Use user_ns as global namespace if it is passed without user_module, and add test for pickling interactively defined objects.

Closes gh-29

IPython/core/interactiveshell.py

@@ -1,2648 +1,2666 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_module=None, user_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_module, user_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
         self.home_dir = get_home_dir()
 
         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_module 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
         self._orig_sys_modules_main_name = self.user_module.__name__
 
     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
         sys.modules[self.user_module.__name__] = self._orig_sys_modules_main_name
 
     #-------------------------------------------------------------------------
     # 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_module=None, user_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.
-        self.user_module = self.prepare_user_module(user_module)
+        # These routines return a properly built module and dict as needed by
+        # the rest of the code, and can also be used by extension writers to
+        # generate properly initialized namespaces.
+        self.user_module, self.user_ns = self.prepare_user_module(user_module, user_ns)
 
-        if user_ns is None:
-            user_ns = self.user_module.__dict__
-        self.user_ns = user_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.
+        # A record of hidden variables we have added to the user namespace, so
+        # we can list later only variables defined in actual interactive use.
         self.user_ns_hidden = set()
 
         # 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_global':self.user_module.__dict__,
                          'user_local':user_ns,
                          'builtin':builtin_mod.__dict__
                          }
     
     @property
     def user_global_ns(self):
         return self.user_module.__dict__
 
-    def prepare_user_module(self, user_module=None):
-        """Prepares a module for use as the interactive __main__ module in
-        which user code is run.
+    def prepare_user_module(self, user_module=None, user_ns=None):
+        """Prepare the module and namespace in which user code will be run.
+        
+        When IPython is started normally, both parameters are None: a new module
+        is created automatically, and its __dict__ used as the namespace.
+        
+        If only user_module is provided, its __dict__ is used as the namespace.
+        If only user_ns is provided, a dummy module is created, and user_ns
+        becomes the global namespace. If both are provided (as they may be
+        when embedding), user_ns is the local namespace, and user_module
+        provides the global namespace.
 
         Parameters
         ----------
         user_module : module, optional
             The current user module in which IPython is being run. If None,
             a clean module will be created.
+        user_ns : dict, optional
+            A namespace in which to run interactive commands.
 
         Returns
         -------
-        A module object.
+        A tuple of user_module and user_ns, each properly initialised.
         """
+        if user_module is None and user_ns is not None:
+            user_ns.setdefault("__name__", "__main__")
+            class DummyMod(object):
+                "A dummy module used for IPython's interactive namespace."
+                pass
+            user_module = DummyMod()
+            user_module.__dict__ = user_ns
+            
         if user_module is None:
             user_module = types.ModuleType("__main__",
                 doc="Automatically created module for IPython interactive environment")
         
         # 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
         user_module.__dict__.setdefault('__builtin__',__builtin__)
         user_module.__dict__.setdefault('__builtins__',__builtin__)
 
-        return user_module
+        if user_ns is None:
+            user_ns = user_module.__dict__
+
+        return user_module, user_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.
         main_name = self.user_module.__name__
         sys.modules[main_name] = self.user_module
 
     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()
         
         # 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()
 
         # 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]:
+        if self.user_ns is not self.user_global_ns:
+            self.user_ns.clear()
+        ns = self.user_global_ns
             drop_keys = set(ns.keys())
             drop_keys.discard('__builtin__')
             drop_keys.discard('__builtins__')
+        drop_keys.discard('__name__')
             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.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.user_ns, self.user_global_ns]:
                 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
         user_ns_hidden = self.user_ns_hidden
         if interactive:
             for name in vdict:
                 user_ns_hidden.discard(name)
         else:
             for name in vdict:
                 user_ns_hidden.add(name)
     
     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.discard(name)
 
     #-------------------------------------------------------------------------
     # 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),
                            ('Interactive (global)', self.user_global_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:
                 inputrc_name = '.inputrc'
                 if readline.uses_libedit:
                     inputrc_name = '.editrc'
                 inputrc_name = os.path.join(self.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
         
         Example::
 
           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
 
           ip.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=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/tests/test_interactiveshell.py

@@ -1,240 +1,273 b''
 # -*- coding: utf-8 -*-
 """Tests for the key interactiveshell module.
 
 Historically the main classes in interactiveshell have been under-tested.  This
 module should grow as many single-method tests as possible to trap many of the
 recurring bugs we seem to encounter with high-level interaction.
 
 Authors
 -------
 * Fernando Perez
 """
 #-----------------------------------------------------------------------------
 #  Copyright (C) 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
 #-----------------------------------------------------------------------------
 # stdlib
 import os
 import shutil
 import tempfile
 import unittest
 from os.path import join
+import sys
 from StringIO import StringIO
 
 from IPython.testing import decorators as dec
 from IPython.utils import io
 
 #-----------------------------------------------------------------------------
 # Tests
 #-----------------------------------------------------------------------------
 
 class InteractiveShellTestCase(unittest.TestCase):
     def test_naked_string_cells(self):
         """Test that cells with only naked strings are fully executed"""
         ip = get_ipython()
         # First, single-line inputs
         ip.run_cell('"a"\n')
         self.assertEquals(ip.user_ns['_'], 'a')
         # And also multi-line cells
         ip.run_cell('"""a\nb"""\n')
         self.assertEquals(ip.user_ns['_'], 'a\nb')
 
     def test_run_empty_cell(self):
         """Just make sure we don't get a horrible error with a blank
         cell of input. Yes, I did overlook that."""
         ip = get_ipython()
         old_xc = ip.execution_count
         ip.run_cell('')
         self.assertEquals(ip.execution_count, old_xc)
 
     def test_run_cell_multiline(self):
         """Multi-block, multi-line cells must execute correctly.
         """
         ip = get_ipython()
         src = '\n'.join(["x=1",
                          "y=2",
                          "if 1:",
                          "    x += 1",
                          "    y += 1",])
         ip.run_cell(src)
         self.assertEquals(ip.user_ns['x'], 2)
         self.assertEquals(ip.user_ns['y'], 3)
 
     def test_multiline_string_cells(self):
         "Code sprinkled with multiline strings should execute (GH-306)"
         ip = get_ipython()
         ip.run_cell('tmp=0')
         self.assertEquals(ip.user_ns['tmp'], 0)
         ip.run_cell('tmp=1;"""a\nb"""\n')
         self.assertEquals(ip.user_ns['tmp'], 1)
 
     def test_dont_cache_with_semicolon(self):
         "Ending a line with semicolon should not cache the returned object (GH-307)"
         ip = get_ipython()
         oldlen = len(ip.user_ns['Out'])
         a = ip.run_cell('1;', store_history=True)
         newlen = len(ip.user_ns['Out'])
         self.assertEquals(oldlen, newlen)
         #also test the default caching behavior
         ip.run_cell('1', store_history=True)
         newlen = len(ip.user_ns['Out'])
         self.assertEquals(oldlen+1, newlen)
 
     def test_In_variable(self):
         "Verify that In variable grows with user input (GH-284)"
         ip = get_ipython()
         oldlen = len(ip.user_ns['In'])
         ip.run_cell('1;', store_history=True)
         newlen = len(ip.user_ns['In'])
         self.assertEquals(oldlen+1, newlen)
         self.assertEquals(ip.user_ns['In'][-1],'1;')
         
     def test_magic_names_in_string(self):
         ip = get_ipython()
         ip.run_cell('a = """\n%exit\n"""')
         self.assertEquals(ip.user_ns['a'], '\n%exit\n')
     
     def test_alias_crash(self):
         """Errors in prefilter can't crash IPython"""
         ip = get_ipython()
         ip.run_cell('%alias parts echo first %s second %s')
         # capture stderr:
         save_err = io.stderr
         io.stderr = StringIO()
         ip.run_cell('parts 1')
         err = io.stderr.getvalue()
         io.stderr = save_err
         self.assertEquals(err.split(':')[0], 'ERROR')
     
     def test_trailing_newline(self):
         """test that running !(command) does not raise a SyntaxError"""
         ip = get_ipython()
         ip.run_cell('!(true)\n', False)
         ip.run_cell('!(true)\n\n\n', False)
     
     def test_gh_597(self):
         """Pretty-printing lists of objects with non-ascii reprs may cause
         problems."""
         class Spam(object):
           def __repr__(self):
             return "\xe9"*50
         import IPython.core.formatters
         f = IPython.core.formatters.PlainTextFormatter()
         f([Spam(),Spam()])
     
+
     def test_future_flags(self):
         """Check that future flags are used for parsing code (gh-777)"""
         ip = get_ipython()
         ip.run_cell('from __future__ import print_function')
         try:
             ip.run_cell('prfunc_return_val = print(1,2, sep=" ")')
             assert 'prfunc_return_val' in ip.user_ns
         finally:
             # Reset compiler flags so we don't mess up other tests.
             ip.compile.reset_compiler_flags()
 
     def test_future_unicode(self):
         """Check that unicode_literals is imported from __future__ (gh #786)"""
         ip = get_ipython()
         try:
             ip.run_cell(u'byte_str = "a"')
             assert isinstance(ip.user_ns['byte_str'], str) # string literals are byte strings by default
             ip.run_cell('from __future__ import unicode_literals')
             ip.run_cell(u'unicode_str = "a"')
             assert isinstance(ip.user_ns['unicode_str'], unicode) # strings literals are now unicode
         finally:
             # Reset compiler flags so we don't mess up other tests.
             ip.compile.reset_compiler_flags()
 
+    def test_can_pickle(self):
+        "Can we pickle objects defined interactively (GH-29)"
+        ip = get_ipython()
+        ip.reset()
+        ip.run_cell(("class Mylist(list):\n"
+                     "    def __init__(self,x=[]):\n"
+                     "        list.__init__(self,x)"))
+        ip.run_cell("w=Mylist([1,2,3])")
+        
+        from cPickle import dumps
+        
+        # We need to swap in our main module - this is only necessary
+        # inside the test framework, because IPython puts the interactive module
+        # in place (but the test framework undoes this).
+        _main = sys.modules['__main__']
+        sys.modules['__main__'] = ip.user_module
+        try:
+            res = dumps(ip.user_ns["w"])
+        finally:
+            sys.modules['__main__'] = _main
+        self.assertTrue(isinstance(res, bytes))
+        
+    def test_global_ns(self):
+        "Code in functions must be able to access variables outside them."
+        ip = get_ipython()
+        ip.run_cell("a = 10")
+        ip.run_cell(("def f(x):"
+                     "    return x + a"))
+        ip.run_cell("b = f(12)")
+        self.assertEqual(ip.user_ns["b"], 22)
+
     def test_bad_custom_tb(self):
         """Check that InteractiveShell is protected from bad custom exception handlers"""
         ip = get_ipython()
         from IPython.utils import io
         save_stderr = io.stderr
         try:
             # capture stderr
             io.stderr = StringIO()
             ip.set_custom_exc((IOError,), lambda etype,value,tb: 1/0)
             self.assertEquals(ip.custom_exceptions, (IOError,))
             ip.run_cell(u'raise IOError("foo")')
             self.assertEquals(ip.custom_exceptions, ())
             self.assertTrue("Custom TB Handler failed" in io.stderr.getvalue())
         finally:
             io.stderr = save_stderr
 
     def test_bad_custom_tb_return(self):
         """Check that InteractiveShell is protected from bad return types in custom exception handlers"""
         ip = get_ipython()
         from IPython.utils import io
         save_stderr = io.stderr
         try:
             # capture stderr
             io.stderr = StringIO()
             ip.set_custom_exc((NameError,),lambda etype,value,tb, tb_offset=None: 1)
             self.assertEquals(ip.custom_exceptions, (NameError,))
             ip.run_cell(u'a=abracadabra')
             self.assertEquals(ip.custom_exceptions, ())
             self.assertTrue("Custom TB Handler failed" in io.stderr.getvalue())
         finally:
             io.stderr = save_stderr
 
     def test_drop_by_id(self):
         ip = get_ipython()
         myvars = {"a":object(), "b":object(), "c": object()}
         ip.push(myvars, interactive=False)
         for name in myvars:
             assert name in ip.user_ns, name
             assert name in ip.user_ns_hidden, name
         ip.user_ns['b'] = 12
         ip.drop_by_id(myvars)
         for name in ["a", "c"]:
             assert name not in ip.user_ns, name
             assert name not in ip.user_ns_hidden, name
         assert ip.user_ns['b'] == 12
         ip.reset()
 
     def test_var_expand(self):
         ip = get_ipython()
         ip.user_ns['f'] = u'Ca\xf1o'
         self.assertEqual(ip.var_expand(u'echo $f'), u'echo Ca\xf1o')
 
         ip.user_ns['f'] = b'Ca\xc3\xb1o'
         # This should not raise any exception:
         ip.var_expand(u'echo $f')
 
 
 class TestSafeExecfileNonAsciiPath(unittest.TestCase):
 
     def setUp(self):
         self.BASETESTDIR = tempfile.mkdtemp()
         self.TESTDIR = join(self.BASETESTDIR, u"åäö")
         os.mkdir(self.TESTDIR)
         with open(join(self.TESTDIR, u"åäötestscript.py"), "w") as sfile:
             sfile.write("pass\n")
         self.oldpath = os.getcwdu()
         os.chdir(self.TESTDIR)
         self.fname = u"åäötestscript.py"
 
 
     def tearDown(self):
         os.chdir(self.oldpath)
         shutil.rmtree(self.BASETESTDIR)
 
     def test_1(self):
         """Test safe_execfile with non-ascii path
         """
         _ip.shell.safe_execfile(self.fname, {}, raise_exceptions=True)
 
 
 class TestSystemRaw(unittest.TestCase):
     def test_1(self):
         """Test system_raw with non-ascii cmd
         """
         cmd = ur'''python -c "'åäö'"   '''
         _ip.shell.system_raw(cmd)

IPython/testing/globalipapp.py

@@ -1,239 +1,238 b''
 """Global IPython app to support test running.
 
 We must start our own ipython object and heavily muck with it so that all the
 modifications IPython makes to system behavior don't send the doctest machinery
 into a fit.  This code should be considered a gross hack, but it gets the job
 done.
 """
 from __future__ import absolute_import
 from __future__ import print_function
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2009-2011  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
 #-----------------------------------------------------------------------------
 
 # stdlib
 import __builtin__ as builtin_mod
 import os
 import sys
 
 # our own
 from . import tools
 
 from IPython.core import page
 from IPython.utils import io
 from IPython.utils import py3compat
 from IPython.frontend.terminal.interactiveshell import TerminalInteractiveShell
 
 #-----------------------------------------------------------------------------
 # Functions
 #-----------------------------------------------------------------------------
 
 class StreamProxy(io.IOStream):
     """Proxy for sys.stdout/err.  This will request the stream *at call time*
     allowing for nose's Capture plugin's redirection of sys.stdout/err.
 
     Parameters
     ----------
     name : str
         The name of the stream. This will be requested anew at every call
     """
 
     def __init__(self, name):
         self.name=name
 
     @property
     def stream(self):
         return getattr(sys, self.name)
 
     def flush(self):
         self.stream.flush()
 
 # Hack to modify the %run command so we can sync the user's namespace with the
 # test globals.  Once we move over to a clean magic system, this will be done
 # with much less ugliness.
 
 class py_file_finder(object):
     def __init__(self,test_filename):
         self.test_filename = test_filename
 
     def __call__(self,name,win32=False):
         from IPython.utils.path import get_py_filename
         try:
             return get_py_filename(name,win32=win32)
         except IOError:
             test_dir = os.path.dirname(self.test_filename)
             new_path = os.path.join(test_dir,name)
             return get_py_filename(new_path,win32=win32)
 
 
 def _run_ns_sync(self,arg_s,runner=None):
     """Modified version of %run that syncs testing namespaces.
 
     This is strictly needed for running doctests that call %run.
     """
     #print('in run_ns_sync', arg_s, file=sys.stderr)  # dbg
     finder = py_file_finder(arg_s)
     return get_ipython().magic_run_ori(arg_s, runner, finder)
 
 
 class ipnsdict(dict):
     """A special subclass of dict for use as an IPython namespace in doctests.
 
     This subclass adds a simple checkpointing capability so that when testing
     machinery clears it (we use it as the test execution context), it doesn't
     get completely destroyed.
 
     In addition, it can handle the presence of the '_' key in a special manner,
     which is needed because of how Python's doctest machinery operates with
     '_'.  See constructor and :meth:`update` for details.
     """
 
     def __init__(self,*a):
         dict.__init__(self,*a)
         self._savedict = {}
         # If this flag is True, the .update() method will unconditionally
         # remove a key named '_'.  This is so that such a dict can be used as a
         # namespace in doctests that call '_'.
         self.protect_underscore = False
 
     def clear(self):
         dict.clear(self)
         self.update(self._savedict)
 
     def _checkpoint(self):
         self._savedict.clear()
         self._savedict.update(self)
 
     def update(self,other):
         self._checkpoint()
         dict.update(self,other)
 
         if self.protect_underscore:
             # If '_' is in the namespace, python won't set it when executing
             # code *in doctests*, and we have multiple doctests that use '_'.
             # So we ensure that the namespace is always 'clean' of it before
             # it's used for test code execution.
             # This flag is only turned on by the doctest machinery, so that
             # normal test code can assume the _ key is updated like any other
             # key and can test for its presence after cell executions.
             self.pop('_', None)
 
         # The builtins namespace must *always* be the real __builtin__ module,
         # else weird stuff happens.  The main ipython code does have provisions
         # to ensure this after %run, but since in this class we do some
         # aggressive low-level cleaning of the execution namespace, we need to
         # correct for that ourselves, to ensure consitency with the 'real'
         # ipython.
         self['__builtins__'] = builtin_mod
 
     def __delitem__(self, key):
         """Part of the test suite checks that we can release all
         references to an object. So we need to make sure that we're not
         keeping a reference in _savedict."""
         dict.__delitem__(self, key)
         try:
             del self._savedict[key]
         except KeyError:
             pass
 
 
 def get_ipython():
     # This will get replaced by the real thing once we start IPython below
     return start_ipython()
 
 
 # A couple of methods to override those in the running IPython to interact
 # better with doctest (doctest captures on raw stdout, so we need to direct
 # various types of output there otherwise it will miss them).
 
 def xsys(self, cmd):
     """Replace the default system call with a capturing one for doctest.
     """
     # We use getoutput, but we need to strip it because pexpect captures
     # the trailing newline differently from commands.getoutput
     print(self.getoutput(cmd, split=False).rstrip(), end='', file=sys.stdout)
     sys.stdout.flush()
 
 
 def _showtraceback(self, etype, evalue, stb):
     """Print the traceback purely on stdout for doctest to capture it.
     """
     print(self.InteractiveTB.stb2text(stb), file=sys.stdout)
 
 
 def start_ipython():
     """Start a global IPython shell, which we need for IPython-specific syntax.
     """
     global get_ipython
 
     # This function should only ever run once!
     if hasattr(start_ipython, 'already_called'):
         return
     start_ipython.already_called = True
 
     # Store certain global objects that IPython modifies
     _displayhook = sys.displayhook
     _excepthook = sys.excepthook
     _main = sys.modules.get('__main__')
 
     # Create custom argv and namespaces for our IPython to be test-friendly
     config = tools.default_config()
 
     # Create and initialize our test-friendly IPython instance.
     shell = TerminalInteractiveShell.instance(config=config,
                                               user_ns=ipnsdict(),
                                               )
 
     # A few more tweaks needed for playing nicely with doctests...
 
     # remove history file
     shell.tempfiles.append(config.HistoryManager.hist_file)
 
     # These traps are normally only active for interactive use, set them
     # permanently since we'll be mocking interactive sessions.
     shell.builtin_trap.activate()
 
     # Modify the IPython system call with one that uses getoutput, so that we
     # can capture subcommands and print them to Python's stdout, otherwise the
     # doctest machinery would miss them.
     shell.system = py3compat.MethodType(xsys, shell)
 
-
     shell._showtraceback = py3compat.MethodType(_showtraceback, shell)
 
     # IPython is ready, now clean up some global state...
 
     # Deactivate the various python system hooks added by ipython for
     # interactive convenience so we don't confuse the doctest system
     sys.modules['__main__'] = _main
     sys.displayhook = _displayhook
     sys.excepthook = _excepthook
 
     # So that ipython magics and aliases can be doctested (they work by making
     # a call into a global _ip object).  Also make the top-level get_ipython
     # now return this without recursively calling here again.
     _ip = shell
     get_ipython = _ip.get_ipython
     builtin_mod._ip = _ip
     builtin_mod.get_ipython = get_ipython
 
     # To avoid extra IPython messages during testing, suppress io.stdout/stderr
     io.stdout = StreamProxy('stdout')
     io.stderr = StreamProxy('stderr')
     
     # Override paging, so we don't require user interaction during the tests.
     def nopage(strng, start=0, screen_lines=0, pager_cmd=None):
         print(strng)
     
     page.orig_page = page.page
     page.page = nopage
 
     return _ip

IPython/testing/plugin/ipdoctest.py

@@ -1,810 +1,814 b''
 """Nose Plugin that supports IPython doctests.
 
 Limitations:
 
 - When generating examples for use as doctests, make sure that you have
   pretty-printing OFF.  This can be done either by setting the
   ``PlainTextFormatter.pprint`` option in your configuration file to  False, or
   by interactively disabling it with  %Pprint.  This is required so that IPython
   output matches that of normal Python, which is used by doctest for internal
   execution.
 
 - Do not rely on specific prompt numbers for results (such as using
   '_34==True', for example).  For IPython tests run via an external process the
   prompt numbers may be different, and IPython tests run as normal python code
   won't even have these special _NN variables set at all.
 """
 
 #-----------------------------------------------------------------------------
 # Module imports
 
 # From the standard library
 import __builtin__
 import commands
 import doctest
 import inspect
 import logging
 import os
 import re
 import sys
 import traceback
 import unittest
 
 from inspect import getmodule
 from StringIO import StringIO
 
 # We are overriding the default doctest runner, so we need to import a few
 # things from doctest directly
 from doctest import (REPORTING_FLAGS, REPORT_ONLY_FIRST_FAILURE,
                      _unittest_reportflags, DocTestRunner,
                      _extract_future_flags, pdb, _OutputRedirectingPdb,
                      _exception_traceback,
                      linecache)
 
 # Third-party modules
 import nose.core
 
 from nose.plugins import doctests, Plugin
 from nose.util import anyp, getpackage, test_address, resolve_name, tolist
 
 #-----------------------------------------------------------------------------
 # Module globals and other constants
 #-----------------------------------------------------------------------------
 
 log = logging.getLogger(__name__)
 
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 def is_extension_module(filename):
     """Return whether the given filename is an extension module.
 
     This simply checks that the extension is either .so or .pyd.
     """
     return os.path.splitext(filename)[1].lower() in ('.so','.pyd')
 
 
 class DocTestSkip(object):
     """Object wrapper for doctests to be skipped."""
 
     ds_skip = """Doctest to skip.
     >>> 1 #doctest: +SKIP
     """
 
     def __init__(self,obj):
         self.obj = obj
 
     def __getattribute__(self,key):
         if key == '__doc__':
             return DocTestSkip.ds_skip
         else:
             return getattr(object.__getattribute__(self,'obj'),key)
 
 # Modified version of the one in the stdlib, that fixes a python bug (doctests
 # not found in extension modules, http://bugs.python.org/issue3158)
 class DocTestFinder(doctest.DocTestFinder):
 
     def _from_module(self, module, object):
         """
         Return true if the given object is defined in the given
         module.
         """
         if module is None:
             return True
         elif inspect.isfunction(object):
             return module.__dict__ is object.func_globals
         elif inspect.isbuiltin(object):
             return module.__name__ == object.__module__
         elif inspect.isclass(object):
             return module.__name__ == object.__module__
         elif inspect.ismethod(object):
             # This one may be a bug in cython that fails to correctly set the
             # __module__ attribute of methods, but since the same error is easy
             # to make by extension code writers, having this safety in place
             # isn't such a bad idea
             return module.__name__ == object.im_class.__module__
         elif inspect.getmodule(object) is not None:
             return module is inspect.getmodule(object)
         elif hasattr(object, '__module__'):
             return module.__name__ == object.__module__
         elif isinstance(object, property):
             return True # [XX] no way not be sure.
         else:
             raise ValueError("object must be a class or function")
 
     def _find(self, tests, obj, name, module, source_lines, globs, seen):
         """
         Find tests for the given object and any contained objects, and
         add them to `tests`.
         """
         #print '_find for:', obj, name, module  # dbg
         if hasattr(obj,"skip_doctest"):
             #print 'SKIPPING DOCTEST FOR:',obj  # dbg
             obj = DocTestSkip(obj)
 
         doctest.DocTestFinder._find(self,tests, obj, name, module,
                                     source_lines, globs, seen)
 
         # Below we re-run pieces of the above method with manual modifications,
         # because the original code is buggy and fails to correctly identify
         # doctests in extension modules.
 
         # Local shorthands
         from inspect import isroutine, isclass, ismodule
 
         # Look for tests in a module's contained objects.
         if inspect.ismodule(obj) and self._recurse:
             for valname, val in obj.__dict__.items():
                 valname1 = '%s.%s' % (name, valname)
                 if ( (isroutine(val) or isclass(val))
                      and self._from_module(module, val) ):
 
                     self._find(tests, val, valname1, module, source_lines,
                                globs, seen)
 
         # Look for tests in a class's contained objects.
         if inspect.isclass(obj) and self._recurse:
             #print 'RECURSE into class:',obj  # dbg
             for valname, val in obj.__dict__.items():
                 # Special handling for staticmethod/classmethod.
                 if isinstance(val, staticmethod):
                     val = getattr(obj, valname)
                 if isinstance(val, classmethod):
                     val = getattr(obj, valname).im_func
 
                 # Recurse to methods, properties, and nested classes.
                 if ((inspect.isfunction(val) or inspect.isclass(val) or
                      inspect.ismethod(val) or
                       isinstance(val, property)) and
                       self._from_module(module, val)):
                     valname = '%s.%s' % (name, valname)
                     self._find(tests, val, valname, module, source_lines,
                                globs, seen)
 
 
 class IPDoctestOutputChecker(doctest.OutputChecker):
     """Second-chance checker with support for random tests.
 
     If the default comparison doesn't pass, this checker looks in the expected
     output string for flags that tell us to ignore the output.
     """
 
     random_re = re.compile(r'#\s*random\s+')
 
     def check_output(self, want, got, optionflags):
         """Check output, accepting special markers embedded in the output.
 
         If the output didn't pass the default validation but the special string
         '#random' is included, we accept it."""
 
         # Let the original tester verify first, in case people have valid tests
         # that happen to have a comment saying '#random' embedded in.
         ret = doctest.OutputChecker.check_output(self, want, got,
                                                  optionflags)
         if not ret and self.random_re.search(want):
             #print >> sys.stderr, 'RANDOM OK:',want  # dbg
             return True
 
         return ret
 
 
 class DocTestCase(doctests.DocTestCase):
     """Proxy for DocTestCase: provides an address() method that
     returns the correct address for the doctest case. Otherwise
     acts as a proxy to the test case. To provide hints for address(),
     an obj may also be passed -- this will be used as the test object
     for purposes of determining the test address, if it is provided.
     """
 
     # Note: this method was taken from numpy's nosetester module.
 
     # Subclass nose.plugins.doctests.DocTestCase to work around a bug in
     # its constructor that blocks non-default arguments from being passed
     # down into doctest.DocTestCase
 
     def __init__(self, test, optionflags=0, setUp=None, tearDown=None,
                  checker=None, obj=None, result_var='_'):
         self._result_var = result_var
         doctests.DocTestCase.__init__(self, test,
                                       optionflags=optionflags,
                                       setUp=setUp, tearDown=tearDown,
                                       checker=checker)
         # Now we must actually copy the original constructor from the stdlib
         # doctest class, because we can't call it directly and a bug in nose
         # means it never gets passed the right arguments.
 
         self._dt_optionflags = optionflags
         self._dt_checker = checker
         self._dt_test = test
         self._dt_test_globs_ori = test.globs
         self._dt_setUp = setUp
         self._dt_tearDown = tearDown
 
         # XXX - store this runner once in the object!
         runner = IPDocTestRunner(optionflags=optionflags,
                                  checker=checker, verbose=False)
         self._dt_runner = runner
 
 
         # Each doctest should remember the directory it was loaded from, so
         # things like %run work without too many contortions
         self._ori_dir = os.path.dirname(test.filename)
 
     # Modified runTest from the default stdlib
     def runTest(self):
         test = self._dt_test
         runner = self._dt_runner
 
         old = sys.stdout
         new = StringIO()
         optionflags = self._dt_optionflags
 
         if not (optionflags & REPORTING_FLAGS):
             # The option flags don't include any reporting flags,
             # so add the default reporting flags
             optionflags |= _unittest_reportflags
 
         try:
             # Save our current directory and switch out to the one where the
             # test was originally created, in case another doctest did a
             # directory change.  We'll restore this in the finally clause.
             curdir = os.getcwdu()
             #print 'runTest in dir:', self._ori_dir  # dbg
             os.chdir(self._ori_dir)
 
             runner.DIVIDER = "-"*70
             failures, tries = runner.run(test,out=new.write,
                                          clear_globs=False)
         finally:
             sys.stdout = old
             os.chdir(curdir)
 
         if failures:
             raise self.failureException(self.format_failure(new.getvalue()))
 
     def setUp(self):
         """Modified test setup that syncs with ipython namespace"""
         #print "setUp test", self._dt_test.examples # dbg
         if isinstance(self._dt_test.examples[0],IPExample):
             # for IPython examples *only*, we swap the globals with the ipython
             # namespace, after updating it with the globals (which doctest
             # fills with the necessary info from the module being tested).
+            self.user_ns_orig = {}
+            self.user_ns_orig.update(_ip.user_ns)
             _ip.user_ns.update(self._dt_test.globs)
             self._dt_test.globs = _ip.user_ns
             # IPython must protect the _ key in the namespace (it can't exist)
             # so that Python's doctest code sets it naturally, so we enable
             # this feature of our testing namespace.
             _ip.user_ns.protect_underscore = True
 
         super(DocTestCase, self).setUp()
 
     def tearDown(self):
 
         # Undo the test.globs reassignment we made, so that the parent class
         # teardown doesn't destroy the ipython namespace
         if isinstance(self._dt_test.examples[0],IPExample):
             self._dt_test.globs = self._dt_test_globs_ori
+            _ip.user_ns.clear()
+            _ip.user_ns.update(self.user_ns_orig)
             # Restore the behavior of the '_' key in the user namespace to
             # normal after each doctest, so that unittests behave normally
             _ip.user_ns.protect_underscore = False
 
         # XXX - fperez: I am not sure if this is truly a bug in nose 0.11, but
         # it does look like one to me: its tearDown method tries to run
         #
         # delattr(__builtin__, self._result_var)
         #
         # without checking that the attribute really is there; it implicitly
         # assumes it should have been set via displayhook.  But if the
         # displayhook was never called, this doesn't necessarily happen.  I
         # haven't been able to find a little self-contained example outside of
         # ipython that would show the problem so I can report it to the nose
         # team, but it does happen a lot in our code.
         #
         # So here, we just protect as narrowly as possible by trapping an
         # attribute error whose message would be the name of self._result_var,
         # and letting any other error propagate.
         try:
             super(DocTestCase, self).tearDown()
         except AttributeError, exc:
             if exc.args[0] != self._result_var:
                 raise
 
 
 # A simple subclassing of the original with a different class name, so we can
 # distinguish and treat differently IPython examples from pure python ones.
 class IPExample(doctest.Example): pass
 
 
 class IPExternalExample(doctest.Example):
     """Doctest examples to be run in an external process."""
 
     def __init__(self, source, want, exc_msg=None, lineno=0, indent=0,
                  options=None):
         # Parent constructor
         doctest.Example.__init__(self,source,want,exc_msg,lineno,indent,options)
 
         # An EXTRA newline is needed to prevent pexpect hangs
         self.source += '\n'
 
 
 class IPDocTestParser(doctest.DocTestParser):
     """
     A class used to parse strings containing doctest examples.
 
     Note: This is a version modified to properly recognize IPython input and
     convert any IPython examples into valid Python ones.
     """
     # This regular expression is used to find doctest examples in a
     # string.  It defines three groups: `source` is the source code
     # (including leading indentation and prompts); `indent` is the
     # indentation of the first (PS1) line of the source code; and
     # `want` is the expected output (including leading indentation).
 
     # Classic Python prompts or default IPython ones
     _PS1_PY = r'>>>'
     _PS2_PY = r'\.\.\.'
 
     _PS1_IP = r'In\ \[\d+\]:'
     _PS2_IP = r'\ \ \ \.\.\.+:'
 
     _RE_TPL = r'''
         # Source consists of a PS1 line followed by zero or more PS2 lines.
         (?P<source>
             (?:^(?P<indent> [ ]*) (?P<ps1> %s) .*)    # PS1 line
             (?:\n           [ ]*  (?P<ps2> %s) .*)*)  # PS2 lines
         \n? # a newline
         # Want consists of any non-blank lines that do not start with PS1.
         (?P<want> (?:(?![ ]*$)    # Not a blank line
                      (?![ ]*%s)   # Not a line starting with PS1
                      (?![ ]*%s)   # Not a line starting with PS2
                      .*$\n?       # But any other line
                   )*)
                   '''
 
     _EXAMPLE_RE_PY = re.compile( _RE_TPL % (_PS1_PY,_PS2_PY,_PS1_PY,_PS2_PY),
                                  re.MULTILINE | re.VERBOSE)
 
     _EXAMPLE_RE_IP = re.compile( _RE_TPL % (_PS1_IP,_PS2_IP,_PS1_IP,_PS2_IP),
                                  re.MULTILINE | re.VERBOSE)
 
     # Mark a test as being fully random.  In this case, we simply append the
     # random marker ('#random') to each individual example's output.  This way
     # we don't need to modify any other code.
     _RANDOM_TEST = re.compile(r'#\s*all-random\s+')
 
     # Mark tests to be executed in an external process - currently unsupported.
     _EXTERNAL_IP = re.compile(r'#\s*ipdoctest:\s*EXTERNAL')
 
     def ip2py(self,source):
         """Convert input IPython source into valid Python."""
         out = []
         newline = out.append
         #print 'IPSRC:\n',source,'\n###'  # dbg
         # The input source must be first stripped of all bracketing whitespace
         # and turned into lines, so it looks to the parser like regular user
         # input
         for lnum,line in enumerate(source.strip().splitlines()):
             newline(_ip.prefilter(line,lnum>0))
         newline('')  # ensure a closing newline, needed by doctest
         #print "PYSRC:", '\n'.join(out)  # dbg
         return '\n'.join(out)
 
     def parse(self, string, name='<string>'):
         """
         Divide the given string into examples and intervening text,
         and return them as a list of alternating Examples and strings.
         Line numbers for the Examples are 0-based.  The optional
         argument `name` is a name identifying this string, and is only
         used for error messages.
         """
 
         #print 'Parse string:\n',string # dbg
 
         string = string.expandtabs()
         # If all lines begin with the same indentation, then strip it.
         min_indent = self._min_indent(string)
         if min_indent > 0:
             string = '\n'.join([l[min_indent:] for l in string.split('\n')])
 
         output = []
         charno, lineno = 0, 0
 
         # We make 'all random' tests by adding the '# random' mark to every
         # block of output in the test.
         if self._RANDOM_TEST.search(string):
             random_marker = '\n# random'
         else:
             random_marker = ''
 
         # Whether to convert the input from ipython to python syntax
         ip2py = False
         # Find all doctest examples in the string.  First, try them as Python
         # examples, then as IPython ones
         terms = list(self._EXAMPLE_RE_PY.finditer(string))
         if terms:
             # Normal Python example
             #print '-'*70  # dbg
             #print 'PyExample, Source:\n',string  # dbg
             #print '-'*70  # dbg
             Example = doctest.Example
         else:
             # It's an ipython example.  Note that IPExamples are run
             # in-process, so their syntax must be turned into valid python.
             # IPExternalExamples are run out-of-process (via pexpect) so they
             # don't need any filtering (a real ipython will be executing them).
             terms = list(self._EXAMPLE_RE_IP.finditer(string))
             if self._EXTERNAL_IP.search(string):
                 #print '-'*70  # dbg
                 #print 'IPExternalExample, Source:\n',string  # dbg
                 #print '-'*70  # dbg
                 Example = IPExternalExample
             else:
                 #print '-'*70  # dbg
                 #print 'IPExample, Source:\n',string  # dbg
                 #print '-'*70  # dbg
                 Example = IPExample
                 ip2py = True
 
         for m in terms:
             # Add the pre-example text to `output`.
             output.append(string[charno:m.start()])
             # Update lineno (lines before this example)
             lineno += string.count('\n', charno, m.start())
             # Extract info from the regexp match.
             (source, options, want, exc_msg) = \
                      self._parse_example(m, name, lineno,ip2py)
 
             # Append the random-output marker (it defaults to empty in most
             # cases, it's only non-empty for 'all-random' tests):
             want += random_marker
 
             if Example is IPExternalExample:
                 options[doctest.NORMALIZE_WHITESPACE] = True
                 want += '\n'
 
             # Create an Example, and add it to the list.
             if not self._IS_BLANK_OR_COMMENT(source):
                 output.append(Example(source, want, exc_msg,
                                       lineno=lineno,
                                       indent=min_indent+len(m.group('indent')),
                                       options=options))
             # Update lineno (lines inside this example)
             lineno += string.count('\n', m.start(), m.end())
             # Update charno.
             charno = m.end()
         # Add any remaining post-example text to `output`.
         output.append(string[charno:])
         return output
 
     def _parse_example(self, m, name, lineno,ip2py=False):
         """
         Given a regular expression match from `_EXAMPLE_RE` (`m`),
         return a pair `(source, want)`, where `source` is the matched
         example's source code (with prompts and indentation stripped);
         and `want` is the example's expected output (with indentation
         stripped).
 
         `name` is the string's name, and `lineno` is the line number
         where the example starts; both are used for error messages.
 
         Optional:
         `ip2py`: if true, filter the input via IPython to convert the syntax
         into valid python.
         """
 
         # Get the example's indentation level.
         indent = len(m.group('indent'))
 
         # Divide source into lines; check that they're properly
         # indented; and then strip their indentation & prompts.
         source_lines = m.group('source').split('\n')
 
         # We're using variable-length input prompts
         ps1 = m.group('ps1')
         ps2 = m.group('ps2')
         ps1_len = len(ps1)
 
         self._check_prompt_blank(source_lines, indent, name, lineno,ps1_len)
         if ps2:
             self._check_prefix(source_lines[1:], ' '*indent + ps2, name, lineno)
 
         source = '\n'.join([sl[indent+ps1_len+1:] for sl in source_lines])
 
         if ip2py:
             # Convert source input from IPython into valid Python syntax
             source = self.ip2py(source)
 
         # Divide want into lines; check that it's properly indented; and
         # then strip the indentation.  Spaces before the last newline should
         # be preserved, so plain rstrip() isn't good enough.
         want = m.group('want')
         want_lines = want.split('\n')
         if len(want_lines) > 1 and re.match(r' *$', want_lines[-1]):
             del want_lines[-1]  # forget final newline & spaces after it
         self._check_prefix(want_lines, ' '*indent, name,
                            lineno + len(source_lines))
 
         # Remove ipython output prompt that might be present in the first line
         want_lines[0] = re.sub(r'Out\[\d+\]: \s*?\n?','',want_lines[0])
 
         want = '\n'.join([wl[indent:] for wl in want_lines])
 
         # If `want` contains a traceback message, then extract it.
         m = self._EXCEPTION_RE.match(want)
         if m:
             exc_msg = m.group('msg')
         else:
             exc_msg = None
 
         # Extract options from the source.
         options = self._find_options(source, name, lineno)
 
         return source, options, want, exc_msg
 
     def _check_prompt_blank(self, lines, indent, name, lineno, ps1_len):
         """
         Given the lines of a source string (including prompts and
         leading indentation), check to make sure that every prompt is
         followed by a space character.  If any line is not followed by
         a space character, then raise ValueError.
 
         Note: IPython-modified version which takes the input prompt length as a
         parameter, so that prompts of variable length can be dealt with.
         """
         space_idx = indent+ps1_len
         min_len = space_idx+1
         for i, line in enumerate(lines):
             if len(line) >=  min_len and line[space_idx] != ' ':
                 raise ValueError('line %r of the docstring for %s '
                                  'lacks blank after %s: %r' %
                                  (lineno+i+1, name,
                                   line[indent:space_idx], line))
 
 
 SKIP = doctest.register_optionflag('SKIP')
 
 
 class IPDocTestRunner(doctest.DocTestRunner,object):
     """Test runner that synchronizes the IPython namespace with test globals.
     """
 
     def run(self, test, compileflags=None, out=None, clear_globs=True):
 
         # Hack: ipython needs access to the execution context of the example,
         # so that it can propagate user variables loaded by %run into
         # test.globs.  We put them here into our modified %run as a function
         # attribute.  Our new %run will then only make the namespace update
         # when called (rather than unconconditionally updating test.globs here
         # for all examples, most of which won't be calling %run anyway).
         #_ip._ipdoctest_test_globs = test.globs
         #_ip._ipdoctest_test_filename = test.filename
 
         test.globs.update(_ip.user_ns)
 
         return super(IPDocTestRunner,self).run(test,
                                                compileflags,out,clear_globs)
 
 
 class DocFileCase(doctest.DocFileCase):
     """Overrides to provide filename
     """
     def address(self):
         return (self._dt_test.filename, None, None)
 
 
 class ExtensionDoctest(doctests.Doctest):
     """Nose Plugin that supports doctests in extension modules.
     """
     name = 'extdoctest'   # call nosetests with --with-extdoctest
     enabled = True
 
     def __init__(self,exclude_patterns=None):
         """Create a new ExtensionDoctest plugin.
 
         Parameters
         ----------
 
         exclude_patterns : sequence of strings, optional
           These patterns are compiled as regular expressions, subsequently used
           to exclude any filename which matches them from inclusion in the test
           suite (using pattern.search(), NOT pattern.match() ).
         """
 
         if exclude_patterns is None:
             exclude_patterns = []
         self.exclude_patterns = map(re.compile,exclude_patterns)
         doctests.Doctest.__init__(self)
 
     def options(self, parser, env=os.environ):
         Plugin.options(self, parser, env)
         parser.add_option('--doctest-tests', action='store_true',
                           dest='doctest_tests',
                           default=env.get('NOSE_DOCTEST_TESTS',True),
                           help="Also look for doctests in test modules. "
                           "Note that classes, methods and functions should "
                           "have either doctests or non-doctest tests, "
                           "not both. [NOSE_DOCTEST_TESTS]")
         parser.add_option('--doctest-extension', action="append",
                           dest="doctestExtension",
                           help="Also look for doctests in files with "
                           "this extension [NOSE_DOCTEST_EXTENSION]")
         # Set the default as a list, if given in env; otherwise
         # an additional value set on the command line will cause
         # an error.
         env_setting = env.get('NOSE_DOCTEST_EXTENSION')
         if env_setting is not None:
             parser.set_defaults(doctestExtension=tolist(env_setting))
 
 
     def configure(self, options, config):
         Plugin.configure(self, options, config)
         # Pull standard doctest plugin out of config; we will do doctesting
         config.plugins.plugins = [p for p in config.plugins.plugins
                                   if p.name != 'doctest']
         self.doctest_tests = options.doctest_tests
         self.extension = tolist(options.doctestExtension)
 
         self.parser = doctest.DocTestParser()
         self.finder = DocTestFinder()
         self.checker = IPDoctestOutputChecker()
         self.globs = None
         self.extraglobs = None
 
 
     def loadTestsFromExtensionModule(self,filename):
         bpath,mod = os.path.split(filename)
         modname = os.path.splitext(mod)[0]
         try:
             sys.path.append(bpath)
             module = __import__(modname)
             tests = list(self.loadTestsFromModule(module))
         finally:
             sys.path.pop()
         return tests
 
     # NOTE: the method below is almost a copy of the original one in nose, with
     # a  few modifications to control output checking.
 
     def loadTestsFromModule(self, module):
         #print '*** ipdoctest - lTM',module  # dbg
 
         if not self.matches(module.__name__):
             log.debug("Doctest doesn't want module %s", module)
             return
 
         tests = self.finder.find(module,globs=self.globs,
                                  extraglobs=self.extraglobs)
         if not tests:
             return
 
         # always use whitespace and ellipsis options
         optionflags = doctest.NORMALIZE_WHITESPACE | doctest.ELLIPSIS
 
         tests.sort()
         module_file = module.__file__
         if module_file[-4:] in ('.pyc', '.pyo'):
             module_file = module_file[:-1]
         for test in tests:
             if not test.examples:
                 continue
             if not test.filename:
                 test.filename = module_file
 
             yield DocTestCase(test,
                               optionflags=optionflags,
                               checker=self.checker)
 
 
     def loadTestsFromFile(self, filename):
         #print "ipdoctest - from file", filename # dbg
         if is_extension_module(filename):
             for t in self.loadTestsFromExtensionModule(filename):
                 yield t
         else:
             if self.extension and anyp(filename.endswith, self.extension):
                 name = os.path.basename(filename)
                 dh = open(filename)
                 try:
                     doc = dh.read()
                 finally:
                     dh.close()
                 test = self.parser.get_doctest(
                     doc, globs={'__file__': filename}, name=name,
                     filename=filename, lineno=0)
                 if test.examples:
                     #print 'FileCase:',test.examples  # dbg
                     yield DocFileCase(test)
                 else:
                     yield False # no tests to load
 
     def wantFile(self,filename):
         """Return whether the given filename should be scanned for tests.
 
         Modified version that accepts extension modules as valid containers for
         doctests.
         """
         #print '*** ipdoctest- wantFile:',filename  # dbg
 
         for pat in self.exclude_patterns:
             if pat.search(filename):
                 # print '###>>> SKIP:',filename  # dbg
                 return False
 
         if is_extension_module(filename):
             return True
         else:
             return doctests.Doctest.wantFile(self,filename)
 
     def wantDirectory(self, directory):
         """Return whether the given directory should be scanned for tests.
 
         Modified version that supports exclusions.
         """
 
         for pat in self.exclude_patterns:
             if pat.search(directory):
                 return False
         return True
 
 
 class IPythonDoctest(ExtensionDoctest):
     """Nose Plugin that supports doctests in extension modules.
     """
     name = 'ipdoctest'   # call nosetests with --with-ipdoctest
     enabled = True
 
     def makeTest(self, obj, parent):
         """Look for doctests in the given object, which will be a
         function, method or class.
         """
         #print 'Plugin analyzing:', obj, parent  # dbg
         # always use whitespace and ellipsis options
         optionflags = doctest.NORMALIZE_WHITESPACE | doctest.ELLIPSIS
 
         doctests = self.finder.find(obj, module=getmodule(parent))
         if doctests:
             for test in doctests:
                 if len(test.examples) == 0:
                     continue
 
                 yield DocTestCase(test, obj=obj,
                                   optionflags=optionflags,
                                   checker=self.checker)
 
     def options(self, parser, env=os.environ):
         #print "Options for nose plugin:", self.name # dbg
         Plugin.options(self, parser, env)
         parser.add_option('--ipdoctest-tests', action='store_true',
                           dest='ipdoctest_tests',
                           default=env.get('NOSE_IPDOCTEST_TESTS',True),
                           help="Also look for doctests in test modules. "
                           "Note that classes, methods and functions should "
                           "have either doctests or non-doctest tests, "
                           "not both. [NOSE_IPDOCTEST_TESTS]")
         parser.add_option('--ipdoctest-extension', action="append",
                           dest="ipdoctest_extension",
                           help="Also look for doctests in files with "
                           "this extension [NOSE_IPDOCTEST_EXTENSION]")
         # Set the default as a list, if given in env; otherwise
         # an additional value set on the command line will cause
         # an error.
         env_setting = env.get('NOSE_IPDOCTEST_EXTENSION')
         if env_setting is not None:
             parser.set_defaults(ipdoctest_extension=tolist(env_setting))
 
     def configure(self, options, config):
         #print "Configuring nose plugin:", self.name # dbg
         Plugin.configure(self, options, config)
         # Pull standard doctest plugin out of config; we will do doctesting
         config.plugins.plugins = [p for p in config.plugins.plugins
                                   if p.name != 'doctest']
         self.doctest_tests = options.ipdoctest_tests
         self.extension = tolist(options.ipdoctest_extension)
 
         self.parser = IPDocTestParser()
         self.finder = DocTestFinder(parser=self.parser)
         self.checker = IPDoctestOutputChecker()
         self.globs = None
         self.extraglobs = None