.refill_readline_hist()
             except (AttributeError, IndexError):
                 pass
         # Returning False will cause exceptions to propagate
         return False
 
     def current_length(self):
         return self.shell.readline.get_current_history_length()
 
     def get_readline_tail(self, n=10):
         """Get the last n items in readline history."""
         end = self.shell.readline.get_current_history_length() + 1
         start = max(end-n, 1)
         ghi = self.shell.readline.get_history_item
         return [ghi(x) for x in range(start, end)]
 
 
 _autocall_help = """
 Make IPython automatically call any callable object even if
 you didn't type explicit parentheses. For example, 'str 43' becomes 'str(43)'
 automatically. The value can be '0' to disable the feature, '1' for 'smart'
 autocall, where it is not applied if there are no more arguments on the line,
 and '2' for 'full' autocall, where all callable objects are automatically
 called (even if no arguments are present). The default is '1'.
 """
 
 #-----------------------------------------------------------------------------
 # Main IPython class
 #-----------------------------------------------------------------------------
 
 class InteractiveShell(SingletonConfigurable, Magic):
     """An enhanced, interactive shell for Python."""
 
     _instance = None
 
     autocall = Enum((0,1,2), default_value=1, config=True, help=
         """
         Make IPython automatically call any callable object even if you didn't
         type explicit parentheses. For example, 'str 43' becomes 'str(43)'
         automatically. The value can be '0' to disable the feature, '1' for
         'smart' autocall, where it is not applied if there are no more
         arguments on the line, and '2' for 'full' autocall, where all callable
         objects are automatically called (even if no arguments are present).
         The default is '1'.
         """
     )
     # TODO: remove all autoindent logic and put into frontends.
     # We can't do this yet because even runlines uses the autoindent.
     autoindent = CBool(True, config=True, help=
         """
         Autoindent IPython code entered interactively.
         """
     )
     automagic = CBool(True, config=True, help=
         """
         Enable magic commands to be called without the leading %.
         """
     )
     cache_size = Integer(1000, config=True, help=
         """
         Set the size of the output cache.  The default is 1000, you can
         change it permanently in your config file.  Setting it to 0 completely
         disables the caching system, and the minimum value accepted is 20 (if
         you provide a value less than 20, it is reset to 0 and a warning is
         issued).  This limit is defined because otherwise you'll spend more
         time re-flushing a too small cache than working
         """
     )
     color_info = CBool(True, config=True, help=
         """
         Use colors for displaying information about objects. Because this
         information is passed through a pager (like 'less'), and some pagers
         get confused with color codes, this capability can be turned off.
         """
     )
     colors = CaselessStrEnum(('NoColor','LightBG','Linux'),
                              default_value=get_default_colors(), config=True,
         help="Set the color scheme (NoColor, Linux, or LightBG)."
     )
     colors_force = CBool(False, help=
         """
         Force use of ANSI color codes, regardless of OS and readline
         availability.
         """
         # FIXME: This is essentially a hack to allow ZMQShell to show colors
         # without readline on Win32. When the ZMQ formatting system is
         # refactored, this should be removed.
     )
     debug = CBool(False, config=True)
     deep_reload = CBool(False, config=True, help=
         """
         Enable deep (recursive) reloading by default. IPython can use the
         deep_reload module which reloads changes in modules recursively (it
         replaces the reload() function, so you don't need to change anything to
         use it). deep_reload() forces a full reload of modules whose code may
         have changed, which the default reload() function does not.  When
         deep_reload is off, IPython will use the normal reload(), but
         deep_reload will still be available as dreload().
         """
     )
     display_formatter = Instance(DisplayFormatter)
     displayhook_class = Type(DisplayHook)
     display_pub_class = Type(DisplayPublisher)
 
     exit_now = CBool(False)
     exiter = Instance(ExitAutocall)
     def _exiter_default(self):
         return ExitAutocall(self)
     # Monotonically increasing execution counter
     execution_count = Integer(1)
     filename = Unicode("<ipython console>")
     ipython_dir= Unicode('', config=True) # Set to get_ipython_dir() in __init__
 
     # Input splitter, to split entire cells of input into either individual
     # interactive statements or whole blocks.
     input_splitter = Instance('IPython.core.inputsplitter.IPythonInputSplitter',
                               (), {})
     logstart = CBool(False, config=True, help=
         """
         Start logging to the default log file.
         """
     )
     logfile = Unicode('', config=True, help=
         """
         The name of the logfile to use.
         """
     )
     logappend = Unicode('', config=True, help=
         """
         Start logging to the given file in append mode.
         """
     )
     object_info_string_level = Enum((0,1,2), default_value=0,
                                     config=True)
     pdb = CBool(False, config=True, help=
         """
         Automatically call the pdb debugger after every exception.
         """
     )
     multiline_history = CBool(sys.platform != 'win32', config=True,
         help="Save multi-line entries as one entry in readline history"
     )
 
     prompt_in1 = Unicode('In [\\#]: ', config=True)
     prompt_in2 = Unicode('   .\\D.: ', config=True)
     prompt_out = Unicode('Out[\\#]: ', config=True)
     prompts_pad_left = CBool(True, config=True)
     quiet = CBool(False, config=True)
 
     history_length = Integer(10000, config=True)
 
     # The readline stuff will eventually be moved to the terminal subclass
     # but for now, we can't do that as readline is welded in everywhere.
     readline_use = CBool(True, config=True)
     readline_remove_delims = Unicode('-/~', config=True)
     # don't use \M- bindings by default, because they
     # conflict with 8-bit encodings. See gh-58,gh-88
     readline_parse_and_bind = List([
             'tab: complete',
             '"\C-l": clear-screen',
             'set show-all-if-ambiguous on',
             '"\C-o": tab-insert',
             '"\C-r": reverse-search-history',
             '"\C-s": forward-search-history',
             '"\C-p": history-search-backward',
             '"\C-n": history-search-forward',
             '"\e[A": history-search-backward',
             '"\e[B": history-search-forward',
             '"\C-k": kill-line',
             '"\C-u": unix-line-discard',
         ], allow_none=False, config=True)
 
     # TODO: this part of prompt management should be moved to the frontends.
     # Use custom TraitTypes that convert '0'->'' and '\\n'->'\n'
     separate_in = SeparateUnicode('\n', config=True)
     separate_out = SeparateUnicode('', config=True)
     separate_out2 = SeparateUnicode('', config=True)
     wildcards_case_sensitive = CBool(True, config=True)
     xmode = CaselessStrEnum(('Context','Plain', 'Verbose'),
                             default_value='Context', config=True)
 
     # Subcomponents of InteractiveShell
     alias_manager = Instance('IPython.core.alias.AliasManager')
     prefilter_manager = Instance('IPython.core.prefilter.PrefilterManager')
     builtin_trap = Instance('IPython.core.builtin_trap.BuiltinTrap')
     display_trap = Instance('IPython.core.display_trap.DisplayTrap')
     extension_manager = Instance('IPython.core.extensions.ExtensionManager')
     plugin_manager = Instance('IPython.core.plugin.PluginManager')
     payload_manager = Instance('IPython.core.payload.PayloadManager')
     history_manager = Instance('IPython.core.history.HistoryManager')
 
     profile_dir = Instance('IPython.core.application.ProfileDir')
     @property
     def profile(self):
         if self.profile_dir is not None:
             name = os.path.basename(self.profile_dir.location)
             return name.replace('profile_','')
 
 
     # Private interface
     _post_execute = Instance(dict)
 
     def __init__(self, config=None, ipython_dir=None, profile_dir=None,
                  user_ns=None, user_global_ns=None,
                  custom_exceptions=((), None)):
 
         # This is where traits with a config_key argument are updated
         # from the values on config.
         super(InteractiveShell, self).__init__(config=config)
         self.configurables = [self]
 
         # These are relatively independent and stateless
         self.init_ipython_dir(ipython_dir)
         self.init_profile_dir(profile_dir)
         self.init_instance_attrs()
         self.init_environment()
 
         # Create namespaces (user_ns, user_global_ns, etc.)
         self.init_create_namespaces(user_ns, user_global_ns)
         # This has to be done after init_create_namespaces because it uses
         # something in self.user_ns, but before init_sys_modules, which
         # is the first thing to modify sys.
         # TODO: When we override sys.stdout and sys.stderr before this class
         # is created, we are saving the overridden ones here. Not sure if this
         # is what we want to do.
         self.save_sys_module_state()
         self.init_sys_modules()
 
         # While we're trying to have each part of the code directly access what
         # it needs without keeping redundant references to objects, we have too
         # much legacy code that expects ip.db to exist.
         self.db = PickleShareDB(os.path.join(self.profile_dir.location, 'db'))
 
         self.init_history()
         self.init_encoding()
         self.init_prefilter()
 
         Magic.__init__(self, self)
 
         self.init_syntax_highlighting()
         self.init_hooks()
         self.init_pushd_popd_magic()
         # self.init_traceback_handlers use to be here, but we moved it below
         # because it and init_io have to come after init_readline.
         self.init_user_ns()
         self.init_logger()
         self.init_alias()
         self.init_builtins()
 
         # pre_config_initialization
 
         # The next section should contain everything that was in ipmaker.
         self.init_logstart()
 
         # The following was in post_config_initialization
         self.init_inspector()
         # init_readline() must come before init_io(), because init_io uses
         # readline related things.
         self.init_readline()
         # We save this here in case user code replaces raw_input, but it needs
         # to be after init_readline(), because PyPy's readline works by replacing
         # raw_input.
         if py3compat.PY3:
             self.raw_input_original = input
         else:
             self.raw_input_original = raw_input
         # init_completer must come after init_readline, because it needs to
         # know whether readline is present or not system-wide to configure the
         # completers, since the completion machinery can now operate
         # independently of readline (e.g. over the network)
         self.init_completer()
         # TODO: init_io() needs to happen before init_traceback handlers
         # because the traceback handlers hardcode the stdout/stderr streams.
         # This logic in in debugger.Pdb and should eventually be changed.
         self.init_io()
         self.init_traceback_handlers(custom_exceptions)
         self.init_prompts()
         self.init_display_formatter()
         self.init_display_pub()
         self.init_displayhook()
         self.init_reload_doctest()
         self.init_magics()
         self.init_pdb()
         self.init_extension_manager()
         self.init_plugin_manager()
         self.init_payload()
         self.hooks.late_startup_hook()
         atexit.register(self.atexit_operations)
 
     def get_ipython(self):
         """Return the currently running IPython instance."""
         return self
 
     #-------------------------------------------------------------------------
     # Trait changed handlers
     #-------------------------------------------------------------------------
 
     def _ipython_dir_changed(self, name, new):
         if not os.path.isdir(new):
             os.makedirs(new, mode = 0777)
 
     def set_autoindent(self,value=None):
         """Set the autoindent flag, checking for readline support.
 
         If called with no arguments, it acts as a toggle."""
 
         if value != 0 and not self.has_readline:
             if os.name == 'posix':
                 warn("The auto-indent feature requires the readline library")
             self.autoindent = 0
             return
         if value is None:
             self.autoindent = not self.autoindent
         else:
             self.autoindent = value
 
     #-------------------------------------------------------------------------
     # init_* methods called by __init__
     #-------------------------------------------------------------------------
 
     def init_ipython_dir(self, ipython_dir):
         if ipython_dir is not None:
             self.ipython_dir = ipython_dir
             return
 
         self.ipython_dir = get_ipython_dir()
 
     def init_profile_dir(self, profile_dir):
         if profile_dir is not None:
             self.profile_dir = profile_dir
             return
         self.profile_dir =\
             ProfileDir.create_profile_dir_by_name(self.ipython_dir, 'default')
 
     def init_instance_attrs(self):
         self.more = False
 
         # command compiler
         self.compile = CachingCompiler()
 
         # Make an empty namespace, which extension writers can rely on both
         # existing and NEVER being used by ipython itself.  This gives them a
         # convenient location for storing additional information and state
         # their extensions may require, without fear of collisions with other
         # ipython names that may develop later.
         self.meta = Struct()
 
         # Temporary files used for various purposes.  Deleted at exit.
         self.tempfiles = []
 
         # Keep track of readline usage (later set by init_readline)
         self.has_readline = False
 
         # keep track of where we started running (mainly for crash post-mortem)
         # This is not being used anywhere currently.
         self.starting_dir = os.getcwdu()
 
         # Indentation management
         self.indent_current_nsp = 0
 
         # Dict to track post-execution functions that have been registered
         self._post_execute = {}
 
     def init_environment(self):
         """Any changes we need to make to the user's environment."""
         pass
 
     def init_encoding(self):
         # Get system encoding at startup time.  Certain terminals (like Emacs
         # under Win32 have it set to None, and we need to have a known valid
         # encoding to use in the raw_input() method
         try:
             self.stdin_encoding = sys.stdin.encoding or 'ascii'
         except AttributeError:
             self.stdin_encoding = 'ascii'
 
     def init_syntax_highlighting(self):
         # Python source parser/formatter for syntax highlighting
         pyformat = PyColorize.Parser().format
         self.pycolorize = lambda src: pyformat(src,'str',self.colors)
 
     def init_pushd_popd_magic(self):
         # for pushd/popd management
         try:
             self.home_dir = get_home_dir()
         except HomeDirError, msg:
             fatal(msg)
 
         self.dir_stack = []
 
     def init_logger(self):
         self.logger = Logger(self.home_dir, logfname='ipython_log.py',
                              logmode='rotate')
 
     def init_logstart(self):
         """Initialize logging in case it was requested at the command line.
         """
         if self.logappend:
             self.magic_logstart(self.logappend + ' append')
         elif self.logfile:
             self.magic_logstart(self.logfile)
         elif self.logstart:
             self.magic_logstart()
 
     def init_builtins(self):
         self.builtin_trap = BuiltinTrap(shell=self)
 
     def init_inspector(self):
         # Object inspector
         self.inspector = oinspect.Inspector(oinspect.InspectColors,
                                             PyColorize.ANSICodeColors,
                                             'NoColor',
                                             self.object_info_string_level)
 
     def init_io(self):
         # This will just use sys.stdout and sys.stderr. If you want to
         # override sys.stdout and sys.stderr themselves, you need to do that
         # *before* instantiating this class, because io holds onto
         # references to the underlying streams.
         if sys.platform == 'win32' and self.has_readline:
             io.stdout = io.stderr = io.IOStream(self.readline._outputfile)
         else:
             io.stdout = io.IOStream(sys.stdout)
             io.stderr = io.IOStream(sys.stderr)
 
     def init_prompts(self):
         # TODO: This is a pass for now because the prompts are managed inside
         # the DisplayHook. Once there is a separate prompt manager, this
         # will initialize that object and all prompt related information.
         pass
 
     def init_display_formatter(self):
         self.display_formatter = DisplayFormatter(config=self.config)
         self.configurables.append(self.display_formatter)
 
     def init_display_pub(self):
         self.display_pub = self.display_pub_class(config=self.config)
         self.configurables.append(self.display_pub)
 
     def init_displayhook(self):
         # Initialize displayhook, set in/out prompts and printing system
         self.displayhook = self.displayhook_class(
             config=self.config,
             shell=self,
             cache_size=self.cache_size,
             input_sep = self.separate_in,
             output_sep = self.separate_out,
             output_sep2 = self.separate_out2,
             ps1 = self.prompt_in1,
             ps2 = self.prompt_in2,
             ps_out = self.prompt_out,
             pad_left = self.prompts_pad_left
         )
         self.configurables.append(self.displayhook)
         # This is a context manager that installs/revmoes the displayhook at
         # the appropriate time.
         self.display_trap = DisplayTrap(hook=self.displayhook)
 
     def init_reload_doctest(self):
         # Do a proper resetting of doctest, including the necessary displayhook
         # monkeypatching
         try:
             doctest_reload()
         except ImportError:
             warn("doctest module does not exist.")
 
     #-------------------------------------------------------------------------
     # Things related to injections into the sys module
     #-------------------------------------------------------------------------
 
     def save_sys_module_state(self):
         """Save the state of hooks in the sys module.
 
         This has to be called after self.user_ns is created.
         """
         self._orig_sys_module_state = {}
         self._orig_sys_module_state['stdin'] = sys.stdin
         self._orig_sys_module_state['stdout'] = sys.stdout
         self._orig_sys_module_state['stderr'] = sys.stderr
         self._orig_sys_module_state['excepthook'] = sys.excepthook
         try:
             self._orig_sys_modules_main_name = self.user_ns['__name__']
         except KeyError:
             pass
 
     def restore_sys_module_state(self):
         """Restore the state of the sys module."""
         try:
             for k, v in self._orig_sys_module_state.iteritems():
                 setattr(sys, k, v)
         except AttributeError:
             pass
         # Reset what what done in self.init_sys_modules
         try:
             sys.modules[self.user_ns['__name__']] = self._orig_sys_modules_main_name
         except (AttributeError, KeyError):
             pass
 
     #-------------------------------------------------------------------------
     # Things related to hooks
     #-------------------------------------------------------------------------
 
     def init_hooks(self):
         # hooks holds pointers used for user-side customizations
         self.hooks = Struct()
 
         self.strdispatchers = {}
 
         # Set all default hooks, defined in the IPython.hooks module.
         hooks = IPython.core.hooks
         for hook_name in hooks.__all__:
             # default hooks have priority 100, i.e. low; user hooks should have
             # 0-100 priority
             self.set_hook(hook_name,getattr(hooks,hook_name), 100)
 
     def set_hook(self,name,hook, priority = 50, str_key = None, re_key = None):
         """set_hook(name,hook) -> sets an internal IPython hook.
 
         IPython exposes some of its internal API as user-modifiable hooks.  By
         adding your function to one of these hooks, you can modify IPython's
         behavior to call at runtime your own routines."""
 
         # At some point in the future, this should validate the hook before it
         # accepts it.  Probably at least check that the hook takes the number
         # of args it's supposed to.
 
         f = types.MethodType(hook,self)
 
         # check if the hook is for strdispatcher first
         if str_key is not None:
             sdp = self.strdispatchers.get(name, StrDispatch())
             sdp.add_s(str_key, f, priority )
             self.strdispatchers[name] = sdp
             return
         if re_key is not None:
             sdp = self.strdispatchers.get(name, StrDispatch())
             sdp.add_re(re.compile(re_key), f, priority )
             self.strdispatchers[name] = sdp
             return
 
         dp = getattr(self.hooks, name, None)
         if name not in IPython.core.hooks.__all__:
             print "Warning! Hook '%s' is not one of %s" % \
                   (name, IPython.core.hooks.__all__ )
         if not dp:
             dp = IPython.core.hooks.CommandChainDispatcher()
 
         try:
             dp.add(f,priority)
         except AttributeError:
             # it was not commandchain, plain old func - replace
             dp = f
 
         setattr(self.hooks,name, dp)
 
     def register_post_execute(self, func):
         """Register a function for calling after code execution.
         """
         if not callable(func):
             raise ValueError('argument %s must be callable' % func)
         self._post_execute[func] = True
 
     #-------------------------------------------------------------------------
     # Things related to the "main" module
     #-------------------------------------------------------------------------
 
     def new_main_mod(self,ns=None):
         """Return a new 'main' module object for user code execution.
         """
         main_mod = self._user_main_module
         init_fakemod_dict(main_mod,ns)
         return main_mod
 
     def cache_main_mod(self,ns,fname):
         """Cache a main module's namespace.
 
         When scripts are executed via %run, we must keep a reference to the
         namespace of their __main__ module (a FakeModule instance) around so
         that Python doesn't clear it, rendering objects defined therein
         useless.
 
         This method keeps said reference in a private dict, keyed by the
         absolute path of the module object (which corresponds to the script
         path).  This way, for multiple executions of the same script we only
         keep one copy of the namespace (the last one), thus preventing memory
         leaks from old references while allowing the objects from the last
         execution to be accessible.
 
         Note: we can not allow the actual FakeModule instances to be deleted,
         because of how Python tears down modules (it hard-sets all their
         references to None without regard for reference counts).  This method
         must therefore make a *copy* of the given namespace, to allow the
         original module's __dict__ to be cleared and reused.
 
 
         Parameters
         ----------
           ns : a namespace (a dict, typically)
 
           fname : str
             Filename associated with the namespace.
 
         Examples
         --------
 
         In [10]: import IPython
 
         In [11]: _ip.cache_main_mod(IPython.__dict__,IPython.__file__)
 
         In [12]: IPython.__file__ in _ip._main_ns_cache
         Out[12]: True
         """
         self._main_ns_cache[os.path.abspath(fname)] = ns.copy()
 
     def clear_main_mod_cache(self):
         """Clear the cache of main modules.
 
         Mainly for use by utilities like %reset.
 
         Examples
         --------
 
         In [15]: import IPython
 
         In [16]: _ip.cache_main_mod(IPython.__dict__,IPython.__file__)
 
         In [17]: len(_ip._main_ns_cache) > 0
         Out[17]: True
 
         In [18]: _ip.clear_main_mod_cache()
 
         In [19]: len(_ip._main_ns_cache) == 0
         Out[19]: True
         """
         self._main_ns_cache.clear()
 
     #-------------------------------------------------------------------------
     # Things related to debugging
     #-------------------------------------------------------------------------
 
     def init_pdb(self):
         # Set calling of pdb on exceptions
         # self.call_pdb is a property
         self.call_pdb = self.pdb
 
     def _get_call_pdb(self):
         return self._call_pdb
 
     def _set_call_pdb(self,val):
 
         if val not in (0,1,False,True):
             raise ValueError,'new call_pdb value must be boolean'
 
         # store value in instance
         self._call_pdb = val
 
         # notify the actual exception handlers
         self.InteractiveTB.call_pdb = val
 
     call_pdb = property(_get_call_pdb,_set_call_pdb,None,
                         'Control auto-activation of pdb at exceptions')
 
     def debugger(self,force=False):
         """Call the pydb/pdb debugger.
 
         Keywords:
 
           - force(False): by default, this routine checks the instance call_pdb
           flag and does not actually invoke the debugger if the flag is false.
           The 'force' option forces the debugger to activate even if the flag
           is false.
         """
 
         if not (force or self.call_pdb):
             return
 
         if not hasattr(sys,'last_traceback'):
             error('No traceback has been produced, nothing to debug.')
             return
 
         # use pydb if available
         if debugger.has_pydb:
             from pydb import pm
         else:
             # fallback to our internal debugger
             pm = lambda : self.InteractiveTB.debugger(force=True)
 
         with self.readline_no_record:
             pm()
 
     #-------------------------------------------------------------------------
     # Things related to IPython's various namespaces
     #-------------------------------------------------------------------------
 
     def init_create_namespaces(self, user_ns=None, user_global_ns=None):
         # Create the namespace where the user will operate.  user_ns is
         # normally the only one used, and it is passed to the exec calls as
         # the locals argument.  But we do carry a user_global_ns namespace
         # given as the exec 'globals' argument,  This is useful in embedding
         # situations where the ipython shell opens in a context where the
         # distinction between locals and globals is meaningful.  For
         # non-embedded contexts, it is just the same object as the user_ns dict.
 
         # FIXME. For some strange reason, __builtins__ is showing up at user
         # level as a dict instead of a module. This is a manual fix, but I
         # should really track down where the problem is coming from. Alex
         # Schmolck reported this problem first.
 
         # A useful post by Alex Martelli on this topic:
         # Re: inconsistent value from __builtins__
         # Von: Alex Martelli <[e-mail]>
         # Datum: Freitag 01 Oktober 2004 04:45:34 nachmittags/abends
         # Gruppen: comp.lang.python
 
         # Michael Hohn <[e-mail]> wrote:
         # > >>> print type(builtin_check.get_global_binding('__builtins__'))
         # > <type 'dict'>
         # > >>> print type(__builtins__)
         # > <type 'module'>
         # > Is this difference in return value intentional?
 
         # Well, it's documented that '__builtins__' can be either a dictionary
         # or a module, and it's been that way for a long time. Whether it's
         # intentional (or sensible), I don't know. In any case, the idea is
         # that if you need to access the built-in namespace directly, you
         # should start with "import __builtin__" (note, no 's') which will
         # definitely give you a module. Yeah, it's somewhat confusing:-(.
 
         # These routines return properly built dicts as needed by the rest of
         # the code, and can also be used by extension writers to generate
         # properly initialized namespaces.
         user_ns, user_global_ns = self.make_user_namespaces(user_ns,
                                                             user_global_ns)
 
         # Assign namespaces
         # This is the namespace where all normal user variables live
         self.user_ns = user_ns
         self.user_global_ns = user_global_ns
 
         # An auxiliary namespace that checks what parts of the user_ns were
         # loaded at startup, so we can list later only variables defined in
         # actual interactive use.  Since it is always a subset of user_ns, it
         # doesn't need to be separately tracked in the ns_table.
         self.user_ns_hidden = {}
 
         # A namespace to keep track of internal data structures to prevent
         # them from cluttering user-visible stuff.  Will be updated later
         self.internal_ns = {}
 
         # Now that FakeModule produces a real module, we've run into a nasty
         # problem: after script execution (via %run), the module where the user
         # code ran is deleted.  Now that this object is a true module (needed
         # so docetst and other tools work correctly), the Python module
         # teardown mechanism runs over it, and sets to None every variable
         # present in that module.  Top-level references to objects from the
         # script survive, because the user_ns is updated with them.  However,
         # calling functions defined in the script that use other things from
         # the script will fail, because the function's closure had references
         # to the original objects, which are now all None.  So we must protect
         # these modules from deletion by keeping a cache.
         #
         # To avoid keeping stale modules around (we only need the one from the
         # last run), we use a dict keyed with the full path to the script, so
         # only the last version of the module is held in the cache.  Note,
         # however, that we must cache the module *namespace contents* (their
         # __dict__).  Because if we try to cache the actual modules, old ones
         # (uncached) could be destroyed while still holding references (such as
         # those held by GUI objects that tend to be long-lived)>
         #
         # The %reset command will flush this cache.  See the cache_main_mod()
         # and clear_main_mod_cache() methods for details on use.
 
         # This is the cache used for 'main' namespaces
         self._main_ns_cache = {}
         # And this is the single instance of FakeModule whose __dict__ we keep
         # copying and clearing for reuse on each %run
         self._user_main_module = FakeModule()
 
         # A table holding all the namespaces IPython deals with, so that
         # introspection facilities can search easily.
         self.ns_table = {'user':user_ns,
                          'user_global':user_global_ns,
                          'internal':self.internal_ns,
                          'builtin':builtin_mod.__dict__
                          }
 
         # Similarly, track all namespaces where references can be held and that
         # we can safely clear (so it can NOT include builtin).  This one can be
         # a simple list.  Note that the main execution namespaces, user_ns and
         # user_global_ns, can NOT be listed here, as clearing them blindly
         # causes errors in object __del__ methods.  Instead, the reset() method
         # clears them manually and carefully.
         self.ns_refs_table = [ self.user_ns_hidden,
                                self.internal_ns, self._main_ns_cache ]
 
     def make_user_namespaces(self, user_ns=None, user_global_ns=None):
         """Return a valid local and global user interactive namespaces.
 
         This builds a dict with the minimal information needed to operate as a
         valid IPython user namespace, which you can pass to the various
         embedding classes in ipython. The default implementation returns the
         same dict for both the locals and the globals to allow functions to
         refer to variables in the namespace. Customized implementations can
         return different dicts. The locals dictionary can actually be anything
         following the basic mapping protocol of a dict, but the globals dict
         must be a true dict, not even a subclass. It is recommended that any
         custom object for the locals namespace synchronize with the globals
         dict somehow.
 
         Raises TypeError if the provided globals namespace is not a true dict.
 
         Parameters
         ----------
         user_ns : dict-like, optional
             The current user namespace. The items in this namespace should
             be included in the output. If None, an appropriate blank
             namespace should be created.
         user_global_ns : dict, optional
             The current user global namespace. The items in this namespace
             should be included in the output. If None, an appropriate
             blank namespace should be created.
 
         Returns
         -------
             A pair of dictionary-like object to be used as the local namespace
             of the interpreter and a dict to be used as the global namespace.
         """
 
 
         # We must ensure that __builtin__ (without the final 's') is always
         # available and pointing to the __builtin__ *module*.  For more details:
         # http://mail.python.org/pipermail/python-dev/2001-April/014068.html
 
         if user_ns is None:
             # Set __name__ to __main__ to better match the behavior of the
             # normal interpreter.
             user_ns = {'__name__'     :'__main__',
                        py3compat.builtin_mod_name: builtin_mod,
                        '__builtins__' : builtin_mod,
                       }
         else:
             user_ns.setdefault('__name__','__main__')
             user_ns.setdefault(py3compat.builtin_mod_name,builtin_mod)
             user_ns.setdefault('__builtins__',builtin_mod)
 
         if user_global_ns is None:
             user_global_ns = user_ns
         if type(user_global_ns) is not dict:
             raise TypeError("user_global_ns must be a true dict; got %r"
                 % type(user_global_ns))
 
         return user_ns, user_global_ns
 
     def init_sys_modules(self):
         # We need to insert into sys.modules something that looks like a
         # module but which accesses the IPython namespace, for shelve and
         # pickle to work interactively. Normally they rely on getting
         # everything out of __main__, but for embedding purposes each IPython
         # instance has its own private namespace, so we can't go shoving
         # everything into __main__.
 
         # note, however, that we should only do this for non-embedded
         # ipythons, which really mimic the __main__.__dict__ with their own
         # namespace.  Embedded instances, on the other hand, should not do
         # this because they need to manage the user local/global namespaces
         # only, but they live within a 'normal' __main__ (meaning, they
         # shouldn't overtake the execution environment of the script they're
         # embedded in).
 
         # This is overridden in the InteractiveShellEmbed subclass to a no-op.
 
         try:
             main_name = self.user_ns['__name__']
         except KeyError:
             raise KeyError('user_ns dictionary MUST have a "__name__" key')
         else:
             sys.modules[main_name] = FakeModule(self.user_ns)
 
     def init_user_ns(self):
         """Initialize all user-visible namespaces to their minimum defaults.
 
         Certain history lists are also initialized here, as they effectively
         act as user namespaces.
 
         Notes
         -----
         All data structures here are only filled in, they are NOT reset by this
         method.  If they were not empty before, data will simply be added to
         therm.
         """
         # This function works in two parts: first we put a few things in
         # user_ns, and we sync that contents into user_ns_hidden so that these
         # initial variables aren't shown by %who.  After the sync, we add the
         # rest of what we *do* want the user to see with %who even on a new
         # session (probably nothing, so theye really only see their own stuff)
 
         # The user dict must *always* have a __builtin__ reference to the
         # Python standard __builtin__ namespace,  which must be imported.
         # This is so that certain operations in prompt evaluation can be
         # reliably executed with builtins.  Note that we can NOT use
         # __builtins__ (note the 's'),  because that can either be a dict or a
         # module, and can even mutate at runtime, depending on the context
         # (Python makes no guarantees on it).  In contrast, __builtin__ is
         # always a module object, though it must be explicitly imported.
 
         # For more details:
         # http://mail.python.org/pipermail/python-dev/2001-April/014068.html
         ns = dict(__builtin__ = builtin_mod)
 
         # Put 'help' in the user namespace
         try:
             from site import _Helper
             ns['help'] = _Helper()
         except ImportError:
             warn('help() not available - check site.py')
 
         # make global variables for user access to the histories
         ns['_ih'] = self.history_manager.input_hist_parsed
         ns['_oh'] = self.history_manager.output_hist
         ns['_dh'] = self.history_manager.dir_hist
 
         ns['_sh'] = shadowns
 
         # user aliases to input and output histories.  These shouldn't show up
         # in %who, as they can have very large reprs.
         ns['In']  = self.history_manager.input_hist_parsed
         ns['Out'] = self.history_manager.output_hist
 
         # Store myself as the public api!!!
         ns['get_ipython'] = self.get_ipython
 
         ns['exit'] = self.exiter
         ns['quit'] = self.exiter
 
         # Sync what we've added so far to user_ns_hidden so these aren't seen
         # by %who
         self.user_ns_hidden.update(ns)
 
         # Anything put into ns now would show up in %who.  Think twice before
         # putting anything here, as we really want %who to show the user their
         # stuff, not our variables.
 
         # Finally, update the real user's namespace
         self.user_ns.update(ns)
 
     def reset(self, new_session=True):
         """Clear all internal namespaces, and attempt to release references to
         user objects.
 
         If new_session is True, a new history session will be opened.
         """
         # Clear histories
         self.history_manager.reset(new_session)
         # Reset counter used to index all histories
         if new_session:
             self.execution_count = 1
 
         # Flush cached output items
         if self.displayhook.do_full_cache:
             self.displayhook.flush()
 
         # Restore the user namespaces to minimal usability
         for ns in self.ns_refs_table:
             ns.clear()
 
         # The main execution namespaces must be cleared very carefully,
         # skipping the deletion of the builtin-related keys, because doing so
         # would cause errors in many object's __del__ methods.
         for ns in [self.user_ns, self.user_global_ns]:
             drop_keys = set(ns.keys())
             drop_keys.discard('__builtin__')
             drop_keys.discard('__builtins__')
             for k in drop_keys:
                 del ns[k]
 
         # Restore the user namespaces to minimal usability
         self.init_user_ns()
 
         # Restore the default and user aliases
         self.alias_manager.clear_aliases()
         self.alias_manager.init_aliases()
 
         # Flush the private list of module references kept for script
         # execution protection
         self.clear_main_mod_cache()
 
         # Clear out the namespace from the last %run
         self.new_main_mod()
 
     def del_var(self, varname, by_name=False):
         """Delete a variable from the various namespaces, so that, as
         far as possible, we're not keeping any hidden references to it.
 
         Parameters
         ----------
         varname : str
             The name of the variable to delete.
         by_name : bool
             If True, delete variables with the given name in each
             namespace. If False (default), find the variable in the user
             namespace, and delete references to it.
         """
         if varname in ('__builtin__', '__builtins__'):
             raise ValueError("Refusing to delete %s" % varname)
         ns_refs = self.ns_refs_table + [self.user_ns,
                 self.user_global_ns, self._user_main_module.__dict__] +\
                 self._main_ns_cache.values()
 
         if by_name:                    # Delete by name
             for ns in ns_refs:
                 try:
                     del ns[varname]
                 except KeyError:
                     pass
         else:                         # Delete by object
             try:
                 obj = self.user_ns[varname]
             except KeyError:
                 raise NameError("name '%s' is not defined" % varname)
             # Also check in output history
             ns_refs.append(self.history_manager.output_hist)
             for ns in ns_refs:
                 to_delete = [n for n, o in ns.iteritems() if o is obj]
                 for name in to_delete:
                     del ns[name]
 
             # displayhook keeps extra references, but not in a dictionary
             for name in ('_', '__', '___'):
                 if getattr(self.displayhook, name) is obj:
                     setattr(self.displayhook, name, None)
 
     def reset_selective(self, regex=None):
         """Clear selective variables from internal namespaces based on a
         specified regular expression.
 
         Parameters
         ----------
         regex : string or compiled pattern, optional
             A regular expression pattern that will be used in searching
             variable names in the users namespaces.
         """
         if regex is not None:
             try:
                 m = re.compile(regex)
             except TypeError:
                 raise TypeError('regex must be a string or compiled pattern')
             # Search for keys in each namespace that match the given regex
             # If a match is found, delete the key/value pair.
             for ns in self.ns_refs_table:
                 for var in ns:
                     if m.search(var):
                         del ns[var]
 
     def push(self, variables, interactive=True):
         """Inject a group of variables into the IPython user namespace.
 
         Parameters
         ----------
         variables : dict, str or list/tuple of str
             The variables to inject into the user's namespace.  If a dict, a
             simple update is done.  If a str, the string is assumed to have
             variable names separated by spaces.  A list/tuple of str can also
             be used to give the variable names.  If just the variable names are
             give (list/tuple/str) then the variable values looked up in the
             callers frame.
         interactive : bool
             If True (default), the variables will be listed with the ``who``
             magic.
         """
         vdict = None
 
         # We need a dict of name/value pairs to do namespace updates.
         if isinstance(variables, dict):
             vdict = variables
         elif isinstance(variables, (basestring, list, tuple)):
             if isinstance(variables, basestring):
                 vlist = variables.split()
             else:
                 vlist = variables
             vdict = {}
             cf = sys._getframe(1)
             for name in vlist:
                 try:
                     vdict[name] = eval(name, cf.f_globals, cf.f_locals)
                 except:
                     print ('Could not get variable %s from %s' %
                            (name,cf.f_code.co_name))
         else:
             raise ValueError('variables must be a dict/str/list/tuple')
 
         # Propagate variables to user namespace
         self.user_ns.update(vdict)
 
         # And configure interactive visibility
         config_ns = self.user_ns_hidden
         if interactive:
             for name, val in vdict.iteritems():
                 config_ns.pop(name, None)
         else:
             for name,val in vdict.iteritems():
                 config_ns[name] = val
     
     def drop_by_id(self, variables):
         """Remove a dict of variables from the user namespace, if they are the
         same as the values in the dictionary.
         
         This is intended for use by extensions: variables that they've added can
         be taken back out if they are unloaded, without removing any that the
         user has overwritten.
         
         Parameters
         ----------
         variables : dict
           A dictionary mapping object names (as strings) to the objects.
         """
         for name, obj in variables.iteritems():
             if name in self.user_ns and self.user_ns[name] is obj:
                 del self.user_ns[name]
                 self.user_ns_hidden.pop(name, None)
 
     #-------------------------------------------------------------------------
     # Things related to object introspection
     #-------------------------------------------------------------------------
 
     def _ofind(self, oname, namespaces=None):
         """Find an object in the available namespaces.
 
         self._ofind(oname) -> dict with keys: found,obj,ospace,ismagic
 
         Has special code to detect magic functions.
         """
         oname = oname.strip()
         #print '1- oname: <%r>' % oname  # dbg
         if not py3compat.isidentifier(oname.lstrip(ESC_MAGIC), dotted=True):
             return dict(found=False)
 
         alias_ns = None
         if namespaces is None:
             # Namespaces to search in:
             # Put them in a list. The order is important so that we
             # find things in the same order that Python finds them.
             namespaces = [ ('Interactive', self.user_ns),
                            ('IPython internal', self.internal_ns),
                            ('Python builtin', builtin_mod.__dict__),
                            ('Alias', self.alias_manager.alias_table),
                            ]
             alias_ns = self.alias_manager.alias_table
 
         # initialize results to 'null'
         found = False; obj = None;  ospace = None;  ds = None;
         ismagic = False; isalias = False; parent = None
 
         # We need to special-case 'print', which as of python2.6 registers as a
         # function but should only be treated as one if print_function was
         # loaded with a future import.  In this case, just bail.
         if (oname == 'print' and not py3compat.PY3 and not \
             (self.compile.compiler_flags & __future__.CO_FUTURE_PRINT_FUNCTION)):
             return {'found':found, 'obj':obj, 'namespace':ospace,
                     'ismagic':ismagic, 'isalias':isalias, 'parent':parent}
 
         # Look for the given name by splitting it in parts.  If the head is
         # found, then we look for all the remaining parts as members, and only
         # declare success if we can find them all.
         oname_parts = oname.split('.')
         oname_head, oname_rest = oname_parts[0],oname_parts[1:]
         for nsname,ns in namespaces:
             try:
                 obj = ns[oname_head]
             except KeyError:
                 continue
             else:
                 #print 'oname_rest:', oname_rest  # dbg
                 for part in oname_rest:
                     try:
                         parent = obj
                         obj = getattr(obj,part)
                     except:
                         # Blanket except b/c some badly implemented objects
                         # allow __getattr__ to raise exceptions other than
                         # AttributeError, which then crashes IPython.
                         break
                 else:
                     # If we finish the for loop (no break), we got all members
                     found = True
                     ospace = nsname
                     if ns == alias_ns:
                         isalias = True
                     break  # namespace loop
 
         # Try to see if it's magic
         if not found:
             if oname.startswith(ESC_MAGIC):
                 oname = oname[1:]
             obj = getattr(self,'magic_'+oname,None)
             if obj is not None:
                 found = True
                 ospace = 'IPython internal'
                 ismagic = True
 
         # Last try: special-case some literals like '', [], {}, etc:
         if not found and oname_head in ["''",'""','[]','{}','()']:
             obj = eval(oname_head)
             found = True
             ospace = 'Interactive'
 
         return {'found':found, 'obj':obj, 'namespace':ospace,
                 'ismagic':ismagic, 'isalias':isalias, 'parent':parent}
 
     def _ofind_property(self, oname, info):
         """Second part of object finding, to look for property details."""
         if info.found:
             # Get the docstring of the class property if it exists.
             path = oname.split('.')
             root = '.'.join(path[:-1])
             if info.parent is not None:
                 try:
                     target = getattr(info.parent, '__class__')
                     # The object belongs to a class instance.
                     try:
                         target = getattr(target, path[-1])
                         # The class defines the object.
                         if isinstance(target, property):
                             oname = root + '.__class__.' + path[-1]
                             info = Struct(self._ofind(oname))
                     except AttributeError: pass
                 except AttributeError: pass
 
         # We return either the new info or the unmodified input if the object
         # hadn't been found
         return info
 
     def _object_find(self, oname, namespaces=None):
         """Find an object and return a struct with info about it."""
         inf = Struct(self._ofind(oname, namespaces))
         return Struct(self._ofind_property(oname, inf))
 
     def _inspect(self, meth, oname, namespaces=None, **kw):
         """Generic interface to the inspector system.
 
         This function is meant to be called by pdef, pdoc & friends."""
         info = self._object_find(oname)
         if info.found:
             pmethod = getattr(self.inspector, meth)
             formatter = format_screen if info.ismagic else None
             if meth == 'pdoc':
                 pmethod(info.obj, oname, formatter)
             elif meth == 'pinfo':
                 pmethod(info.obj, oname, formatter, info, **kw)
             else:
                 pmethod(info.obj, oname)
         else:
             print 'Object `%s` not found.' % oname
             return 'not found'  # so callers can take other action
 
     def object_inspect(self, oname):
         with self.builtin_trap:
             info = self._object_find(oname)
             if info.found:
                 return self.inspector.info(info.obj, oname, info=info)
             else:
                 return oinspect.object_info(name=oname, found=False)
 
     #-------------------------------------------------------------------------
     # Things related to history management
     #-------------------------------------------------------------------------
 
     def init_history(self):
         """Sets up the command history, and starts regular autosaves."""
         self.history_manager = HistoryManager(shell=self, config=self.config)
         self.configurables.append(self.history_manager)
 
     #-------------------------------------------------------------------------
     # Things related to exception handling and tracebacks (not debugging)
     #-------------------------------------------------------------------------
 
     def init_traceback_handlers(self, custom_exceptions):
         # Syntax error handler.
         self.SyntaxTB = ultratb.SyntaxTB(color_scheme='NoColor')
 
         # The interactive one is initialized with an offset, meaning we always
         # want to remove the topmost item in the traceback, which is our own
         # internal code. Valid modes: ['Plain','Context','Verbose']
         self.InteractiveTB = ultratb.AutoFormattedTB(mode = 'Plain',
                                                      color_scheme='NoColor',
                                                      tb_offset = 1,
                                    check_cache=self.compile.check_cache)
 
         # The instance will store a pointer to the system-wide exception hook,
         # so that runtime code (such as magics) can access it.  This is because
         # during the read-eval loop, it may get temporarily overwritten.
         self.sys_excepthook = sys.excepthook
 
         # and add any custom exception handlers the user may have specified
         self.set_custom_exc(*custom_exceptions)
 
         # Set the exception mode
         self.InteractiveTB.set_mode(mode=self.xmode)
 
     def set_custom_exc(self, exc_tuple, handler):
         """set_custom_exc(exc_tuple,handler)
 
         Set a custom exception handler, which will be called if any of the
         exceptions in exc_tuple occur in the mainloop (specifically, in the
         run_code() method).
 
         Parameters
         ----------
 
         exc_tuple : tuple of exception classes
             A *tuple* of exception classes, for which to call the defined
             handler.  It is very important that you use a tuple, and NOT A
             LIST here, because of the way Python's except statement works.  If
             you only want to trap a single exception, use a singleton tuple::
 
                 exc_tuple == (MyCustomException,)
 
         handler : callable
             handler must have the following signature::
 
                 def my_handler(self, etype, value, tb, tb_offset=None):
                     ...
                     return structured_traceback
 
             Your handler must return a structured traceback (a list of strings),
             or None.
 
             This will be made into an instance method (via types.MethodType)
             of IPython itself, and it will be called if any of the exceptions
             listed in the exc_tuple are caught. If the handler is None, an
             internal basic one is used, which just prints basic info.
 
             To protect IPython from crashes, if your handler ever raises an
             exception or returns an invalid result, it will be immediately
             disabled.
 
         WARNING: by putting in your own exception handler into IPython's main
         execution loop, you run a very good chance of nasty crashes.  This
         facility should only be used if you really know what you are doing."""
 
         assert type(exc_tuple)==type(()) , \
                "The custom exceptions must be given AS A TUPLE."
 
         def dummy_handler(self,etype,value,tb,tb_offset=None):
             print '*** Simple custom exception handler ***'
             print 'Exception type :',etype
             print 'Exception value:',value
             print 'Traceback      :',tb
             #print 'Source code    :','\n'.join(self.buffer)
         
         def validate_stb(stb):
             """validate structured traceback return type
             
             return type of CustomTB *should* be a list of strings, but allow
             single strings or None, which are harmless.
             
             This function will *always* return a list of strings,
             and will raise a TypeError if stb is inappropriate.
             """
             msg = "CustomTB must return list of strings, not %r" % stb
             if stb is None:
                 return []
             elif isinstance(stb, basestring):
                 return [stb]
             elif not isinstance(stb, list):
                 raise TypeError(msg)
             # it's a list
             for line in stb:
                 # check every element
                 if not isinstance(line, basestring):
                     raise TypeError(msg)
             return stb
 
         if handler is None:
             wrapped = dummy_handler
         else:
             def wrapped(self,etype,value,tb,tb_offset=None):
                 """wrap CustomTB handler, to protect IPython from user code
                 
                 This makes it harder (but not impossible) for custom exception
                 handlers to crash IPython.
                 """
                 try:
                     stb = handler(self,etype,value,tb,tb_offset=tb_offset)
                     return validate_stb(stb)
                 except:
                     # clear custom handler immediately
                     self.set_custom_exc((), None)
                     print >> io.stderr, "Custom TB Handler failed, unregistering"
                     # show the exception in handler first
                     stb = self.InteractiveTB.structured_traceback(*sys.exc_info())
                     print >> io.stdout, self.InteractiveTB.stb2text(stb)
                     print >> io.stdout, "The original exception:"
                     stb = self.InteractiveTB.structured_traceback(
                                             (etype,value,tb), tb_offset=tb_offset
                     )
                 return stb
 
         self.CustomTB = types.MethodType(wrapped,self)
         self.custom_exceptions = exc_tuple
 
     def excepthook(self, etype, value, tb):
       """One more defense for GUI apps that call sys.excepthook.
 
       GUI frameworks like wxPython trap exceptions and call
       sys.excepthook themselves.  I guess this is a feature that
       enables them to keep running after exceptions that would
       otherwise kill their mainloop. This is a bother for IPython
       which excepts to catch all of the program exceptions with a try:
       except: statement.
 
       Normally, IPython sets sys.excepthook to a CrashHandler instance, so if
       any app directly invokes sys.excepthook, it will look to the user like
       IPython crashed.  In order to work around this, we can disable the
       CrashHandler and replace it with this excepthook instead, which prints a
       regular traceback using our InteractiveTB.  In this fashion, apps which
       call sys.excepthook will generate a regular-looking exception from
       IPython, and the CrashHandler will only be triggered by real IPython
       crashes.
 
       This hook should be used sparingly, only in places which are not likely
       to be true IPython errors.
       """
       self.showtraceback((etype,value,tb),tb_offset=0)
 
     def showtraceback(self,exc_tuple = None,filename=None,tb_offset=None,
                       exception_only=False):
         """Display the exception that just occurred.
 
         If nothing is known about the exception, this is the method which
         should be used throughout the code for presenting user tracebacks,
         rather than directly invoking the InteractiveTB object.
 
         A specific showsyntaxerror() also exists, but this method can take
         care of calling it if needed, so unless you are explicitly catching a
         SyntaxError exception, don't try to analyze the stack manually and
         simply call this method."""
 
         try:
             if exc_tuple is None:
                 etype, value, tb = sys.exc_info()
             else:
                 etype, value, tb = exc_tuple
 
             if etype is None:
                 if hasattr(sys, 'last_type'):
                     etype, value, tb = sys.last_type, sys.last_value, \
                                        sys.last_traceback
                 else:
                     self.write_err('No traceback available to show.\n')
                     return
 
             if etype is SyntaxError:
                 # Though this won't be called by syntax errors in the input
                 # line, there may be SyntaxError cases with imported code.
                 self.showsyntaxerror(filename)
             elif etype is UsageError:
                 self.write_err("UsageError: %s" % value)
             else:
                 # WARNING: these variables are somewhat deprecated and not
                 # necessarily safe to use in a threaded environment, but tools
                 # like pdb depend on their existence, so let's set them.  If we
                 # find problems in the field, we'll need to revisit their use.
                 sys.last_type = etype
                 sys.last_value = value
                 sys.last_traceback = tb
                 if etype in self.custom_exceptions:
                     stb = self.CustomTB(etype, value, tb, tb_offset)
                 else:
                     if exception_only:
                         stb = ['An exception has occurred, use %tb to see '
                                'the full traceback.\n']
                         stb.extend(self.InteractiveTB.get_exception_only(etype,
                                                                          value))
                     else:
                         stb = self.InteractiveTB.structured_traceback(etype,
                                                 value, tb, tb_offset=tb_offset)
 
                         self._showtraceback(etype, value, stb)
                         if self.call_pdb:
                             # drop into debugger
                             self.debugger(force=True)
                         return
 
                 # Actually show the traceback
                 self._showtraceback(etype, value, stb)
 
         except KeyboardInterrupt:
             self.write_err("\nKeyboardInterrupt\n")
 
     def _showtraceback(self, etype, evalue, stb):
         """Actually show a traceback.
 
         Subclasses may override this method to put the traceback on a different
         place, like a side channel.
         """
         print >> io.stdout, self.InteractiveTB.stb2text(stb)
 
     def showsyntaxerror(self, filename=None):
         """Display the syntax error that just occurred.
 
         This doesn't display a stack trace because there isn't one.
 
         If a filename is given, it is stuffed in the exception instead
         of what was there before (because Python's parser always uses
         "<string>" when reading from a string).
         """
         etype, value, last_traceback = sys.exc_info()
 
         # See note about these variables in showtraceback() above
         sys.last_type = etype
         sys.last_value = value
         sys.last_traceback = last_traceback
 
         if filename and etype is SyntaxError:
             # Work hard to stuff the correct filename in the exception
             try:
                 msg, (dummy_filename, lineno, offset, line) = value
             except:
                 # Not the format we expect; leave it alone
                 pass
             else:
                 # Stuff in the right filename
                 try:
                     # Assume SyntaxError is a class exception
                     value = SyntaxError(msg, (filename, lineno, offset, line))
                 except:
                     # If that failed, assume SyntaxError is a string
                     value = msg, (filename, lineno, offset, line)
         stb = self.SyntaxTB.structured_traceback(etype, value, [])
         self._showtraceback(etype, value, stb)
 
     # This is overridden in TerminalInteractiveShell to show a message about
     # the %paste magic.
     def showindentationerror(self):
         """Called by run_cell when there's an IndentationError in code entered
         at the prompt.
 
         This is overridden in TerminalInteractiveShell to show a message about
         the %paste magic."""
         self.showsyntaxerror()
 
     #-------------------------------------------------------------------------
     # Things related to readline
     #-------------------------------------------------------------------------
 
     def init_readline(self):
         """Command history completion/saving/reloading."""
 
         if self.readline_use:
             import IPython.utils.rlineimpl as readline
 
         self.rl_next_input = None
         self.rl_do_indent = False
 
         if not self.readline_use or not readline.have_readline:
             self.has_readline = False
             self.readline = None
             # Set a number of methods that depend on readline to be no-op
             self.readline_no_record = no_op_context
             self.set_readline_completer = no_op
             self.set_custom_completer = no_op
             self.set_completer_frame = no_op
             if self.readline_use:
                 warn('Readline services not available or not loaded.')
         else:
             self.has_readline = True
             self.readline = readline
             sys.modules['readline'] = readline
 
             # Platform-specific configuration
             if os.name == 'nt':
                 # FIXME - check with Frederick to see if we can harmonize
                 # naming conventions with pyreadline to avoid this
                 # platform-dependent check
                 self.readline_startup_hook = readline.set_pre_input_hook
             else:
                 self.readline_startup_hook = readline.set_startup_hook
 
             # Load user's initrc file (readline config)
             # Or if libedit is used, load editrc.
             inputrc_name = os.environ.get('INPUTRC')
             if inputrc_name is None:
                 home_dir = get_home_dir()
                 if home_dir is not None:
                     inputrc_name = '.inputrc'
                     if readline.uses_libedit:
                         inputrc_name = '.editrc'
                     inputrc_name = os.path.join(home_dir, inputrc_name)
             if os.path.isfile(inputrc_name):
                 try:
                     readline.read_init_file(inputrc_name)
                 except:
                     warn('Problems reading readline initialization file <%s>'
                          % inputrc_name)
 
             # Configure readline according to user's prefs
             # This is only done if GNU readline is being used.  If libedit
             # is being used (as on Leopard) the readline config is
             # not run as the syntax for libedit is different.
             if not readline.uses_libedit:
                 for rlcommand in self.readline_parse_and_bind:
                     #print "loading rl:",rlcommand  # dbg
                     readline.parse_and_bind(rlcommand)
 
             # Remove some chars from the delimiters list.  If we encounter
             # unicode chars, discard them.
             delims = readline.get_completer_delims()
             if not py3compat.PY3:
                 delims = delims.encode("ascii", "ignore")
             for d in self.readline_remove_delims:
                 delims = delims.replace(d, "")
             delims = delims.replace(ESC_MAGIC, '')
             readline.set_completer_delims(delims)
             # otherwise we end up with a monster history after a while:
             readline.set_history_length(self.history_length)
 
             self.refill_readline_hist()
             self.readline_no_record = ReadlineNoRecord(self)
 
         # Configure auto-indent for all platforms
         self.set_autoindent(self.autoindent)
 
     def refill_readline_hist(self):
         # Load the last 1000 lines from history
         self.readline.clear_history()
         stdin_encoding = sys.stdin.encoding or "utf-8"
         last_cell = u""
         for _, _, cell in self.history_manager.get_tail(1000,
                                                         include_latest=True):
             # Ignore blank lines and consecutive duplicates
             cell = cell.rstrip()
             if cell and (cell != last_cell):
                 if self.multiline_history:
                       self.readline.add_history(py3compat.unicode_to_str(cell,
                                                                 stdin_encoding))
                 else:
                     for line in cell.splitlines():
                         self.readline.add_history(py3compat.unicode_to_str(line,
                                                                 stdin_encoding))
                 last_cell = cell
 
     def set_next_input(self, s):
         """ Sets the 'default' input string for the next command line.
 
         Requires readline.
 
         Example:
 
         [D:\ipython]|1> _ip.set_next_input("Hello Word")
         [D:\ipython]|2> Hello Word_  # cursor is here
         """
         self.rl_next_input = py3compat.cast_bytes_py2(s)
 
     # Maybe move this to the terminal subclass?
     def pre_readline(self):
         """readline hook to be used at the start of each line.
 
         Currently it handles auto-indent only."""
 
         if self.rl_do_indent:
             self.readline.insert_text(self._indent_current_str())
         if self.rl_next_input is not None:
             self.readline.insert_text(self.rl_next_input)
             self.rl_next_input = None
 
     def _indent_current_str(self):
         """return the current level of indentation as a string"""
         return self.input_splitter.indent_spaces * ' '
 
     #-------------------------------------------------------------------------
     # Things related to text completion
     #-------------------------------------------------------------------------
 
     def init_completer(self):
         """Initialize the completion machinery.
 
         This creates completion machinery that can be used by client code,
         either interactively in-process (typically triggered by the readline
         library), programatically (such as in test suites) or out-of-prcess
         (typically over the network by remote frontends).
         """
         from IPython.core.completer import IPCompleter
         from IPython.core.completerlib import (module_completer,
                                                magic_run_completer, cd_completer)
 
         self.Completer = IPCompleter(shell=self,
                                      namespace=self.user_ns,
                                      global_namespace=self.user_global_ns,
                                      alias_table=self.alias_manager.alias_table,
                                      use_readline=self.has_readline,
                                      config=self.config,
                                      )
         self.configurables.append(self.Completer)
 
         # Add custom completers to the basic ones built into IPCompleter
         sdisp = self.strdispatchers.get('complete_command', StrDispatch())
         self.strdispatchers['complete_command'] = sdisp
         self.Completer.custom_completers = sdisp
 
         self.set_hook('complete_command', module_completer, str_key = 'import')
         self.set_hook('complete_command', module_completer, str_key = 'from')
         self.set_hook('complete_command', magic_run_completer, str_key = '%run')
         self.set_hook('complete_command', cd_completer, str_key = '%cd')
 
         # Only configure readline if we truly are using readline.  IPython can
         # do tab-completion over the network, in GUIs, etc, where readline
         # itself may be absent
         if self.has_readline:
             self.set_readline_completer()
 
     def complete(self, text, line=None, cursor_pos=None):
         """Return the completed text and a list of completions.
 
         Parameters
         ----------
 
            text : string
              A string of text to be completed on.  It can be given as empty and
              instead a line/position pair are given.  In this case, the
              completer itself will split the line like readline does.
 
            line : string, optional
              The complete line that text is part of.
 
            cursor_pos : int, optional
              The position of the cursor on the input line.
 
         Returns
         -------
           text : string
             The actual text that was completed.
 
           matches : list
             A sorted list with all possible completions.
 
         The optional arguments allow the completion to take more context into
         account, and are part of the low-level completion API.
 
         This is a wrapper around the completion mechanism, similar to what
         readline does at the command line when the TAB key is hit.  By
         exposing it as a method, it can be used by other non-readline
         environments (such as GUIs) for text completion.
 
         Simple usage example:
 
         In [1]: x = 'hello'
 
         In [2]: _ip.complete('x.l')
         Out[2]: ('x.l', ['x.ljust', 'x.lower', 'x.lstrip'])
         """
 
         # Inject names into __builtin__ so we can complete on the added names.
         with self.builtin_trap:
             return self.Completer.complete(text, line, cursor_pos)
 
     def set_custom_completer(self, completer, pos=0):
         """Adds a new custom completer function.
 
         The position argument (defaults to 0) is the index in the completers
         list where you want the completer to be inserted."""
 
         newcomp = types.MethodType(completer,self.Completer)
         self.Completer.matchers.insert(pos,newcomp)
 
     def set_readline_completer(self):
         """Reset readline's completer to be our own."""
         self.readline.set_completer(self.Completer.rlcomplete)
 
     def set_completer_frame(self, frame=None):
         """Set the frame of the completer."""
         if frame:
             self.Completer.namespace = frame.f_locals
             self.Completer.global_namespace = frame.f_globals
         else:
             self.Completer.namespace = self.user_ns
             self.Completer.global_namespace = self.user_global_ns
 
     #-------------------------------------------------------------------------
     # Things related to magics
     #-------------------------------------------------------------------------
 
     def init_magics(self):
         # FIXME: Move the color initialization to the DisplayHook, which
         # should be split into a prompt manager and displayhook. We probably
         # even need a centralize colors management object.
         self.magic_colors(self.colors)
         # History was moved to a separate module
         from . import history
         history.init_ipython(self)
 
     def magic(self, arg_s, next_input=None):
         """Call a magic function by name.
 
         Input: a string containing the name of the magic function to call and
         any additional arguments to be passed to the magic.
 
         magic('name -opt foo bar') is equivalent to typing at the ipython
         prompt:
 
         In[1]: %name -opt foo bar
 
         To call a magic without arguments, simply use magic('name').
 
         This provides a proper Python function to call IPython's magics in any
         valid Python code you can type at the interpreter, including loops and
         compound statements.
         """
         # Allow setting the next input - this is used if the user does `a=abs?`.
         # We do this first so that magic functions can override it.
         if next_input:
             self.set_next_input(next_input)
 
         args = arg_s.split(' ',1)
         magic_name = args[0]
         magic_name = magic_name.lstrip(prefilter.ESC_MAGIC)
 
         try:
             magic_args = args[1]
         except IndexError:
             magic_args = ''
         fn = getattr(self,'magic_'+magic_name,None)
         if fn is None:
             error("Magic function `%s` not found." % magic_name)
         else:
             magic_args = self.var_expand(magic_args,1)
             # Grab local namespace if we need it:
             if getattr(fn, "needs_local_scope", False):
                 self._magic_locals = sys._getframe(1).f_locals
             with self.builtin_trap:
                 result = fn(magic_args)
             # Ensure we're not keeping object references around:
             self._magic_locals = {}
             return result
 
     def define_magic(self, magicname, func):
         """Expose own function as magic function for ipython
 
         def foo_impl(self,parameter_s=''):
             'My very own magic!. (Use docstrings, IPython reads them).'
             print 'Magic function. Passed parameter is between < >:'
             print '<%s>' % parameter_s
             print 'The self object is:',self
 
         self.define_magic('foo',foo_impl)
         """
         im = types.MethodType(func,self)
         old = getattr(self, "magic_" + magicname, None)
         setattr(self, "magic_" + magicname, im)
         return old
 
     #-------------------------------------------------------------------------
     # Things related to macros
     #-------------------------------------------------------------------------
 
     def define_macro(self, name, themacro):
         """Define a new macro
 
         Parameters
         ----------
         name : str
             The name of the macro.
         themacro : str or Macro
             The action to do upon invoking the macro.  If a string, a new
             Macro object is created by passing the string to it.
         """
 
         from IPython.core import macro
 
         if isinstance(themacro, basestring):
             themacro = macro.Macro(themacro)
         if not isinstance(themacro, macro.Macro):
             raise ValueError('A macro must be a string or a Macro instance.')
         self.user_ns[name] = themacro
 
     #-------------------------------------------------------------------------
     # Things related to the running of system commands
     #-------------------------------------------------------------------------
 
     def system_piped(self, cmd):
         """Call the given cmd in a subprocess, piping stdout/err
 
         Parameters
         ----------
         cmd : str
           Command to execute (can not end in '&', as background processes are
           not supported.  Should not be a command that expects input
           other than simple text.
         """
         if cmd.rstrip().endswith('&'):
             # this is *far* from a rigorous test
             # We do not support backgrounding processes because we either use
             # pexpect or pipes to read from.  Users can always just call
             # os.system() or use ip.system=ip.system_raw
             # if they really want a background process.
             raise OSError("Background processes not supported.")
 
         # we explicitly do NOT return the subprocess status code, because
         # a non-None value would trigger :func:`sys.displayhook` calls.
         # Instead, we store the exit_code in user_ns.
         self.user_ns['_exit_code'] = system(self.var_expand(cmd, depth=2))
 
     def system_raw(self, cmd):
         """Call the given cmd in a subprocess using os.system
 
         Parameters
         ----------
         cmd : str
           Command to execute.
         """
         cmd = self.var_expand(cmd, depth=2)
         # protect os.system from UNC paths on Windows, which it can't handle:
         if sys.platform == 'win32':
             from IPython.utils._process_win32 import AvoidUNCPath
             with AvoidUNCPath() as path:
                 if path is not None:
                     cmd = '"pushd %s &&"%s' % (path, cmd)
                 cmd = py3compat.unicode_to_str(cmd)
                 ec = os.system(cmd)
         else:
             cmd = py3compat.unicode_to_str(cmd)
             ec = os.system(cmd)
         
         # We explicitly do NOT return the subprocess status code, because
         # a non-None value would trigger :func:`sys.displayhook` calls.
         # Instead, we store the exit_code in user_ns.
         self.user_ns['_exit_code'] = ec
 
     # use piped system by default, because it is better behaved
     system = system_piped
 
     def getoutput(self, cmd, split=True):
         """Get output (possibly including stderr) from a subprocess.
 
         Parameters
         ----------
         cmd : str
           Command to execute (can not end in '&', as background processes are
           not supported.
         split : bool, optional
 
           If True, split the output into an IPython SList.  Otherwise, an
           IPython LSString is returned.  These are objects similar to normal
           lists and strings, with a few convenience attributes for easier
           manipulation of line-based output.  You can use '?' on them for
           details.
           """
         if cmd.rstrip().endswith('&'):
             # this is *far* from a rigorous test
             raise OSError("Background processes not supported.")
         out = getoutput(self.var_expand(cmd, depth=2))
         if split:
             out = SList(out.splitlines())
         else:
             out = LSString(out)
         return out
 
     #-------------------------------------------------------------------------
     # Things related to aliases
     #-------------------------------------------------------------------------
 
     def init_alias(self):
         self.alias_manager = AliasManager(shell=self, config=self.config)
         self.configurables.append(self.alias_manager)
         self.ns_table['alias'] = self.alias_manager.alias_table,
 
     #-------------------------------------------------------------------------
     # Things related to extensions and plugins
     #-------------------------------------------------------------------------
 
     def init_extension_manager(self):
         self.extension_manager = ExtensionManager(shell=self, config=self.config)
         self.configurables.append(self.extension_manager)
 
     def init_plugin_manager(self):
         self.plugin_manager = PluginManager(config=self.config)
         self.configurables.append(self.plugin_manager)
         
 
     #-------------------------------------------------------------------------
     # Things related to payloads
     #-------------------------------------------------------------------------
 
     def init_payload(self):
         self.payload_manager = PayloadManager(config=self.config)
         self.configurables.append(self.payload_manager)
 
     #-------------------------------------------------------------------------
     # Things related to the prefilter
     #-------------------------------------------------------------------------
 
     def init_prefilter(self):
         self.prefilter_manager = PrefilterManager(shell=self, config=self.config)
         self.configurables.append(self.prefilter_manager)
         # Ultimately this will be refactored in the new interpreter code, but
         # for now, we should expose the main prefilter method (there's legacy
         # code out there that may rely on this).
         self.prefilter = self.prefilter_manager.prefilter_lines
 
     def auto_rewrite_input(self, cmd):
         """Print to the screen the rewritten form of the user's command.
 
         This shows visual feedback by rewriting input lines that cause
         automatic calling to kick in, like::
 
           /f x
 
         into::
 
           ------> f(x)
 
         after the user's input prompt.  This helps the user understand that the
         input line was transformed automatically by IPython.
         """
         rw = self.displayhook.prompt1.auto_rewrite() + cmd
 
         try:
             # plain ascii works better w/ pyreadline, on some machines, so
             # we use it and only print uncolored rewrite if we have unicode
             rw = str(rw)
             print >> io.stdout, rw
         except UnicodeEncodeError:
             print "------> " + cmd
 
     #-------------------------------------------------------------------------
     # Things related to extracting values/expressions from kernel and user_ns
     #-------------------------------------------------------------------------
 
     def _simple_error(self):
         etype, value = sys.exc_info()[:2]
         return u'[ERROR] {e.__name__}: {v}'.format(e=etype, v=value)
 
     def user_variables(self, names):
         """Get a list of variable names from the user's namespace.
 
         Parameters
         ----------
         names : list of strings
           A list of names of variables to be read from the user namespace.
 
         Returns
         -------
         A dict, keyed by the input names and with the repr() of each value.
         """
         out = {}
         user_ns = self.user_ns
         for varname in names:
             try:
                 value = repr(user_ns[varname])
             except:
                 value = self._simple_error()
             out[varname] = value
         return out
 
     def user_expressions(self, expressions):
         """Evaluate a dict of expressions in the user's namespace.
 
         Parameters
         ----------
         expressions : dict
           A dict with string keys and string values.  The expression values
           should be valid Python expressions, each of which will be evaluated
           in the user namespace.
 
         Returns
         -------
         A dict, keyed like the input expressions dict, with the repr() of each
         value.
         """
         out = {}
         user_ns = self.user_ns
         global_ns = self.user_global_ns
         for key, expr in expressions.iteritems():
             try:
                 value = repr(eval(expr, global_ns, user_ns))
             except:
                 value = self._simple_error()
             out[key] = value
         return out
 
     #-------------------------------------------------------------------------
     # Things related to the running of code
     #-------------------------------------------------------------------------
 
     def ex(self, cmd):
         """Execute a normal python statement in user namespace."""
         with self.builtin_trap:
             exec cmd in self.user_global_ns, self.user_ns
 
     def ev(self, expr):
         """Evaluate python expression expr in user namespace.
 
         Returns the result of evaluation
         """
         with self.builtin_trap:
             return eval(expr, self.user_global_ns, self.user_ns)
 
     def safe_execfile(self, fname, *where, **kw):
         """A safe version of the builtin execfile().
 
         This version will never throw an exception, but instead print
         helpful error messages to the screen.  This only works on pure
         Python files with the .py extension.
 
         Parameters
         ----------
         fname : string
             The name of the file to be executed.
         where : tuple
             One or two namespaces, passed to execfile() as (globals,locals).
             If only one is given, it is passed as both.
         exit_ignore : bool (False)
             If True, then silence SystemExit for non-zero status (it is always
             silenced for zero status, as it is so common).
         raise_exceptions : bool (False)
             If True raise exceptions everywhere. Meant for testing.
 
         """
         kw.setdefault('exit_ignore', False)
         kw.setdefault('raise_exceptions', False)
 
         fname = os.path.abspath(os.path.expanduser(fname))
 
         # Make sure we can open the file
         try:
             with open(fname) as thefile:
                 pass
         except:
             warn('Could not open file <%s> for safe execution.' % fname)
             return
 
         # Find things also in current directory.  This is needed to mimic the
         # behavior of running a script from the system command line, where
         # Python inserts the script's directory into sys.path
         dname = os.path.dirname(fname)
 
         with prepended_to_syspath(dname):
             try:
                 py3compat.execfile(fname,*where)
             except SystemExit, status:
                 # If the call was made with 0 or None exit status (sys.exit(0)
                 # or sys.exit() ), don't bother showing a traceback, as both of
                 # these are considered normal by the OS:
                 # > python -c'import sys;sys.exit(0)'; echo $?
                 # 0
                 # > python -c'import sys;sys.exit()'; echo $?
                 # 0
                 # For other exit status, we show the exception unless
                 # explicitly silenced, but only in short form.
                 if kw['raise_exceptions']:
                     raise
                 if status.code not in (0, None) and not kw['exit_ignore']:
                     self.showtraceback(exception_only=True)
             except:
                 if kw['raise_exceptions']:
                     raise
                 self.showtraceback()
 
     def safe_execfile_ipy(self, fname):
         """Like safe_execfile, but for .ipy files with IPython syntax.
 
         Parameters
         ----------
         fname : str
             The name of the file to execute.  The filename must have a
             .ipy extension.
         """
         fname = os.path.abspath(os.path.expanduser(fname))
 
         # Make sure we can open the file
         try:
             with open(fname) as thefile:
                 pass
         except:
             warn('Could not open file <%s> for safe execution.' % fname)
             return
 
         # Find things also in current directory.  This is needed to mimic the
         # behavior of running a script from the system command line, where
         # Python inserts the script's directory into sys.path
         dname = os.path.dirname(fname)
 
         with prepended_to_syspath(dname):
             try:
                 with open(fname) as thefile:
                     # self.run_cell currently captures all exceptions
                     # raised in user code.  It would be nice if there were
                     # versions of runlines, execfile that did raise, so
                     # we could catch the errors.
                     self.run_cell(thefile.read(), store_history=False)
             except:
                 self.showtraceback()
                 warn('Unknown failure executing file: <%s>' % fname)
 
     def run_cell(self, raw_cell, store_history=False):
         """Run a complete IPython cell.
 
         Parameters
         ----------
         raw_cell : str
           The code (including IPython code such as %magic functions) to run.
         store_history : bool
           If True, the raw and translated cell will be stored in IPython's
           history. For user code calling back into IPython's machinery, this
           should be set to False.
         """
         if (not raw_cell) or raw_cell.isspace():
             return
 
         for line in raw_cell.splitlines():
             self.input_splitter.push(line)
         cell = self.input_splitter.source_reset()
 
         with self.builtin_trap:
             prefilter_failed = False
             if len(cell.splitlines()) == 1:
                 try:
                     # use prefilter_lines to handle trailing newlines
                     # restore trailing newline for ast.parse
                     cell = self.prefilter_manager.prefilter_lines(cell) + '\n'
                 except AliasError as e:
                     error(e)
                     prefilter_failed = True
                 except Exception:
                     # don't allow prefilter errors to crash IPython
                     self.showtraceback()
                     prefilter_failed = True
 
             # Store raw and processed history
             if store_history:
                 self.history_manager.store_inputs(self.execution_count,
                                                   cell, raw_cell)
 
             self.logger.log(cell, raw_cell)
 
             if not prefilter_failed:
                 # don't run if prefilter failed
                 cell_name = self.compile.cache(cell, self.execution_count)
 
                 with self.display_trap:
                     try:
                         code_ast = self.compile.ast_parse(cell, filename=cell_name)
                     except IndentationError:
                         self.showindentationerror()
                         self.execution_count += 1
                         return None
                     except (OverflowError, SyntaxError, ValueError, TypeError,
                             MemoryError):
                         self.showsyntaxerror()
                         self.execution_count += 1
                         return None
 
                     self.run_ast_nodes(code_ast.body, cell_name,
                                        interactivity="last_expr")
 
                     # Execute any registered post-execution functions.
                     for func, status in self._post_execute.iteritems():
                         if not status:
                             continue
                         try:
                             func()
                         except KeyboardInterrupt:
                             print >> io.stderr, "\nKeyboardInterrupt"
                         except Exception:
                             print >> io.stderr, "Disabling failed post-execution function: %s" % func
                             self.showtraceback()
                             # Deactivate failing function
                             self._post_execute[func] = False
 
         if store_history:
             # Write output to the database. Does nothing unless
             # history output logging is enabled.
             self.history_manager.store_output(self.execution_count)
             # Each cell is a *single* input, regardless of how many lines it has
             self.execution_count += 1
 
     def run_ast_nodes(self, nodelist, cell_name, interactivity='last_expr'):
         """Run a sequence of AST nodes. The execution mode depends on the
         interactivity parameter.
 
         Parameters
         ----------
         nodelist : list
           A sequence of AST nodes to run.
         cell_name : str
           Will be passed to the compiler as the filename of the cell. Typically
           the value returned by ip.compile.cache(cell).
         interactivity : str
           'all', 'last', 'last_expr' or 'none', specifying which nodes should be
           run interactively (displaying output from expressions). 'last_expr'
           will run the last node interactively only if it is an expression (i.e.
           expressions in loops or other blocks are not displayed. Other values
           for this parameter will raise a ValueError.
         """
         if not nodelist:
             return
 
         if interactivity == 'last_expr':
             if isinstance(nodelist[-1], ast.Expr):
                 interactivity = "last"
             else:
                 interactivity = "none"
 
         if interactivity == 'none':
             to_run_exec, to_run_interactive = nodelist, []
         elif interactivity == 'last':
             to_run_exec, to_run_interactive = nodelist[:-1], nodelist[-1:]
         elif interactivity == 'all':
             to_run_exec, to_run_interactive = [], nodelist
         else:
             raise ValueError("Interactivity was %r" % interactivity)
 
         exec_count = self.execution_count
 
         try:
             for i, node in enumerate(to_run_exec):
                 mod = ast.Module([node])
                 code = self.compile(mod, cell_name, "exec")
                 if self.run_code(code):
                     return True
 
             for i, node in enumerate(to_run_interactive):
                 mod = ast.Interactive([node])
                 code = self.compile(mod, cell_name, "single")
                 if self.run_code(code):
                     return True
         except:
             # It's possible to have exceptions raised here, typically by
             # compilation of odd code (such as a naked 'return' outside a
             # function) that did parse but isn't valid. Typically the exception
             # is a SyntaxError, but it's safest just to catch anything and show
             # the user a traceback.
 
             # We do only one try/except outside the loop to minimize the impact
             # on runtime, and also because if any node in the node list is
             # broken, we should stop execution completely.
             self.showtraceback()
 
         return False
 
     def run_code(self, code_obj):
         """Execute a code object.
 
         When an exception occurs, self.showtraceback() is called to display a
         traceback.
 
         Parameters
         ----------
         code_obj : code object
           A compiled code object, to be executed
         post_execute : bool [default: True]
           whether to call post_execute hooks after this particular execution.
 
         Returns
         -------
         False : successful execution.
         True : an error occurred.
         """
 
         # Set our own excepthook in case the user code tries to call it
         # directly, so that the IPython crash handler doesn't get triggered
         old_excepthook,sys.excepthook = sys.excepthook, self.excepthook
 
         # we save the original sys.excepthook in the instance, in case config
         # code (such as magics) needs access to it.
         self.sys_excepthook = old_excepthook
         outflag = 1  # happens in more places, so it's easier as default
         try:
             try:
                 self.hooks.pre_run_code_hook()
                 #rprint('Running code', repr(code_obj)) # dbg
                 exec code_obj in self.user_global_ns, self.user_ns
             finally:
                 # Reset our crash handler in place
                 sys.excepthook = old_excepthook
         except SystemExit:
             self.showtraceback(exception_only=True)
             warn("To exit: use 'exit', 'quit', or Ctrl-D.", level=1)
         except self.custom_exceptions:
             etype,value,tb = sys.exc_info()
             self.CustomTB(etype,value,tb)
         except:
             self.showtraceback()
         else:
             outflag = 0
             if softspace(sys.stdout, 0):
                 print
 
         return outflag
 
     # For backwards compatibility
     runcode = run_code
 
     #-------------------------------------------------------------------------
     # Things related to GUI support and pylab
     #-------------------------------------------------------------------------
 
     def enable_pylab(self, gui=None, import_all=True):
         raise NotImplementedError('Implement enable_pylab in a subclass')
 
     #-------------------------------------------------------------------------
     # Utilities
     #-------------------------------------------------------------------------
 
     def var_expand(self, cmd, depth=0, formatter=DollarFormatter()):
         """Expand python variables in a string.
 
         The depth argument indicates how many frames above the caller should
         be walked to look for the local namespace where to expand variables.
 
         The global namespace for expansion is always the user's interactive
         namespace.
         """
         ns = self.user_ns.copy()
         ns.update(sys._getframe(depth+1).f_locals)
         ns.pop('self', None)
         return formatter.format(cmd, **ns)
 
     def mktempfile(self, data=None, prefix='ipython_edit_'):
         """Make a new tempfile and return its filename.
 
         This makes a call to tempfile.mktemp, but it registers the created
         filename internally so ipython cleans it up at exit time.
 
         Optional inputs:
 
           - data(None): if data is given, it gets written out to the temp file
           immediately, and the file is closed again."""
 
         filename = tempfile.mktemp('.py', prefix)
         self.tempfiles.append(filename)
 
         if data:
             tmp_file = open(filename,'w')
             tmp_file.write(data)
             tmp_file.close()
         return filename
 
     # TODO:  This should be removed when Term is refactored.
     def write(self,data):
         """Write a string to the default output"""
         io.stdout.write(data)
 
     # TODO:  This should be removed when Term is refactored.
     def write_err(self,data):
         """Write a string to the default error output"""
         io.stderr.write(data)
 
-    def ask_yes_no(self,prompt,default=True):
+    def ask_yes_no(self, prompt, default=None):
         if self.quiet:
             return True
         return ask_yes_no(prompt,default)
 
     def show_usage(self):
         """Show a usage message"""
         page.page(IPython.core.usage.interactive_usage)
 
     def find_user_code(self, target, raw=True):
         """Get a code string from history, file, or a string or macro.
 
         This is mainly used by magic functions.
 
         Parameters
         ----------
         target : str
           A string specifying code to retrieve. This will be tried respectively
           as: ranges of input history (see %history for syntax), a filename, or
           an expression evaluating to a string or Macro in the user namespace.
         raw : bool
           If true (default), retrieve raw history. Has no effect on the other
           retrieval mechanisms.
 
         Returns
         -------
         A string of code.
 
         ValueError is raised if nothing is found, and TypeError if it evaluates
         to an object of another type. In each case, .args[0] is a printable
         message.
         """
         code = self.extract_input_lines(target, raw=raw)  # Grab history
         if code:
             return code
         if os.path.isfile(target):                        # Read file
             return open(target, "r").read()
 
         try:                                              # User namespace
             codeobj = eval(target, self.user_ns)
         except Exception:
             raise ValueError(("'%s' was not found in history, as a file, nor in"
                                 " the user namespace.") % target)
         if isinstance(codeobj, basestring):
             return codeobj
         elif isinstance(codeobj, Macro):
             return codeobj.value
 
         raise TypeError("%s is neither a string nor a macro." % target,
                         codeobj)
 
     #-------------------------------------------------------------------------
     # Things related to IPython exiting
     #-------------------------------------------------------------------------
     def atexit_operations(self):
         """This will be executed at the time of exit.
 
         Cleanup operations and saving of persistent data that is done
         unconditionally by IPython should be performed here.
 
         For things that may depend on startup flags or platform specifics (such
         as having readline or not), register a separate atexit function in the
         code that has the appropriate information, rather than trying to
         clutter
         """
         # Close the history session (this stores the end time and line count)
         # this must be *before* the tempfile cleanup, in case of temporary
         # history db
         self.history_manager.end_session()
 
         # Cleanup all tempfiles left around
         for tfile in self.tempfiles:
             try:
                 os.unlink(tfile)
             except OSError:
                 pass
 
         # Clear all user namespaces to release all references cleanly.
         self.reset(new_session=False)
 
         # Run user hooks
         self.hooks.shutdown_hook()
 
     def cleanup(self):
         self.restore_sys_module_state()
 
 
 class InteractiveShellABC(object):
     """An abstract base class for InteractiveShell."""
     __metaclass__ = abc.ABCMeta
 
 InteractiveShellABC.register(InteractiveShell)

IPython/core/magic.py

@@ -1,3738 +1,3739 b''
 # encoding: utf-8
 """Magic functions for InteractiveShell.
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2001 Janko Hauser <[e-mail]> and
 #  Copyright (C) 2001-2007 Fernando Perez <[e-mail]>
 #  Copyright (C) 2008-2009  The IPython Development Team
 
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import __builtin__ as builtin_mod
 import __future__
 import bdb
 import inspect
 import imp
 import os
 import sys
 import shutil
 import re
 import time
 import textwrap
 from StringIO import StringIO
 from getopt import getopt,GetoptError
 from pprint import pformat
 from xmlrpclib import ServerProxy
 
 # cProfile was added in Python2.5
 try:
     import cProfile as profile
     import pstats
 except ImportError:
     # profile isn't bundled by default in Debian for license reasons
     try:
         import profile,pstats
     except ImportError:
         profile = pstats = None
 
 import IPython
 from IPython.core import debugger, oinspect
 from IPython.core.error import TryNext
 from IPython.core.error import UsageError
 from IPython.core.fakemodule import FakeModule
 from IPython.core.profiledir import ProfileDir
 from IPython.core.macro import Macro
 from IPython.core import magic_arguments, page
 from IPython.core.prefilter import ESC_MAGIC
 from IPython.lib.pylabtools import mpl_runner
 from IPython.testing.skipdoctest import skip_doctest
 from IPython.utils import py3compat
 from IPython.utils.io import file_read, nlprint
 from IPython.utils.module_paths import find_mod
 from IPython.utils.path import get_py_filename, unquote_filename
 from IPython.utils.process import arg_split, abbrev_cwd
 from IPython.utils.terminal import set_term_title
 from IPython.utils.text import LSString, SList, format_screen
 from IPython.utils.timing import clock, clock2
 from IPython.utils.warn import warn, error
 from IPython.utils.ipstruct import Struct
 from IPython.config.application import Application
 
 #-----------------------------------------------------------------------------
 # Utility functions
 #-----------------------------------------------------------------------------
 
 def on_off(tag):
     """Return an ON/OFF string for a 1/0 input. Simple utility function."""
     return ['OFF','ON'][tag]
 
 class Bunch: pass
 
 def compress_dhist(dh):
     head, tail = dh[:-10], dh[-10:]
 
     newhead = []
     done = set()
     for h in head:
         if h in done:
             continue
         newhead.append(h)
         done.add(h)
 
     return newhead + tail
 
 def needs_local_scope(func):
     """Decorator to mark magic functions which need to local scope to run."""
     func.needs_local_scope = True
     return func
 
     
 # Used for exception handling in magic_edit
 class MacroToEdit(ValueError): pass
 
 #***************************************************************************
 # Main class implementing Magic functionality
 
 # XXX - for some odd reason, if Magic is made a new-style class, we get errors
 # on construction of the main InteractiveShell object.  Something odd is going
 # on with super() calls, Configurable and the MRO... For now leave it as-is, but
 # eventually this needs to be clarified.
 # BG: This is because InteractiveShell inherits from this, but is itself a
 # Configurable. This messes up the MRO in some way. The fix is that we need to
 # make Magic a configurable that InteractiveShell does not subclass.
 
 class Magic:
     """Magic functions for InteractiveShell.
 
     Shell functions which can be reached as %function_name. All magic
     functions should accept a string, which they can parse for their own
     needs. This can make some functions easier to type, eg `%cd ../`
     vs. `%cd("../")`
 
     ALL definitions MUST begin with the prefix magic_. The user won't need it
     at the command line, but it is is needed in the definition. """
 
     # class globals
     auto_status = ['Automagic is OFF, % prefix IS needed for magic functions.',
                    'Automagic is ON, % prefix NOT needed for magic functions.']
 
 
     configurables = None
     #......................................................................
     # some utility functions
 
     def __init__(self,shell):
 
         self.options_table = {}
         if profile is None:
             self.magic_prun = self.profile_missing_notice
         self.shell = shell
         if self.configurables is None:
             self.configurables = []
 
         # namespace for holding state we may need
         self._magic_state = Bunch()
 
     def profile_missing_notice(self, *args, **kwargs):
         error("""\
 The profile module could not be found. It has been removed from the standard
 python packages because of its non-free license. To use profiling, install the
 python-profiler package from non-free.""")
 
     def default_option(self,fn,optstr):
         """Make an entry in the options_table for fn, with value optstr"""
 
         if fn not in self.lsmagic():
             error("%s is not a magic function" % fn)
         self.options_table[fn] = optstr
 
     def lsmagic(self):
         """Return a list of currently available magic functions.
 
         Gives a list of the bare names after mangling (['ls','cd', ...], not
         ['magic_ls','magic_cd',...]"""
 
         # FIXME. This needs a cleanup, in the way the magics list is built.
 
         # magics in class definition
         class_magic = lambda fn: fn.startswith('magic_') and \
                       callable(Magic.__dict__[fn])
         # in instance namespace (run-time user additions)
         inst_magic =  lambda fn: fn.startswith('magic_') and \
                      callable(self.__dict__[fn])
         # and bound magics by user (so they can access self):
         inst_bound_magic =  lambda fn: fn.startswith('magic_') and \
                            callable(self.__class__.__dict__[fn])
         magics = filter(class_magic,Magic.__dict__.keys()) + \
                  filter(inst_magic,self.__dict__.keys()) + \
                  filter(inst_bound_magic,self.__class__.__dict__.keys())
         out = []
         for fn in set(magics):
             out.append(fn.replace('magic_','',1))
         out.sort()
         return out
 
     def extract_input_lines(self, range_str, raw=False):
         """Return as a string a set of input history slices.
 
         Inputs:
 
           - range_str: the set of slices is given as a string, like
           "~5/6-~4/2 4:8 9", since this function is for use by magic functions
           which get their arguments as strings. The number before the / is the
           session number: ~n goes n back from the current session.
 
         Optional inputs:
 
           - raw(False): by default, the processed input is used.  If this is
           true, the raw input history is used instead.
 
         Note that slices can be called with two notations:
 
         N:M -> standard python form, means including items N...(M-1).
 
         N-M -> include items N..M (closed endpoint)."""
         lines = self.shell.history_manager.\
                                     get_range_by_str(range_str, raw=raw)
         return "\n".join(x for _, _, x in lines)
 
     def arg_err(self,func):
         """Print docstring if incorrect arguments were passed"""
         print 'Error in arguments:'
         print oinspect.getdoc(func)
 
     def format_latex(self,strng):
         """Format a string for latex inclusion."""
 
         # Characters that need to be escaped for latex:
         escape_re = re.compile(r'(%|_|\$|#|&)',re.MULTILINE)
         # Magic command names as headers:
         cmd_name_re = re.compile(r'^(%s.*?):' % ESC_MAGIC,
                                  re.MULTILINE)
         # Magic commands
         cmd_re = re.compile(r'(?P<cmd>%s.+?\b)(?!\}\}:)' % ESC_MAGIC,
                             re.MULTILINE)
         # Paragraph continue
         par_re = re.compile(r'\\$',re.MULTILINE)
 
         # The "\n" symbol
         newline_re = re.compile(r'\\n')
 
         # Now build the string for output:
         #strng = cmd_name_re.sub(r'\n\\texttt{\\textsl{\\large \1}}:',strng)
         strng = cmd_name_re.sub(r'\n\\bigskip\n\\texttt{\\textbf{ \1}}:',
                                 strng)
         strng = cmd_re.sub(r'\\texttt{\g<cmd>}',strng)
         strng = par_re.sub(r'\\\\',strng)
         strng = escape_re.sub(r'\\\1',strng)
         strng = newline_re.sub(r'\\textbackslash{}n',strng)
         return strng
 
     def parse_options(self,arg_str,opt_str,*long_opts,**kw):
         """Parse options passed to an argument string.
 
         The interface is similar to that of getopt(), but it returns back a
         Struct with the options as keys and the stripped argument string still
         as a string.
 
         arg_str is quoted as a true sys.argv vector by using shlex.split.
         This allows us to easily expand variables, glob files, quote
         arguments, etc.
 
         Options:
           -mode: default 'string'. If given as 'list', the argument string is
           returned as a list (split on whitespace) instead of a string.
 
           -list_all: put all option values in lists. Normally only options
           appearing more than once are put in a list.
 
           -posix (True): whether to split the input line in POSIX mode or not,
           as per the conventions outlined in the shlex module from the
           standard library."""
 
         # inject default options at the beginning of the input line
         caller = sys._getframe(1).f_code.co_name.replace('magic_','')
         arg_str = '%s %s' % (self.options_table.get(caller,''),arg_str)
 
         mode = kw.get('mode','string')
         if mode not in ['string','list']:
             raise ValueError,'incorrect mode given: %s' % mode
         # Get options
         list_all = kw.get('list_all',0)
         posix = kw.get('posix', os.name == 'posix')
 
         # Check if we have more than one argument to warrant extra processing:
         odict = {}  # Dictionary with options
         args = arg_str.split()
         if len(args) >= 1:
             # If the list of inputs only has 0 or 1 thing in it, there's no
             # need to look for options
             argv = arg_split(arg_str,posix)
             # Do regular option processing
             try:
                 opts,args = getopt(argv,opt_str,*long_opts)
             except GetoptError,e:
                 raise UsageError('%s ( allowed: "%s" %s)' % (e.msg,opt_str,
                                         " ".join(long_opts)))
             for o,a in opts:
                 if o.startswith('--'):
                     o = o[2:]
                 else:
                     o = o[1:]
                 try:
                     odict[o].append(a)
                 except AttributeError:
                     odict[o] = [odict[o],a]
                 except KeyError:
                     if list_all:
                         odict[o] = [a]
                     else:
                         odict[o] = a
 
         # Prepare opts,args for return
         opts = Struct(odict)
         if mode == 'string':
             args = ' '.join(args)
 
         return opts,args
 
     #......................................................................
     # And now the actual magic functions
 
     # Functions for IPython shell work (vars,funcs, config, etc)
     def magic_lsmagic(self, parameter_s = ''):
         """List currently available magic functions."""
         mesc = ESC_MAGIC
         print 'Available magic functions:\n'+mesc+\
               ('  '+mesc).join(self.lsmagic())
         print '\n' + Magic.auto_status[self.shell.automagic]
         return None
 
     def magic_magic(self, parameter_s = ''):
         """Print information about the magic function system.
 
         Supported formats: -latex, -brief, -rest
         """
 
         mode = ''
         try:
             if parameter_s.split()[0] == '-latex':
                 mode = 'latex'
             if parameter_s.split()[0] == '-brief':
                 mode = 'brief'
             if parameter_s.split()[0] == '-rest':
                 mode = 'rest'
                 rest_docs = []
         except:
             pass
 
         magic_docs = []
         for fname in self.lsmagic():
             mname = 'magic_' + fname
             for space in (Magic,self,self.__class__):
                 try:
                     fn = space.__dict__[mname]
                 except KeyError:
                     pass
                 else:
                     break
             if mode == 'brief':
                 # only first line
                 if fn.__doc__:
                     fndoc = fn.__doc__.split('\n',1)[0]
                 else:
                     fndoc = 'No documentation'
             else:
                 if fn.__doc__:
                     fndoc = fn.__doc__.rstrip()
                 else:
                     fndoc = 'No documentation'
 
 
             if mode == 'rest':
                 rest_docs.append('**%s%s**::\n\n\t%s\n\n' %(ESC_MAGIC,
                                                     fname,fndoc))
 
             else:
                 magic_docs.append('%s%s:\n\t%s\n' %(ESC_MAGIC,
                                                     fname,fndoc))
 
         magic_docs = ''.join(magic_docs)
 
         if mode == 'rest':
             return "".join(rest_docs)
 
         if mode == 'latex':
             print self.format_latex(magic_docs)
             return
         else:
             magic_docs = format_screen(magic_docs)
         if mode == 'brief':
             return magic_docs
 
         outmsg = """
 IPython's 'magic' functions
 ===========================
 
 The magic function system provides a series of functions which allow you to
 control the behavior of IPython itself, plus a lot of system-type
 features. All these functions are prefixed with a % character, but parameters
 are given without parentheses or quotes.
 
 NOTE: If you have 'automagic' enabled (via the command line option or with the
 %automagic function), you don't need to type in the % explicitly.  By default,
 IPython ships with automagic on, so you should only rarely need the % escape.
 
 Example: typing '%cd mydir' (without the quotes) changes you working directory
 to 'mydir', if it exists.
 
 For a list of the available magic functions, use %lsmagic. For a description
 of any of them, type %magic_name?, e.g. '%cd?'.
 
 Currently the magic system has the following functions:\n"""
 
         mesc = ESC_MAGIC
         outmsg = ("%s\n%s\n\nSummary of magic functions (from %slsmagic):"
                   "\n\n%s%s\n\n%s" % (outmsg,
                                      magic_docs,mesc,mesc,
                                      ('  '+mesc).join(self.lsmagic()),
                                      Magic.auto_status[self.shell.automagic] ) )
         page.page(outmsg)
 
     def magic_automagic(self, parameter_s = ''):
         """Make magic functions callable without having to type the initial %.
 
         Without argumentsl toggles on/off (when off, you must call it as
         %automagic, of course).  With arguments it sets the value, and you can
         use any of (case insensitive):
 
          - on,1,True: to activate
 
          - off,0,False: to deactivate.
 
         Note that magic functions have lowest priority, so if there's a
         variable whose name collides with that of a magic fn, automagic won't
         work for that function (you get the variable instead). However, if you
         delete the variable (del var), the previously shadowed magic function
         becomes visible to automagic again."""
 
         arg = parameter_s.lower()
         if parameter_s in ('on','1','true'):
             self.shell.automagic = True
         elif parameter_s in ('off','0','false'):
             self.shell.automagic = False
         else:
             self.shell.automagic = not self.shell.automagic
         print '\n' + Magic.auto_status[self.shell.automagic]
 
     @skip_doctest
     def magic_autocall(self, parameter_s = ''):
         """Make functions callable without having to type parentheses.
 
         Usage:
 
            %autocall [mode]
 
         The mode can be one of: 0->Off, 1->Smart, 2->Full.  If not given, the
         value is toggled on and off (remembering the previous state).
 
         In more detail, these values mean:
 
         0 -> fully disabled
 
         1 -> active, but do not apply if there are no arguments on the line.
 
         In this mode, you get:
 
         In [1]: callable
         Out[1]: <built-in function callable>
 
         In [2]: callable 'hello'
         ------> callable('hello')
         Out[2]: False
 
         2 -> Active always.  Even if no arguments are present, the callable
         object is called:
 
         In [2]: float
         ------> float()
         Out[2]: 0.0
 
         Note that even with autocall off, you can still use '/' at the start of
         a line to treat the first argument on the command line as a function
         and add parentheses to it:
 
         In [8]: /str 43
         ------> str(43)
         Out[8]: '43'
 
         # all-random (note for auto-testing)
         """
 
         if parameter_s:
             arg = int(parameter_s)
         else:
             arg = 'toggle'
 
         if not arg in (0,1,2,'toggle'):
             error('Valid modes: (0->Off, 1->Smart, 2->Full')
             return
 
         if arg in (0,1,2):
             self.shell.autocall = arg
         else: # toggle
             if self.shell.autocall:
                 self._magic_state.autocall_save = self.shell.autocall
                 self.shell.autocall = 0
             else:
                 try:
                     self.shell.autocall = self._magic_state.autocall_save
                 except AttributeError:
                     self.shell.autocall = self._magic_state.autocall_save = 1
 
         print "Automatic calling is:",['OFF','Smart','Full'][self.shell.autocall]
 
 
     def magic_page(self, parameter_s=''):
         """Pretty print the object and display it through a pager.
 
         %page [options] OBJECT
 
         If no object is given, use _ (last output).
 
         Options:
 
           -r: page str(object), don't pretty-print it."""
 
         # After a function contributed by Olivier Aubert, slightly modified.
 
         # Process options/args
         opts,args = self.parse_options(parameter_s,'r')
         raw = 'r' in opts
 
         oname = args and args or '_'
         info = self._ofind(oname)
         if info['found']:
             txt = (raw and str or pformat)( info['obj'] )
             page.page(txt)
         else:
             print 'Object `%s` not found' % oname
 
     def magic_profile(self, parameter_s=''):
         """Print your currently active IPython profile."""
         from IPython.core.application import BaseIPythonApplication
         if BaseIPythonApplication.initialized():
             print BaseIPythonApplication.instance().profile
         else:
             error("profile is an application-level value, but you don't appear to be in an IPython application")
 
     def magic_pinfo(self, parameter_s='', namespaces=None):
         """Provide detailed information about an object.
 
         '%pinfo object' is just a synonym for object? or ?object."""
 
         #print 'pinfo par: <%s>' % parameter_s  # dbg
 
 
         # detail_level: 0 -> obj? , 1 -> obj??
         detail_level = 0
         # We need to detect if we got called as 'pinfo pinfo foo', which can
         # happen if the user types 'pinfo foo?' at the cmd line.
         pinfo,qmark1,oname,qmark2 = \
                re.match('(pinfo )?(\?*)(.*?)(\??$)',parameter_s).groups()
         if pinfo or qmark1 or qmark2:
             detail_level = 1
         if "*" in oname:
             self.magic_psearch(oname)
         else:
             self.shell._inspect('pinfo', oname, detail_level=detail_level,
                                 namespaces=namespaces)
 
     def magic_pinfo2(self, parameter_s='', namespaces=None):
         """Provide extra detailed information about an object.
 
         '%pinfo2 object' is just a synonym for object?? or ??object."""
         self.shell._inspect('pinfo', parameter_s, detail_level=1,
                             namespaces=namespaces)
 
     @skip_doctest
     def magic_pdef(self, parameter_s='', namespaces=None):
         """Print the definition header for any callable object.
 
         If the object is a class, print the constructor information.
 
         Examples
         --------
         ::
 
           In [3]: %pdef urllib.urlopen
           urllib.urlopen(url, data=None, proxies=None)
         """
         self._inspect('pdef',parameter_s, namespaces)
 
     def magic_pdoc(self, parameter_s='', namespaces=None):
         """Print the docstring for an object.
 
         If the given object is a class, it will print both the class and the
         constructor docstrings."""
         self._inspect('pdoc',parameter_s, namespaces)
 
     def magic_psource(self, parameter_s='', namespaces=None):
         """Print (or run through pager) the source code for an object."""
         self._inspect('psource',parameter_s, namespaces)
 
     def magic_pfile(self, parameter_s=''):
         """Print (or run through pager) the file where an object is defined.
 
         The file opens at the line where the object definition begins. IPython
         will honor the environment variable PAGER if set, and otherwise will
         do its best to print the file in a convenient form.
 
         If the given argument is not an object currently defined, IPython will
         try to interpret it as a filename (automatically adding a .py extension
         if needed). You can thus use %pfile as a syntax highlighting code
         viewer."""
 
         # first interpret argument as an object name
         out = self._inspect('pfile',parameter_s)
         # if not, try the input as a filename
         if out == 'not found':
             try:
                 filename = get_py_filename(parameter_s)
             except IOError,msg:
                 print msg
                 return
             page.page(self.shell.inspector.format(file(filename).read()))
 
     def magic_psearch(self, parameter_s=''):
         """Search for object in namespaces by wildcard.
 
         %psearch [options] PATTERN [OBJECT TYPE]
 
         Note: ? can be used as a synonym for %psearch, at the beginning or at
         the end: both a*? and ?a* are equivalent to '%psearch a*'.  Still, the
         rest of the command line must be unchanged (options come first), so
         for example the following forms are equivalent
 
         %psearch -i a* function
         -i a* function?
         ?-i a* function
 
         Arguments:
 
           PATTERN
 
           where PATTERN is a string containing * as a wildcard similar to its
           use in a shell.  The pattern is matched in all namespaces on the
           search path. By default objects starting with a single _ are not
           matched, many IPython generated objects have a single
           underscore. The default is case insensitive matching. Matching is
           also done on the attributes of objects and not only on the objects
           in a module.
 
           [OBJECT TYPE]
 
           Is the name of a python type from the types module. The name is
           given in lowercase without the ending type, ex. StringType is
           written string. By adding a type here only objects matching the
           given type are matched. Using all here makes the pattern match all
           types (this is the default).
 
         Options:
 
           -a: makes the pattern match even objects whose names start with a
           single underscore.  These names are normally ommitted from the
           search.
 
           -i/-c: make the pattern case insensitive/sensitive.  If neither of
           these options are given, the default is read from your configuration
           file, with the option ``InteractiveShell.wildcards_case_sensitive``.
           If this option is not specified in your configuration file, IPython's
           internal default is to do a case sensitive search.
 
           -e/-s NAMESPACE: exclude/search a given namespace.  The pattern you
           specifiy can be searched in any of the following namespaces:
           'builtin', 'user', 'user_global','internal', 'alias', where
           'builtin' and 'user' are the search defaults.  Note that you should
           not use quotes when specifying namespaces.
 
           'Builtin' contains the python module builtin, 'user' contains all
           user data, 'alias' only contain the shell aliases and no python
           objects, 'internal' contains objects used by IPython.  The
           'user_global' namespace is only used by embedded IPython instances,
           and it contains module-level globals.  You can add namespaces to the
           search with -s or exclude them with -e (these options can be given
           more than once).
 
         Examples:
 
         %psearch a*            -> objects beginning with an a
         %psearch -e builtin a* -> objects NOT in the builtin space starting in a
         %psearch a* function   -> all functions beginning with an a
         %psearch re.e*         -> objects beginning with an e in module re
         %psearch r*.e*         -> objects that start with e in modules starting in r
         %psearch r*.* string   -> all strings in modules beginning with r
 
         Case sensitve search:
 
         %psearch -c a*         list all object beginning with lower case a
 
         Show objects beginning with a single _:
 
         %psearch -a _*         list objects beginning with a single underscore"""
         try:
             parameter_s.encode('ascii')
         except UnicodeEncodeError:
             print 'Python identifiers can only contain ascii characters.'
             return
 
         # default namespaces to be searched
         def_search = ['user','builtin']
 
         # Process options/args
         opts,args = self.parse_options(parameter_s,'cias:e:',list_all=True)
         opt = opts.get
         shell = self.shell
         psearch = shell.inspector.psearch
 
         # select case options
         if opts.has_key('i'):
             ignore_case = True
         elif opts.has_key('c'):
             ignore_case = False
         else:
             ignore_case = not shell.wildcards_case_sensitive
 
         # Build list of namespaces to search from user options
         def_search.extend(opt('s',[]))
         ns_exclude = ns_exclude=opt('e',[])
         ns_search = [nm for nm in def_search if nm not in ns_exclude]
 
         # Call the actual search
         try:
             psearch(args,shell.ns_table,ns_search,
                     show_all=opt('a'),ignore_case=ignore_case)
         except:
             shell.showtraceback()
 
     @skip_doctest
     def magic_who_ls(self, parameter_s=''):
         """Return a sorted list of all interactive variables.
 
         If arguments are given, only variables of types matching these
         arguments are returned.
 
         Examples
         --------
 
         Define two variables and list them with who_ls::
 
           In [1]: alpha = 123
 
           In [2]: beta = 'test'
 
           In [3]: %who_ls
           Out[3]: ['alpha', 'beta']
 
           In [4]: %who_ls int
           Out[4]: ['alpha']
 
           In [5]: %who_ls str
           Out[5]: ['beta']
         """
 
         user_ns = self.shell.user_ns
         internal_ns = self.shell.internal_ns
         user_ns_hidden = self.shell.user_ns_hidden
         out = [ i for i in user_ns
                 if not i.startswith('_') \
                 and not (i in internal_ns or i in user_ns_hidden) ]
 
         typelist = parameter_s.split()
         if typelist:
             typeset = set(typelist)
             out = [i for i in out if type(user_ns[i]).__name__ in typeset]
 
         out.sort()
         return out
 
     @skip_doctest
     def magic_who(self, parameter_s=''):
         """Print all interactive variables, with some minimal formatting.
 
         If any arguments are given, only variables whose type matches one of
         these are printed.  For example:
 
           %who function str
 
         will only list functions and strings, excluding all other types of
         variables.  To find the proper type names, simply use type(var) at a
         command line to see how python prints type names.  For example:
 
           In [1]: type('hello')\\
           Out[1]: <type 'str'>
 
         indicates that the type name for strings is 'str'.
 
         %who always excludes executed names loaded through your configuration
         file and things which are internal to IPython.
 
         This is deliberate, as typically you may load many modules and the
         purpose of %who is to show you only what you've manually defined.
 
         Examples
         --------
 
         Define two variables and list them with who::
 
           In [1]: alpha = 123
 
           In [2]: beta = 'test'
 
           In [3]: %who
           alpha   beta
 
           In [4]: %who int
           alpha
 
           In [5]: %who str
           beta
         """
 
         varlist = self.magic_who_ls(parameter_s)
         if not varlist:
             if parameter_s:
                 print 'No variables match your requested type.'
             else:
                 print 'Interactive namespace is empty.'
             return
 
         # if we have variables, move on...
         count = 0
         for i in varlist:
             print i+'\t',
             count += 1
             if count > 8:
                 count = 0
                 print
         print
 
     @skip_doctest
     def magic_whos(self, parameter_s=''):
         """Like %who, but gives some extra information about each variable.
 
         The same type filtering of %who can be applied here.
 
         For all variables, the type is printed. Additionally it prints:
 
           - For {},[],(): their length.
 
           - For numpy arrays, a summary with shape, number of
           elements, typecode and size in memory.
 
           - Everything else: a string representation, snipping their middle if
           too long.
 
         Examples
         --------
 
         Define two variables and list them with whos::
 
           In [1]: alpha = 123
 
           In [2]: beta = 'test'
 
           In [3]: %whos
           Variable   Type        Data/Info
           --------------------------------
           alpha      int         123
           beta       str         test
         """
 
         varnames = self.magic_who_ls(parameter_s)
         if not varnames:
             if parameter_s:
                 print 'No variables match your requested type.'
             else:
                 print 'Interactive namespace is empty.'
             return
 
         # if we have variables, move on...
 
         # for these types, show len() instead of data:
         seq_types = ['dict', 'list', 'tuple']
 
         # for numpy arrays, display summary info
         ndarray_type = None
         if 'numpy' in sys.modules:
             try:
                 from numpy import ndarray
             except ImportError:
                 pass
             else:
                 ndarray_type = ndarray.__name__
 
         # Find all variable names and types so we can figure out column sizes
         def get_vars(i):
             return self.shell.user_ns[i]
 
         # some types are well known and can be shorter
         abbrevs = {'IPython.core.macro.Macro' : 'Macro'}
         def type_name(v):
             tn = type(v).__name__
             return abbrevs.get(tn,tn)
 
         varlist = map(get_vars,varnames)
 
         typelist = []
         for vv in varlist:
             tt = type_name(vv)
 
             if tt=='instance':
                 typelist.append( abbrevs.get(str(vv.__class__),
                                              str(vv.__class__)))
             else:
                 typelist.append(tt)
 
         # column labels and # of spaces as separator
         varlabel = 'Variable'
         typelabel = 'Type'
         datalabel = 'Data/Info'
         colsep = 3
         # variable format strings
         vformat    = "{0:<{varwidth}}{1:<{typewidth}}"
         aformat    = "%s: %s elems, type `%s`, %s bytes"
         # find the size of the columns to format the output nicely
         varwidth = max(max(map(len,varnames)), len(varlabel)) + colsep
         typewidth = max(max(map(len,typelist)), len(typelabel)) + colsep
         # table header
         print varlabel.ljust(varwidth) + typelabel.ljust(typewidth) + \
               ' '+datalabel+'\n' + '-'*(varwidth+typewidth+len(datalabel)+1)
         # and the table itself
         kb = 1024
         Mb = 1048576  # kb**2
         for vname,var,vtype in zip(varnames,varlist,typelist):
             print vformat.format(vname, vtype, varwidth=varwidth, typewidth=typewidth),
             if vtype in seq_types:
                 print "n="+str(len(var))
             elif vtype == ndarray_type:
                 vshape = str(var.shape).replace(',','').replace(' ','x')[1:-1]
                 if vtype==ndarray_type:
                     # numpy
                     vsize  = var.size
                     vbytes = vsize*var.itemsize
                     vdtype = var.dtype
                 else:
                     # Numeric
                     vsize  = Numeric.size(var)
                     vbytes = vsize*var.itemsize()
                     vdtype = var.typecode()
 
                 if vbytes < 100000:
                     print aformat % (vshape,vsize,vdtype,vbytes)
                 else:
                     print aformat % (vshape,vsize,vdtype,vbytes),
                     if vbytes < Mb:
                         print '(%s kb)' % (vbytes/kb,)
                     else:
                         print '(%s Mb)' % (vbytes/Mb,)
             else:
                 try:
                     vstr = str(var)
                 except UnicodeEncodeError:
                     vstr = unicode(var).encode(sys.getdefaultencoding(),
                                                'backslashreplace')
                 vstr = vstr.replace('\n','\\n')
                 if len(vstr) < 50:
                     print vstr
                 else:
                     print vstr[:25] + "<...>" + vstr[-25:]
 
     def magic_reset(self, parameter_s=''):
         """Resets the namespace by removing all names defined by the user.
 
         Parameters
         ----------
           -f : force reset without asking for confirmation.
 
           -s : 'Soft' reset: Only clears your namespace, leaving history intact.
           References to objects may be kept. By default (without this option),
           we do a 'hard' reset, giving you a new session and removing all
           references to objects from the current session.
 
         Examples
         --------
         In [6]: a = 1
 
         In [7]: a
         Out[7]: 1
 
         In [8]: 'a' in _ip.user_ns
         Out[8]: True
 
         In [9]: %reset -f
 
         In [1]: 'a' in _ip.user_ns
         Out[1]: False
         """
         opts, args = self.parse_options(parameter_s,'sf')
         if 'f' in opts:
             ans = True
         else:
             ans = self.shell.ask_yes_no(
                 "Once deleted, variables cannot be recovered. Proceed (y/[n])? ", default='n')
         if not ans:
             print 'Nothing done.'
             return
 
         if 's' in opts:                     # Soft reset
             user_ns = self.shell.user_ns
             for i in self.magic_who_ls():
                 del(user_ns[i])
 
         else:                     # Hard reset
             self.shell.reset(new_session = False)
 
 
 
     def magic_reset_selective(self, parameter_s=''):
         """Resets the namespace by removing names defined by the user.
 
         Input/Output history are left around in case you need them.
 
         %reset_selective [-f] regex
 
         No action is taken if regex is not included
 
         Options
           -f : force reset without asking for confirmation.
 
         Examples
         --------
 
         We first fully reset the namespace so your output looks identical to
         this example for pedagogical reasons; in practice you do not need a
         full reset.
 
         In [1]: %reset -f
 
         Now, with a clean namespace we can make a few variables and use
         %reset_selective to only delete names that match our regexp:
 
         In [2]: a=1; b=2; c=3; b1m=4; b2m=5; b3m=6; b4m=7; b2s=8
 
         In [3]: who_ls
         Out[3]: ['a', 'b', 'b1m', 'b2m', 'b2s', 'b3m', 'b4m', 'c']
 
         In [4]: %reset_selective -f b[2-3]m
 
         In [5]: who_ls
         Out[5]: ['a', 'b', 'b1m', 'b2s', 'b4m', 'c']
 
         In [6]: %reset_selective -f d
 
         In [7]: who_ls
         Out[7]: ['a', 'b', 'b1m', 'b2s', 'b4m', 'c']
 
         In [8]: %reset_selective -f c
 
         In [9]: who_ls
         Out[9]: ['a', 'b', 'b1m', 'b2s', 'b4m']
 
         In [10]: %reset_selective -f b
 
         In [11]: who_ls
         Out[11]: ['a']
         """
 
         opts, regex = self.parse_options(parameter_s,'f')
 
         if opts.has_key('f'):
             ans = True
         else:
             ans = self.shell.ask_yes_no(
-                "Once deleted, variables cannot be recovered. Proceed (y/[n])? ")
+                "Once deleted, variables cannot be recovered. Proceed (y/[n])? ",
+                default='n')
         if not ans:
             print 'Nothing done.'
             return
         user_ns = self.shell.user_ns
         if not regex:
             print 'No regex pattern specified. Nothing done.'
             return
         else:
             try:
                 m = re.compile(regex)
             except TypeError:
                 raise TypeError('regex must be a string or compiled pattern')
             for i in self.magic_who_ls():
                 if m.search(i):
                     del(user_ns[i])
 
     def magic_xdel(self, parameter_s=''):
         """Delete a variable, trying to clear it from anywhere that
         IPython's machinery has references to it. By default, this uses
         the identity of the named object in the user namespace to remove
         references held under other names. The object is also removed
         from the output history.
 
         Options
           -n : Delete the specified name from all namespaces, without
           checking their identity.
         """
         opts, varname = self.parse_options(parameter_s,'n')
         try:
             self.shell.del_var(varname, ('n' in opts))
         except (NameError, ValueError) as e:
             print type(e).__name__ +": "+ str(e)
 
     def magic_logstart(self,parameter_s=''):
         """Start logging anywhere in a session.
 
         %logstart [-o|-r|-t] [log_name [log_mode]]
 
         If no name is given, it defaults to a file named 'ipython_log.py' in your
         current directory, in 'rotate' mode (see below).
 
         '%logstart name' saves to file 'name' in 'backup' mode.  It saves your
         history up to that point and then continues logging.
 
         %logstart takes a second optional parameter: logging mode. This can be one
         of (note that the modes are given unquoted):\\
           append: well, that says it.\\
           backup: rename (if exists) to name~ and start name.\\
           global: single logfile in your home dir, appended to.\\
           over  : overwrite existing log.\\
           rotate: create rotating logs name.1~, name.2~, etc.
 
         Options:
 
           -o: log also IPython's output.  In this mode, all commands which
           generate an Out[NN] prompt are recorded to the logfile, right after
           their corresponding input line.  The output lines are always
           prepended with a '#[Out]# ' marker, so that the log remains valid
           Python code.
 
           Since this marker is always the same, filtering only the output from
           a log is very easy, using for example a simple awk call:
 
             awk -F'#\\[Out\\]# ' '{if($2) {print $2}}' ipython_log.py
 
           -r: log 'raw' input.  Normally, IPython's logs contain the processed
           input, so that user lines are logged in their final form, converted
           into valid Python.  For example, %Exit is logged as
           '_ip.magic("Exit").  If the -r flag is given, all input is logged
           exactly as typed, with no transformations applied.
 
           -t: put timestamps before each input line logged (these are put in
           comments)."""
 
         opts,par = self.parse_options(parameter_s,'ort')
         log_output = 'o' in opts
         log_raw_input = 'r' in opts
         timestamp = 't' in opts
 
         logger = self.shell.logger
 
         # if no args are given, the defaults set in the logger constructor by
         # ipytohn remain valid
         if par:
             try:
                 logfname,logmode = par.split()
             except:
                 logfname = par
                 logmode = 'backup'
         else:
             logfname = logger.logfname
             logmode = logger.logmode
         # put logfname into rc struct as if it had been called on the command
         # line, so it ends up saved in the log header Save it in case we need
         # to restore it...
         old_logfile = self.shell.logfile
         if logfname:
             logfname = os.path.expanduser(logfname)
         self.shell.logfile = logfname
 
         loghead = '# IPython log file\n\n'
         try:
             started  = logger.logstart(logfname,loghead,logmode,
                                        log_output,timestamp,log_raw_input)
         except:
             self.shell.logfile = old_logfile
             warn("Couldn't start log: %s" % sys.exc_info()[1])
         else:
             # log input history up to this point, optionally interleaving
             # output if requested
 
             if timestamp:
                 # disable timestamping for the previous history, since we've
                 # lost those already (no time machine here).
                 logger.timestamp = False
 
             if log_raw_input:
                 input_hist = self.shell.history_manager.input_hist_raw
             else:
                 input_hist = self.shell.history_manager.input_hist_parsed
 
             if log_output:
                 log_write = logger.log_write
                 output_hist = self.shell.history_manager.output_hist
                 for n in range(1,len(input_hist)-1):
                     log_write(input_hist[n].rstrip() + '\n')
                     if n in output_hist:
                         log_write(repr(output_hist[n]),'output')
             else:
                 logger.log_write('\n'.join(input_hist[1:]))
                 logger.log_write('\n')
             if timestamp:
                 # re-enable timestamping
                 logger.timestamp = True
 
             print ('Activating auto-logging. '
                    'Current session state plus future input saved.')
             logger.logstate()
 
     def magic_logstop(self,parameter_s=''):
         """Fully stop logging and close log file.
 
         In order to start logging again, a new %logstart call needs to be made,
         possibly (though not necessarily) with a new filename, mode and other
         options."""
         self.logger.logstop()
 
     def magic_logoff(self,parameter_s=''):
         """Temporarily stop logging.
 
         You must have previously started logging."""
         self.shell.logger.switch_log(0)
 
     def magic_logon(self,parameter_s=''):
         """Restart logging.
 
         This function is for restarting logging which you've temporarily
         stopped with %logoff. For starting logging for the first time, you
         must use the %logstart function, which allows you to specify an
         optional log filename."""
 
         self.shell.logger.switch_log(1)
 
     def magic_logstate(self,parameter_s=''):
         """Print the status of the logging system."""
 
         self.shell.logger.logstate()
 
     def magic_pdb(self, parameter_s=''):
         """Control the automatic calling of the pdb interactive debugger.
 
         Call as '%pdb on', '%pdb 1', '%pdb off' or '%pdb 0'. If called without
         argument it works as a toggle.
 
         When an exception is triggered, IPython can optionally call the
         interactive pdb debugger after the traceback printout. %pdb toggles
         this feature on and off.
 
         The initial state of this feature is set in your configuration
         file (the option is ``InteractiveShell.pdb``).
 
         If you want to just activate the debugger AFTER an exception has fired,
         without having to type '%pdb on' and rerunning your code, you can use
         the %debug magic."""
 
         par = parameter_s.strip().lower()
 
         if par:
             try:
                 new_pdb = {'off':0,'0':0,'on':1,'1':1}[par]
             except KeyError:
                 print ('Incorrect argument. Use on/1, off/0, '
                        'or nothing for a toggle.')
                 return
         else:
             # toggle
             new_pdb = not self.shell.call_pdb
 
         # set on the shell
         self.shell.call_pdb = new_pdb
         print 'Automatic pdb calling has been turned',on_off(new_pdb)
 
     def magic_debug(self, parameter_s=''):
         """Activate the interactive debugger in post-mortem mode.
 
         If an exception has just occurred, this lets you inspect its stack
         frames interactively.  Note that this will always work only on the last
         traceback that occurred, so you must call this quickly after an
         exception that you wish to inspect has fired, because if another one
         occurs, it clobbers the previous one.
 
         If you want IPython to automatically do this on every exception, see
         the %pdb magic for more details.
         """
         self.shell.debugger(force=True)
 
     @skip_doctest
     def magic_prun(self, parameter_s ='',user_mode=1,
                    opts=None,arg_lst=None,prog_ns=None):
 
         """Run a statement through the python code profiler.
 
         Usage:
           %prun [options] statement
 
         The given statement (which doesn't require quote marks) is run via the
         python profiler in a manner similar to the profile.run() function.
         Namespaces are internally managed to work correctly; profile.run
         cannot be used in IPython because it makes certain assumptions about
         namespaces which do not hold under IPython.
 
         Options:
 
         -l <limit>: you can place restrictions on what or how much of the
         profile gets printed. The limit value can be:
 
           * A string: only information for function names containing this string
           is printed.
 
           * An integer: only these many lines are printed.
 
           * A float (between 0 and 1): this fraction of the report is printed
           (for example, use a limit of 0.4 to see the topmost 40% only).
 
         You can combine several limits with repeated use of the option. For
         example, '-l __init__ -l 5' will print only the topmost 5 lines of
         information about class constructors.
 
         -r: return the pstats.Stats object generated by the profiling. This
         object has all the information about the profile in it, and you can
         later use it for further analysis or in other functions.
 
        -s <key>: sort profile by given key. You can provide more than one key
         by using the option several times: '-s key1 -s key2 -s key3...'. The
         default sorting key is 'time'.
 
         The following is copied verbatim from the profile documentation
         referenced below:
 
         When more than one key is provided, additional keys are used as
         secondary criteria when the there is equality in all keys selected
         before them.
 
         Abbreviations can be used for any key names, as long as the
         abbreviation is unambiguous.  The following are the keys currently
         defined:
 
                 Valid Arg       Meaning
                   "calls"      call count
                   "cumulative" cumulative time
                   "file"       file name
                   "module"     file name
                   "pcalls"     primitive call count
                   "line"       line number
                   "name"       function name
                   "nfl"        name/file/line
                   "stdname"    standard name
                   "time"       internal time
 
         Note that all sorts on statistics are in descending order (placing
         most time consuming items first), where as name, file, and line number
         searches are in ascending order (i.e., alphabetical). The subtle
         distinction between "nfl" and "stdname" is that the standard name is a
         sort of the name as printed, which means that the embedded line
         numbers get compared in an odd way.  For example, lines 3, 20, and 40
         would (if the file names were the same) appear in the string order
         "20" "3" and "40".  In contrast, "nfl" does a numeric compare of the
         line numbers.  In fact, sort_stats("nfl") is the same as
         sort_stats("name", "file", "line").
 
         -T <filename>: save profile results as shown on screen to a text
         file. The profile is still shown on screen.
 
         -D <filename>: save (via dump_stats) profile statistics to given
         filename. This data is in a format understod by the pstats module, and
         is generated by a call to the dump_stats() method of profile
         objects. The profile is still shown on screen.
 
         If you want to run complete programs under the profiler's control, use
         '%run -p [prof_opts] filename.py [args to program]' where prof_opts
         contains profiler specific options as described here.
 
         You can read the complete documentation for the profile module with::
 
           In [1]: import profile; profile.help()
         """
 
         opts_def = Struct(D=[''],l=[],s=['time'],T=[''])
         # protect user quote marks
         parameter_s = parameter_s.replace('"',r'\"').replace("'",r"\'")
 
         if user_mode:  # regular user call
             opts,arg_str = self.parse_options(parameter_s,'D:l:rs:T:',
                                               list_all=1)
             namespace = self.shell.user_ns
         else:  # called to run a program by %run -p
             try:
                 filename = get_py_filename(arg_lst[0])
             except IOError as e:
                 try:
                     msg = str(e)
                 except UnicodeError:
                     msg = e.message
                 error(msg)
                 return
 
             arg_str = 'execfile(filename,prog_ns)'
             namespace = {
                 'execfile': self.shell.safe_execfile,
                 'prog_ns': prog_ns,
                 'filename': filename
                 }
 
         opts.merge(opts_def)
 
         prof = profile.Profile()
         try:
             prof = prof.runctx(arg_str,namespace,namespace)
             sys_exit = ''
         except SystemExit:
             sys_exit = """*** SystemExit exception caught in code being profiled."""
 
         stats = pstats.Stats(prof).strip_dirs().sort_stats(*opts.s)
 
         lims = opts.l
         if lims:
             lims = []  # rebuild lims with ints/floats/strings
             for lim in opts.l:
                 try:
                     lims.append(int(lim))
                 except ValueError:
                     try:
                         lims.append(float(lim))
                     except ValueError:
                         lims.append(lim)
 
         # Trap output.
         stdout_trap = StringIO()
 
         if hasattr(stats,'stream'):
             # In newer versions of python, the stats object has a 'stream'
             # attribute to write into.
             stats.stream = stdout_trap
             stats.print_stats(*lims)
         else:
             # For older versions, we manually redirect stdout during printing
             sys_stdout = sys.stdout
             try:
                 sys.stdout = stdout_trap
                 stats.print_stats(*lims)
             finally:
                 sys.stdout = sys_stdout
 
         output = stdout_trap.getvalue()
         output = output.rstrip()
 
         page.page(output)
         print sys_exit,
 
         dump_file = opts.D[0]
         text_file = opts.T[0]
         if dump_file:
             dump_file = unquote_filename(dump_file)
             prof.dump_stats(dump_file)
             print '\n*** Profile stats marshalled to file',\
                   `dump_file`+'.',sys_exit
         if text_file:
             text_file = unquote_filename(text_file)
             pfile = file(text_file,'w')
             pfile.write(output)
             pfile.close()
             print '\n*** Profile printout saved to text file',\
                   `text_file`+'.',sys_exit
 
         if opts.has_key('r'):
             return stats
         else:
             return None
 
     @skip_doctest
     def magic_run(self, parameter_s ='', runner=None,
                   file_finder=get_py_filename):
         """Run the named file inside IPython as a program.
 
         Usage:\\
           %run [-n -i -t [-N<N>] -d [-b<N>] -p [profile options]] file [args]
 
         Parameters after the filename are passed as command-line arguments to
         the program (put in sys.argv). Then, control returns to IPython's
         prompt.
 
         This is similar to running at a system prompt:\\
           $ python file args\\
         but with the advantage of giving you IPython's tracebacks, and of
         loading all variables into your interactive namespace for further use
         (unless -p is used, see below).
 
         The file is executed in a namespace initially consisting only of
         __name__=='__main__' and sys.argv constructed as indicated. It thus
         sees its environment as if it were being run as a stand-alone program
         (except for sharing global objects such as previously imported
         modules). But after execution, the IPython interactive namespace gets
         updated with all variables defined in the program (except for __name__
         and sys.argv). This allows for very convenient loading of code for
         interactive work, while giving each program a 'clean sheet' to run in.
 
         Options:
 
         -n: __name__ is NOT set to '__main__', but to the running file's name
         without extension (as python does under import).  This allows running
         scripts and reloading the definitions in them without calling code
         protected by an ' if __name__ == "__main__" ' clause.
 
         -i: run the file in IPython's namespace instead of an empty one. This
         is useful if you are experimenting with code written in a text editor
         which depends on variables defined interactively.
 
         -e: ignore sys.exit() calls or SystemExit exceptions in the script
         being run.  This is particularly useful if IPython is being used to
         run unittests, which always exit with a sys.exit() call.  In such
         cases you are interested in the output of the test results, not in
         seeing a traceback of the unittest module.
 
         -t: print timing information at the end of the run.  IPython will give
         you an estimated CPU time consumption for your script, which under
         Unix uses the resource module to avoid the wraparound problems of
         time.clock().  Under Unix, an estimate of time spent on system tasks
         is also given (for Windows platforms this is reported as 0.0).
 
         If -t is given, an additional -N<N> option can be given, where <N>
         must be an integer indicating how many times you want the script to
         run.  The final timing report will include total and per run results.
 
         For example (testing the script uniq_stable.py):
 
             In [1]: run -t uniq_stable
 
             IPython CPU timings (estimated):\\
               User  :    0.19597 s.\\
               System:        0.0 s.\\
 
             In [2]: run -t -N5 uniq_stable
 
             IPython CPU timings (estimated):\\
             Total runs performed: 5\\
               Times :      Total       Per run\\
               User  :   0.910862 s,  0.1821724 s.\\
               System:        0.0 s,        0.0 s.
 
         -d: run your program under the control of pdb, the Python debugger.
         This allows you to execute your program step by step, watch variables,
         etc.  Internally, what IPython does is similar to calling:
 
           pdb.run('execfile("YOURFILENAME")')
 
         with a breakpoint set on line 1 of your file.  You can change the line
         number for this automatic breakpoint to be <N> by using the -bN option
         (where N must be an integer).  For example:
 
           %run -d -b40 myscript
 
         will set the first breakpoint at line 40 in myscript.py.  Note that
         the first breakpoint must be set on a line which actually does
         something (not a comment or docstring) for it to stop execution.
 
         When the pdb debugger starts, you will see a (Pdb) prompt.  You must
         first enter 'c' (without qoutes) to start execution up to the first
         breakpoint.
 
         Entering 'help' gives information about the use of the debugger.  You
         can easily see pdb's full documentation with "import pdb;pdb.help()"
         at a prompt.
 
         -p: run program under the control of the Python profiler module (which
         prints a detailed report of execution times, function calls, etc).
 
         You can pass other options after -p which affect the behavior of the
         profiler itself. See the docs for %prun for details.
 
         In this mode, the program's variables do NOT propagate back to the
         IPython interactive namespace (because they remain in the namespace
         where the profiler executes them).
 
         Internally this triggers a call to %prun, see its documentation for
         details on the options available specifically for profiling.
 
         There is one special usage for which the text above doesn't apply:
         if the filename ends with .ipy, the file is run as ipython script,
         just as if the commands were written on IPython prompt.
 
         -m: specify module name to load instead of script path. Similar to
         the -m option for the python interpreter. Use this option last if you
         want to combine with other %run options. Unlike the python interpreter
         only source modules are allowed no .pyc or .pyo files.
         For example:
 
             %run -m example
 
         will run the example module.
 
         """
 
         # get arguments and set sys.argv for program to be run.
         opts, arg_lst = self.parse_options(parameter_s, 'nidtN:b:pD:l:rs:T:em:',
                                            mode='list', list_all=1)
         if "m" in opts:
             modulename = opts["m"][0]
             modpath = find_mod(modulename)
             if modpath is None:
                 warn('%r is not a valid modulename on sys.path'%modulename)
                 return
             arg_lst = [modpath] + arg_lst
         try:
             filename = file_finder(arg_lst[0])
         except IndexError:
             warn('you must provide at least a filename.')
             print '\n%run:\n', oinspect.getdoc(self.magic_run)
             return
         except IOError as e:
             try:
                 msg = str(e)
             except UnicodeError:
                 msg = e.message
             error(msg)
             return
 
         if filename.lower().endswith('.ipy'):
             self.shell.safe_execfile_ipy(filename)
             return
 
         # Control the response to exit() calls made by the script being run
         exit_ignore = 'e' in opts
 
         # Make sure that the running script gets a proper sys.argv as if it
         # were run from a system shell.
         save_argv = sys.argv # save it for later restoring
 
         # simulate shell expansion on arguments, at least tilde expansion
         args = [ os.path.expanduser(a) for a in arg_lst[1:] ]
 
         sys.argv = [filename] + args  # put in the proper filename
         # protect sys.argv from potential unicode strings on Python 2:
         if not py3compat.PY3:
             sys.argv = [ py3compat.cast_bytes(a) for a in sys.argv ]
 
         if 'i' in opts:
             # Run in user's interactive namespace
             prog_ns = self.shell.user_ns
             __name__save = self.shell.user_ns['__name__']
             prog_ns['__name__'] = '__main__'
             main_mod = self.shell.new_main_mod(prog_ns)
         else:
             # Run in a fresh, empty namespace
             if 'n' in opts:
                 name = os.path.splitext(os.path.basename(filename))[0]
             else:
                 name = '__main__'
 
             main_mod = self.shell.new_main_mod()
             prog_ns = main_mod.__dict__
             prog_ns['__name__'] = name
 
         # Since '%run foo' emulates 'python foo.py' at the cmd line, we must
         # set the __file__ global in the script's namespace
         prog_ns['__file__'] = filename
 
         # pickle fix.  See interactiveshell for an explanation.  But we need to make sure
         # that, if we overwrite __main__, we replace it at the end
         main_mod_name = prog_ns['__name__']
 
         if main_mod_name == '__main__':
             restore_main = sys.modules['__main__']
         else:
             restore_main = False
 
         # This needs to be undone at the end to prevent holding references to
         # every single object ever created.
         sys.modules[main_mod_name] = main_mod
 
         try:
             stats = None
             with self.readline_no_record:
                 if 'p' in opts:
                     stats = self.magic_prun('', 0, opts, arg_lst, prog_ns)
                 else:
                     if 'd' in opts:
                         deb = debugger.Pdb(self.shell.colors)
                         # reset Breakpoint state, which is moronically kept
                         # in a class
                         bdb.Breakpoint.next = 1
                         bdb.Breakpoint.bplist = {}
                         bdb.Breakpoint.bpbynumber = [None]
                         # Set an initial breakpoint to stop execution
                         maxtries = 10
                         bp = int(opts.get('b', [1])[0])
                         checkline = deb.checkline(filename, bp)
                         if not checkline:
                             for bp in range(bp + 1, bp + maxtries + 1):
                                 if deb.checkline(filename, bp):
                                     break
                             else:
                                 msg = ("\nI failed to find a valid line to set "
                                        "a breakpoint\n"
                                        "after trying up to line: %s.\n"
                                        "Please set a valid breakpoint manually "
                                        "with the -b option." % bp)
                                 error(msg)
                                 return
                         # if we find a good linenumber, set the breakpoint
                         deb.do_break('%s:%s' % (filename, bp))
                         # Start file run
                         print "NOTE: Enter 'c' at the",
                         print "%s prompt to start your script." % deb.prompt
                         try:
                             deb.run('execfile("%s")' % filename, prog_ns)
 
                         except:
                             etype, value, tb = sys.exc_info()
                             # Skip three frames in the traceback: the %run one,
                             # one inside bdb.py, and the command-line typed by the
                             # user (run by exec in pdb itself).
                             self.shell.InteractiveTB(etype, value, tb, tb_offset=3)
                     else:
                         if runner is None:
                             runner = self.shell.safe_execfile
                         if 't' in opts:
                             # timed execution
                             try:
                                 nruns = int(opts['N'][0])
                                 if nruns < 1:
                                     error('Number of runs must be >=1')
                                     return
                             except (KeyError):
                                 nruns = 1
                             twall0 = time.time()
                             if nruns == 1:
                                 t0 = clock2()
                                 runner(filename, prog_ns, prog_ns,
                                        exit_ignore=exit_ignore)
                                 t1 = clock2()
                                 t_usr = t1[0] - t0[0]
                                 t_sys = t1[1] - t0[1]
                                 print "\nIPython CPU timings (estimated):"
                                 print "  User   : %10.2f s." % t_usr
                                 print "  System : %10.2f s." % t_sys
                             else:
                                 runs = range(nruns)
                                 t0 = clock2()
                                 for nr in runs:
                                     runner(filename, prog_ns, prog_ns,
                                            exit_ignore=exit_ignore)
                                 t1 = clock2()
                                 t_usr = t1[0] - t0[0]
                                 t_sys = t1[1] - t0[1]
                                 print "\nIPython CPU timings (estimated):"
                                 print "Total runs performed:", nruns
                                 print "  Times  : %10.2f    %10.2f" % ('Total', 'Per run')
                                 print "  User   : %10.2f s, %10.2f s." % (t_usr, t_usr / nruns)
                                 print "  System : %10.2f s, %10.2f s." % (t_sys, t_sys / nruns)
                             twall1 = time.time()
                             print "Wall time: %10.2f s." % (twall1 - twall0)
 
                         else:
                             # regular execution
                             runner(filename, prog_ns, prog_ns, exit_ignore=exit_ignore)
 
                 if 'i' in opts:
                     self.shell.user_ns['__name__'] = __name__save
                 else:
                     # The shell MUST hold a reference to prog_ns so after %run
                     # exits, the python deletion mechanism doesn't zero it out
                     # (leaving dangling references).
                     self.shell.cache_main_mod(prog_ns, filename)
                     # update IPython interactive namespace
 
                     # Some forms of read errors on the file may mean the
                     # __name__ key was never set; using pop we don't have to
                     # worry about a possible KeyError.
                     prog_ns.pop('__name__', None)
 
                     self.shell.user_ns.update(prog_ns)
         finally:
             # It's a bit of a mystery why, but __builtins__ can change from
             # being a module to becoming a dict missing some key data after
             # %run.  As best I can see, this is NOT something IPython is doing
             # at all, and similar problems have been reported before:
             # http://coding.derkeiler.com/Archive/Python/comp.lang.python/2004-10/0188.html
             # Since this seems to be done by the interpreter itself, the best
             # we can do is to at least restore __builtins__ for the user on
             # exit.
             self.shell.user_ns['__builtins__'] = builtin_mod
 
             # Ensure key global structures are restored
             sys.argv = save_argv
             if restore_main:
                 sys.modules['__main__'] = restore_main
             else:
                 # Remove from sys.modules the reference to main_mod we'd
                 # added.  Otherwise it will trap references to objects
                 # contained therein.
                 del sys.modules[main_mod_name]
 
         return stats
 
     @skip_doctest
     def magic_timeit(self, parameter_s =''):
         """Time execution of a Python statement or expression
 
         Usage:\\
           %timeit [-n<N> -r<R> [-t|-c]] statement
 
         Time execution of a Python statement or expression using the timeit
         module.
 
         Options:
         -n<N>: execute the given statement <N> times in a loop. If this value
         is not given, a fitting value is chosen.
 
         -r<R>: repeat the loop iteration <R> times and take the best result.
         Default: 3
 
         -t: use time.time to measure the time, which is the default on Unix.
         This function measures wall time.
 
         -c: use time.clock to measure the time, which is the default on
         Windows and measures wall time. On Unix, resource.getrusage is used
         instead and returns the CPU user time.
 
         -p<P>: use a precision of <P> digits to display the timing result.
         Default: 3
 
 
         Examples:
 
           In [1]: %timeit pass
           10000000 loops, best of 3: 53.3 ns per loop
 
           In [2]: u = None
 
           In [3]: %timeit u is None
           10000000 loops, best of 3: 184 ns per loop
 
           In [4]: %timeit -r 4 u == None
           1000000 loops, best of 4: 242 ns per loop
 
           In [5]: import time
 
           In [6]: %timeit -n1 time.sleep(2)
           1 loops, best of 3: 2 s per loop
 
 
         The times reported by %timeit will be slightly higher than those
         reported by the timeit.py script when variables are accessed. This is
         due to the fact that %timeit executes the statement in the namespace
         of the shell, compared with timeit.py, which uses a single setup
         statement to import function or create variables. Generally, the bias
         does not matter as long as results from timeit.py are not mixed with
         those from %timeit."""
 
         import timeit
         import math
 
         # XXX: Unfortunately the unicode 'micro' symbol can cause problems in
         # certain terminals.  Until we figure out a robust way of
         # auto-detecting if the terminal can deal with it, use plain 'us' for
         # microseconds.  I am really NOT happy about disabling the proper
         # 'micro' prefix, but crashing is worse... If anyone knows what the
         # right solution for this is, I'm all ears...
         #
         # Note: using
         #
         # s = u'\xb5'
         # s.encode(sys.getdefaultencoding())
         #
         # is not sufficient, as I've seen terminals where that fails but
         # print s
         #
         # succeeds
         #
         # See bug: https://bugs.launchpad.net/ipython/+bug/348466
 
         #units = [u"s", u"ms",u'\xb5',"ns"]
         units = [u"s", u"ms",u'us',"ns"]
 
         scaling = [1, 1e3, 1e6, 1e9]
 
         opts, stmt = self.parse_options(parameter_s,'n:r:tcp:',
                                         posix=False)
         if stmt == "":
             return
         timefunc = timeit.default_timer
         number = int(getattr(opts, "n", 0))
         repeat = int(getattr(opts, "r", timeit.default_repeat))
         precision = int(getattr(opts, "p", 3))
         if hasattr(opts, "t"):
             timefunc = time.time
         if hasattr(opts, "c"):
             timefunc = clock
 
         timer = timeit.Timer(timer=timefunc)
         # this code has tight coupling to the inner workings of timeit.Timer,
         # but is there a better way to achieve that the code stmt has access
         # to the shell namespace?
 
         src = timeit.template % {'stmt': timeit.reindent(stmt, 8),
                                  'setup': "pass"}
         # Track compilation time so it can be reported if too long
         # Minimum time above which compilation time will be reported
         tc_min = 0.1
 
         t0 = clock()
         code = compile(src, "<magic-timeit>", "exec")
         tc = clock()-t0
 
         ns = {}
         exec code in self.shell.user_ns, ns
         timer.inner = ns["inner"]
 
         if number == 0:
             # determine number so that 0.2 <= total time < 2.0
             number = 1
             for i in range(1, 10):
                 if timer.timeit(number) >= 0.2:
                     break
                 number *= 10
 
         best = min(timer.repeat(repeat, number)) / number
 
         if best > 0.0 and best < 1000.0:
             order = min(-int(math.floor(math.log10(best)) // 3), 3)
         elif best >= 1000.0:
             order = 0
         else:
             order = 3
         print u"%d loops, best of %d: %.*g %s per loop" % (number, repeat,
                                                           precision,
                                                           best * scaling[order],
                                                           units[order])
         if tc > tc_min:
             print "Compiler time: %.2f s" % tc
 
     @skip_doctest
     @needs_local_scope
     def magic_time(self,parameter_s = ''):
         """Time execution of a Python statement or expression.
 
         The CPU and wall clock times are printed, and the value of the
         expression (if any) is returned.  Note that under Win32, system time
         is always reported as 0, since it can not be measured.
 
         This function provides very basic timing functionality.  In Python
         2.3, the timeit module offers more control and sophistication, so this
         could be rewritten to use it (patches welcome).
 
         Some examples:
 
           In [1]: time 2**128
           CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
           Wall time: 0.00
           Out[1]: 340282366920938463463374607431768211456L
 
           In [2]: n = 1000000
 
           In [3]: time sum(range(n))
           CPU times: user 1.20 s, sys: 0.05 s, total: 1.25 s
           Wall time: 1.37
           Out[3]: 499999500000L
 
           In [4]: time print 'hello world'
           hello world
           CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
           Wall time: 0.00
 
           Note that the time needed by Python to compile the given expression
           will be reported if it is more than 0.1s.  In this example, the
           actual exponentiation is done by Python at compilation time, so while
           the expression can take a noticeable amount of time to compute, that
           time is purely due to the compilation:
 
           In [5]: time 3**9999;
           CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
           Wall time: 0.00 s
 
           In [6]: time 3**999999;
           CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
           Wall time: 0.00 s
           Compiler : 0.78 s
           """
 
         # fail immediately if the given expression can't be compiled
 
         expr = self.shell.prefilter(parameter_s,False)
 
         # Minimum time above which compilation time will be reported
         tc_min = 0.1
 
         try:
             mode = 'eval'
             t0 = clock()
             code = compile(expr,'<timed eval>',mode)
             tc = clock()-t0
         except SyntaxError:
             mode = 'exec'
             t0 = clock()
             code = compile(expr,'<timed exec>',mode)
             tc = clock()-t0
         # skew measurement as little as possible
         glob = self.shell.user_ns
         locs = self._magic_locals
         clk = clock2
         wtime = time.time
         # time execution
         wall_st = wtime()
         if mode=='eval':
             st = clk()
             out = eval(code, glob, locs)
             end = clk()
         else:
             st = clk()
             exec code in glob, locs
             end = clk()
             out = None
         wall_end = wtime()
         # Compute actual times and report
         wall_time = wall_end-wall_st
         cpu_user = end[0]-st[0]
         cpu_sys = end[1]-st[1]
         cpu_tot = cpu_user+cpu_sys
         print "CPU times: user %.2f s, sys: %.2f s, total: %.2f s" % \
               (cpu_user,cpu_sys,cpu_tot)
         print "Wall time: %.2f s" % wall_time
         if tc > tc_min:
             print "Compiler : %.2f s" % tc
         return out
 
     @skip_doctest
     def magic_macro(self,parameter_s = ''):
         """Define a macro for future re-execution. It accepts ranges of history,
         filenames or string objects.
 
         Usage:\\
           %macro [options] name n1-n2 n3-n4 ... n5 .. n6 ...
 
         Options:
 
           -r: use 'raw' input.  By default, the 'processed' history is used,
           so that magics are loaded in their transformed version to valid
           Python.  If this option is given, the raw input as typed as the
           command line is used instead.
 
         This will define a global variable called `name` which is a string
         made of joining the slices and lines you specify (n1,n2,... numbers
         above) from your input history into a single string. This variable
         acts like an automatic function which re-executes those lines as if
         you had typed them. You just type 'name' at the prompt and the code
         executes.
 
         The syntax for indicating input ranges is described in %history.
 
         Note: as a 'hidden' feature, you can also use traditional python slice
         notation, where N:M means numbers N through M-1.
 
         For example, if your history contains (%hist prints it):
 
           44: x=1
           45: y=3
           46: z=x+y
           47: print x
           48: a=5
           49: print 'x',x,'y',y
 
         you can create a macro with lines 44 through 47 (included) and line 49
         called my_macro with:
 
           In [55]: %macro my_macro 44-47 49
 
         Now, typing `my_macro` (without quotes) will re-execute all this code
         in one pass.
 
         You don't need to give the line-numbers in order, and any given line
         number can appear multiple times. You can assemble macros with any
         lines from your input history in any order.
 
         The macro is a simple object which holds its value in an attribute,
         but IPython's display system checks for macros and executes them as
         code instead of printing them when you type their name.
 
         You can view a macro's contents by explicitly printing it with:
 
           'print macro_name'.
 
         """
         opts,args = self.parse_options(parameter_s,'r',mode='list')
         if not args:   # List existing macros
             return sorted(k for k,v in self.shell.user_ns.iteritems() if\
                                                         isinstance(v, Macro))
         if len(args) == 1:
             raise UsageError(
                 "%macro insufficient args; usage '%macro name n1-n2 n3-4...")
         name, codefrom = args[0], " ".join(args[1:])
 
         #print 'rng',ranges  # dbg
         try:
             lines = self.shell.find_user_code(codefrom, 'r' in opts)
         except (ValueError, TypeError) as e:
             print e.args[0]
             return
         macro = Macro(lines)
         self.shell.define_macro(name, macro)
         print 'Macro `%s` created. To execute, type its name (without quotes).' % name
         print '=== Macro contents: ==='
         print macro,
 
     def magic_save(self,parameter_s = ''):
         """Save a set of lines or a macro to a given filename.
 
         Usage:\\
           %save [options] filename n1-n2 n3-n4 ... n5 .. n6 ...
 
         Options:
 
           -r: use 'raw' input.  By default, the 'processed' history is used,
           so that magics are loaded in their transformed version to valid
           Python.  If this option is given, the raw input as typed as the
           command line is used instead.
 
         This function uses the same syntax as %history for input ranges,
         then saves the lines to the filename you specify.
 
         It adds a '.py' extension to the file if you don't do so yourself, and
         it asks for confirmation before overwriting existing files."""
 
         opts,args = self.parse_options(parameter_s,'r',mode='list')
         fname, codefrom = unquote_filename(args[0]), " ".join(args[1:])
         if not fname.endswith('.py'):
             fname += '.py'
         if os.path.isfile(fname):
             ans = raw_input('File `%s` exists. Overwrite (y/[N])? ' % fname)
             if ans.lower() not in ['y','yes']:
                 print 'Operation cancelled.'
                 return
         try:
             cmds = self.shell.find_user_code(codefrom, 'r' in opts)
         except (TypeError, ValueError) as e:
             print e.args[0]
             return
         with py3compat.open(fname,'w', encoding="utf-8") as f:
             f.write(u"# coding: utf-8\n")
             f.write(py3compat.cast_unicode(cmds))
         print 'The following commands were written to file `%s`:' % fname
         print cmds
 
     def magic_pastebin(self, parameter_s = ''):
         """Upload code to the 'Lodge it' paste bin, returning the URL."""
         try:
             code = self.shell.find_user_code(parameter_s)
         except (ValueError, TypeError) as e:
             print e.args[0]
             return
         pbserver = ServerProxy('http://paste.pocoo.org/xmlrpc/')
         id = pbserver.pastes.newPaste("python", code)
         return "http://paste.pocoo.org/show/" + id
 
     def magic_loadpy(self, arg_s):
         """Load a .py python script into the GUI console.
 
         This magic command can either take a local filename or a url::
 
         %loadpy myscript.py
         %loadpy http://www.example.com/myscript.py
         """
         arg_s = unquote_filename(arg_s)
         if not arg_s.endswith('.py'):
             raise ValueError('%%load only works with .py files: %s' % arg_s)
         if arg_s.startswith('http'):
             import urllib2
             response = urllib2.urlopen(arg_s)
             content = response.read()
         else:
             with open(arg_s) as f:
                 content = f.read()
         self.set_next_input(content)
 
     def _find_edit_target(self, args, opts, last_call):
         """Utility method used by magic_edit to find what to edit."""
 
         def make_filename(arg):
             "Make a filename from the given args"
             arg = unquote_filename(arg)
             try:
                 filename = get_py_filename(arg)
             except IOError:
                 # If it ends with .py but doesn't already exist, assume we want
                 # a new file.
                 if arg.endswith('.py'):
                     filename = arg
                 else:
                     filename = None
             return filename
 
         # Set a few locals from the options for convenience:
         opts_prev = 'p' in opts
         opts_raw = 'r' in opts
 
         # custom exceptions
         class DataIsObject(Exception): pass
 
         # Default line number value
         lineno = opts.get('n',None)
 
         if opts_prev:
             args = '_%s' % last_call[0]
             if not self.shell.user_ns.has_key(args):
                 args = last_call[1]
 
         # use last_call to remember the state of the previous call, but don't
         # let it be clobbered by successive '-p' calls.
         try:
             last_call[0] = self.shell.displayhook.prompt_count
             if not opts_prev:
                 last_call[1] = parameter_s
         except:
             pass
 
         # by default this is done with temp files, except when the given
         # arg is a filename
         use_temp = True
 
         data = ''
 
         # First, see if the arguments should be a filename.
         filename = make_filename(args)
         if filename:
             use_temp = False
         elif args:
             # Mode where user specifies ranges of lines, like in %macro.
             data = self.extract_input_lines(args, opts_raw)
             if not data:
                 try:
                     # Load the parameter given as a variable. If not a string,
                     # process it as an object instead (below)
 
                     #print '*** args',args,'type',type(args)  # dbg
                     data = eval(args, self.shell.user_ns)
                     if not isinstance(data, basestring):
                         raise DataIsObject
 
                 except (NameError,SyntaxError):
                     # given argument is not a variable, try as a filename
                     filename = make_filename(args)
                     if filename is None:
                         warn("Argument given (%s) can't be found as a variable "
                              "or as a filename." % args)
                         return
                     use_temp = False
 
                 except DataIsObject:
                     # macros have a special edit function
                     if isinstance(data, Macro):
                         raise MacroToEdit(data)
 
                     # For objects, try to edit the file where they are defined
                     try:
                         filename = inspect.getabsfile(data)
                         if 'fakemodule' in filename.lower() and inspect.isclass(data):
                             # class created by %edit? Try to find source
                             # by looking for method definitions instead, the
                             # __module__ in those classes is FakeModule.
                             attrs = [getattr(data, aname) for aname in dir(data)]
                             for attr in attrs:
                                 if not inspect.ismethod(attr):
                                     continue
                                 filename = inspect.getabsfile(attr)
                                 if filename and 'fakemodule' not in filename.lower():
                                     # change the attribute to be the edit target instead
                                     data = attr
                                     break
 
                         datafile = 1
                     except TypeError:
                         filename = make_filename(args)
                         datafile = 1
                         warn('Could not find file where `%s` is defined.\n'
                              'Opening a file named `%s`' % (args,filename))
                     # Now, make sure we can actually read the source (if it was in
                     # a temp file it's gone by now).
                     if datafile:
                         try:
                             if lineno is None:
                                 lineno = inspect.getsourcelines(data)[1]
                         except IOError:
                             filename = make_filename(args)
                             if filename is None:
                                 warn('The file `%s` where `%s` was defined cannot '
                                      'be read.' % (filename,data))
                                 return
                     use_temp = False
 
         if use_temp:
             filename = self.shell.mktempfile(data)
             print 'IPython will make a temporary file named:',filename
 
         return filename, lineno, use_temp
 
     def _edit_macro(self,mname,macro):
         """open an editor with the macro data in a file"""
         filename = self.shell.mktempfile(macro.value)
         self.shell.hooks.editor(filename)
 
         # and make a new macro object, to replace the old one
         mfile = open(filename)
         mvalue = mfile.read()
         mfile.close()
         self.shell.user_ns[mname] = Macro(mvalue)
 
     def magic_ed(self,parameter_s=''):
         """Alias to %edit."""
         return self.magic_edit(parameter_s)
 
     @skip_doctest
     def magic_edit(self,parameter_s='',last_call=['','']):
         """Bring up an editor and execute the resulting code.
 
         Usage:
           %edit [options] [args]
 
         %edit runs IPython's editor hook. The default version of this hook is
         set to call the editor specified by your $EDITOR environment variable.
         If this isn't found, it will default to vi under Linux/Unix and to
         notepad under Windows. See the end of this docstring for how to change
         the editor hook.
 
         You can also set the value of this editor via the
         ``TerminalInteractiveShell.editor`` option in your configuration file.
         This is useful if you wish to use a different editor from your typical
         default with IPython (and for Windows users who typically don't set
         environment variables).
 
         This command allows you to conveniently edit multi-line code right in
         your IPython session.
 
         If called without arguments, %edit opens up an empty editor with a
         temporary file and will execute the contents of this file when you
         close it (don't forget to save it!).
 
 
         Options:
 
         -n <number>: open the editor at a specified line number.  By default,
         the IPython editor hook uses the unix syntax 'editor +N filename', but
         you can configure this by providing your own modified hook if your
         favorite editor supports line-number specifications with a different
         syntax.
 
         -p: this will call the editor with the same data as the previous time
         it was used, regardless of how long ago (in your current session) it
         was.
 
         -r: use 'raw' input.  This option only applies to input taken from the
         user's history.  By default, the 'processed' history is used, so that
         magics are loaded in their transformed version to valid Python.  If
         this option is given, the raw input as typed as the command line is
         used instead.  When you exit the editor, it will be executed by
         IPython's own processor.
 
         -x: do not execute the edited code immediately upon exit. This is
         mainly useful if you are editing programs which need to be called with
         command line arguments, which you can then do using %run.
 
 
         Arguments:
 
         If arguments are given, the following possibilites exist:
 
         - If the argument is a filename, IPython will load that into the
           editor. It will execute its contents with execfile() when you exit,
           loading any code in the file into your interactive namespace.
 
         - The arguments are ranges of input history,  e.g. "7 ~1/4-6".
           The syntax is the same as in the %history magic.
 
         - If the argument is a string variable, its contents are loaded
           into the editor. You can thus edit any string which contains
           python code (including the result of previous edits).
 
         - If the argument is the name of an object (other than a string),
           IPython will try to locate the file where it was defined and open the
           editor at the point where it is defined. You can use `%edit function`
           to load an editor exactly at the point where 'function' is defined,
           edit it and have the file be executed automatically.
 
         - If the object is a macro (see %macro for details), this opens up your
           specified editor with a temporary file containing the macro's data.
           Upon exit, the macro is reloaded with the contents of the file.
 
         Note: opening at an exact line is only supported under Unix, and some
         editors (like kedit and gedit up to Gnome 2.8) do not understand the
         '+NUMBER' parameter necessary for this feature. Good editors like
         (X)Emacs, vi, jed, pico and joe all do.
 
         After executing your code, %edit will return as output the code you
         typed in the editor (except when it was an existing file). This way
         you can reload the code in further invocations of %edit as a variable,
         via _<NUMBER> or Out[<NUMBER>], where <NUMBER> is the prompt number of
         the output.
 
         Note that %edit is also available through the alias %ed.
 
         This is an example of creating a simple function inside the editor and
         then modifying it. First, start up the editor:
 
         In [1]: ed
         Editing... done. Executing edited code...
         Out[1]: 'def foo():n    print "foo() was defined in an editing session"n'
 
         We can then call the function foo():
 
         In [2]: foo()
         foo() was defined in an editing session
 
         Now we edit foo.  IPython automatically loads the editor with the
         (temporary) file where foo() was previously defined:
 
         In [3]: ed foo
         Editing... done. Executing edited code...
 
         And if we call foo() again we get the modified version:
 
         In [4]: foo()
         foo() has now been changed!
 
         Here is an example of how to edit a code snippet successive
         times. First we call the editor:
 
         In [5]: ed
         Editing... done. Executing edited code...
         hello
         Out[5]: "print 'hello'n"
 
         Now we call it again with the previous output (stored in _):
 
         In [6]: ed _
         Editing... done. Executing edited code...
         hello world
         Out[6]: "print 'hello world'n"
 
         Now we call it with the output #8 (stored in _8, also as Out[8]):
 
         In [7]: ed _8
         Editing... done. Executing edited code...
         hello again
         Out[7]: "print 'hello again'n"
 
 
         Changing the default editor hook:
 
         If you wish to write your own editor hook, you can put it in a
         configuration file which you load at startup time.  The default hook
         is defined in the IPython.core.hooks module, and you can use that as a
         starting example for further modifications.  That file also has
         general instructions on how to set a new hook for use once you've
         defined it."""
         opts,args = self.parse_options(parameter_s,'prxn:')
 
         try:
             filename, lineno, is_temp = self._find_edit_target(args, opts, last_call)
         except MacroToEdit as e:
             self._edit_macro(args, e.args[0])
             return
 
         # do actual editing here
         print 'Editing...',
         sys.stdout.flush()
         try:
             # Quote filenames that may have spaces in them
             if ' ' in filename:
                 filename = "'%s'" % filename
             self.shell.hooks.editor(filename,lineno)
         except TryNext:
             warn('Could not open editor')
             return
 
         # XXX TODO: should this be generalized for all string vars?
         # For now, this is special-cased to blocks created by cpaste
         if args.strip() == 'pasted_block':
             self.shell.user_ns['pasted_block'] = file_read(filename)
 
         if 'x' in opts:  # -x prevents actual execution
             print
         else:
             print 'done. Executing edited code...'
             if 'r' in opts:    # Untranslated IPython code
                 self.shell.run_cell(file_read(filename),
                                                     store_history=False)
             else:
                 self.shell.safe_execfile(filename,self.shell.user_ns,
                                          self.shell.user_ns)
 
         if is_temp:
             try:
                 return open(filename).read()
             except IOError,msg:
                 if msg.filename == filename:
                     warn('File not found. Did you forget to save?')
                     return
                 else:
                     self.shell.showtraceback()
 
     def magic_xmode(self,parameter_s = ''):
         """Switch modes for the exception handlers.
 
         Valid modes: Plain, Context and Verbose.
 
         If called without arguments, acts as a toggle."""
 
         def xmode_switch_err(name):
             warn('Error changing %s exception modes.\n%s' %
                  (name,sys.exc_info()[1]))
 
         shell = self.shell
         new_mode = parameter_s.strip().capitalize()
         try:
             shell.InteractiveTB.set_mode(mode=new_mode)
             print 'Exception reporting mode:',shell.InteractiveTB.mode
         except:
             xmode_switch_err('user')
 
     def magic_colors(self,parameter_s = ''):
         """Switch color scheme for prompts, info system and exception handlers.
 
         Currently implemented schemes: NoColor, Linux, LightBG.
 
         Color scheme names are not case-sensitive.
 
         Examples
         --------
         To get a plain black and white terminal::
 
           %colors nocolor
         """
 
         def color_switch_err(name):
             warn('Error changing %s color schemes.\n%s' %
                  (name,sys.exc_info()[1]))
 
 
         new_scheme = parameter_s.strip()
         if not new_scheme:
             raise UsageError(
                 "%colors: you must specify a color scheme. See '%colors?'")
             return
         # local shortcut
         shell = self.shell
 
         import IPython.utils.rlineimpl as readline
 
         if not shell.colors_force and \
                 not readline.have_readline and sys.platform == "win32":
             msg = """\
 Proper color support under MS Windows requires the pyreadline library.
 You can find it at:
 http://ipython.org/pyreadline.html
 Gary's readline needs the ctypes module, from:
 http://starship.python.net/crew/theller/ctypes
 (Note that ctypes is already part of Python versions 2.5 and newer).
 
 Defaulting color scheme to 'NoColor'"""
             new_scheme = 'NoColor'
             warn(msg)
 
         # readline option is 0
         if not shell.colors_force and not shell.has_readline:
             new_scheme = 'NoColor'
 
         # Set prompt colors
         try:
             shell.displayhook.set_colors(new_scheme)
         except:
             color_switch_err('prompt')
         else:
             shell.colors = \
                        shell.displayhook.color_table.active_scheme_name
         # Set exception colors
         try:
             shell.InteractiveTB.set_colors(scheme = new_scheme)
             shell.SyntaxTB.set_colors(scheme = new_scheme)
         except:
             color_switch_err('exception')
 
         # Set info (for 'object?') colors
         if shell.color_info:
             try:
                 shell.inspector.set_active_scheme(new_scheme)
             except:
                 color_switch_err('object inspector')
         else:
             shell.inspector.set_active_scheme('NoColor')
 
     def magic_pprint(self, parameter_s=''):
         """Toggle pretty printing on/off."""
         ptformatter = self.shell.display_formatter.formatters['text/plain']
         ptformatter.pprint = bool(1 - ptformatter.pprint)
         print 'Pretty printing has been turned', \
               ['OFF','ON'][ptformatter.pprint]
 
     #......................................................................
     # Functions to implement unix shell-type things
 
     @skip_doctest
     def magic_alias(self, parameter_s = ''):
         """Define an alias for a system command.
 
         '%alias alias_name cmd' defines 'alias_name' as an alias for 'cmd'
 
         Then, typing 'alias_name params' will execute the system command 'cmd
         params' (from your underlying operating system).
 
         Aliases have lower precedence than magic functions and Python normal
         variables, so if 'foo' is both a Python variable and an alias, the
         alias can not be executed until 'del foo' removes the Python variable.
 
         You can use the %l specifier in an alias definition to represent the
         whole line when the alias is called.  For example:
 
           In [2]: alias bracket echo "Input in brackets: <%l>"
           In [3]: bracket hello world
           Input in brackets: <hello world>
 
         You can also define aliases with parameters using %s specifiers (one
         per parameter):
 
           In [1]: alias parts echo first %s second %s
           In [2]: %parts A B
           first A second B
           In [3]: %parts A
           Incorrect number of arguments: 2 expected.
           parts is an alias to: 'echo first %s second %s'
 
         Note that %l and %s are mutually exclusive.  You can only use one or
         the other in your aliases.
 
         Aliases expand Python variables just like system calls using ! or !!
         do: all expressions prefixed with '$' get expanded.  For details of
         the semantic rules, see PEP-215:
         http://www.python.org/peps/pep-0215.html.  This is the library used by
         IPython for variable expansion.  If you want to access a true shell
         variable, an extra $ is necessary to prevent its expansion by IPython:
 
         In [6]: alias show echo
         In [7]: PATH='A Python string'
         In [8]: show $PATH
         A Python string
         In [9]: show $$PATH
         /usr/local/lf9560/bin:/usr/local/intel/compiler70/ia32/bin:...
 
         You can use the alias facility to acess all of $PATH.  See the %rehash
         and %rehashx functions, which automatically create aliases for the
         contents of your $PATH.
 
         If called with no parameters, %alias prints the current alias table."""
 
         par = parameter_s.strip()
         if not par:
             stored = self.db.get('stored_aliases', {} )
             aliases = sorted(self.shell.alias_manager.aliases)
             # for k, v in stored:
             #     atab.append(k, v[0])
 
             print "Total number of aliases:", len(aliases)
             sys.stdout.flush()
             return aliases
 
         # Now try to define a new one
         try:
             alias,cmd = par.split(None, 1)
         except:
             print oinspect.getdoc(self.magic_alias)
         else:
             self.shell.alias_manager.soft_define_alias(alias, cmd)
     # end magic_alias
 
     def magic_unalias(self, parameter_s = ''):
         """Remove an alias"""
 
         aname = parameter_s.strip()
         self.shell.alias_manager.undefine_alias(aname)
         stored = self.db.get('stored_aliases', {} )
         if aname in stored:
             print "Removing %stored alias",aname
             del stored[aname]
             self.db['stored_aliases'] = stored
 
     def magic_rehashx(self, parameter_s = ''):
         """Update the alias table with all executable files in $PATH.
 
         This version explicitly checks that every entry in $PATH is a file
         with execute access (os.X_OK), so it is much slower than %rehash.
 
         Under Windows, it checks executability as a match agains a
         '|'-separated string of extensions, stored in the IPython config
         variable win_exec_ext.  This defaults to 'exe|com|bat'.
 
         This function also resets the root module cache of module completer,
         used on slow filesystems.
         """
         from IPython.core.alias import InvalidAliasError
 
         # for the benefit of module completer in ipy_completers.py
         del self.db['rootmodules']
 
         path = [os.path.abspath(os.path.expanduser(p)) for p in
             os.environ.get('PATH','').split(os.pathsep)]
         path = filter(os.path.isdir,path)
 
         syscmdlist = []
         # Now define isexec in a cross platform manner.
         if os.name == 'posix':
             isexec = lambda fname:os.path.isfile(fname) and \
                      os.access(fname,os.X_OK)
         else:
             try:
                 winext = os.environ['pathext'].replace(';','|').replace('.','')
             except KeyError:
                 winext = 'exe|com|bat|py'
             if 'py' not in winext:
                 winext += '|py'
             execre = re.compile(r'(.*)\.(%s)$' % winext,re.IGNORECASE)
             isexec = lambda fname:os.path.isfile(fname) and execre.match(fname)
         savedir = os.getcwdu()
 
         # Now walk the paths looking for executables to alias.
         try:
             # write the whole loop for posix/Windows so we don't have an if in
             # the innermost part
             if os.name == 'posix':
                 for pdir in path:
                     os.chdir(pdir)
                     for ff in os.listdir(pdir):
                         if isexec(ff):
                             try:
                                 # Removes dots from the name since ipython
                                 # will assume names with dots to be python.
                                 self.shell.alias_manager.define_alias(
                                     ff.replace('.',''), ff)
                             except InvalidAliasError:
                                 pass
                             else:
                                 syscmdlist.append(ff)
             else:
                 no_alias = self.shell.alias_manager.no_alias
                 for pdir in path:
                     os.chdir(pdir)
                     for ff in os.listdir(pdir):
                         base, ext = os.path.splitext(ff)
                         if isexec(ff) and base.lower() not in no_alias:
                             if ext.lower() == '.exe':
                                 ff = base
                                 try:
                                     # Removes dots from the name since ipython
                                     # will assume names with dots to be python.
                                     self.shell.alias_manager.define_alias(
                                         base.lower().replace('.',''), ff)
                                 except InvalidAliasError:
                                     pass
                                 syscmdlist.append(ff)
             db = self.db
             db['syscmdlist'] = syscmdlist
         finally:
             os.chdir(savedir)
 
     @skip_doctest
     def magic_pwd(self, parameter_s = ''):
         """Return the current working directory path.
 
         Examples
         --------
         ::
 
           In [9]: pwd
           Out[9]: '/home/tsuser/sprint/ipython'
         """
         return os.getcwdu()
 
     @skip_doctest
     def magic_cd(self, parameter_s=''):
         """Change the current working directory.
 
         This command automatically maintains an internal list of directories
         you visit during your IPython session, in the variable _dh. The
         command %dhist shows this history nicely formatted. You can also
         do 'cd -<tab>' to see directory history conveniently.
 
         Usage:
 
           cd 'dir': changes to directory 'dir'.
 
           cd -: changes to the last visited directory.
 
           cd -<n>: changes to the n-th directory in the directory history.
 
           cd --foo: change to directory that matches 'foo' in history
 
           cd -b <bookmark_name>: jump to a bookmark set by %bookmark
              (note: cd <bookmark_name> is enough if there is no
               directory <bookmark_name>, but a bookmark with the name exists.)
               'cd -b <tab>' allows you to tab-complete bookmark names.
 
         Options:
 
         -q: quiet.  Do not print the working directory after the cd command is
         executed.  By default IPython's cd command does print this directory,
         since the default prompts do not display path information.
 
         Note that !cd doesn't work for this purpose because the shell where
         !command runs is immediately discarded after executing 'command'.
 
         Examples
         --------
         ::
 
           In [10]: cd parent/child
           /home/tsuser/parent/child
         """
 
         parameter_s = parameter_s.strip()
         #bkms = self.shell.persist.get("bookmarks",{})
 
         oldcwd = os.getcwdu()
         numcd = re.match(r'(-)(\d+)$',parameter_s)
         # jump in directory history by number
         if numcd:
             nn = int(numcd.group(2))
             try:
                 ps = self.shell.user_ns['_dh'][nn]
             except IndexError:
                 print 'The requested directory does not exist in history.'
                 return
             else:
                 opts = {}
         elif parameter_s.startswith('--'):
             ps = None
             fallback = None
             pat = parameter_s[2:]
             dh = self.shell.user_ns['_dh']
             # first search only by basename (last component)
             for ent in reversed(dh):
                 if pat in os.path.basename(ent) and os.path.isdir(ent):
                     ps = ent
                     break
 
                 if fallback is None and pat in ent and os.path.isdir(ent):
                     fallback = ent
 
             # if we have no last part match, pick the first full path match
             if ps is None:
                 ps = fallback
 
             if ps is None:
                 print "No matching entry in directory history"
                 return
             else:
                 opts = {}
 
 
         else:
             #turn all non-space-escaping backslashes to slashes,
             # for c:\windows\directory\names\
             parameter_s = re.sub(r'\\(?! )','/', parameter_s)
             opts,ps = self.parse_options(parameter_s,'qb',mode='string')
         # jump to previous
         if ps == '-':
             try:
                 ps = self.shell.user_ns['_dh'][-2]
             except IndexError:
                 raise UsageError('%cd -: No previous directory to change to.')
         # jump to bookmark if needed
         else:
             if not os.path.isdir(ps) or opts.has_key('b'):
                 bkms = self.db.get('bookmarks', {})
 
                 if bkms.has_key(ps):
                     target = bkms[ps]
                     print '(bookmark:%s) -> %s' % (ps,target)
                     ps = target
                 else:
                     if opts.has_key('b'):
                         raise UsageError("Bookmark '%s' not found.  "
                               "Use '%%bookmark -l' to see your bookmarks." % ps)
 
         # strip extra quotes on Windows, because os.chdir doesn't like them
         ps = unquote_filename(ps)
         # at this point ps should point to the target dir
         if ps:
             try:
                 os.chdir(os.path.expanduser(ps))
                 if hasattr(self.shell, 'term_title') and self.shell.term_title:
                     set_term_title('IPython: ' + abbrev_cwd())
             except OSError:
                 print sys.exc_info()[1]
             else:
                 cwd = os.getcwdu()
                 dhist = self.shell.user_ns['_dh']
                 if oldcwd != cwd:
                     dhist.append(cwd)
                     self.db['dhist'] = compress_dhist(dhist)[-100:]
 
         else:
             os.chdir(self.shell.home_dir)
             if hasattr(self.shell, 'term_title') and self.shell.term_title:
                 set_term_title('IPython: ' + '~')
             cwd = os.getcwdu()
             dhist = self.shell.user_ns['_dh']
 
             if oldcwd != cwd:
                 dhist.append(cwd)
                 self.db['dhist'] = compress_dhist(dhist)[-100:]
         if not 'q' in opts and self.shell.user_ns['_dh']:
             print self.shell.user_ns['_dh'][-1]
 
 
     def magic_env(self, parameter_s=''):
         """List environment variables."""
 
         return os.environ.data
 
     def magic_pushd(self, parameter_s=''):
         """Place the current dir on stack and change directory.
 
         Usage:\\
           %pushd ['dirname']
         """
 
         dir_s = self.shell.dir_stack
         tgt = os.path.expanduser(unquote_filename(parameter_s))
         cwd = os.getcwdu().replace(self.home_dir,'~')
         if tgt:
             self.magic_cd(parameter_s)
         dir_s.insert(0,cwd)
         return self.magic_dirs()
 
     def magic_popd(self, parameter_s=''):
         """Change to directory popped off the top of the stack.
         """
         if not self.shell.dir_stack:
             raise UsageError("%popd on empty stack")
         top = self.shell.dir_stack.pop(0)
         self.magic_cd(top)
         print "popd ->",top
 
     def magic_dirs(self, parameter_s=''):
         """Return the current directory stack."""
 
         return self.shell.dir_stack
 
     def magic_dhist(self, parameter_s=''):
         """Print your history of visited directories.
 
         %dhist       -> print full history\\
         %dhist n     -> print last n entries only\\
         %dhist n1 n2 -> print entries between n1 and n2 (n1 not included)\\
 
         This history is automatically maintained by the %cd command, and
         always available as the global list variable _dh. You can use %cd -<n>
         to go to directory number <n>.
 
         Note that most of time, you should view directory history by entering
         cd -<TAB>.
 
         """
 
         dh = self.shell.user_ns['_dh']
         if parameter_s:
             try:
                 args = map(int,parameter_s.split())
             except:
                 self.arg_err(Magic.magic_dhist)
                 return
             if len(args) == 1:
                 ini,fin = max(len(dh)-(args[0]),0),len(dh)
             elif len(args) == 2:
                 ini,fin = args
             else:
                 self.arg_err(Magic.magic_dhist)
                 return
         else:
             ini,fin = 0,len(dh)
         nlprint(dh,
                 header = 'Directory history (kept in _dh)',
                 start=ini,stop=fin)
 
     @skip_doctest
     def magic_sc(self, parameter_s=''):
         """Shell capture - execute a shell command and capture its output.
 
         DEPRECATED. Suboptimal, retained for backwards compatibility.
 
         You should use the form 'var = !command' instead. Example:
 
          "%sc -l myfiles = ls ~" should now be written as
 
          "myfiles = !ls ~"
 
         myfiles.s, myfiles.l and myfiles.n still apply as documented
         below.
 
         --
         %sc [options] varname=command
 
         IPython will run the given command using commands.getoutput(), and
         will then update the user's interactive namespace with a variable
         called varname, containing the value of the call.  Your command can
         contain shell wildcards, pipes, etc.
 
         The '=' sign in the syntax is mandatory, and the variable name you
         supply must follow Python's standard conventions for valid names.
 
         (A special format without variable name exists for internal use)
 
         Options:
 
           -l: list output.  Split the output on newlines into a list before
           assigning it to the given variable.  By default the output is stored
           as a single string.
 
           -v: verbose.  Print the contents of the variable.
 
         In most cases you should not need to split as a list, because the
         returned value is a special type of string which can automatically
         provide its contents either as a list (split on newlines) or as a
         space-separated string.  These are convenient, respectively, either
         for sequential processing or to be passed to a shell command.
 
         For example:
 
         # all-random
 
             # Capture into variable a
             In [1]: sc a=ls *py
 
             # a is a string with embedded newlines
             In [2]: a
             Out[2]: 'setup.py\\nwin32_manual_post_install.py'
 
             # which can be seen as a list:
             In [3]: a.l
             Out[3]: ['setup.py', 'win32_manual_post_install.py']
 
             # or as a whitespace-separated string:
             In [4]: a.s
             Out[4]: 'setup.py win32_manual_post_install.py'
 
             # a.s is useful to pass as a single command line:
             In [5]: !wc -l $a.s
               146 setup.py
               130 win32_manual_post_install.py
               276 total
 
             # while the list form is useful to loop over:
             In [6]: for f in a.l:
               ...:      !wc -l $f
               ...:
             146 setup.py
             130 win32_manual_post_install.py
 
         Similiarly, the lists returned by the -l option are also special, in
         the sense that you can equally invoke the .s attribute on them to
         automatically get a whitespace-separated string from their contents:
 
             In [7]: sc -l b=ls *py
 
             In [8]: b
             Out[8]: ['setup.py', 'win32_manual_post_install.py']
 
             In [9]: b.s
             Out[9]: 'setup.py win32_manual_post_install.py'
 
         In summary, both the lists and strings used for ouptut capture have
         the following special attributes:
 
             .l (or .list) : value as list.
             .n (or .nlstr): value as newline-separated string.
             .s (or .spstr): value as space-separated string.
         """
 
         opts,args = self.parse_options(parameter_s,'lv')
         # Try to get a variable name and command to run
         try:
             # the variable name must be obtained from the parse_options
             # output, which uses shlex.split to strip options out.
             var,_ = args.split('=',1)
             var = var.strip()
             # But the the command has to be extracted from the original input
             # parameter_s, not on what parse_options returns, to avoid the
             # quote stripping which shlex.split performs on it.
             _,cmd = parameter_s.split('=',1)
         except ValueError:
             var,cmd = '',''
         # If all looks ok, proceed
         split = 'l' in opts
         out = self.shell.getoutput(cmd, split=split)
         if opts.has_key('v'):
             print '%s ==\n%s' % (var,pformat(out))
         if var:
             self.shell.user_ns.update({var:out})
         else:
             return out
 
     def magic_sx(self, parameter_s=''):
         """Shell execute - run a shell command and capture its output.
 
         %sx command
 
         IPython will run the given command using commands.getoutput(), and
         return the result formatted as a list (split on '\\n').  Since the
         output is _returned_, it will be stored in ipython's regular output
         cache Out[N] and in the '_N' automatic variables.
 
         Notes:
 
         1) If an input line begins with '!!', then %sx is automatically
         invoked.  That is, while:
           !ls
         causes ipython to simply issue system('ls'), typing
           !!ls
         is a shorthand equivalent to:
           %sx ls
 
         2) %sx differs from %sc in that %sx automatically splits into a list,
         like '%sc -l'.  The reason for this is to make it as easy as possible
         to process line-oriented shell output via further python commands.
         %sc is meant to provide much finer control, but requires more
         typing.
 
         3) Just like %sc -l, this is a list with special attributes:
 
           .l (or .list) : value as list.
           .n (or .nlstr): value as newline-separated string.
           .s (or .spstr): value as whitespace-separated string.
 
         This is very useful when trying to use such lists as arguments to
         system commands."""
 
         if parameter_s:
             return self.shell.getoutput(parameter_s)
 
 
     def magic_bookmark(self, parameter_s=''):
         """Manage IPython's bookmark system.
 
         %bookmark <name>       - set bookmark to current dir
         %bookmark <name> <dir> - set bookmark to <dir>
         %bookmark -l           - list all bookmarks
         %bookmark -d <name>    - remove bookmark
         %bookmark -r           - remove all bookmarks
 
         You can later on access a bookmarked folder with:
           %cd -b <name>
         or simply '%cd <name>' if there is no directory called <name> AND
         there is such a bookmark defined.
 
         Your bookmarks persist through IPython sessions, but they are
         associated with each profile."""
 
         opts,args = self.parse_options(parameter_s,'drl',mode='list')
         if len(args) > 2:
             raise UsageError("%bookmark: too many arguments")
 
         bkms = self.db.get('bookmarks',{})
 
         if opts.has_key('d'):
             try:
                 todel = args[0]
             except IndexError:
                 raise UsageError(
                     "%bookmark -d: must provide a bookmark to delete")
             else:
                 try:
                     del bkms[todel]
                 except KeyError:
                     raise UsageError(
                         "%%bookmark -d: Can't delete bookmark '%s'" % todel)
 
         elif opts.has_key('r'):
             bkms = {}
         elif opts.has_key('l'):
             bks = bkms.keys()
             bks.sort()
             if bks:
                 size = max(map(len,bks))
             else:
                 size = 0
             fmt = '%-'+str(size)+'s -> %s'
             print 'Current bookmarks:'
             for bk in bks:
                 print fmt % (bk,bkms[bk])
         else:
             if not args:
                 raise UsageError("%bookmark: You must specify the bookmark name")
             elif len(args)==1:
                 bkms[args[0]] = os.getcwdu()
             elif len(args)==2:
                 bkms[args[0]] = args[1]
         self.db['bookmarks'] = bkms
 
     def magic_pycat(self, parameter_s=''):
         """Show a syntax-highlighted file through a pager.
 
         This magic is similar to the cat utility, but it will assume the file
         to be Python source and will show it with syntax highlighting. """
 
         try:
             filename = get_py_filename(parameter_s)
             cont = file_read(filename)
         except IOError:
             try:
                 cont = eval(parameter_s,self.user_ns)
             except NameError:
                 cont = None
         if cont is None:
             print "Error: no such file or variable"
             return
 
         page.page(self.shell.pycolorize(cont))
 
     def _rerun_pasted(self):
         """ Rerun a previously pasted command.
         """
         b = self.user_ns.get('pasted_block', None)
         if b is None:
             raise UsageError('No previous pasted block available')
         print "Re-executing '%s...' (%d chars)"% (b.split('\n',1)[0], len(b))
         exec b in self.user_ns
 
     def _get_pasted_lines(self, sentinel):
         """ Yield pasted lines until the user enters the given sentinel value.
         """
         from IPython.core import interactiveshell
         print "Pasting code; enter '%s' alone on the line to stop." % sentinel
         while True:
             try:
                 l = self.shell.raw_input_original(':')
                 if l == sentinel:
                     return
                 else:
                     yield l
             except EOFError:
                 print '<EOF>'
                 return
 
     def _strip_pasted_lines_for_code(self, raw_lines):
         """ Strip non-code parts of a sequence of lines to return a block of
         code.
         """
         # Regular expressions that declare text we strip from the input:
         strip_re =  [r'^\s*In \[\d+\]:', # IPython input prompt
                      r'^\s*(\s?>)+', # Python input prompt
                      r'^\s*\.{3,}', # Continuation prompts
                      r'^\++',
                      ]
 
         strip_from_start = map(re.compile,strip_re)
 
         lines = []
         for l in raw_lines:
             for pat in strip_from_start:
                 l = pat.sub('',l)
             lines.append(l)
 
         block = "\n".join(lines) + '\n'
         #print "block:\n",block
         return block
 
     def _execute_block(self, block, par):
         """ Execute a block, or store it in a variable, per the user's request.
         """
         if not par:
             b = textwrap.dedent(block)
             self.user_ns['pasted_block'] = b
             self.run_cell(b)
         else:
             self.user_ns[par] = SList(block.splitlines())
             print "Block assigned to '%s'" % par
 
     def magic_quickref(self,arg):
         """ Show a quick reference sheet """
         import IPython.core.usage
         qr = IPython.core.usage.quick_reference + self.magic_magic('-brief')
 
         page.page(qr)
 
     def magic_doctest_mode(self,parameter_s=''):
         """Toggle doctest mode on and off.
 
         This mode is intended to make IPython behave as much as possible like a
         plain Python shell, from the perspective of how its prompts, exceptions
         and output look.  This makes it easy to copy and paste parts of a
         session into doctests.  It does so by:
 
         - Changing the prompts to the classic ``>>>`` ones.
         - Changing the exception reporting mode to 'Plain'.
         - Disabling pretty-printing of output.
 
         Note that IPython also supports the pasting of code snippets that have
         leading '>>>' and '...' prompts in them.  This means that you can paste
         doctests from files or docstrings (even if they have leading
         whitespace), and the code will execute correctly.  You can then use
         '%history -t' to see the translated history; this will give you the
         input after removal of all the leading prompts and whitespace, which
         can be pasted back into an editor.
 
         With these features, you can switch into this mode easily whenever you
         need to do testing and changes to doctests, without having to leave
         your existing IPython session.
         """
 
         from IPython.utils.ipstruct import Struct
 
         # Shorthands
         shell = self.shell
         oc = shell.displayhook
         meta = shell.meta
         disp_formatter = self.shell.display_formatter
         ptformatter = disp_formatter.formatters['text/plain']
         # dstore is a data store kept in the instance metadata bag to track any
         # changes we make, so we can undo them later.
         dstore = meta.setdefault('doctest_mode',Struct())
         save_dstore = dstore.setdefault
 
         # save a few values we'll need to recover later
         mode = save_dstore('mode',False)
         save_dstore('rc_pprint',ptformatter.pprint)
         save_dstore('xmode',shell.InteractiveTB.mode)
         save_dstore('rc_separate_out',shell.separate_out)
         save_dstore('rc_separate_out2',shell.separate_out2)
         save_dstore('rc_prompts_pad_left',shell.prompts_pad_left)
         save_dstore('rc_separate_in',shell.separate_in)
         save_dstore('rc_plain_text_only',disp_formatter.plain_text_only)
 
         if mode == False:
             # turn on
             oc.prompt1.p_template = '>>> '
             oc.prompt2.p_template = '... '
             oc.prompt_out.p_template = ''
 
             # Prompt separators like plain python
             oc.input_sep = oc.prompt1.sep = ''
             oc.output_sep = ''
             oc.output_sep2 = ''
 
             oc.prompt1.pad_left = oc.prompt2.pad_left = \
                                   oc.prompt_out.pad_left = False
 
             ptformatter.pprint = False
             disp_formatter.plain_text_only = True
 
             shell.magic_xmode('Plain')
         else:
             # turn off
             oc.prompt1.p_template = shell.prompt_in1
             oc.prompt2.p_template = shell.prompt_in2
             oc.prompt_out.p_template = shell.prompt_out
 
             oc.input_sep = oc.prompt1.sep = dstore.rc_separate_in
 
             oc.output_sep = dstore.rc_separate_out
             oc.output_sep2 = dstore.rc_separate_out2
 
             oc.prompt1.pad_left = oc.prompt2.pad_left = \
                          oc.prompt_out.pad_left = dstore.rc_prompts_pad_left
 
             ptformatter.pprint = dstore.rc_pprint
             disp_formatter.plain_text_only = dstore.rc_plain_text_only
 
             shell.magic_xmode(dstore.xmode)
 
         # Store new mode and inform
         dstore.mode = bool(1-int(mode))
         mode_label = ['OFF','ON'][dstore.mode]
         print 'Doctest mode is:', mode_label
 
     def magic_gui(self, parameter_s=''):
         """Enable or disable IPython GUI event loop integration.
 
         %gui [GUINAME]
 
         This magic replaces IPython's threaded shells that were activated
         using the (pylab/wthread/etc.) command line flags.  GUI toolkits
         can now be enabled, disabled and changed at runtime and keyboard
         interrupts should work without any problems.  The following toolkits
         are supported:  wxPython, PyQt4, PyGTK, and Tk::
 
             %gui wx      # enable wxPython event loop integration
             %gui qt4|qt  # enable PyQt4 event loop integration
             %gui gtk     # enable PyGTK event loop integration
             %gui tk      # enable Tk event loop integration
             %gui         # disable all event loop integration
 
         WARNING:  after any of these has been called you can simply create
         an application object, but DO NOT start the event loop yourself, as
         we have already handled that.
         """
         from IPython.lib.inputhook import enable_gui
         opts, arg = self.parse_options(parameter_s, '')
         if arg=='': arg = None
         return enable_gui(arg)
 
     def magic_load_ext(self, module_str):
         """Load an IPython extension by its module name."""
         return self.extension_manager.load_extension(module_str)
 
     def magic_unload_ext(self, module_str):
         """Unload an IPython extension by its module name."""
         self.extension_manager.unload_extension(module_str)
 
     def magic_reload_ext(self, module_str):
         """Reload an IPython extension by its module name."""
         self.extension_manager.reload_extension(module_str)
 
     @skip_doctest
     def magic_install_profiles(self, s):
         """Install the default IPython profiles into the .ipython dir.
 
         If the default profiles have already been installed, they will not
         be overwritten. You can force overwriting them by using the ``-o``
         option::
 
             In [1]: %install_profiles -o
         """
         if '-o' in s:
             overwrite = True
         else:
             overwrite = False
         from IPython.config import profile
         profile_dir = os.path.dirname(profile.__file__)
         ipython_dir = self.ipython_dir
         print "Installing profiles to: %s [overwrite=%s]"%(ipython_dir,overwrite)
         for src in os.listdir(profile_dir):
             if src.startswith('profile_'):
                 name = src.replace('profile_', '')
                 print "    %s"%name
                 pd = ProfileDir.create_profile_dir_by_name(ipython_dir, name)
                 pd.copy_config_file('ipython_config.py', path=src,
                                 overwrite=overwrite)
 
     @skip_doctest
     def magic_install_default_config(self, s):
         """Install IPython's default config file into the .ipython dir.
 
         If the default config file (:file:`ipython_config.py`) is already
         installed, it will not be overwritten. You can force overwriting
         by using the ``-o`` option::
 
             In [1]: %install_default_config
         """
         if '-o' in s:
             overwrite = True
         else:
             overwrite = False
         pd = self.shell.profile_dir
         print "Installing default config file in: %s" % pd.location
         pd.copy_config_file('ipython_config.py', overwrite=overwrite)
 
     # Pylab support: simple wrappers that activate pylab, load gui input
     # handling and modify slightly %run
 
     @skip_doctest
     def _pylab_magic_run(self, parameter_s=''):
         Magic.magic_run(self, parameter_s,
                         runner=mpl_runner(self.shell.safe_execfile))
 
     _pylab_magic_run.__doc__ = magic_run.__doc__
 
     @skip_doctest
     def magic_pylab(self, s):
         """Load numpy and matplotlib to work interactively.
 
         %pylab [GUINAME]
 
         This function lets you activate pylab (matplotlib, numpy and
         interactive support) at any point during an IPython session.
 
         It will import at the top level numpy as np, pyplot as plt, matplotlib,
         pylab and mlab, as well as all names from numpy and pylab.
 
         If you are using the inline matplotlib backend for embedded figures,
         you can adjust its behavior via the %config magic::
 
             # enable SVG figures, necessary for SVG+XHTML export in the qtconsole
             In [1]: %config InlineBackend.figure_format = 'svg'
             
             # change the behavior of closing all figures at the end of each
             # execution (cell), or allowing reuse of active figures across
             # cells:
             In [2]: %config InlineBackend.close_figures = False
 
         Parameters
         ----------
         guiname : optional
           One of the valid arguments to the %gui magic ('qt', 'wx', 'gtk', 'osx' or
           'tk').  If given, the corresponding Matplotlib backend is used,
           otherwise matplotlib's default (which you can override in your
           matplotlib config file) is used.
 
         Examples
         --------
         In this case, where the MPL default is TkAgg::
 
             In [2]: %pylab
 
             Welcome to pylab, a matplotlib-based Python environment.
             Backend in use: TkAgg
             For more information, type 'help(pylab)'.
 
         But you can explicitly request a different backend::
 
             In [3]: %pylab qt
 
             Welcome to pylab, a matplotlib-based Python environment.
             Backend in use: Qt4Agg
             For more information, type 'help(pylab)'.
         """
 
         if Application.initialized():
             app = Application.instance()
             try:
                 import_all_status = app.pylab_import_all
             except AttributeError:
                 import_all_status = True
         else:
             import_all_status = True
 
         self.shell.enable_pylab(s,import_all=import_all_status)
 
     def magic_tb(self, s):
         """Print the last traceback with the currently active exception mode.
 
         See %xmode for changing exception reporting modes."""
         self.shell.showtraceback()
 
     @skip_doctest
     def magic_precision(self, s=''):
         """Set floating point precision for pretty printing.
 
         Can set either integer precision or a format string.
 
         If numpy has been imported and precision is an int,
         numpy display precision will also be set, via ``numpy.set_printoptions``.
 
         If no argument is given, defaults will be restored.
 
         Examples
         --------
         ::
 
             In [1]: from math import pi
 
             In [2]: %precision 3
             Out[2]: u'%.3f'
 
             In [3]: pi
             Out[3]: 3.142
 
             In [4]: %precision %i
             Out[4]: u'%i'
 
             In [5]: pi
             Out[5]: 3
 
             In [6]: %precision %e
             Out[6]: u'%e'
 
             In [7]: pi**10
             Out[7]: 9.364805e+04
 
             In [8]: %precision
             Out[8]: u'%r'
 
             In [9]: pi**10
             Out[9]: 93648.047476082982
 
         """
 
         ptformatter = self.shell.display_formatter.formatters['text/plain']
         ptformatter.float_precision = s
         return ptformatter.float_format
 
 
     @magic_arguments.magic_arguments()
     @magic_arguments.argument(
         '-e', '--export', action='store_true', default=False,
         help='Export IPython history as a notebook. The filename argument '
              'is used to specify the notebook name and format. For example '
              'a filename of notebook.ipynb will result in a notebook name '
              'of "notebook" and a format of "xml". Likewise using a ".json" '
              'or ".py" file extension will write the notebook in the json '
              'or py formats.'
     )
     @magic_arguments.argument(
         '-f', '--format',
         help='Convert an existing IPython notebook to a new format. This option '
              'specifies the new format and can have the values: xml, json, py. '
              'The target filename is choosen automatically based on the new '
              'format. The filename argument gives the name of the source file.'
     )
     @magic_arguments.argument(
         'filename', type=unicode,
         help='Notebook name or filename'
     )
     def magic_notebook(self, s):
         """Export and convert IPython notebooks.
 
         This function can export the current IPython history to a notebook file
         or can convert an existing notebook file into a different format. For
         example, to export the history to "foo.ipynb" do "%notebook -e foo.ipynb".
         To export the history to "foo.py" do "%notebook -e foo.py". To convert
         "foo.ipynb" to "foo.json" do "%notebook -f json foo.ipynb". Possible
         formats include (json/ipynb, py).
         """
         args = magic_arguments.parse_argstring(self.magic_notebook, s)
 
         from IPython.nbformat import current
         args.filename = unquote_filename(args.filename)
         if args.export:
             fname, name, format = current.parse_filename(args.filename)
             cells = []
             hist = list(self.history_manager.get_range())
             for session, prompt_number, input in hist[:-1]:
                 cells.append(current.new_code_cell(prompt_number=prompt_number, input=input))
             worksheet = current.new_worksheet(cells=cells)
             nb = current.new_notebook(name=name,worksheets=[worksheet])
             with open(fname, 'w') as f:
                 current.write(nb, f, format);
         elif args.format is not None:
             old_fname, old_name, old_format = current.parse_filename(args.filename)
             new_format = args.format
             if new_format == u'xml':
                 raise ValueError('Notebooks cannot be written as xml.')
             elif new_format == u'ipynb' or new_format == u'json':
                 new_fname = old_name + u'.ipynb'
                 new_format = u'json'
             elif new_format == u'py':
                 new_fname = old_name + u'.py'
             else:
                 raise ValueError('Invalid notebook format: %s' % new_format)
             with open(old_fname, 'r') as f:
                 s = f.read()
                 try:
                     nb = current.reads(s, old_format)
                 except:
                     nb = current.reads(s, u'xml')
             with open(new_fname, 'w') as f:
                 current.write(nb, f, new_format)
 
     def magic_config(self, s):
         """configure IPython
         
             %config Class[.trait=value]
         
         This magic exposes most of the IPython config system. Any
         Configurable class should be able to be configured with the simple
         line::
         
             %config Class.trait=value
         
         Where `value` will be resolved in the user's namespace, if it is an
         expression or variable name.
         
         Examples
         --------
         
         To see what classes are availabe for config, pass no arguments::
 
             In [1]: %config
             Available objects for config:
                 TerminalInteractiveShell
                 HistoryManager
                 PrefilterManager
                 AliasManager
                 IPCompleter
                 DisplayFormatter
 
         To view what is configurable on a given class, just pass the class name::
 
             In [2]: %config IPCompleter
             IPCompleter options
             -----------------
             IPCompleter.omit__names=<Enum>
                 Current: 2
                 Choices: (0, 1, 2)
                 Instruct the completer to omit private method names
                 Specifically, when completing on ``object.<tab>``.
                 When 2 [default]: all names that start with '_' will be excluded.
                 When 1: all 'magic' names (``__foo__``) will be excluded.
                 When 0: nothing will be excluded.
             IPCompleter.merge_completions=<CBool>
                 Current: True
                 Whether to merge completion results into a single list
                 If False, only the completion results from the first non-empty completer
                 will be returned.
             IPCompleter.greedy=<CBool>
                 Current: False
                 Activate greedy completion
                 This will enable completion on elements of lists, results of function calls,
                 etc., but can be unsafe because the code is actually evaluated on TAB.
 
         but the real use is in setting values::
 
             In [3]: %config IPCompleter.greedy = True
 
         and these values are read from the user_ns if they are variables::
 
             In [4]: feeling_greedy=False
 
             In [5]: %config IPCompleter.greedy = feeling_greedy
 
         """
         from IPython.config.loader import Config
         # some IPython objects are Configurable, but do not yet have
         # any configurable traits.  Exclude them from the effects of
         # this magic, as their presence is just noise:
         configurables = [ c for c in self.configurables if c.__class__.class_traits(config=True) ]
         classnames = [ c.__class__.__name__ for c in configurables ]
         
         line = s.strip()
         if not line:
             # print available configurable names
             print "Available objects for config:"
             for name in classnames:
                 print "    ", name
             return
         elif line in classnames:
             # `%config TerminalInteractiveShell` will print trait info for
             # TerminalInteractiveShell
             c = configurables[classnames.index(line)]
             cls = c.__class__
             help = cls.class_get_help(c)
             # strip leading '--' from cl-args:
             help = re.sub(re.compile(r'^--', re.MULTILINE), '', help)
             print help
             return
         elif '=' not in line:
             raise UsageError("Invalid config statement: %r, should be Class.trait = value" % line)
             
         
         # otherwise, assume we are setting configurables.
         # leave quotes on args when splitting, because we want
         # unquoted args to eval in user_ns
         cfg = Config()
         exec "cfg."+line in locals(), self.user_ns
         
         for configurable in configurables:
             try:
                 configurable.update_config(cfg)
             except Exception as e:
                 error(e)
 
 # end Magic