Reasonably complete object_info request implemented.

IPython/core/interactiveshell.py

@@ -1,2340 +1,2340 b''
 # -*- coding: utf-8 -*-
 """Main IPython class."""
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2001 Janko Hauser <[e-mail]>
 #  Copyright (C) 2001-2007 Fernando Perez. <[e-mail]>
 #  Copyright (C) 2008-2010  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__
 import __future__
 import abc
 import codeop
 import exceptions
 import new
 import os
 import re
 import string
 import sys
 import tempfile
 from contextlib import nested
 
 from IPython.config.configurable import Configurable
 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
 from IPython.core.builtin_trap import BuiltinTrap
 from IPython.core.display_trap import DisplayTrap
 from IPython.core.displayhook import DisplayHook
 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.inputlist import InputList
 from IPython.core.logger import Logger
 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.external.Itpl import ItplNS
 from IPython.utils import PyColorize
 from IPython.utils import io
 from IPython.utils import pickleshare
 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.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
 from IPython.utils.traitlets import (Int, Str, CBool, CaselessStrEnum, Enum,
                                      List, Unicode, Instance, Type)
 from IPython.utils.warn import warn, error, fatal
 import IPython.core.hooks
 
 # from IPython.utils import growl
 # growl.start("IPython")
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 # compiled regexps for autoindent management
 dedent_re = re.compile(r'^\s+raise|^\s+return|^\s+pass')
 
 #-----------------------------------------------------------------------------
 # Utilities
 #-----------------------------------------------------------------------------
 
 # store the builtin raw_input globally, and use this always, in case user code
 # overwrites it (like wx.py.PyShell does)
 raw_input_original = raw_input
 
 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 SpaceInInput(exceptions.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 SeparateStr(Str):
     """A Str subclass to validate separate_in, separate_out, etc.
 
     This is a Str based trait that converts '0'->'' and '\\n'->'\n'.
     """
 
     def validate(self, obj, value):
         if value == '0': value = ''
         value = value.replace('\\n','\n')
         return super(SeparateStr, self).validate(obj, value)
 
 class MultipleInstanceError(Exception):
     pass
 
 
 #-----------------------------------------------------------------------------
 # Main IPython class
 #-----------------------------------------------------------------------------
 
 
 class InteractiveShell(Configurable, Magic):
     """An enhanced, interactive shell for Python."""
 
     _instance = None
     autocall = Enum((0,1,2), default_value=1, config=True)
     # 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)
     automagic = CBool(True, config=True)
     cache_size = Int(1000, config=True)
     color_info = CBool(True, config=True)
     colors = CaselessStrEnum(('NoColor','LightBG','Linux'), 
                              default_value=get_default_colors(), config=True)
     debug = CBool(False, config=True)
     deep_reload = CBool(False, config=True)
     displayhook_class = Type(DisplayHook)
     filename = Str("<ipython console>")
     ipython_dir= Unicode('', config=True) # Set to get_ipython_dir() in __init__
     logstart = CBool(False, config=True)
     logfile = Str('', config=True)
     logappend = Str('', config=True)
     object_info_string_level = Enum((0,1,2), default_value=0,
                                     config=True)
     pdb = CBool(False, config=True)
     pprint = CBool(True, config=True)
     profile = Str('', config=True)
     prompt_in1 = Str('In [\\#]: ', config=True)
     prompt_in2 = Str('   .\\D.: ', config=True)
     prompt_out = Str('Out[\\#]: ', config=True)
     prompts_pad_left = CBool(True, config=True)
     quiet = CBool(False, 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_merge_completions = CBool(True, config=True)
     readline_omit__names = Enum((0,1,2), default_value=0, config=True)
     readline_remove_delims = Str('-/~', config=True)
     readline_parse_and_bind = List([
             'tab: complete',
             '"\C-l": clear-screen',
             'set show-all-if-ambiguous on',
             '"\C-o": tab-insert',
             '"\M-i": "    "',
             '"\M-o": "\d\d\d\d"',
             '"\M-I": "\d\d\d\d"',
             '"\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 = SeparateStr('\n', config=True)
     separate_out = SeparateStr('', config=True)
     separate_out2 = SeparateStr('', 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')
 
     def __init__(self, config=None, ipython_dir=None,
                  user_ns=None, user_global_ns=None,
                  custom_exceptions=((),None)):
 
         # This is where traits with a config_key argument are updated
         # from the values on config.
         super(InteractiveShell, self).__init__(config=config)
 
         # These are relatively independent and stateless
         self.init_ipython_dir(ipython_dir)
         self.init_instance_attrs()
 
         # Create namespaces (user_ns, user_global_ns, etc.)
         self.init_create_namespaces(user_ns, user_global_ns)
         # This has to be done after init_create_namespaces because it uses
         # something in self.user_ns, but before init_sys_modules, which
         # is the first thing to modify sys.
         # TODO: When we override sys.stdout and sys.stderr before this class
         # is created, we are saving the overridden ones here. Not sure if this
         # is what we want to do.
         self.save_sys_module_state()
         self.init_sys_modules()
 
         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
         self.init_shadow_hist()
 
         # The next section should contain averything 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()
         # 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_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()
 
     @classmethod
     def instance(cls, *args, **kwargs):
         """Returns a global InteractiveShell instance."""
         if cls._instance is None:
             inst = cls(*args, **kwargs)
             # Now make sure that the instance will also be returned by
             # the subclasses instance attribute.
             for subclass in cls.mro():
                 if issubclass(cls, subclass) and issubclass(subclass, InteractiveShell):
                     subclass._instance = inst
                 else:
                     break
         if isinstance(cls._instance, cls):
             return cls._instance
         else:
             raise MultipleInstanceError(
                 'Multiple incompatible subclass instances of '
                 'InteractiveShell are being created.'
             )
 
     @classmethod
     def initialized(cls):
         return hasattr(cls, "_instance")
 
     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 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
             self.config.Global.ipython_dir = self.ipython_dir
             return
 
         if hasattr(self.config.Global, 'ipython_dir'):
             self.ipython_dir = self.config.Global.ipython_dir
         else:
             self.ipython_dir = get_ipython_dir()
 
         # All children can just read this
         self.config.Global.ipython_dir = self.ipython_dir
 
     def init_instance_attrs(self):
         self.more = False
 
         # command compiler
         self.compile = codeop.CommandCompiler()
 
         # User input buffer
         self.buffer = []
 
         # 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()
 
         # Object variable to store code object waiting execution.  This is
         # used mainly by the multithreaded shells, but it can come in handy in
         # other situations.  No need to use a Queue here, since it's a single
         # item which gets cleared once run.
         self.code_to_run = None
 
         # 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.getcwd()
 
         # Indentation management
         self.indent_current_nsp = 0
 
     def init_encoding(self):
         # Get system encoding at startup time.  Certain terminals (like Emacs
         # under Win32 have it set to None, and we need to have a known valid
         # encoding to use in the raw_input() method
         try:
             self.stdin_encoding = sys.stdin.encoding or 'ascii'
         except AttributeError:
             self.stdin_encoding = 'ascii'
 
     def init_syntax_highlighting(self):
         # Python source parser/formatter for syntax highlighting
         pyformat = PyColorize.Parser().format
         self.pycolorize = lambda src: pyformat(src,'str',self.colors)
 
     def init_pushd_popd_magic(self):
         # for pushd/popd management
         try:
             self.home_dir = get_home_dir()
         except HomeDirError, msg:
             fatal(msg)
 
         self.dir_stack = []
 
     def init_logger(self):
         self.logger = Logger(self, logfname='ipython_log.py', logmode='rotate')
         # local shortcut, this is used a LOT
         self.log = self.logger.log
 
     def init_logstart(self):
         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):
         import IPython.utils.io
         if sys.platform == 'win32' and self.has_readline:
             Term = io.IOTerm(
                 cout=self.readline._outputfile,cerr=self.readline._outputfile
             )
         else:
             Term = io.IOTerm()
         io.Term = Term
 
     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_displayhook(self):
         # Initialize displayhook, set in/out prompts and printing system
         self.displayhook = self.displayhook_class(
             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
         )
         # This is a context manager that installs/revmoes the displayhook at
         # the appropriate time.
         self.display_trap = DisplayTrap(hook=self.displayhook)
 
     def init_reload_doctest(self):
         # Do a proper resetting of doctest, including the necessary displayhook
         # monkeypatching
         try:
             doctest_reload()
         except ImportError:
             warn("doctest module does not exist.")
 
     #-------------------------------------------------------------------------
     # Things related to injections into the sys module
     #-------------------------------------------------------------------------
 
     def save_sys_module_state(self):
         """Save the state of hooks in the sys module.
 
         This has to be called after self.user_ns is created.
         """
         self._orig_sys_module_state = {}
         self._orig_sys_module_state['stdin'] = sys.stdin
         self._orig_sys_module_state['stdout'] = sys.stdout
         self._orig_sys_module_state['stderr'] = sys.stderr
         self._orig_sys_module_state['excepthook'] = sys.excepthook
         try:
             self._orig_sys_modules_main_name = self.user_ns['__name__']
         except KeyError:
             pass
 
     def restore_sys_module_state(self):
         """Restore the state of the sys module."""
         try:
             for k, v in self._orig_sys_module_state.items():
                 setattr(sys, k, v)
         except AttributeError:
             pass
         try:
             delattr(sys, 'ipcompleter')
         except AttributeError:
             pass
         # Reset what what done in self.init_sys_modules
         try:
             sys.modules[self.user_ns['__name__']] = self._orig_sys_modules_main_name
         except (AttributeError, KeyError):
             pass
 
     #-------------------------------------------------------------------------
     # Things related to hooks
     #-------------------------------------------------------------------------
 
     def init_hooks(self):
         # hooks holds pointers used for user-side customizations
         self.hooks = Struct()
 
         self.strdispatchers = {}
 
         # Set all default hooks, defined in the IPython.hooks module.
         hooks = IPython.core.hooks
         for hook_name in hooks.__all__:
             # default hooks have priority 100, i.e. low; user hooks should have
             # 0-100 priority
             self.set_hook(hook_name,getattr(hooks,hook_name), 100)
 
     def set_hook(self,name,hook, priority = 50, str_key = None, re_key = None):
         """set_hook(name,hook) -> sets an internal IPython hook.
 
         IPython exposes some of its internal API as user-modifiable hooks.  By
         adding your function to one of these hooks, you can modify IPython's 
         behavior to call at runtime your own routines."""
 
         # At some point in the future, this should validate the hook before it
         # accepts it.  Probably at least check that the hook takes the number
         # of args it's supposed to.
         
         f = new.instancemethod(hook,self,self.__class__)
 
         # 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)
 
     #-------------------------------------------------------------------------
     # 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)
         self.history_saving_wrapper(pm)()
 
     #-------------------------------------------------------------------------
     # Things related to IPython's various namespaces
     #-------------------------------------------------------------------------
 
     def init_create_namespaces(self, user_ns=None, user_global_ns=None):
         # Create the namespace where the user will operate.  user_ns is
         # normally the only one used, and it is passed to the exec calls as
         # the locals argument.  But we do carry a user_global_ns namespace
         # given as the exec 'globals' argument,  This is useful in embedding
         # situations where the ipython shell opens in a context where the
         # distinction between locals and globals is meaningful.  For
         # non-embedded contexts, it is just the same object as the user_ns dict.
 
         # FIXME. For some strange reason, __builtins__ is showing up at user
         # level as a dict instead of a module. This is a manual fix, but I
         # should really track down where the problem is coming from. Alex
         # Schmolck reported this problem first.
 
         # A useful post by Alex Martelli on this topic:
         # Re: inconsistent value from __builtins__
         # Von: Alex Martelli <[e-mail]>
         # Datum: Freitag 01 Oktober 2004 04:45:34 nachmittags/abends
         # Gruppen: comp.lang.python
 
         # Michael Hohn <[e-mail]> wrote:
         # > >>> print type(builtin_check.get_global_binding('__builtins__'))
         # > <type 'dict'>
         # > >>> print type(__builtins__)
         # > <type 'module'>
         # > Is this difference in return value intentional?
 
         # Well, it's documented that '__builtins__' can be either a dictionary
         # or a module, and it's been that way for a long time. Whether it's
         # intentional (or sensible), I don't know. In any case, the idea is
         # that if you need to access the built-in namespace directly, you
         # should start with "import __builtin__" (note, no 's') which will
         # definitely give you a module. Yeah, it's somewhat confusing:-(.
 
         # These routines return properly built dicts as needed by the rest of
         # the code, and can also be used by extension writers to generate
         # properly initialized namespaces.
         user_ns, user_global_ns = self.make_user_namespaces(user_ns, user_global_ns)
 
         # Assign namespaces
         # This is the namespace where all normal user variables live
         self.user_ns = user_ns
         self.user_global_ns = user_global_ns
 
         # An auxiliary namespace that checks what parts of the user_ns were
         # loaded at startup, so we can list later only variables defined in
         # actual interactive use.  Since it is always a subset of user_ns, it
         # doesn't need to be separately tracked in the ns_table.
         self.user_ns_hidden = {}
 
         # A namespace to keep track of internal data structures to prevent
         # them from cluttering user-visible stuff.  Will be updated later
         self.internal_ns = {}
 
         # Now that FakeModule produces a real module, we've run into a nasty
         # problem: after script execution (via %run), the module where the user
         # code ran is deleted.  Now that this object is a true module (needed
         # so docetst and other tools work correctly), the Python module
         # teardown mechanism runs over it, and sets to None every variable
         # present in that module.  Top-level references to objects from the
         # script survive, because the user_ns is updated with them.  However,
         # calling functions defined in the script that use other things from
         # the script will fail, because the function's closure had references
         # to the original objects, which are now all None.  So we must protect
         # these modules from deletion by keeping a cache.
         # 
         # To avoid keeping stale modules around (we only need the one from the
         # last run), we use a dict keyed with the full path to the script, so
         # only the last version of the module is held in the cache.  Note,
         # however, that we must cache the module *namespace contents* (their
         # __dict__).  Because if we try to cache the actual modules, old ones
         # (uncached) could be destroyed while still holding references (such as
         # those held by GUI objects that tend to be long-lived)>
         # 
         # The %reset command will flush this cache.  See the cache_main_mod()
         # and clear_main_mod_cache() methods for details on use.
 
         # This is the cache used for 'main' namespaces
         self._main_ns_cache = {}
         # And this is the single instance of FakeModule whose __dict__ we keep
         # copying and clearing for reuse on each %run
         self._user_main_module = FakeModule()
 
         # A table holding all the namespaces IPython deals with, so that
         # introspection facilities can search easily.
         self.ns_table = {'user':user_ns,
                          'user_global':user_global_ns,
                          'internal':self.internal_ns,
                          'builtin':__builtin__.__dict__
                          }
 
         # Similarly, track all namespaces where references can be held and that
         # we can safely clear (so it can NOT include builtin).  This one can be
         # a simple list.
         self.ns_refs_table = [ user_ns, user_global_ns, self.user_ns_hidden,
                                self.internal_ns, self._main_ns_cache ]
 
     def make_user_namespaces(self, user_ns=None, user_global_ns=None):
         """Return a valid local and global user interactive namespaces.
 
         This builds a dict with the minimal information needed to operate as a
         valid IPython user namespace, which you can pass to the various
         embedding classes in ipython. The default implementation returns the
         same dict for both the locals and the globals to allow functions to
         refer to variables in the namespace. Customized implementations can
         return different dicts. The locals dictionary can actually be anything
         following the basic mapping protocol of a dict, but the globals dict
         must be a true dict, not even a subclass. It is recommended that any
         custom object for the locals namespace synchronize with the globals
         dict somehow.
 
         Raises TypeError if the provided globals namespace is not a true dict.
 
         Parameters
         ----------
         user_ns : dict-like, optional
             The current user namespace. The items in this namespace should
             be included in the output. If None, an appropriate blank
             namespace should be created.
         user_global_ns : dict, optional
             The current user global namespace. The items in this namespace
             should be included in the output. If None, an appropriate
             blank namespace should be created.
 
         Returns
         -------
             A pair of dictionary-like object to be used as the local namespace
             of the interpreter and a dict to be used as the global namespace.
         """
 
 
         # We must ensure that __builtin__ (without the final 's') is always
         # available and pointing to the __builtin__ *module*.  For more details:
         # http://mail.python.org/pipermail/python-dev/2001-April/014068.html
 
         if user_ns is None:
             # Set __name__ to __main__ to better match the behavior of the
             # normal interpreter.
             user_ns = {'__name__'     :'__main__',
                        '__builtin__' : __builtin__,
                        '__builtins__' : __builtin__,
                       }
         else:
             user_ns.setdefault('__name__','__main__')
             user_ns.setdefault('__builtin__',__builtin__)
             user_ns.setdefault('__builtins__',__builtin__)
 
         if user_global_ns is None:
             user_global_ns = user_ns
         if type(user_global_ns) is not dict:
             raise TypeError("user_global_ns must be a true dict; got %r"
                 % type(user_global_ns))
 
         return user_ns, user_global_ns
 
     def init_sys_modules(self):
         # We need to insert into sys.modules something that looks like a
         # module but which accesses the IPython namespace, for shelve and
         # pickle to work interactively. Normally they rely on getting
         # everything out of __main__, but for embedding purposes each IPython
         # instance has its own private namespace, so we can't go shoving
         # everything into __main__.
 
         # note, however, that we should only do this for non-embedded
         # ipythons, which really mimic the __main__.__dict__ with their own
         # namespace.  Embedded instances, on the other hand, should not do
         # this because they need to manage the user local/global namespaces
         # only, but they live within a 'normal' __main__ (meaning, they
         # shouldn't overtake the execution environment of the script they're
         # embedded in).
 
         # This is overridden in the InteractiveShellEmbed subclass to a no-op.
 
         try:
             main_name = self.user_ns['__name__']
         except KeyError:
             raise KeyError('user_ns dictionary MUST have a "__name__" key')
         else:
             sys.modules[main_name] = FakeModule(self.user_ns)
 
     def init_user_ns(self):
         """Initialize all user-visible namespaces to their minimum defaults.
 
         Certain history lists are also initialized here, as they effectively
         act as user namespaces.
 
         Notes
         -----
         All data structures here are only filled in, they are NOT reset by this
         method.  If they were not empty before, data will simply be added to
         therm.
         """
         # This function works in two parts: first we put a few things in
         # user_ns, and we sync that contents into user_ns_hidden so that these
         # initial variables aren't shown by %who.  After the sync, we add the
         # rest of what we *do* want the user to see with %who even on a new
         # session (probably nothing, so theye really only see their own stuff)
 
         # The user dict must *always* have a __builtin__ reference to the
         # Python standard __builtin__ namespace,  which must be imported.
         # This is so that certain operations in prompt evaluation can be
         # reliably executed with builtins.  Note that we can NOT use
         # __builtins__ (note the 's'),  because that can either be a dict or a
         # module, and can even mutate at runtime, depending on the context
         # (Python makes no guarantees on it).  In contrast, __builtin__ is
         # always a module object, though it must be explicitly imported.
         
         # For more details:
         # http://mail.python.org/pipermail/python-dev/2001-April/014068.html
         ns = dict(__builtin__ = __builtin__)
         
         # 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.input_hist
         ns['_oh'] = self.output_hist
         ns['_dh'] = self.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.input_hist
         ns['Out'] = self.output_hist
 
         # Store myself as the public api!!!
         ns['get_ipython'] = self.get_ipython
 
         # 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):
         """Clear all internal namespaces.
 
         Note that this is much more aggressive than %reset, since it clears
         fully all namespaces, as well as all input/output lists.
         """
         for ns in self.ns_refs_table:
             ns.clear()
 
         self.alias_manager.clear_aliases()
 
         # Clear input and output histories
         self.input_hist[:] = []
         self.input_hist_raw[:] = []
         self.output_hist.clear()
 
         # Restore the user namespaces to minimal usability
         self.init_user_ns()
 
         # Restore the default and user aliases
         self.alias_manager.init_aliases()
 
     def reset_selective(self, regex=None):
         """Clear selective variables from internal namespaces based on a specified regular expression.
 
         Parameters
         ----------
         regex : string or compiled pattern, optional
             A regular expression pattern that will be used in searching variable names in the users 
             namespaces.
         """
         if regex is not None:
             try:
                 m = re.compile(regex)
             except TypeError:
                 raise TypeError('regex must be a string or compiled pattern')
             # Search for keys in each namespace that match the given regex
             # If a match is found, delete the key/value pair.
             for ns in self.ns_refs_table:
                 for var in ns:
                     if m.search(var):
                         del ns[var]        
         
     def push(self, variables, interactive=True):
         """Inject a group of variables into the IPython user namespace.
 
         Parameters
         ----------
         variables : dict, str or list/tuple of str
             The variables to inject into the user's namespace.  If a dict,
             a simple update is done.  If a str, the string is assumed to 
             have variable names separated by spaces.  A list/tuple of str
             can also be used to give the variable names.  If just the variable
             names are give (list/tuple/str) then the variable values looked
             up in the callers frame.
         interactive : bool
             If True (default), the variables will be listed with the ``who``
             magic.
         """
         vdict = None
 
         # We need a dict of name/value pairs to do namespace updates.
         if isinstance(variables, dict):
             vdict = variables
         elif isinstance(variables, (basestring, list, tuple)):
             if isinstance(variables, basestring):
                 vlist = variables.split()
             else:
                 vlist = variables
             vdict = {}
             cf = sys._getframe(1)
             for name in vlist:
                 try:
                     vdict[name] = eval(name, cf.f_globals, cf.f_locals)
                 except:
                     print ('Could not get variable %s from %s' %
                            (name,cf.f_code.co_name))
         else:
             raise ValueError('variables must be a dict/str/list/tuple')
             
         # Propagate variables to user namespace
         self.user_ns.update(vdict)
 
         # And configure interactive visibility
         config_ns = self.user_ns_hidden
         if interactive:
             for name, val in vdict.iteritems():
                 config_ns.pop(name, None)
         else:
             for name,val in vdict.iteritems():
                 config_ns[name] = val
 
     #-------------------------------------------------------------------------
     # 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
         try:
             oname = oname.strip().encode('ascii')
             #print '2- oname: <%r>' % oname  # dbg
         except UnicodeEncodeError:
             print 'Python identifiers can only contain ascii characters.'
             return dict(found=False)
 
         alias_ns = None
         if namespaces is None:
             # Namespaces to search in:
             # Put them in a list. The order is important so that we
             # find things in the same order that Python finds them.
             namespaces = [ ('Interactive', self.user_ns),
                            ('IPython internal', self.internal_ns),
                            ('Python builtin', __builtin__.__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 (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):
         info = self._object_find(oname)
         if info.found:
             return self.inspector.info(info.obj, info=info)
         else:
-            return {}
+            return oinspect.mk_object_info({})
         
     #-------------------------------------------------------------------------
     # Things related to history management
     #-------------------------------------------------------------------------
 
     def init_history(self):
         # List of input with multi-line handling.
         self.input_hist = InputList()
         # This one will hold the 'raw' input history, without any
         # pre-processing.  This will allow users to retrieve the input just as
         # it was exactly typed in by the user, with %hist -r.
         self.input_hist_raw = InputList()
 
         # list of visited directories
         try:
             self.dir_hist = [os.getcwd()]
         except OSError:
             self.dir_hist = []
 
         # dict of output history
         self.output_hist = {}
 
         # Now the history file
         if self.profile:
             histfname = 'history-%s' % self.profile
         else:
             histfname = 'history'
         self.histfile = os.path.join(self.ipython_dir, histfname)
 
         # Fill the history zero entry, user counter starts at 1
         self.input_hist.append('\n')
         self.input_hist_raw.append('\n')
 
     def init_shadow_hist(self):
         try:
             self.db = pickleshare.PickleShareDB(self.ipython_dir + "/db")
         except exceptions.UnicodeDecodeError:
             print "Your ipython_dir can't be decoded to unicode!"
             print "Please set HOME environment variable to something that"
             print r"only has ASCII characters, e.g. c:\home"
             print "Now it is", self.ipython_dir
             sys.exit()
         self.shadowhist = ipcorehist.ShadowHist(self.db)
 
     def savehist(self):
         """Save input history to a file (via readline library)."""
 
         try:
             self.readline.write_history_file(self.histfile)
         except:
             print 'Unable to save IPython command history to file: ' + \
                   `self.histfile`
 
     def reloadhist(self):
         """Reload the input history from disk file."""
 
         try:
             self.readline.clear_history()
             self.readline.read_history_file(self.shell.histfile)
         except AttributeError:
             pass
 
     def history_saving_wrapper(self, func):
         """ Wrap func for readline history saving
 
         Convert func into callable that saves & restores
         history around the call """
 
         if self.has_readline:
             from IPython.utils import rlineimpl as readline
         else:
             return func
 
         def wrapper():
             self.savehist()
             try:
                 func()
             finally:
                 readline.read_history_file(self.histfile)
         return wrapper
 
     def get_history(self, index=None, raw=False, output=True):
         """Get the history list.
 
         Get the input and output history.
 
         Parameters
         ----------
         index : n or (n1, n2) or None
             If n, then the last entries. If a tuple, then all in
             range(n1, n2). If None, then all entries. Raises IndexError if
             the format of index is incorrect.
         raw : bool
             If True, return the raw input.
         output : bool
             If True, then return the output as well.
 
         Returns
         -------
         If output is True, then return a dict of tuples, keyed by the prompt
         numbers and with values of (input, output). If output is False, then
         a dict, keyed by the prompt number with the values of input. Raises
         IndexError if no history is found.
         """
         if raw:
             input_hist = self.input_hist_raw
         else:
             input_hist = self.input_hist
         if output:
             output_hist = self.user_ns['Out']
         n = len(input_hist)
         if index is None:
             start=0; stop=n
         elif isinstance(index, int):
             start=n-index; stop=n
         elif isinstance(index, tuple) and len(index) == 2:
             start=index[0]; stop=index[1]
         else:
             raise IndexError('Not a valid index for the input history: %r' % index)
         hist = {}
         for i in range(start, stop):
             if output:
                 hist[i] = (input_hist[i], output_hist.get(i))
             else:
                 hist[i] = input_hist[i]
         if len(hist)==0:
             raise IndexError('No history for range of indices: %r' % index)
         return hist
 
     #-------------------------------------------------------------------------
     # 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)
 
         # 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
         runcode() method.
 
         Inputs:
 
           - exc_tuple: a *tuple* of valid exceptions to call the defined
           handler for.  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: this must be defined as a function with the following
           basic interface::
 
             def my_handler(self, etype, value, tb, tb_offset=None)
                 ...
                 # The return value must be
                 return structured_traceback
 
           This will be made into an instance method (via new.instancemethod)
           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.
 
         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):
             print '*** Simple custom exception handler ***'
             print 'Exception type :',etype
             print 'Exception value:',value
             print 'Traceback      :',tb
             print 'Source code    :','\n'.join(self.buffer)
 
         if handler is None: handler = dummy_handler
 
         self.CustomTB = new.instancemethod(handler,self,self.__class__)
         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 whith imported code.
                 self.showsyntaxerror(filename)
             elif etype is UsageError:
                 print "UsageError:", 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:
                     # FIXME: Old custom traceback objects may just return a
                     # string, in that case we just put it into a list
                     stb = self.CustomTB(etype, value, tb, tb_offset)
                     if isinstance(ctb, basestring):
                         stb = [stb]
                 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)
                         # FIXME: the pdb calling should be done by us, not by
                         # the code computing the traceback.
                         if self.InteractiveTB.call_pdb:
                             # pdb mucks up readline, fix it back
                             self.set_completer()
 
                 # 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.
         """
         # FIXME: this should use the proper write channels, but our test suite
         # relies on it coming out of stdout...
         print >> sys.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)
 
     #-------------------------------------------------------------------------
     # Things related to tab completion
     #-------------------------------------------------------------------------
 
     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 = new.instancemethod(completer,self.Completer,
                                      self.Completer.__class__)
         self.Completer.matchers.insert(pos,newcomp)
 
     def set_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 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.savehist = no_op
             self.reloadhist = no_op
             self.set_completer = no_op
             self.set_custom_completer = no_op
             self.set_completer_frame = no_op
             warn('Readline services not available or not loaded.')
         else:
             self.has_readline = True
             self.readline = readline
             sys.modules['readline'] = readline
             import atexit
             from IPython.core.completer import IPCompleter
             self.Completer = IPCompleter(self,
                                          self.user_ns,
                                          self.user_global_ns,
                                          self.readline_omit__names,
                                          self.alias_manager.alias_table)
             sdisp = self.strdispatchers.get('complete_command', StrDispatch())
             self.strdispatchers['complete_command'] = sdisp
             self.Completer.custom_completers = sdisp
             # Platform-specific configuration
             if os.name == 'nt':
                 self.readline_startup_hook = readline.set_pre_input_hook
             else:
                 self.readline_startup_hook = readline.set_startup_hook
 
             # Load user's initrc file (readline config)
             # Or if libedit is used, load editrc.
             inputrc_name = os.environ.get('INPUTRC')
             if inputrc_name is None:
                 home_dir = get_home_dir()
                 if home_dir is not None:
                     inputrc_name = '.inputrc'
                     if readline.uses_libedit:
                         inputrc_name = '.editrc'
                     inputrc_name = os.path.join(home_dir, inputrc_name)
             if os.path.isfile(inputrc_name):
                 try:
                     readline.read_init_file(inputrc_name)
                 except:
                     warn('Problems reading readline initialization file <%s>'
                          % inputrc_name)
             
             # save this in sys so embedded copies can restore it properly
             sys.ipcompleter = self.Completer.rlcomplete
             self.set_completer()
 
             # 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().encode("ascii", "ignore")
             delims = delims.translate(string._idmap,
                                       self.readline_remove_delims)
             readline.set_completer_delims(delims)
             # otherwise we end up with a monster history after a while:
             readline.set_history_length(1000)
             try:
                 #print '*** Reading readline history'  # dbg
                 readline.read_history_file(self.histfile)
             except IOError:
                 pass  # It doesn't exist yet.
 
             atexit.register(self.atexit_operations)
             del atexit
 
         # Configure auto-indent for all platforms
         self.set_autoindent(self.autoindent)
 
     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 = 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.indent_current_nsp * ' '
 
     #-------------------------------------------------------------------------
     # 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):
         """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.
         """
         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)
             with nested(self.builtin_trap,):
                 result = fn(magic_args)
                 return result
 
     def define_magic(self, magicname, func):
         """Expose own function as magic function for ipython 
     
         def foo_impl(self,parameter_s=''):
             'My very own magic!. (Use docstrings, IPython reads them).'
             print 'Magic function. Passed parameter is between < >:'
             print '<%s>' % parameter_s
             print 'The self object is:',self
     
         self.define_magic('foo',foo_impl)
         """
         
         import new
         im = new.instancemethod(func,self, self.__class__)
         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(self, cmd):
         """Call the given cmd in a subprocess."""
         # We do not support backgrounding processes because we either use
         # pexpect or pipes to read from.  Users can always just call
         # os.system() if they really want a background process.
         if cmd.endswith('&'):
             raise OSError("Background processes not supported.")
 
         return system(self.var_expand(cmd, depth=2))
 
     def getoutput(self, cmd):
         """Get output (possibly including stderr) from a subprocess."""
         if cmd.endswith('&'):
             raise OSError("Background processes not supported.")
         return getoutput(self.var_expand(cmd, depth=2))
 
     #-------------------------------------------------------------------------
     # Things related to aliases
     #-------------------------------------------------------------------------
 
     def init_alias(self):
         self.alias_manager = AliasManager(shell=self, config=self.config)
         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)
 
     def init_plugin_manager(self):
         self.plugin_manager = PluginManager(config=self.config)
 
     #-------------------------------------------------------------------------
     # Things related to payloads
     #-------------------------------------------------------------------------
 
     def init_payload(self):
         self.payload_manager = PayloadManager(config=self.config)
 
     #-------------------------------------------------------------------------
     # Things related to the prefilter
     #-------------------------------------------------------------------------
 
     def init_prefilter(self):
         self.prefilter_manager = PrefilterManager(shell=self, config=self.config)
         # 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
 
     #-------------------------------------------------------------------------
     # 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 get_user_variables(self, names):
         """Get a list of variable names from the user's namespace.
 
         The return value is a dict 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 eval_expressions(self, expressions):
         """Evaluate a dict of expressions in the user's namespace.
 
         The return value is a 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 nested(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 nested(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).
         """
         kw.setdefault('exit_ignore', False)
 
         fname = os.path.abspath(os.path.expanduser(fname))
 
         # Make sure we have a .py file
         if not fname.endswith('.py'):
             warn('File must end with .py to be run using execfile: <%s>' % 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:
                 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 status.code not in (0, None) and not kw['exit_ignore']:
                     self.showtraceback(exception_only=True)
             except:
                 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 have a .py file
         if not fname.endswith('.ipy'):
             warn('File must end with .py to be run using execfile: <%s>' % 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:
                     script = thefile.read()
                     # self.runlines currently captures all exceptions
                     # raise in user code.  It would be nice if there were
                     # versions of runlines, execfile that did raise, so
                     # we could catch the errors.
                     self.runlines(script, clean=True)
             except:
                 self.showtraceback()
                 warn('Unknown failure executing file: <%s>' % fname)
 
     def runlines(self, lines, clean=False):
         """Run a string of one or more lines of source.
 
         This method is capable of running a string containing multiple source
         lines, as if they had been entered at the IPython prompt.  Since it
         exposes IPython's processing machinery, the given strings can contain
         magic calls (%magic), special shell access (!cmd), etc.
         """
         
         if isinstance(lines, (list, tuple)):
             lines = '\n'.join(lines)
 
         if clean:
             lines = self._cleanup_ipy_script(lines)
 
         # We must start with a clean buffer, in case this is run from an
         # interactive IPython session (via a magic, for example).
         self.resetbuffer()
         lines = lines.splitlines()
         more = 0
         with nested(self.builtin_trap, self.display_trap):
             for line in lines:
                 # skip blank lines so we don't mess up the prompt counter, but do
                 # NOT skip even a blank line if we are in a code block (more is
                 # true)
             
                 if line or more:
                     # push to raw history, so hist line numbers stay in sync
                     self.input_hist_raw.append(line + '\n')
                     prefiltered = self.prefilter_manager.prefilter_lines(line,
                                                                          more)
                     more = self.push_line(prefiltered)
                     # IPython's runsource returns None if there was an error
                     # compiling the code.  This allows us to stop processing right
                     # away, so the user gets the error message at the right place.
                     if more is None:
                         break
                 else:
                     self.input_hist_raw.append("\n")
             # final newline in case the input didn't have it, so that the code
             # actually does get executed
             if more:
                 self.push_line('\n')
 
     def runsource(self, source, filename='<input>', symbol='single'):
         """Compile and run some source in the interpreter.
 
         Arguments are as for compile_command().
 
         One several things can happen:
 
         1) The input is incorrect; compile_command() raised an
         exception (SyntaxError or OverflowError).  A syntax traceback
         will be printed by calling the showsyntaxerror() method.
 
         2) The input is incomplete, and more input is required;
         compile_command() returned None.  Nothing happens.
 
         3) The input is complete; compile_command() returned a code
         object.  The code is executed by calling self.runcode() (which
         also handles run-time exceptions, except for SystemExit).
 
         The return value is:
 
           - True in case 2
 
           - False in the other cases, unless an exception is raised, where
           None is returned instead.  This can be used by external callers to
           know whether to continue feeding input or not.
 
         The return value can be used to decide whether to use sys.ps1 or
         sys.ps2 to prompt the next line."""
 
         # if the source code has leading blanks, add 'if 1:\n' to it
         # this allows execution of indented pasted code. It is tempting
         # to add '\n' at the end of source to run commands like ' a=1'
         # directly, but this fails for more complicated scenarios
         source=source.encode(self.stdin_encoding)
         if source[:1] in [' ', '\t']:
             source = 'if 1:\n%s' % source
 
         try:
             code = self.compile(source,filename,symbol)
         except (OverflowError, SyntaxError, ValueError, TypeError, MemoryError):
             # Case 1
             self.showsyntaxerror(filename)
             return None
 
         if code is None:
             # Case 2
             return True
 
         # Case 3
         # We store the code object so that threaded shells and
         # custom exception handlers can access all this info if needed.
         # The source corresponding to this can be obtained from the
         # buffer attribute as '\n'.join(self.buffer).
         self.code_to_run = code
         # now actually execute the code object
         if self.runcode(code) == 0:
             return False
         else:
             return None
 
     def runcode(self,code_obj):
         """Execute a code object.
 
         When an exception occurs, self.showtraceback() is called to display a
         traceback.
 
         Return value: a flag indicating whether the code to be run completed
         successfully:
 
           - 0: successful execution.
           - 1: 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_runcode_hook()
                 #rprint('Running code') # 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.resetbuffer()
             self.showtraceback(exception_only=True)
             warn("To exit: use any of 'exit', 'quit', %Exit 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
         # Flush out code object which has been run (and source)
         self.code_to_run = None
         return outflag
         
     def push_line(self, line):
         """Push a line to the interpreter.
 
         The line should not have a trailing newline; it may have
         internal newlines.  The line is appended to a buffer and the
         interpreter's runsource() method is called with the
         concatenated contents of the buffer as source.  If this
         indicates that the command was executed or invalid, the buffer
         is reset; otherwise, the command is incomplete, and the buffer
         is left as it was after the line was appended.  The return
         value is 1 if more input is required, 0 if the line was dealt
         with in some way (this is the same as runsource()).
         """
 
         # autoindent management should be done here, and not in the
         # interactive loop, since that one is only seen by keyboard input.  We
         # need this done correctly even for code run via runlines (which uses
         # push).
 
         #print 'push line: <%s>' % line  # dbg
         for subline in line.splitlines():
             self._autoindent_update(subline)
         self.buffer.append(line)
         more = self.runsource('\n'.join(self.buffer), self.filename)
         if not more:
             self.resetbuffer()
         return more
 
     def resetbuffer(self):
         """Reset the input buffer."""
         self.buffer[:] = []
 
     def _is_secondary_block_start(self, s):
         if not s.endswith(':'):
             return False
         if (s.startswith('elif') or 
             s.startswith('else') or 
             s.startswith('except') or
             s.startswith('finally')):
             return True
 
     def _cleanup_ipy_script(self, script):
         """Make a script safe for self.runlines()
 
         Currently, IPython is lines based, with blocks being detected by
         empty lines.  This is a problem for block based scripts that may
         not have empty lines after blocks.  This script adds those empty
         lines to make scripts safe for running in the current line based
         IPython.
         """
         res = []
         lines = script.splitlines()
         level = 0
 
         for l in lines:
             lstripped = l.lstrip()
             stripped = l.strip()                
             if not stripped:
                 continue
             newlevel = len(l) - len(lstripped)                    
             if level > 0 and newlevel == 0 and \
                    not self._is_secondary_block_start(stripped): 
                 # add empty line
                 res.append('')
             res.append(l)
             level = newlevel
 
         return '\n'.join(res) + '\n'
 
     def _autoindent_update(self,line):
         """Keep track of the indent level."""
 
         #debugx('line')
         #debugx('self.indent_current_nsp')
         if self.autoindent:
             if line:
                 inisp = num_ini_spaces(line)
                 if inisp < self.indent_current_nsp:
                     self.indent_current_nsp = inisp
 
                 if line[-1] == ':':
                     self.indent_current_nsp += 4
                 elif dedent_re.match(line):
                     self.indent_current_nsp -= 4
             else:
                 self.indent_current_nsp = 0
 
     #-------------------------------------------------------------------------
     # Things related to GUI support and pylab
     #-------------------------------------------------------------------------
 
     def enable_pylab(self, gui=None):
         raise NotImplementedError('Implement enable_pylab in a subclass')
 
     #-------------------------------------------------------------------------
     # Utilities
     #-------------------------------------------------------------------------
 
     def var_expand(self,cmd,depth=0):
         """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.
         """
 
         return str(ItplNS(cmd,
                           self.user_ns,  # globals
                           # Skip our own frame in searching for locals:
                           sys._getframe(depth+1).f_locals # locals
                           ))
 
     def mktempfile(self,data=None):
         """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','ipython_edit_')
         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.Term.cout.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.Term.cerr.write(data)
 
     def ask_yes_no(self,prompt,default=True):
         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)
 
     #-------------------------------------------------------------------------
     # Things related to IPython exiting
     #-------------------------------------------------------------------------
 
     def atexit_operations(self):
         """This will be executed at the time of exit.
 
         Saving of persistent data should be performed here.
         """
         self.savehist()
 
         # 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()
 
         # 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/oinspect.py

@@ -1,806 +1,810 b''
 # -*- coding: utf-8 -*-
 """Tools for inspecting Python objects.
 
 Uses syntax highlighting for presenting the various information elements.
 
 Similar in spirit to the inspect module, but all calls take a name argument to
 reference the name under which an object is being read.
 """
 
 #*****************************************************************************
 #       Copyright (C) 2001-2004 Fernando Perez <[e-mail]>
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #*****************************************************************************
 
 __all__ = ['Inspector','InspectColors']
 
 # stdlib modules
 import __builtin__
 import StringIO
 import inspect
 import linecache
 import os
 import string
 import sys
 import types
 from collections import namedtuple
 from itertools import izip_longest
 
 # IPython's own
 from IPython.core import page
 from IPython.external.Itpl import itpl
 from IPython.utils import PyColorize
 import IPython.utils.io
 from IPython.utils.text import indent
 from IPython.utils.wildcard import list_namespace
 from IPython.utils.coloransi import *
 
 #****************************************************************************
 # Builtin color schemes
 
 Colors = TermColors  # just a shorthand
 
 # Build a few color schemes
 NoColor = ColorScheme(
     'NoColor',{
     'header' : Colors.NoColor,
     'normal' : Colors.NoColor  # color off (usu. Colors.Normal)
     }  )
 
 LinuxColors = ColorScheme(
     'Linux',{
     'header' : Colors.LightRed,
     'normal' : Colors.Normal  # color off (usu. Colors.Normal)
     } )
 
 LightBGColors = ColorScheme(
     'LightBG',{
     'header' : Colors.Red,
     'normal' : Colors.Normal  # color off (usu. Colors.Normal)
     }  )
 
 # Build table of color schemes (needed by the parser)
 InspectColors = ColorSchemeTable([NoColor,LinuxColors,LightBGColors],
                                  'Linux')
 
 #****************************************************************************
 # Auxiliary functions and objects
 
 # See the messaging spec for the definition of all these fields.  This list
 # effectively defines the order of display
 info_fields = ['type_name', 'base_class', 'string_form', 'namespace',
                'length', 'file', 'definition', 'docstring', 'source',
                'init_definition', 'class_docstring', 'init_docstring',
                'call_def', 'call_docstring',
                # These won't be printed but will be used to determine how to
                # format the object
-               'ismagic', 'isalias', 
+               'ismagic', 'isalias', 'argspec', 'found',
                ]
 
 
 ObjectInfo = namedtuple('ObjectInfo', info_fields)
 
 
 def mk_object_info(kw):
     """Make a f"""
     infodict = dict(izip_longest(info_fields, [None]))
     infodict.update(kw)
     return ObjectInfo(**infodict)
 
 
 def getdoc(obj):
     """Stable wrapper around inspect.getdoc.
 
     This can't crash because of attribute problems.
 
     It also attempts to call a getdoc() method on the given object.  This
     allows objects which provide their docstrings via non-standard mechanisms
     (like Pyro proxies) to still be inspected by ipython's ? system."""
 
     ds = None  # default return value
     try:
         ds = inspect.getdoc(obj)
     except:
         # Harden against an inspect failure, which can occur with
         # SWIG-wrapped extensions.
         pass
     # Allow objects to offer customized documentation via a getdoc method:
     try:
         ds2 = obj.getdoc()
     except:
         pass
     else:
         # if we get extra info, we add it to the normal docstring.
         if ds is None:
             ds = ds2
         else:
             ds = '%s\n%s' % (ds,ds2)
     return ds
 
 
 def getsource(obj,is_binary=False):
     """Wrapper around inspect.getsource.
 
     This can be modified by other projects to provide customized source
     extraction.
 
     Inputs:
 
     - obj: an object whose source code we will attempt to extract.
 
     Optional inputs:
 
     - is_binary: whether the object is known to come from a binary source.
     This implementation will skip returning any output for binary objects, but
     custom extractors may know how to meaningfully process them."""
     
     if is_binary:
         return None
     else:
         try:
             src = inspect.getsource(obj)
         except TypeError:
             if hasattr(obj,'__class__'):
                 src = inspect.getsource(obj.__class__)
         return src
 
 def getargspec(obj):
     """Get the names and default values of a function's arguments.
 
     A tuple of four things is returned: (args, varargs, varkw, defaults).
     'args' is a list of the argument names (it may contain nested lists).
     'varargs' and 'varkw' are the names of the * and ** arguments or None.
     'defaults' is an n-tuple of the default values of the last n arguments.
 
     Modified version of inspect.getargspec from the Python Standard
     Library."""
 
     if inspect.isfunction(obj):
         func_obj = obj
     elif inspect.ismethod(obj):
         func_obj = obj.im_func
     else:
-        raise TypeError, 'arg is not a Python function'
+        raise TypeError('arg is not a Python function')
     args, varargs, varkw = inspect.getargs(func_obj.func_code)
     return args, varargs, varkw, func_obj.func_defaults
 
 #****************************************************************************
 # Class definitions
 
 class myStringIO(StringIO.StringIO):
     """Adds a writeln method to normal StringIO."""
     def writeln(self,*arg,**kw):
         """Does a write() and then a write('\n')"""
         self.write(*arg,**kw)
         self.write('\n')
 
 
 class Inspector:
     def __init__(self,color_table,code_color_table,scheme,
                  str_detail_level=0):
         self.color_table = color_table
         self.parser = PyColorize.Parser(code_color_table,out='str')
         self.format = self.parser.format
         self.str_detail_level = str_detail_level
         self.set_active_scheme(scheme)
 
     def _getdef(self,obj,oname=''):
         """Return the definition header for any callable object.
 
         If any exception is generated, None is returned instead and the
         exception is suppressed."""
         
         try:
             # We need a plain string here, NOT unicode!
             hdef = oname + inspect.formatargspec(*getargspec(obj))
             return hdef.encode('ascii')
         except:
             return None
  
     def __head(self,h):
         """Return a header string with proper colors."""
         return '%s%s%s' % (self.color_table.active_colors.header,h,
                            self.color_table.active_colors.normal)
 
     def set_active_scheme(self,scheme):
         self.color_table.set_active_scheme(scheme)
         self.parser.color_table.set_active_scheme(scheme)
     
     def noinfo(self,msg,oname):
         """Generic message when no information is found."""
         print 'No %s found' % msg,
         if oname:
             print 'for %s' % oname
         else:
             print
             
     def pdef(self,obj,oname=''):
         """Print the definition header for any callable object.
 
         If the object is a class, print the constructor information."""
 
         if not callable(obj):
             print 'Object is not callable.'
             return
 
         header = ''
 
         if inspect.isclass(obj):
             header = self.__head('Class constructor information:\n')
             obj = obj.__init__
         elif type(obj) is types.InstanceType:
             obj = obj.__call__
 
         output = self._getdef(obj,oname)
         if output is None:
             self.noinfo('definition header',oname)
         else:
             print >>IPython.utils.io.Term.cout, header,self.format(output),
 
     def pdoc(self,obj,oname='',formatter = None):
         """Print the docstring for any object.
 
         Optional:
         -formatter: a function to run the docstring through for specially
         formatted docstrings."""
 
         head = self.__head  # so that itpl can find it even if private
         ds = getdoc(obj)
         if formatter:
             ds = formatter(ds)
         if inspect.isclass(obj):
             init_ds = getdoc(obj.__init__)
             output = itpl('$head("Class Docstring:")\n'
                           '$indent(ds)\n'
                           '$head("Constructor Docstring"):\n'
                           '$indent(init_ds)')
         elif (type(obj) is types.InstanceType or isinstance(obj,object)) \
                  and hasattr(obj,'__call__'):
             call_ds = getdoc(obj.__call__)
             if call_ds:
                 output = itpl('$head("Class Docstring:")\n$indent(ds)\n'
                               '$head("Calling Docstring:")\n$indent(call_ds)')
             else:
                 output = ds
         else:
             output = ds
         if output is None:
             self.noinfo('documentation',oname)
             return
         page.page(output)
     
     def psource(self,obj,oname=''):
         """Print the source code for an object."""
 
         # Flush the source cache because inspect can return out-of-date source
         linecache.checkcache()
         try:
             src = getsource(obj) 
         except:
             self.noinfo('source',oname)
         else:
             page.page(self.format(src))
 
     def pfile(self,obj,oname=''):
         """Show the whole file where an object was defined."""
 
         try:
             try:
                 lineno = inspect.getsourcelines(obj)[1]
             except TypeError:
                 # For instances, try the class object like getsource() does
                 if hasattr(obj,'__class__'):
                     lineno = inspect.getsourcelines(obj.__class__)[1]
                     # Adjust the inspected object so getabsfile() below works
                     obj = obj.__class__
         except:
             self.noinfo('file',oname)
             return
 
         # We only reach this point if object was successfully queried
         
         # run contents of file through pager starting at line
         # where the object is defined
         ofile = inspect.getabsfile(obj)
 
         if (ofile.endswith('.so') or ofile.endswith('.dll')):
             print 'File %r is binary, not printing.' % ofile
         elif not os.path.isfile(ofile):
             print 'File %r does not exist, not printing.' % ofile
         else:
             # Print only text files, not extension binaries.  Note that
             # getsourcelines returns lineno with 1-offset and page() uses
             # 0-offset, so we must adjust.
             page.page(self.format(open(ofile).read()),lineno-1)
 
     def pinfo(self,obj,oname='',formatter=None,info=None,detail_level=0):
         """Show detailed information about an object.
 
         Optional arguments:
         
         - oname: name of the variable pointing to the object.
 
         - formatter: special formatter for docstrings (see pdoc)
 
         - info: a structure with some information fields which may have been
         precomputed already.
 
         - detail_level: if set to 1, more information is given.
         """
 
         obj_type = type(obj)
 
         header = self.__head
         if info is None:
             ismagic = 0
             isalias = 0
             ospace = ''
         else:
             ismagic = info.ismagic
             isalias = info.isalias
             ospace = info.namespace
         # Get docstring, special-casing aliases:
         if isalias:
             if not callable(obj):
                 try:
                     ds = "Alias to the system command:\n  %s" % obj[1]
                 except:
                     ds = "Alias: " + str(obj)
             else:
                 ds = "Alias to " + str(obj)
                 if obj.__doc__:
                     ds += "\nDocstring:\n" + obj.__doc__
         else:
             ds = getdoc(obj)
             if ds is None:
                 ds = '<no docstring>'
         if formatter is not None:
             ds = formatter(ds)
 
         # store output in a list which gets joined with \n at the end.
         out = myStringIO()
         
         string_max = 200 # max size of strings to show (snipped if longer)
         shalf = int((string_max -5)/2)
 
         if ismagic:
             obj_type_name = 'Magic function'
         elif isalias:
             obj_type_name = 'System alias'
         else:
             obj_type_name = obj_type.__name__
         out.writeln(header('Type:\t\t')+obj_type_name)
 
         try:
             bclass = obj.__class__
             out.writeln(header('Base Class:\t')+str(bclass))
         except: pass
 
         # String form, but snip if too long in ? form (full in ??)
         if detail_level >= self.str_detail_level:
             try:
                 ostr = str(obj)
                 str_head = 'String Form:'
                 if not detail_level and len(ostr)>string_max:
                     ostr = ostr[:shalf] + ' <...> ' + ostr[-shalf:]
                     ostr = ("\n" + " " * len(str_head.expandtabs())).\
                            join(map(string.strip,ostr.split("\n")))
                 if ostr.find('\n') > -1:
                     # Print multi-line strings starting at the next line.
                     str_sep = '\n'
                 else:
                     str_sep = '\t'
                 out.writeln("%s%s%s" % (header(str_head),str_sep,ostr))
             except:
                 pass
 
         if ospace:
             out.writeln(header('Namespace:\t')+ospace)
 
         # Length (for strings and lists)
         try:
             length = str(len(obj))
             out.writeln(header('Length:\t\t')+length)
         except: pass
 
         # Filename where object was defined
         binary_file = False
         try:
             try:
                 fname = inspect.getabsfile(obj)
             except TypeError:
                 # For an instance, the file that matters is where its class was
                 # declared.
                 if hasattr(obj,'__class__'):
                     fname = inspect.getabsfile(obj.__class__)
             if fname.endswith('<string>'):
                 fname = 'Dynamically generated function. No source code available.'
             if (fname.endswith('.so') or fname.endswith('.dll')):
                 binary_file = True
             out.writeln(header('File:\t\t')+fname)
         except:
             # if anything goes wrong, we don't want to show source, so it's as
             # if the file was binary
             binary_file = True
 
         # reconstruct the function definition and print it:
         defln = self._getdef(obj,oname)
         if defln:
             out.write(header('Definition:\t')+self.format(defln))
  
         # Docstrings only in detail 0 mode, since source contains them (we
         # avoid repetitions).  If source fails, we add them back, see below.
         if ds and detail_level == 0:
                 out.writeln(header('Docstring:\n') + indent(ds))
                 
         # Original source code for any callable
         if detail_level:
             # Flush the source cache because inspect can return out-of-date
             # source
             linecache.checkcache()
             source_success = False
             try:
                 try:
                     src = getsource(obj,binary_file)
                 except TypeError:
                     if hasattr(obj,'__class__'):
                         src = getsource(obj.__class__,binary_file)
                 if src is not None:
                     source = self.format(src)
                     out.write(header('Source:\n')+source.rstrip())
                     source_success = True
             except Exception, msg:
                 pass
             
             if ds and not source_success:
                 out.writeln(header('Docstring [source file open failed]:\n')
                             + indent(ds))
 
         # Constructor docstring for classes
         if inspect.isclass(obj):
             # reconstruct the function definition and print it:
             try:
                 obj_init =  obj.__init__
             except AttributeError:
                 init_def = init_ds = None
             else:
                 init_def = self._getdef(obj_init,oname)
                 init_ds  = getdoc(obj_init)
                 # Skip Python's auto-generated docstrings
                 if init_ds and \
                        init_ds.startswith('x.__init__(...) initializes'):
                     init_ds = None
 
             if init_def or init_ds:
                 out.writeln(header('\nConstructor information:'))
                 if init_def:
                     out.write(header('Definition:\t')+ self.format(init_def))
                 if init_ds:
                     out.writeln(header('Docstring:\n') + indent(init_ds))
         # and class docstring for instances:
         elif obj_type is types.InstanceType or \
                  isinstance(obj,object):
 
             # First, check whether the instance docstring is identical to the
             # class one, and print it separately if they don't coincide.  In
             # most cases they will, but it's nice to print all the info for
             # objects which use instance-customized docstrings.
             if ds:
                 try:
                     cls = getattr(obj,'__class__')
                 except:
                     class_ds = None
                 else:
                     class_ds = getdoc(cls)
                 # Skip Python's auto-generated docstrings
                 if class_ds and \
                        (class_ds.startswith('function(code, globals[,') or \
                    class_ds.startswith('instancemethod(function, instance,') or \
                    class_ds.startswith('module(name[,') ):
                     class_ds = None
                 if class_ds and ds != class_ds:
                     out.writeln(header('Class Docstring:\n') +
                                 indent(class_ds))
 
             # Next, try to show constructor docstrings
             try:
                 init_ds = getdoc(obj.__init__)
                 # Skip Python's auto-generated docstrings
                 if init_ds and \
                        init_ds.startswith('x.__init__(...) initializes'):
                     init_ds = None
             except AttributeError:
                 init_ds = None
             if init_ds:
                 out.writeln(header('Constructor Docstring:\n') +
                             indent(init_ds))
 
             # Call form docstring for callable instances
             if hasattr(obj,'__call__'):
                 #out.writeln(header('Callable:\t')+'Yes')
                 call_def = self._getdef(obj.__call__,oname)
                 #if call_def is None:
                 #    out.writeln(header('Call def:\t')+
                 #              'Calling definition not available.')
                 if call_def is not None:
                     out.writeln(header('Call def:\t')+self.format(call_def))
                 call_ds = getdoc(obj.__call__)
                 # Skip Python's auto-generated docstrings
                 if call_ds and call_ds.startswith('x.__call__(...) <==> x(...)'):
                     call_ds = None
                 if call_ds:
                     out.writeln(header('Call docstring:\n') + indent(call_ds))
 
         # Finally send to printer/pager
         output = out.getvalue()
         if output:
             page.page(output)
         # end pinfo
 
     def info(self, obj, oname='', formatter=None, info=None, detail_level=0):
         """Compute a dict with detailed information about an object.
 
         Optional arguments:
         
         - oname: name of the variable pointing to the object.
 
         - formatter: special formatter for docstrings (see pdoc)
 
         - info: a structure with some information fields which may have been
         precomputed already.
 
         - detail_level: if set to 1, more information is given.
         """
 
         obj_type = type(obj)
 
         header = self.__head
         if info is None:
             ismagic = 0
             isalias = 0
             ospace = ''
         else:
             ismagic = info.ismagic
             isalias = info.isalias
             ospace = info.namespace
         # Get docstring, special-casing aliases:
         if isalias:
             if not callable(obj):
                 try:
                     ds = "Alias to the system command:\n  %s" % obj[1]
                 except:
                     ds = "Alias: " + str(obj)
             else:
                 ds = "Alias to " + str(obj)
                 if obj.__doc__:
                     ds += "\nDocstring:\n" + obj.__doc__
         else:
             ds = getdoc(obj)
             if ds is None:
                 ds = '<no docstring>'
         if formatter is not None:
             ds = formatter(ds)
 
-        # store output in a dict, we'll later convert it to an ObjectInfo
-        out  = {}
+        # store output in a dict, we'll later convert it to an ObjectInfo.  We
+        # initialize it here and fill it as we go
+        out = dict(isalias=isalias, ismagic=ismagic)
         
         string_max = 200 # max size of strings to show (snipped if longer)
         shalf = int((string_max -5)/2)
 
         if ismagic:
             obj_type_name = 'Magic function'
         elif isalias:
             obj_type_name = 'System alias'
         else:
             obj_type_name = obj_type.__name__
         out['type_name'] = obj_type_name
 
         try:
             bclass = obj.__class__
             out['base_class'] = str(bclass)
         except: pass
 
         # String form, but snip if too long in ? form (full in ??)
         if detail_level >= self.str_detail_level:
             try:
                 ostr = str(obj)
                 str_head = 'string_form'
                 if not detail_level and len(ostr)>string_max:
                     ostr = ostr[:shalf] + ' <...> ' + ostr[-shalf:]
                     ostr = ("\n" + " " * len(str_head.expandtabs())).\
                            join(map(string.strip,ostr.split("\n")))
                 if ostr.find('\n') > -1:
                     # Print multi-line strings starting at the next line.
                     str_sep = '\n'
                 else:
                     str_sep = '\t'
                 out[str_head] = ostr
             except:
                 pass
 
         if ospace:
             out['namespace'] = ospace
 
         # Length (for strings and lists)
         try:
             out['length'] = str(len(obj))
         except: pass
 
         # Filename where object was defined
         binary_file = False
         try:
             try:
                 fname = inspect.getabsfile(obj)
             except TypeError:
                 # For an instance, the file that matters is where its class was
                 # declared.
                 if hasattr(obj,'__class__'):
                     fname = inspect.getabsfile(obj.__class__)
             if fname.endswith('<string>'):
                 fname = 'Dynamically generated function. No source code available.'
             if (fname.endswith('.so') or fname.endswith('.dll')):
                 binary_file = True
             out['file'] = fname
         except:
             # if anything goes wrong, we don't want to show source, so it's as
             # if the file was binary
             binary_file = True
 
         # reconstruct the function definition and print it:
         defln = self._getdef(obj,oname)
         if defln:
             out['definition'] = self.format(defln)
- 
+            args,  varargs, varkw, func_defaults = getargspec(obj)
+            out['argspec'] = dict(args=args, varargs=varargs,
+                                  varkw=varkw, func_defaults=func_defaults)
+            
         # Docstrings only in detail 0 mode, since source contains them (we
         # avoid repetitions).  If source fails, we add them back, see below.
         if ds and detail_level == 0:
                 out['docstring'] = indent(ds)
                 
         # Original source code for any callable
         if detail_level:
             # Flush the source cache because inspect can return out-of-date
             # source
             linecache.checkcache()
             source_success = False
             try:
                 try:
                     src = getsource(obj,binary_file)
                 except TypeError:
                     if hasattr(obj,'__class__'):
                         src = getsource(obj.__class__,binary_file)
                 if src is not None:
                     source = self.format(src)
                     out['source'] = source.rstrip()
                     source_success = True
             except Exception, msg:
                 pass
 
         # Constructor docstring for classes
         if inspect.isclass(obj):
             # reconstruct the function definition and print it:
             try:
                 obj_init =  obj.__init__
             except AttributeError:
                 init_def = init_ds = None
             else:
                 init_def = self._getdef(obj_init,oname)
                 init_ds  = getdoc(obj_init)
                 # Skip Python's auto-generated docstrings
                 if init_ds and \
                        init_ds.startswith('x.__init__(...) initializes'):
                     init_ds = None
 
             if init_def or init_ds:
                 if init_def:
                     out['init_definition'] = self.format(init_def)
                 if init_ds:
                     out['init_docstring'] = indent(init_ds)
         # and class docstring for instances:
         elif obj_type is types.InstanceType or \
                  isinstance(obj,object):
 
             # First, check whether the instance docstring is identical to the
             # class one, and print it separately if they don't coincide.  In
             # most cases they will, but it's nice to print all the info for
             # objects which use instance-customized docstrings.
             if ds:
                 try:
                     cls = getattr(obj,'__class__')
                 except:
                     class_ds = None
                 else:
                     class_ds = getdoc(cls)
                 # Skip Python's auto-generated docstrings
                 if class_ds and \
                        (class_ds.startswith('function(code, globals[,') or \
                    class_ds.startswith('instancemethod(function, instance,') or \
                    class_ds.startswith('module(name[,') ):
                     class_ds = None
                 if class_ds and ds != class_ds:
                     out['class_docstring'] = indent(class_ds)
 
             # Next, try to show constructor docstrings
             try:
                 init_ds = getdoc(obj.__init__)
                 # Skip Python's auto-generated docstrings
                 if init_ds and \
                        init_ds.startswith('x.__init__(...) initializes'):
                     init_ds = None
             except AttributeError:
                 init_ds = None
             if init_ds:
                 out['init_docstring'] = indent(init_ds)
 
             # Call form docstring for callable instances
             if hasattr(obj,'__call__'):
                 call_def = self._getdef(obj.__call__,oname)
                 if call_def is not None:
                     out['call_def'] = self.format(call_def)
                 call_ds = getdoc(obj.__call__)
                 # Skip Python's auto-generated docstrings
                 if call_ds and call_ds.startswith('x.__call__(...) <==> x(...)'):
                     call_ds = None
                 if call_ds:
                     out['call_docstring'] = indent(call_ds)
 
         return mk_object_info(out)
 
 
     def psearch(self,pattern,ns_table,ns_search=[],
                 ignore_case=False,show_all=False):
         """Search namespaces with wildcards for objects.
 
         Arguments:
 
         - pattern: string containing shell-like wildcards to use in namespace
         searches and optionally a type specification to narrow the search to
         objects of that type.
 
         - ns_table: dict of name->namespaces for search.
 
         Optional arguments:
         
           - ns_search: list of namespace names to include in search.
 
           - ignore_case(False): make the search case-insensitive.
 
           - show_all(False): show all names, including those starting with
           underscores.
         """
         #print 'ps pattern:<%r>' % pattern # dbg
         
         # defaults
         type_pattern = 'all'
         filter = ''
 
         cmds = pattern.split()
         len_cmds  =  len(cmds)
         if len_cmds == 1:
             # Only filter pattern given
             filter = cmds[0]
         elif len_cmds == 2:
             # Both filter and type specified
             filter,type_pattern = cmds
         else:
             raise ValueError('invalid argument string for psearch: <%s>' %
                              pattern)
 
         # filter search namespaces
         for name in ns_search:
             if name not in ns_table:
                 raise ValueError('invalid namespace <%s>. Valid names: %s' %
                                  (name,ns_table.keys()))
 
         #print 'type_pattern:',type_pattern # dbg
         search_result = []
         for ns_name in ns_search:
             ns = ns_table[ns_name]
             tmp_res = list(list_namespace(ns,type_pattern,filter,
                                           ignore_case=ignore_case,
                                           show_all=show_all))
             search_result.extend(tmp_res)
         search_result.sort()
 
         page.page('\n'.join(search_result))

docs/source/development/messaging.txt

@@ -1,712 +1,716 b''
 .. _messaging:
 
 ======================
  Messaging in IPython
 ======================
 
 
 Introduction
 ============
 
 This document explains the basic communications design and messaging
 specification for how the various IPython objects interact over a network
 transport.  The current implementation uses the ZeroMQ_ library for messaging
 within and between hosts.
 
 .. Note::
 
    This document should be considered the authoritative description of the
    IPython messaging protocol, and all developers are strongly encouraged to
    keep it updated as the implementation evolves, so that we have a single
    common reference for all protocol details.
    
 The basic design is explained in the following diagram:
 
 .. image:: frontend-kernel.png
    :width: 450px
    :alt: IPython kernel/frontend messaging architecture.
    :align: center
    :target: ../_images/frontend-kernel.png
 
 A single kernel can be simultaneously connected to one or more frontends.  The
 kernel has three sockets that serve the following functions:
 
 1. REQ: this socket is connected to a *single* frontend at a time, and it allows
    the kernel to request input from a frontend when :func:`raw_input` is called.
    The frontend holding the matching REP socket acts as a 'virtual keyboard'
    for the kernel while this communication is happening (illustrated in the
    figure by the black outline around the central keyboard).  In practice,
    frontends may display such kernel requests using a special input widget or
    otherwise indicating that the user is to type input for the kernel instead
    of normal commands in the frontend.
 
 2. XREP: this single sockets allows multiple incoming connections from
    frontends, and this is the socket where requests for code execution, object
    information, prompts, etc. are made to the kernel by any frontend.  The
    communication on this socket is a sequence of request/reply actions from
    each frontend and the kernel.
 
 3. PUB: this socket is the 'broadcast channel' where the kernel publishes all
    side effects (stdout, stderr, etc.) as well as the requests coming from any
    client over the XREP socket and its own requests on the REP socket.  There
    are a number of actions in Python which generate side effects: :func:`print`
    writes to ``sys.stdout``, errors generate tracebacks, etc.  Additionally, in
    a multi-client scenario, we want all frontends to be able to know what each
    other has sent to the kernel (this can be useful in collaborative scenarios,
    for example).  This socket allows both side effects and the information
    about communications taking place with one client over the XREQ/XREP channel
    to be made available to all clients in a uniform manner.
 
    All messages are tagged with enough information (details below) for clients
    to know which messages come from their own interaction with the kernel and
    which ones are from other clients, so they can display each type
    appropriately.
 
 The actual format of the messages allowed on each of these channels is
 specified below.  Messages are dicts of dicts with string keys and values that
 are reasonably representable in JSON.  Our current implementation uses JSON
 explicitly as its message format, but this shouldn't be considered a permanent
 feature.  As we've discovered that JSON has non-trivial performance issues due
 to excessive copying, we may in the future move to a pure pickle-based raw
 message format.  However, it should be possible to easily convert from the raw
 objects to JSON, since we may have non-python clients (e.g. a web frontend).
 As long as it's easy to make a JSON version of the objects that is a faithful
 representation of all the data, we can communicate with such clients.
 
 .. Note::
 
    Not all of these have yet been fully fleshed out, but the key ones are, see
    kernel and frontend files for actual implementation details.
 
    
 Python functional API
 =====================
 
 As messages are dicts, they map naturally to a ``func(**kw)`` call form.  We
 should develop, at a few key points, functional forms of all the requests that
 take arguments in this manner and automatically construct the necessary dict
 for sending.
 
 
 General Message Format
 ======================
 
 All messages send or received by any IPython process should have the following
 generic structure::
     
     {
       # The message header contains a pair of unique identifiers for the
       # originating session and the actual message id, in addition to the
       # username for the process that generated the message.  This is useful in
       # collaborative settings where multiple users may be interacting with the
       # same kernel simultaneously, so that frontends can label the various
       # messages in a meaningful way.
       'header' : { 'msg_id' : uuid,
                    'username' : str,
            'session' : uuid
          },
 
       # In a chain of messages, the header from the parent is copied so that
       # clients can track where messages come from.
       'parent_header' : dict,
 
       # All recognized message type strings are listed below.
       'msg_type' : str,
 
       # The actual content of the message must be a dict, whose structure
       # depends on the message type.x
       'content' : dict,
     }
 
 For each message type, the actual content will differ and all existing message
 types are specified in what follows of this document.
 
 
 Messages on the XREP/XREQ socket
 ================================
 
 .. _execute:
 
 Execute
 -------
 
 This message type is used by frontends to ask the kernel to execute code on
 behalf of the user, in a namespace reserved to the user's variables (and thus
 separate from the kernel's own internal code and variables).
 
 Message type: ``execute_request``::
 
     content = {
         # Source code to be executed by the kernel, one or more lines.
     'code' : str,
 
     # A boolean flag which, if True, signals the kernel to execute this
     # code as quietly as possible.  This means that the kernel will compile
     # the code witIPython/core/tests/h 'exec' instead of 'single' (so
     # sys.displayhook will not fire), and will *not*:
     #   - broadcast exceptions on the PUB socket
     #   - do any logging
     #   - populate any history
     #
     # The default is False.
     'silent' : bool,
 
     # A list of variable names from the user's namespace to be retrieved.  What
     # returns is a JSON string of the variable's repr(), not a python object.
     'user_variables' : list,
 
     # Similarly, a dict mapping names to expressions to be evaluated in the
     # user's dict.
     'user_expressions' : dict,
     }
 
 The ``code`` field contains a single string, but this may be a multiline
 string.  The kernel is responsible for splitting this into possibly more than
 one block and deciding whether to compile these in 'single' or 'exec' mode.
 We're still sorting out this policy.  The current inputsplitter is capable of
 splitting the input for blocks that can all be run as 'single', but in the long
 run it may prove cleaner to only use 'single' mode for truly single-line
 inputs, and run all multiline input in 'exec' mode.  This would preserve the
 natural behavior of single-line inputs while allowing long cells to behave more
 likea a script.  This design will be refined as we complete the implementation.
 
 The ``user_`` fields deserve a detailed explanation.  In the past, IPython had
 the notion of a prompt string that allowed arbitrary code to be evaluated, and
 this was put to good use by many in creating prompts that displayed system
 status, path information, and even more esoteric uses like remote instrument
 status aqcuired over the network.  But now that IPython has a clean separation
 between the kernel and the clients, the notion of embedding 'prompt'
 maninpulations into the kernel itself feels awkward.  Prompts should be a
 frontend-side feature, and it should be even possible for different frontends
 to display different prompts while interacting with the same kernel.
 
 We have therefore abandoned the idea of a 'prompt string' to be evaluated by
 the kernel, and instead provide the ability to retrieve from the user's
 namespace information after the execution of the main ``code``, with two fields
 of the execution request:
 
 - ``user_variables``: If only variables from the user's namespace are needed, a
   list of variable names can be passed and a dict with these names as keys and
   their :func:`repr()` as values will be returned.
 
 - ``user_expressions``: For more complex expressions that require function
   evaluations, a dict can be provided with string keys and arbitrary python
   expressions as values.  The return message will contain also a dict with the
   same keys and the :func:`repr()` of the evaluated expressions as value.
 
 With this information, frontends can display any status information they wish
 in the form that best suits each frontend (a status line, a popup, inline for a
 terminal, etc).
 
 .. Note::
 
    In order to obtain the current execution counter for the purposes of
    displaying input prompts, frontends simply make an execution request with an
    empty code string and ``silent=True``.
 
 Execution semantics
     Upon completion of the execution request, the kernel *always* sends a
     reply, with a status code indicating what happened and additional data
     depending on the outcome.
 
     The ``code`` field is executed first, and then the ``user_variables`` and
     ``user_expressions`` are computed.  This ensures that any error in the
     latter don't harm the main code execution.
 
     Any error in retrieving the ``user_variables`` or evaluating the
     ``user_expressions`` will result in a simple error message in the return
     fields of the form::
 
        [ERROR] ExceptionType: Exception message
 
     The user can simply send the same variable name or expression for
     evaluation to see a regular traceback.
 
 Execution counter (old prompt number)
     The kernel has a single, monotonically increasing counter of all execution
     requests that are made with ``silent=False``.  This counter is used to
     populate the ``In[n]``, ``Out[n]`` and ``_n`` variables, so clients will
     likely want to display it in some form to the user, which will typically
     (but not necessarily) be done in the prompts.  The value of this counter
     will be returned as the ``execution_count`` field of all ``execute_reply```
     messages.
 
 Message type: ``execute_reply``::
 
     content = {
       # One of: 'ok' OR 'error' OR 'abort'
       'status' : str,
 
       # The global kernel counter that increases by one with each non-silent
       # executed request.  This will typically be used by clients to display
       # prompt numbers to the user.  If the request was a silent one, this will
       # be the current value of the counter in the kernel.
       'execution_count' : int,
     }
 
 When status is 'ok', the following extra fields are present::
 
     {
       # The execution payload is a dict with string keys that may have been
       # produced by the code being executed.  It is retrieved by the kernel at
       # the end of the execution and sent back to the front end, which can take
       # action on it as needed.  See main text for further details.
       'payload' : dict,
 
       # Results for the user_variables and user_expressions.
       'user_variables' : dict,
       'user_expressions' : dict,
 
       # The kernel will often transform the input provided to it.  If the
       # '---->' transform had been applied, this is filled, otherwise it's the
       # empty string.  So transformations like magics don't appear here, only
       # autocall ones.
       'transformed_code' : str,
       }
 
 .. admonition:: Execution payloads
     
    The notion of an 'execution payload' is different from a return value of a
    given set of code, which normally is just displayed on the pyout stream
    through the PUB socket.  The idea of a payload is to allow special types of
    code, typically magics, to populate a data container in the IPython kernel
    that will be shipped back to the caller via this channel.  The kernel will
    have an API for this, probably something along the lines of::
 
        ip.exec_payload_add(key, value)
 
    though this API is still in the design stages.  The data returned in this
    payload will allow frontends to present special views of what just happened.
 
    
 When status is 'error', the following extra fields are present::
 
     {
       'exc_name' : str,   # Exception name, as a string
       'exc_value' : str,  # Exception value, as a string
 
       # The traceback will contain a list of frames, represented each as a
       # string.  For now we'll stick to the existing design of ultraTB, which
       # controls exception level of detail statefully.  But eventually we'll
       # want to grow into a model where more information is collected and
       # packed into the traceback object, with clients deciding how little or
       # how much of it to unpack.  But for now, let's start with a simple list
       # of strings, since that requires only minimal changes to ultratb as
       # written.
       'traceback' : list,
     }
 
 
 When status is 'abort', there are for now no additional data fields.  This
 happens when the kernel was interrupted by a signal.
 
 Kernel attribute access
 -----------------------
 
 While this protocol does not specify full RPC access to arbitrary methods of
 the kernel object, the kernel does allow read (and in some cases write) access
 to certain attributes.
 
 The policy for which attributes can be read is: any attribute of the kernel, or
 its sub-objects, that belongs to a :class:`Configurable` object and has been
 declared at the class-level with Traits validation, is in principle accessible
 as long as its name does not begin with a leading underscore.  The attribute
 itself will have metadata indicating whether it allows remote read and/or write
 access.  The message spec follows for attribute read and write requests.
 
 Message type: ``getattr_request``::
 
     content = {
         # The (possibly dotted) name of the attribute
 	'name' : str,
     }
 
 When a ``getattr_request`` fails, there are two possible error types:
 
 - AttributeError: this type of error was raised when trying to access the
   given name by the kernel itself.  This means that the attribute likely
   doesn't exist.
 
 - AccessError: the attribute exists but its value is not readable remotely.
 
 
 Message type: ``getattr_reply``::
 
     content = {
         # One of ['ok', 'AttributeError', 'AccessError'].
         'status' : str,
 	# If status is 'ok', a JSON object.
 	'value' : object,
     }
 
 Message type: ``setattr_request``::
 
     content = {
         # The (possibly dotted) name of the attribute
 	'name' : str,
 	
 	# A JSON-encoded object, that will be validated by the Traits
 	# information in the kernel
 	'value' : object,
     }
 
 When a ``setattr_request`` fails, there are also two possible error types with
 similar meanings  as those of the ``getattr_request`` case, but for writing.
     
 Message type: ``setattr_reply``::
 
     content = {
         # One of ['ok', 'AttributeError', 'AccessError'].
         'status' : str,
     }
 
 
 Object information
 ------------------
 
 One of IPython's most used capabilities is the introspection of Python objects
 in the user's namespace, typically invoked via the ``?`` and ``??`` characters
 (which in reality are shorthands for the ``%pinfo`` magic).  This is used often
 enough that it warrants an explicit message type, especially because frontends
 may want to get object information in response to user keystrokes (like Tab or
 F1) besides from the user explicitly typing code like ``x??``.
 
 Message type: ``object_info_request``::
 
     content = {
         # The (possibly dotted) name of the object to be searched in all
 	# relevant namespaces
         'name' : str,
 
     	# The level of detail desired.  The default (0) is equivalent to typing
 	# 'x?' at the prompt, 1 is equivalent to 'x??'.
 	'detail_level' : int,
     }
 
 The returned information will be a dictionary with keys very similar to the
 field names that IPython prints at the terminal.
     
 Message type: ``object_info_reply``::
 
     content = {
-        # Flags for magics and system aliases
+    # Boolean flag indicating whether the named object was found or not.  If
+    # it's false, all other fields will be empty.
+    'found' : bool,
+    
+    # Flags for magics and system aliases
     'ismagic' : bool,
     'isalias' : bool,
 
     # The name of the namespace where the object was found ('builtin',
     # 'magics', 'alias', 'interactive', etc.)
     'namespace' : str,
 
     # The type name will be type.__name__ for normal Python objects, but it
     # can also be a string like 'Magic function' or 'System alias'
     'type_name' : str,
 
     'string_form' : str,
 
     # For objects with a __class__ attribute this will be set
     'base_class' : str,
 
     # For objects with a __len__ attribute this will be set
     'length' : int,
 
     # If the object is a function, class or method whose file we can find,
     # we give its full path
     'file' : str,
 
     # For pure Python callable objects, we can reconstruct the object
     # definition line which provides its call signature.  For convenience this
     # is returned as a single 'definition' field, but below the raw parts that
     # compose it are also returned as the argspec field.
     'definition' : str,
 
     # The individual parts that together form the definition string.  Clients
     # with rich display capabilities may use this to provide a richer and more
     # precise representation of the definition line (e.g. by highlighting
     # arguments based on the user's cursor position).  For non-callable
     # objects, this field is empty.
     'argspec' : { # The names of all the arguments
                   args : list,
 		  # The name of the varargs (*args), if any
                   varargs : str,
 		  # The name of the varkw (**kw), if any
 		  varkw : str,
 		  # The values (as strings) of all default arguments.  Note
 		  # that these must be matched *in reverse* with the 'args'
 		  # list above, since the first positional args have no default
 		  # value at all.
 		  func_defaults : list,
 		  },
 
     # For instances, provide the constructor signature (the definition of
     # the __init__ method):
     'init_definition' : str,
     
     # Docstrings: for any object (function, method, module, package) with a
     # docstring, we show it.  But in addition, we may provide additional
     # docstrings.  For example, for instances we will show the constructor
     # and class docstrings as well, if available.
     'docstring' : str,
 
     # For instances, provide the constructor and class docstrings
     'init_docstring' : str,
     'class_docstring' : str,
     
     # If it's a callable object whose call method has a separate docstring and
     # definition line:
     'call_def' : str,
     'call_docstring' : str,
     
     # If detail_level was 1, we also try to find the source code that
     # defines the object, if possible.  The string 'None' will indicate
     # that no source was found.
     'source' : str,
     }
 '
     
 Complete
 --------
 
 Message type: ``complete_request``::
 
     content = {
         # The text to be completed, such as 'a.is'
     'text' : str,
 
     # The full line, such as 'print a.is'.  This allows completers to
     # make decisions that may require information about more than just the
     # current word.
     'line' : str,
 
     # The entire block of text where the line is.  This may be useful in the
     # case of multiline completions where more context may be needed.  Note: if
     # in practice this field proves unnecessary, remove it to lighten the
     # messages.
     
     'block' : str,
 
     # The position of the cursor where the user hit 'TAB' on the line.
     'cursor_pos' : int,
     }
 
 Message type: ``complete_reply``::
 
     content = {
         # The list of all matches to the completion request, such as
     # ['a.isalnum', 'a.isalpha'] for the above example.
     'matches' : list
     }
 
     
 History
 -------
 
 For clients to explicitly request history from a kernel.  The kernel has all
 the actual execution history stored in a single location, so clients can
 request it from the kernel when needed.
 
 Message type: ``history_request``::
 
     content = {
     
       # If True, also return output history in the resulting dict.
       'output' : bool,
 
       # If True, return the raw input history, else the transformed input.
       'raw' : bool,
 
       # This parameter can be one of: A number,  a pair of numbers, None
       # If not given, last 40 are returned.
       #  - number n: return the last n entries.
       #  - pair n1, n2: return entries in the range(n1, n2).
       #  - None: return all history
       'index' : n or (n1, n2) or None,
     }
 
 Message type: ``history_reply``::
 
     content = {
       # A dict with prompt numbers as keys and either (input, output) or input
       # as the value depending on whether output was True or False,
       # respectively.
       'history' : dict,
     }
     
 Messages on the PUB/SUB socket
 ==============================
 
 Streams (stdout,  stderr, etc)
 ------------------------------
 
 Message type: ``stream``::
 
     content = {
         # The name of the stream is one of 'stdin', 'stdout', 'stderr'
     'name' : str,
     
     # The data is an arbitrary string to be written to that stream
     'data' : str,
     }
 
 When a kernel receives a raw_input call, it should also broadcast it on the pub
 socket with the names 'stdin' and 'stdin_reply'.  This will allow other clients
 to monitor/display kernel interactions and possibly replay them to their user
 or otherwise expose them.
 
 Python inputs
 -------------
 
 These messages are the re-broadcast of the ``execute_request``.
 
 Message type: ``pyin``::
 
     content = {
         # Source code to be executed, one or more lines
     'code' : str
     }
 
 Python outputs
 --------------
 
 When Python produces output from code that has been compiled in with the
 'single' flag to :func:`compile`, any expression that produces a value (such as
 ``1+1``) is passed to ``sys.displayhook``, which is a callable that can do with
 this value whatever it wants.  The default behavior of ``sys.displayhook`` in
 the Python interactive prompt is to print to ``sys.stdout`` the :func:`repr` of
 the value as long as it is not ``None`` (which isn't printed at all).  In our
 case, the kernel instantiates as ``sys.displayhook`` an object which has
 similar behavior, but which instead of printing to stdout, broadcasts these
 values as ``pyout`` messages for clients to display appropriately.
 
 Message type: ``pyout``::
 
     content = {
         # The data is typically the repr() of the object.
     'data' : str,
     
     # The counter for this execution is also provided so that clients can
     # display it, since IPython automatically creates variables called _N (for
     # prompt N).
     'execution_count' : int,
     }
     
 Python errors
 -------------
 
 When an error occurs during code execution
 
 Message type: ``pyerr``::
 
     content = {
        # Similar content to the execute_reply messages for the 'error' case,
        # except the 'status' field is omitted.
     }
 
 Kernel crashes
 --------------
 
 When the kernel has an unexpected exception, caught by the last-resort
 sys.excepthook, we should broadcast the crash handler's output before exiting.
 This will allow clients to notice that a kernel died, inform the user and
 propose further actions.
 
 Message type: ``crash``::
 
     content = {
        # Similarly to the 'error' case for execute_reply messages, this will
        # contain exc_name, exc_type and traceback fields.
 
        # An additional field with supplementary information such as where to
        # send the crash message
        'info' : str,
     }
 
 
 Future ideas
 ------------
     
 Other potential message types, currently unimplemented, listed below as ideas.
     
 Message type: ``file``::
 
     content = {
     'path' : 'cool.jpg',
     'mimetype' : str,
     'data' : str,
     }
 
     
 Messages on the REQ/REP socket
 ==============================
 
 This is a socket that goes in the opposite direction: from the kernel to a
 *single* frontend, and its purpose is to allow ``raw_input`` and similar
 operations that read from ``sys.stdin`` on the kernel to be fulfilled by the
 client.  For now we will keep these messages as simple as possible, since they
 basically only mean to convey the ``raw_input(prompt)`` call.
 
 Message type: ``input_request``::
 
     content = { 'prompt' : str }
 
 Message type: ``input_reply``::
 
     content = { 'value' : str }
     
 .. Note::
 
    We do not explicitly try to forward the raw ``sys.stdin`` object, because in
    practice the kernel should behave like an interactive program.  When a
    program is opened on the console, the keyboard effectively takes over the
    ``stdin`` file descriptor, and it can't be used for raw reading anymore.
    Since the IPython kernel effectively behaves like a console program (albeit
    one whose "keyboard" is actually living in a separate process and
    transported over the zmq connection), raw ``stdin`` isn't expected to be
    available.
 
    
 Heartbeat for kernels
 =====================
 
 Initially we had considered using messages like those above over ZMQ for a
 kernel 'heartbeat' (a way to detect quickly and reliably whether a kernel is
 alive at all, even if it may be busy executing user code).  But this has the
 problem that if the kernel is locked inside extension code, it wouldn't execute
 the python heartbeat code.  But it turns out that we can implement a basic
 heartbeat with pure ZMQ, without using any Python messaging at all.
 
 The monitor sends out a single zmq message (right now, it is a str of the
 monitor's lifetime in seconds), and gets the same message right back, prefixed
 with the zmq identity of the XREQ socket in the heartbeat process. This can be
 a uuid, or even a full message, but there doesn't seem to be a need for packing
 up a message when the sender and receiver are the exact same Python object.
 
 The model is this::
 
     monitor.send(str(self.lifetime)) # '1.2345678910'
 
 and the monitor receives some number of messages of the form::
 
     ['uuid-abcd-dead-beef', '1.2345678910']
 
 where the first part is the zmq.IDENTITY of the heart's XREQ on the engine, and
 the rest is the message sent by the monitor.  No Python code ever has any
 access to the message between the monitor's send, and the monitor's recv.
 
 
 ToDo
 ====
 
 Missing things include:
 
 * Important: finish thinking through the payload concept and API.
 
 * Important: ensure that we have a good solution for magics like %edit.  It's
   likely that with the payload concept we can build a full solution, but not
   100% clear yet.
 
 * Finishing the details of the heartbeat protocol.
 
 * Signal handling: specify what kind of information kernel should broadcast (or
   not) when it receives signals.
 
 .. include:: ../links.rst