Finishing work on configurables, plugins and extensions.

IPython/core/plugin.py

@@ -0,0 +1,51 b''
+# encoding: utf-8
+"""IPython plugins.
+
+Authors:
+
+* Brian Granger
+"""
+
+#-----------------------------------------------------------------------------
+#  Copyright (C) 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 IPython.config.configurable import Configurable
+from IPython.utils.traitlets import Dict
+
+#-----------------------------------------------------------------------------
+# Main class
+#-----------------------------------------------------------------------------
+
+class PluginManager(Configurable):
+    """A manager for IPython plugins."""
+
+    plugins = Dict({})
+
+    def __init__(self, config=None):
+        super(PluginManager, self).__init__(config=config)
+
+    def register_plugin(self, name, plugin):
+        if not isinstance(plugin, Plugin):
+            raise TypeError('Expected Plugin, got: %r' % plugin)
+        if self.plugins.has_key(name):
+            raise KeyError('Plugin with name already exists: %r' % name)
+        self.plugins[name] = plugin
+
+    def unregister_plugin(self, name):
+        del self.plugins[name]
+
+    def get_plugin(self, name, default=None):
+        return self.plugins.get(name, default)
+
+
+class Plugin(Configurable):
+    """Base class for IPython plugins."""
+    pass

IPython/core/tests/test_plugin.py

@@ -0,0 +1,46 b''
+"""Tests for plugin.py"""
+
+#-----------------------------------------------------------------------------
+# Imports
+#-----------------------------------------------------------------------------
+
+from unittest import TestCase
+
+from IPython.core.plugin import Plugin, PluginManager
+
+#-----------------------------------------------------------------------------
+# Tests
+#-----------------------------------------------------------------------------
+
+class FooPlugin(Plugin):
+    pass
+
+
+class BarPlugin(Plugin):
+    pass
+
+
+class BadPlugin(object):
+    pass
+
+
+class PluginTest(TestCase):
+
+    def setUp(self):
+        self.manager = PluginManager()
+
+    def test_register_get(self):
+        self.assertEquals(None, self.manager.get_plugin('foo'))
+        foo = FooPlugin()
+        self.manager.register_plugin('foo', foo)
+        self.assertEquals(foo, self.manager.get_plugin('foo'))
+        bar = BarPlugin()
+        self.assertRaises(KeyError, self.manager.register_plugin, 'foo', bar)
+        bad = BadPlugin()
+        self.assertRaises(TypeError, self.manager.register_plugin, 'bad')
+
+    def test_unregister(self):
+        foo = FooPlugin()
+        self.manager.register_plugin('foo', foo)
+        self.manager.unregister_plugin('foo')
+        self.assertEquals(None, self.manager.get_plugin('foo'))

IPython/core/alias.py

@@ -1,259 +1,259 b''
 #!/usr/bin/env python
 # encoding: utf-8
 """
 System command aliases.
 
 Authors:
 
 * Fernando Perez
 * Brian Granger
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2009  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import __builtin__
 import keyword
 import os
 import re
 import sys
 
 from IPython.config.configurable import Configurable
 from IPython.core.splitinput import split_user_input
 
 from IPython.utils.traitlets import List, Instance
 from IPython.utils.autoattr import auto_attr
 from IPython.utils.warn import warn, error
 
 #-----------------------------------------------------------------------------
 # Utilities
 #-----------------------------------------------------------------------------
 
 # This is used as the pattern for calls to split_user_input.
 shell_line_split = re.compile(r'^(\s*)(\S*\s*)(.*$)')
 
 def default_aliases():
     # Make some aliases automatically
     # Prepare list of shell aliases to auto-define
     if os.name == 'posix':
         default_aliases = ('mkdir mkdir', 'rmdir rmdir',
                       'mv mv -i','rm rm -i','cp cp -i',
                       'cat cat','less less','clear clear',
                       # a better ls
                       'ls ls -F',
                       # long ls
                       'll ls -lF')
         # Extra ls aliases with color, which need special treatment on BSD
         # variants
         ls_extra = ( # color ls
                      'lc ls -F -o --color',
                      # ls normal files only
                      'lf ls -F -o --color %l | grep ^-',
                      # ls symbolic links
                      'lk ls -F -o --color %l | grep ^l',
                      # directories or links to directories,
                      'ldir ls -F -o --color %l | grep /$',
                      # things which are executable
                      'lx ls -F -o --color %l | grep ^-..x',
                      )
         # The BSDs don't ship GNU ls, so they don't understand the
         # --color switch out of the box
         if 'bsd' in sys.platform:
             ls_extra = ( # ls normal files only
                          'lf ls -lF | grep ^-',
                          # ls symbolic links
                          'lk ls -lF | grep ^l',
                          # directories or links to directories,
                          'ldir ls -lF | grep /$',
                          # things which are executable
                          'lx ls -lF | grep ^-..x',
                          )
         default_aliases = default_aliases + ls_extra
     elif os.name in ['nt','dos']:
         default_aliases = ('ls dir /on',
                       'ddir dir /ad /on', 'ldir dir /ad /on',
                       'mkdir mkdir','rmdir rmdir','echo echo',
                       'ren ren','cls cls','copy copy')
     else:
         default_aliases = ()
     return [s.split(None,1) for s in default_aliases]
 
 
 class AliasError(Exception):
     pass
 
 
 class InvalidAliasError(AliasError):
     pass
 
 
 #-----------------------------------------------------------------------------
 # Main AliasManager class
 #-----------------------------------------------------------------------------
 
 
 class AliasManager(Configurable):
 
     default_aliases = List(default_aliases(), config=True)
     user_aliases = List(default_value=[], config=True)
-    shell = Instance('IPython.core.iplib.InteractiveShell')
+    shell = Instance('IPython.core.iplib.InteractiveShellABC')
 
     def __init__(self, shell, config=None):
         super(AliasManager, self).__init__(config=config)
         self.alias_table = {}
         self.exclude_aliases()
         self.init_aliases()
         self.shell = shell
 
     def __contains__(self, name):
         if name in self.alias_table:
             return True
         else:
             return False
 
     @property
     def aliases(self):
         return [(item[0], item[1][1]) for item in self.alias_table.iteritems()]
 
     def exclude_aliases(self):
         # set of things NOT to alias (keywords, builtins and some magics)
         no_alias = set(['cd','popd','pushd','dhist','alias','unalias'])
         no_alias.update(set(keyword.kwlist))
         no_alias.update(set(__builtin__.__dict__.keys()))
         self.no_alias = no_alias
 
     def init_aliases(self):
         # Load default aliases
         for name, cmd in self.default_aliases:
             self.soft_define_alias(name, cmd)
 
         # Load user aliases
         for name, cmd in self.user_aliases:
             self.soft_define_alias(name, cmd)
 
     def clear_aliases(self):
         self.alias_table.clear()
 
     def soft_define_alias(self, name, cmd):
         """Define an alias, but don't raise on an AliasError."""
         try:
             self.define_alias(name, cmd)
         except AliasError, e:
             error("Invalid alias: %s" % e)
 
     def define_alias(self, name, cmd):
         """Define a new alias after validating it.
 
         This will raise an :exc:`AliasError` if there are validation
         problems.
         """
         nargs = self.validate_alias(name, cmd)
         self.alias_table[name] = (nargs, cmd)
 
     def undefine_alias(self, name):
         if self.alias_table.has_key(name):
             del self.alias_table[name]
 
     def validate_alias(self, name, cmd):
         """Validate an alias and return the its number of arguments."""
         if name in self.no_alias:
             raise InvalidAliasError("The name %s can't be aliased "
                                     "because it is a keyword or builtin." % name)
         if not (isinstance(cmd, basestring)):
             raise InvalidAliasError("An alias command must be a string, "
                                     "got: %r" % name)
         nargs = cmd.count('%s')
         if nargs>0 and cmd.find('%l')>=0:
             raise InvalidAliasError('The %s and %l specifiers are mutually '
                                     'exclusive in alias definitions.')
         return nargs
 
     def call_alias(self, alias, rest=''):
         """Call an alias given its name and the rest of the line."""
         cmd = self.transform_alias(alias, rest)
         try:
             self.shell.system(cmd)
         except:
             self.shell.showtraceback()
 
     def transform_alias(self, alias,rest=''):
         """Transform alias to system command string."""
         nargs, cmd = self.alias_table[alias]
 
         if ' ' in cmd and os.path.isfile(cmd):
             cmd = '"%s"' % cmd
 
         # Expand the %l special to be the user's input line
         if cmd.find('%l') >= 0:
             cmd = cmd.replace('%l', rest)
             rest = ''
         if nargs==0:
             # Simple, argument-less aliases
             cmd = '%s %s' % (cmd, rest)
         else:
             # Handle aliases with positional arguments
             args = rest.split(None, nargs)
             if len(args) < nargs:
                 raise AliasError('Alias <%s> requires %s arguments, %s given.' %
                       (alias, nargs, len(args)))
             cmd = '%s %s' % (cmd % tuple(args[:nargs]),' '.join(args[nargs:]))
         return cmd
 
     def expand_alias(self, line):
         """ Expand an alias in the command line 
         
         Returns the provided command line, possibly with the first word 
         (command) translated according to alias expansion rules.
         
         [ipython]|16> _ip.expand_aliases("np myfile.txt")
                  <16> 'q:/opt/np/notepad++.exe myfile.txt'
         """
         
         pre,fn,rest = split_user_input(line)
         res = pre + self.expand_aliases(fn, rest)
         return res
 
     def expand_aliases(self, fn, rest):
         """Expand multiple levels of aliases:
         
         if:
         
         alias foo bar /tmp
         alias baz foo
         
         then:
         
         baz huhhahhei -> bar /tmp huhhahhei
         
         """
         line = fn + " " + rest
         
         done = set()
         while 1:
             pre,fn,rest = split_user_input(line, shell_line_split)
             if fn in self.alias_table:
                 if fn in done:
                     warn("Cyclic alias definition, repeated '%s'" % fn)
                     return ""
                 done.add(fn)
 
                 l2 = self.transform_alias(fn, rest)
                 if l2 == line:
                     break
                 # ls -> ls -F should not recurse forever
                 if l2.split(None,1)[0] == line.split(None,1)[0]:
                     line = l2
                     break
                 line=l2
             else:
                 break
                 
         return line

IPython/core/builtin_trap.py

@@ -1,115 +1,115 b''
 #!/usr/bin/env python
 # encoding: utf-8
 """
 A context manager for managing things injected into :mod:`__builtin__`.
 
 Authors:
 
 * Brian Granger
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2009  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import __builtin__
 
 from IPython.config.configurable import Configurable
 from IPython.core.quitter import Quitter
 
 from IPython.utils.traitlets import Instance
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 
 class __BuiltinUndefined(object): pass
 BuiltinUndefined = __BuiltinUndefined()
 
 
 class BuiltinTrap(Configurable):
 
-    shell = Instance('IPython.core.iplib.InteractiveShell')
+    shell = Instance('IPython.core.iplib.InteractiveShellABC')
 
     def __init__(self, shell):
         super(BuiltinTrap, self).__init__(None)
         self._orig_builtins = {}
         # We define this to track if a single BuiltinTrap is nested.
         # Only turn off the trap when the outermost call to __exit__ is made.
         self._nested_level = 0
         self.shell = shell
 
     def __enter__(self):
         if self._nested_level == 0:
             self.set()
         self._nested_level += 1
         # I return self, so callers can use add_builtin in a with clause.
         return self
 
     def __exit__(self, type, value, traceback):
         if self._nested_level == 1:
             self.unset()
         self._nested_level -= 1
         # Returning False will cause exceptions to propagate
         return False
 
     def add_builtin(self, key, value):
         """Add a builtin and save the original."""
         orig = __builtin__.__dict__.get(key, BuiltinUndefined)
         self._orig_builtins[key] = orig
         __builtin__.__dict__[key] = value
 
     def remove_builtin(self, key):
         """Remove an added builtin and re-set the original."""
         try:
             orig = self._orig_builtins.pop(key)
         except KeyError:
             pass
         else:
             if orig is BuiltinUndefined:
                 del __builtin__.__dict__[key]
             else:
                 __builtin__.__dict__[key] = orig
 
     def set(self):
         """Store ipython references in the __builtin__ namespace."""
         self.add_builtin('exit', Quitter(self.shell, 'exit'))
         self.add_builtin('quit', Quitter(self.shell, 'quit'))
         self.add_builtin('get_ipython', self.shell.get_ipython)
 
         # Recursive reload function
         try:
             from IPython.lib import deepreload
             if self.shell.deep_reload:
                 self.add_builtin('reload', deepreload.reload)
             else:
                 self.add_builtin('dreload', deepreload.reload)
             del deepreload
         except ImportError:
             pass
 
         # Keep in the builtins a flag for when IPython is active.  We set it
         # with setdefault so that multiple nested IPythons don't clobber one
         # another.  Each will increase its value by one upon being activated,
         # which also gives us a way to determine the nesting level.
         __builtin__.__dict__.setdefault('__IPYTHON__active',0)
 
     def unset(self):
         """Remove any builtins which might have been added by add_builtins, or
         restore overwritten ones to their previous values."""
         for key in self._orig_builtins.keys():
             self.remove_builtin(key)
         self._orig_builtins.clear()
         self._builtins_added = False
         try:
             del __builtin__.__dict__['__IPYTHON__active']
         except KeyError:
             pass

IPython/core/extensions.py

@@ -1,124 +1,126 b''
 # encoding: utf-8
 """A class for managing IPython extensions.
 
 Authors:
 
 * Brian Granger
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 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
 #-----------------------------------------------------------------------------
 
 import os
 import sys
 
 from IPython.config.configurable import Configurable
 from IPython.utils.traitlets import Instance
 
 #-----------------------------------------------------------------------------
 # Main class
 #-----------------------------------------------------------------------------
 
 class ExtensionManager(Configurable):
+    """A class to manage IPython extensions.
 
-    shell = Instance('IPython.core.iplib.InteractiveShell')
+    An IPython extension is an importable Python module that has
+    a function with the signature::
+
+        def load_ipython_extension(ipython):
+            # Do things with ipython
+
+    This function is called after your extension is imported and the 
+    currently active :class:`InteractiveShell` instance is passed as
+    the only argument.  You can do anything you want with IPython at
+    that point, including defining new magic and aliases, adding new
+    components, etc.
+
+    The :func:`load_ipython_extension` will be called again is you 
+    load or reload the extension again.  It is up to the extension
+    author to add code to manage that.
+
+    You can put your extension modules anywhere you want, as long as
+    they can be imported by Python's standard import mechanism.  However,
+    to make it easy to write extensions, you can also put your extensions
+    in ``os.path.join(self.ipython_dir, 'extensions')``.  This directory
+    is added to ``sys.path`` automatically.
+    """
+
+    shell = Instance('IPython.core.iplib.InteractiveShellABC')
 
     def __init__(self, shell, config=None):
         super(ExtensionManager, self).__init__(config=config)
         self.shell = shell
         self.shell.on_trait_change(
             self._on_ipython_dir_changed, 'ipython_dir'
         )
 
     def __del__(self):
         self.shell.on_trait_change(
             self._on_ipython_dir_changed, 'ipython_dir', remove=True
         )
 
     @property
     def ipython_extension_dir(self):
         return os.path.join(self.shell.ipython_dir, u'extensions')
 
     def _on_ipython_dir_changed(self):
         if not os.path.isdir(self.ipython_extension_dir):
             os.makedirs(self.ipython_extension_dir, mode = 0777)
 
     def load_extension(self, module_str):
         """Load an IPython extension by its module name.
 
-        An IPython extension is an importable Python module that has
-        a function with the signature::
-
-            def load_ipython_extension(ipython):
-                # Do things with ipython
-
-        This function is called after your extension is imported and the 
-        currently active :class:`InteractiveShell` instance is passed as
-        the only argument.  You can do anything you want with IPython at
-        that point, including defining new magic and aliases, adding new
-        components, etc.
-
-        The :func:`load_ipython_extension` will be called again is you 
-        load or reload the extension again.  It is up to the extension
-        author to add code to manage that.
-
-        You can put your extension modules anywhere you want, as long as
-        they can be imported by Python's standard import mechanism.  However,
-        to make it easy to write extensions, you can also put your extensions
-        in ``os.path.join(self.ipython_dir, 'extensions')``.  This directory
-        is added to ``sys.path`` automatically.
-
         If :func:`load_ipython_extension` returns anything, this function
         will return that object.
         """
         from IPython.utils.syspathcontext import prepended_to_syspath
 
         if module_str not in sys.modules:
             with prepended_to_syspath(self.ipython_extension_dir):
                 __import__(module_str)
         mod = sys.modules[module_str]
         return self._call_load_ipython_extension(mod)
 
     def unload_extension(self, module_str):
         """Unload an IPython extension by its module name.
 
         This function looks up the extension's name in ``sys.modules`` and
         simply calls ``mod.unload_ipython_extension(self)``.
         """
         if module_str in sys.modules:
             mod = sys.modules[module_str]
             self._call_unload_ipython_extension(mod)
 
     def reload_extension(self, module_str):
         """Reload an IPython extension by calling reload.
 
         If the module has not been loaded before,
         :meth:`InteractiveShell.load_extension` is called. Otherwise
         :func:`reload` is called and then the :func:`load_ipython_extension`
         function of the module, if it exists is called.
         """
         from IPython.utils.syspathcontext import prepended_to_syspath
 
         with prepended_to_syspath(self.ipython_extension_dir):
             if module_str in sys.modules:
                 mod = sys.modules[module_str]
                 reload(mod)
                 self._call_load_ipython_extension(mod)
             else:
                 self.load_extension(module_str)
 
     def _call_load_ipython_extension(self, mod):
         if hasattr(mod, 'load_ipython_extension'):
             return mod.load_ipython_extension(self.shell)
 
     def _call_unload_ipython_extension(self, mod):
         if hasattr(mod, 'unload_ipython_extension'):
-            return mod.unload_ipython_extension(self.shell)
  No newline at end of file
+            return mod.unload_ipython_extension(self.shell)

IPython/core/iplib.py

@@ -1,2511 +1,2523 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 abc
 import bdb
 import codeop
 import exceptions
 import new
 import os
 import re
 import string
 import sys
 import tempfile
 from contextlib import nested
 
 from IPython.core import debugger, oinspect
 from IPython.core import history as ipcorehist
 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.config.configurable import Configurable
 from IPython.core.display_trap import DisplayTrap
 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.logger import Logger
 from IPython.core.magic import Magic
+from IPython.core.plugin import PluginManager
 from IPython.core.prefilter import PrefilterManager
 from IPython.core.prompts import CachedOutput
 from IPython.core.usage import interactive_usage, default_banner
 import IPython.core.hooks
 from IPython.external.Itpl import ItplNS
 from IPython.lib.inputhook import enable_gui
 from IPython.lib.backgroundjobs import BackgroundJobManager
 from IPython.lib.pylabtools import pylab_activate
 from IPython.utils import PyColorize
 from IPython.utils import pickleshare
 from IPython.utils.doctestreload import doctest_reload
 from IPython.utils.ipstruct import Struct
 from IPython.utils.io import Term, ask_yes_no
 from IPython.utils.path import get_home_dir, get_ipython_dir, HomeDirError
 from IPython.utils.process import (
     abbrev_cwd,
     getoutput,
     getoutputerror
 )
 # import IPython.utils.rlineimpl as readline
 from IPython.utils.strdispatch import StrDispatch
 from IPython.utils.syspathcontext import prepended_to_syspath
 from IPython.utils.terminal import toggle_set_term_title, set_term_title
 from IPython.utils.warn import warn, error, fatal
 from IPython.utils.traitlets import (
     Int, Str, CBool, CaselessStrEnum, Enum, List, Unicode, Instance
 )
 
 # from IPython.utils import growl
 # growl.start("IPython")
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 # 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
 
 # compiled regexps for autoindent management
 dedent_re = re.compile(r'^\s+raise|^\s+return|^\s+pass')
 
 #-----------------------------------------------------------------------------
 # Utilities
 #-----------------------------------------------------------------------------
 
 ini_spaces_re = re.compile(r'^(\s+)')
 
 
 def num_ini_spaces(strng):
     """Return the number of initial spaces in a string"""
 
     ini_spaces = ini_spaces_re.match(strng)
     if ini_spaces:
         return ini_spaces.end()
     else:
         return 0
 
 
 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
 
 class InputList(list):
     """Class to store user input.
 
     It's basically a list, but slices return a string instead of a list, thus
     allowing things like (assuming 'In' is an instance):
 
     exec In[4:7]
 
     or
 
     exec In[5:9] + In[14] + In[21:25]"""
 
     def __getslice__(self,i,j):
         return ''.join(list.__getslice__(self,i,j))
 
 
 class SyntaxTB(ultratb.ListTB):
     """Extension which holds some state: the last exception value"""
 
     def __init__(self,color_scheme = 'NoColor'):
         ultratb.ListTB.__init__(self,color_scheme)
         self.last_syntax_error = None
 
     def __call__(self, etype, value, elist):
         self.last_syntax_error = value
         ultratb.ListTB.__call__(self,etype,value,elist)
 
     def clear_err_state(self):
         """Return the current error state and clear it"""
         e = self.last_syntax_error
         self.last_syntax_error = None
         return e
 
 
 def get_default_editor():
     try:
         ed = os.environ['EDITOR']
     except KeyError:
         if os.name == 'posix':
             ed = 'vi'  # the only one guaranteed to be there!
         else:
             ed = 'notepad' # same in Windows!
     return ed
 
 
 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)
 
 
 #-----------------------------------------------------------------------------
 # Main IPython class
 #-----------------------------------------------------------------------------
 
 
 class InteractiveShell(Configurable, Magic):
     """An enhanced, interactive shell for Python."""
 
     autocall = Enum((0,1,2), default_value=1, config=True)
     autoedit_syntax = CBool(False, config=True)
     autoindent = CBool(True, config=True)
     automagic = CBool(True, config=True)
     banner = Str('')
     banner1 = Str(default_banner, config=True)
     banner2 = Str('', 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)
     confirm_exit = CBool(True, config=True)
     debug = CBool(False, config=True)
     deep_reload = CBool(False, config=True)
     # This display_banner only controls whether or not self.show_banner()
     # is called when mainloop/interact are called.  The default is False
     # because for the terminal based application, the banner behavior
     # is controlled by Global.display_banner, which IPythonApp looks at
     # to determine if *it* should call show_banner() by hand or not.
     display_banner = CBool(False) # This isn't configurable!
     embedded = CBool(False)
     embedded_active = CBool(False)
     editor = Str(get_default_editor(), config=True)
     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)
     pager = Str('less', 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)
 
     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)
 
     screen_length = Int(0, config=True)
     
     # 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)
 
     system_header = Str('IPython system call: ', config=True)
     system_verbose = CBool(False, config=True)
     term_title = CBool(False, config=True)
     wildcards_case_sensitive = CBool(True, config=True)
     xmode = CaselessStrEnum(('Context','Plain', 'Verbose'), 
                             default_value='Context', config=True)
 
     autoexec = List(allow_none=False)
 
     # class attribute to indicate whether the class supports threads or not.
     # Subclasses with thread support should override this as needed.
     isthreaded = False
 
     # 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')
 
     def __init__(self, config=None, ipython_dir=None, usage=None,
                  user_ns=None, user_global_ns=None,
                  banner1=None, banner2=None, display_banner=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()
         self.init_term_title()
         self.init_usage(usage)
         self.init_banner(banner1, banner2, display_banner)
 
         # 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.
         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(custom_exceptions)
         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()
         self.init_readline()
         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.hooks.late_startup_hook()
 
     @classmethod
     def instance(cls, *args, **kwargs):
         """Returns a global InteractiveShell instance."""
         if not hasattr(cls, "_instance"):
             cls._instance = cls(*args, **kwargs)
         return cls._instance
 
     @classmethod
     def initialized(cls):
         return hasattr(cls, "_instance")
 
     def get_ipython(self):
         """Return the currently running IPython instance."""
         return self
 
     #-------------------------------------------------------------------------
     # Trait changed handlers
     #-------------------------------------------------------------------------
 
     def _banner1_changed(self):
         self.compute_banner()
 
     def _banner2_changed(self):
         self.compute_banner()
 
     def _ipython_dir_changed(self, name, new):
         if not os.path.isdir(new):
             os.makedirs(new, mode = 0777)
 
     @property
     def usable_screen_length(self):
         if self.screen_length == 0:
             return 0
         else:
             num_lines_bot = self.separate_in.count('\n')+1
             return self.screen_length - num_lines_bot
 
     def _term_title_changed(self, name, new_value):
         self.init_term_title()
 
     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.jobs = BackgroundJobManager()
         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
 
         # Flag to mark unconditional exit
         self.exit_now = False
 
         # 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_term_title(self):
         # Enable or disable the terminal title.
         if self.term_title:
             toggle_set_term_title(True)
             set_term_title('IPython: ' + abbrev_cwd())
         else:
             toggle_set_term_title(False)
 
     def init_usage(self, usage=None):
         if usage is None:
             self.usage = interactive_usage
         else:
             self.usage = usage
 
     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(self)
 
     def init_inspector(self):
         # Object inspector
         self.inspector = oinspect.Inspector(oinspect.InspectColors,
                                             PyColorize.ANSICodeColors,
                                             'NoColor',
                                             self.object_info_string_level)
 
     def init_prompts(self):
         # Initialize cache, set in/out prompts and printing system
         self.outputcache = CachedOutput(self,
                                         self.cache_size,
                                         self.pprint,
                                         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)
 
         # user may have over-ridden the default print hook:
         try:
             self.outputcache.__class__.display = self.hooks.display
         except AttributeError:
             pass
 
     def init_displayhook(self):
         self.display_trap = DisplayTrap(self.outputcache)
 
     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 the banner
     #-------------------------------------------------------------------------
 
     def init_banner(self, banner1, banner2, display_banner):
         if banner1 is not None:
             self.banner1 = banner1
         if banner2 is not None:
             self.banner2 = banner2
         if display_banner is not None:
             self.display_banner = display_banner
         self.compute_banner()
 
     def show_banner(self, banner=None):
         if banner is None:
             banner = self.banner
         self.write(banner)
 
     def compute_banner(self):
         self.banner = self.banner1 + '\n'
         if self.profile:
             self.banner += '\nIPython profile: %s\n' % self.profile
         if self.banner2:
             self.banner += '\n' + self.banner2 + '\n'
 
     #-------------------------------------------------------------------------
     # 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
         if self.isthreaded:
             try:
                 self.sys_excepthook.call_pdb = val
             except:
                 warn('Failed to activate pdb for threaded exception handler')
 
     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 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
 
     #-------------------------------------------------------------------------
     # Things related to exception handling and tracebacks (not debugging)
     #-------------------------------------------------------------------------
 
     def init_traceback_handlers(self, custom_exceptions):
         # Syntax error handler.
         self.SyntaxTB = 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).
 
           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('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:
                     self.CustomTB(etype,value,tb)
                 else:
                     if exception_only:
                         m = ('An exception has occurred, use %tb to see the '
                              'full traceback.')
                         print m
                         self.InteractiveTB.show_exception_only(etype, value)
                     else:
                         self.InteractiveTB(etype,value,tb,tb_offset=tb_offset)
                         if self.InteractiveTB.call_pdb:
                             # pdb mucks up readline, fix it back
                             self.set_completer()
                         
         except KeyboardInterrupt:
             self.write("\nKeyboardInterrupt\n")        
         
 
     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)
         self.SyntaxTB(etype,value,[])
 
     def edit_syntax_error(self):
         """The bottom half of the syntax error handler called in the main loop.
 
         Loop until syntax error is fixed or user cancels.
         """
 
         while self.SyntaxTB.last_syntax_error:
             # copy and clear last_syntax_error
             err = self.SyntaxTB.clear_err_state()
             if not self._should_recompile(err):
                 return
             try:
                 # may set last_syntax_error again if a SyntaxError is raised
                 self.safe_execfile(err.filename,self.user_ns)
             except:
                 self.showtraceback()
             else:
                 try:
                     f = file(err.filename)
                     try:
                         # This should be inside a display_trap block and I 
                         # think it is.
                         sys.displayhook(f.read())
                     finally:
                         f.close()
                 except:
                     self.showtraceback()
 
     def _should_recompile(self,e):
         """Utility routine for edit_syntax_error"""
 
         if e.filename in ('<ipython console>','<input>','<string>',
                           '<console>','<BackgroundJob compilation>',
                           None):
                               
             return False
         try:
             if (self.autoedit_syntax and 
                 not self.ask_yes_no('Return to editor to correct syntax error? '
                               '[Y/n] ','y')):
                 return False
         except EOFError:
             return False
 
         def int0(x):
             try:
                 return int(x)
             except TypeError:
                 return 0
         # always pass integer line and offset values to editor hook
         try:
             self.hooks.fix_error_editor(e.filename,
                 int0(e.lineno),int0(e.offset),e.msg)
         except TryNext:
             warn('Could not open editor')
             return False
         return True
 
     #-------------------------------------------------------------------------
     # Things related to tab completion
     #-------------------------------------------------------------------------
 
     def complete(self, text):
         """Return a sorted list of all possible completions on text.
 
         Inputs:
 
           - text: a string of text to be completed on.
 
         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 [7]: x = 'hello'
 
         In [8]: x
         Out[8]: 'hello'
 
         In [9]: print x
         hello
 
         In [10]: _ip.complete('x.l')
         Out[10]: ['x.ljust', 'x.lower', 'x.lstrip']
         """
 
         # Inject names into __builtin__ so we can complete on the added names.
         with self.builtin_trap:
             complete = self.Completer.complete
             state = 0
             # use a dict so we get unique keys, since ipyhton's multiple
             # completers can return duplicates.  When we make 2.4 a requirement,
             # start using sets instead, which are faster.
             comps = {}
             while True:
                 newcomp = complete(text,state,line_buffer=text)
                 if newcomp is None:
                     break
                 comps[newcomp] = 1
                 state += 1
             outcomps = comps.keys()
             outcomps.sort()
             #print "T:",text,"OC:",outcomps  # dbg
             #print "vars:",self.user_ns.keys()
             return outcomps
 
     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.complete)
 
     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.complete
             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
 
     def pre_readline(self):
         """readline hook to be used at the start of each line.
 
         Currently it handles auto-indent only."""
 
         #debugx('self.indent_current_nsp','pre_readline:')
 
         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):
         # Set user colors (don't do it in the constructor above so that it
         # doesn't crash if colors option is invalid)
         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):
         """Make a system call, using IPython."""
         return self.hooks.shell_hook(self.var_expand(cmd, depth=2))
 
     #-------------------------------------------------------------------------
     # Things related to aliases
     #-------------------------------------------------------------------------
 
     def init_alias(self):
         self.alias_manager = AliasManager(self, config=self.config)
         self.ns_table['alias'] = self.alias_manager.alias_table,
 
     #-------------------------------------------------------------------------
-    # Things related to extensions
+    # Things related to extensions and plugins
     #-------------------------------------------------------------------------
 
     def init_extension_manager(self):
         self.extension_manager = ExtensionManager(self, config=self.config)
 
+    def init_plugin_manager(self):
+        self.plugin_manager = PluginManager(config=self.config)
+
     #-------------------------------------------------------------------------
     # 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 mainloop(self, display_banner=None):
         """Start the mainloop.
 
         If an optional banner argument is given, it will override the
         internally created default banner.
         """
         
         with nested(self.builtin_trap, self.display_trap):
 
             # if you run stuff with -c <cmd>, raw hist is not updated
             # ensure that it's in sync
             if len(self.input_hist) != len (self.input_hist_raw):
                 self.input_hist_raw = InputList(self.input_hist)
 
             while 1:
                 try:
                     self.interact(display_banner=display_banner)
                     #self.interact_with_readline()                
                     # XXX for testing of a readline-decoupled repl loop, call
                     # interact_with_readline above
                     break
                 except KeyboardInterrupt:
                     # this should not be necessary, but KeyboardInterrupt
                     # handling seems rather unpredictable...
                     self.write("\nKeyboardInterrupt in interact()\n")
 
     def interact_prompt(self):
         """ Print the prompt (in read-eval-print loop) 
 
         Provided for those who want to implement their own read-eval-print loop (e.g. GUIs), not 
         used in standard IPython flow.
         """
         if self.more:
             try:
                 prompt = self.hooks.generate_prompt(True)
             except:
                 self.showtraceback()
             if self.autoindent:
                 self.rl_do_indent = True
 
         else:
             try:
                 prompt = self.hooks.generate_prompt(False)
             except:
                 self.showtraceback()
         self.write(prompt)
 
     def interact_handle_input(self,line):
         """ Handle the input line (in read-eval-print loop)
         
         Provided for those who want to implement their own read-eval-print loop (e.g. GUIs), not 
         used in standard IPython flow.        
         """
         if line.lstrip() == line:
             self.shadowhist.add(line.strip())
         lineout = self.prefilter_manager.prefilter_lines(line,self.more)
 
         if line.strip():
             if self.more:
                 self.input_hist_raw[-1] += '%s\n' % line
             else:
                 self.input_hist_raw.append('%s\n' % line)                
 
         
         self.more = self.push_line(lineout)
         if (self.SyntaxTB.last_syntax_error and
             self.autoedit_syntax):
             self.edit_syntax_error()
 
     def interact_with_readline(self):
         """ Demo of using interact_handle_input, interact_prompt
         
         This is the main read-eval-print loop. If you need to implement your own (e.g. for GUI),
         it should work like this.
         """ 
         self.readline_startup_hook(self.pre_readline)
         while not self.exit_now:
             self.interact_prompt()
             if self.more:
                 self.rl_do_indent = True
             else:
                 self.rl_do_indent = False
             line = raw_input_original().decode(self.stdin_encoding)
             self.interact_handle_input(line)
 
     def interact(self, display_banner=None):
         """Closely emulate the interactive Python console."""
 
         # batch run -> do not interact        
         if self.exit_now:
             return
 
         if display_banner is None:
             display_banner = self.display_banner
         if display_banner:
             self.show_banner()
 
         more = 0
         
         # Mark activity in the builtins
         __builtin__.__dict__['__IPYTHON__active'] += 1
         
         if self.has_readline:
             self.readline_startup_hook(self.pre_readline)
         # exit_now is set by a call to %Exit or %Quit, through the
         # ask_exit callback.
         
         while not self.exit_now:
             self.hooks.pre_prompt_hook()
             if more:
                 try:
                     prompt = self.hooks.generate_prompt(True)
                 except:
                     self.showtraceback()
                 if self.autoindent:
                     self.rl_do_indent = True
                     
             else:
                 try:
                     prompt = self.hooks.generate_prompt(False)
                 except:
                     self.showtraceback()
             try:
                 line = self.raw_input(prompt, more)
                 if self.exit_now:
                     # quick exit on sys.std[in|out] close
                     break
                 if self.autoindent:
                     self.rl_do_indent = False
                     
             except KeyboardInterrupt:
                 #double-guard against keyboardinterrupts during kbdint handling
                 try:
                     self.write('\nKeyboardInterrupt\n')
                     self.resetbuffer()
                     # keep cache in sync with the prompt counter:
                     self.outputcache.prompt_count -= 1
     
                     if self.autoindent:
                         self.indent_current_nsp = 0
                     more = 0
                 except KeyboardInterrupt:
                     pass
             except EOFError:
                 if self.autoindent:
                     self.rl_do_indent = False
                     if self.has_readline:
                         self.readline_startup_hook(None)
                 self.write('\n')
                 self.exit()
             except bdb.BdbQuit:
                 warn('The Python debugger has exited with a BdbQuit exception.\n'
                      'Because of how pdb handles the stack, it is impossible\n'
                      'for IPython to properly format this particular exception.\n'
                      'IPython will resume normal operation.')
             except:
                 # exceptions here are VERY RARE, but they can be triggered
                 # asynchronously by signal handlers, for example.
                 self.showtraceback()
             else:
                 more = self.push_line(line)
                 if (self.SyntaxTB.last_syntax_error and
                     self.autoedit_syntax):
                     self.edit_syntax_error()
 
         # We are off again...
         __builtin__.__dict__['__IPYTHON__active'] -= 1
 
         # Turn off the exit flag, so the mainloop can be restarted if desired
         self.exit_now = False
 
     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 _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 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()
                 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 _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
 
     def resetbuffer(self):
         """Reset the input buffer."""
         self.buffer[:] = []
         
     def raw_input(self,prompt='',continue_prompt=False):
         """Write a prompt and read a line.
 
         The returned line does not include the trailing newline.
         When the user enters the EOF key sequence, EOFError is raised.
 
         Optional inputs:
 
           - prompt(''): a string to be printed to prompt the user.
 
           - continue_prompt(False): whether this line is the first one or a
           continuation in a sequence of inputs.
         """
         # growl.notify("raw_input: ", "prompt = %r\ncontinue_prompt = %s" % (prompt, continue_prompt))
 
         # Code run by the user may have modified the readline completer state.
         # We must ensure that our completer is back in place.
 
         if self.has_readline:
             self.set_completer()
         
         try:
             line = raw_input_original(prompt).decode(self.stdin_encoding)
         except ValueError:
             warn("\n********\nYou or a %run:ed script called sys.stdin.close()"
                  " or sys.stdout.close()!\nExiting IPython!")
             self.ask_exit()
             return ""
 
         # Try to be reasonably smart about not re-indenting pasted input more
         # than necessary.  We do this by trimming out the auto-indent initial
         # spaces, if the user's actual input started itself with whitespace.
         #debugx('self.buffer[-1]')
 
         if self.autoindent:
             if num_ini_spaces(line) > self.indent_current_nsp:
                 line = line[self.indent_current_nsp:]
                 self.indent_current_nsp = 0
             
         # store the unfiltered input before the user has any chance to modify
         # it.
         if line.strip():
             if continue_prompt:
                 self.input_hist_raw[-1] += '%s\n' % line
                 if self.has_readline and self.readline_use:
                     try:
                         histlen = self.readline.get_current_history_length()
                         if histlen > 1:
                             newhist = self.input_hist_raw[-1].rstrip()
                             self.readline.remove_history_item(histlen-1)
                             self.readline.replace_history_item(histlen-2,
                                             newhist.encode(self.stdin_encoding))
                     except AttributeError:
                         pass # re{move,place}_history_item are new in 2.4.                
             else:
                 self.input_hist_raw.append('%s\n' % line)                
             # only entries starting at first column go to shadow history
             if line.lstrip() == line:
                 self.shadowhist.add(line.strip())
         elif not continue_prompt:
             self.input_hist_raw.append('\n')
         try:
             lineout = self.prefilter_manager.prefilter_lines(line,continue_prompt)
         except:
             # blanket except, in case a user-defined prefilter crashes, so it
             # can't take all of ipython with it.
             self.showtraceback()
             return ''
         else:
             return lineout
 
     #-------------------------------------------------------------------------
     # Things related to the prefilter
     #-------------------------------------------------------------------------
 
     def init_prefilter(self):
         self.prefilter_manager = PrefilterManager(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
 
     #-------------------------------------------------------------------------
     # Utilities
     #-------------------------------------------------------------------------
 
     def getoutput(self, cmd):
         return getoutput(self.var_expand(cmd,depth=2),
                          header=self.system_header,
                          verbose=self.system_verbose)
 
     def getoutputerror(self, cmd):
         return getoutputerror(self.var_expand(cmd,depth=2),
                               header=self.system_header,
                               verbose=self.system_verbose)
 
     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
 
     def write(self,data):
         """Write a string to the default output"""
         Term.cout.write(data)
 
     def write_err(self,data):
         """Write a string to the default error output"""
         Term.cerr.write(data)
 
     def ask_yes_no(self,prompt,default=True):
         if self.quiet:
             return True
         return ask_yes_no(prompt,default)
 
     #-------------------------------------------------------------------------
     # Things related to GUI support and pylab
     #-------------------------------------------------------------------------
 
     def enable_pylab(self, gui=None):
         """Activate pylab support at runtime.
 
         This turns on support for matplotlib, preloads into the interactive
         namespace all of numpy and pylab, and configures IPython to correcdtly
         interact with the GUI event loop.  The GUI backend to be used can be
         optionally selected with the optional :param:`gui` argument.
 
         Parameters
         ----------
         gui : optional, string
 
           If given, dictates the choice of matplotlib GUI backend to use
           (should be one of IPython's supported backends, 'tk', 'qt', 'wx' or
           'gtk'), otherwise we use the default chosen by matplotlib (as
           dictated by the matplotlib build-time options plus the user's
           matplotlibrc configuration file).
         """
         # We want to prevent the loading of pylab to pollute the user's
         # namespace as shown by the %who* magics, so we execute the activation
         # code in an empty namespace, and we update *both* user_ns and
         # user_ns_hidden with this information.
         ns = {}
         gui = pylab_activate(ns, gui)
         self.user_ns.update(ns)
         self.user_ns_hidden.update(ns)
         # Now we must activate the gui pylab wants to use, and fix %run to take
         # plot updates into account
         enable_gui(gui)
         self.magic_run = self._pylab_magic_run
 
     #-------------------------------------------------------------------------
     # Things related to IPython exiting
     #-------------------------------------------------------------------------
 
     def ask_exit(self):
         """ Ask the shell to exit. Can be overiden and used as a callback. """
         self.exit_now = True
 
     def exit(self):
         """Handle interactive exit.
 
         This method calls the ask_exit callback."""
         if self.confirm_exit:
             if self.ask_yes_no('Do you really want to exit ([y]/n)?','y'):
                 self.ask_exit()
         else:
             self.ask_exit()
 
     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/prefilter.py

@@ -1,1016 +1,1016 b''
 #!/usr/bin/env python
 # encoding: utf-8
 """
 Prefiltering components.
 
 Prefilters transform user input before it is exec'd by Python.  These
 transforms are used to implement additional syntax such as !ls and %magic.
 
 Authors:
 
 * Brian Granger
 * Fernando Perez
 * Dan Milstein
 * Ville Vainio
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2009  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import __builtin__
 import codeop
 import re
 
 from IPython.core.alias import AliasManager
 from IPython.core.autocall import IPyAutocall
 from IPython.config.configurable import Configurable
 from IPython.core.splitinput import split_user_input
 from IPython.core.page import page
 
 from IPython.utils.traitlets import List, Int, Any, Str, CBool, Bool, Instance
 from IPython.utils.io import Term
 from IPython.utils.text import make_quoted_expr
 from IPython.utils.autoattr import auto_attr
 
 #-----------------------------------------------------------------------------
 # Global utilities, errors and constants
 #-----------------------------------------------------------------------------
 
 # Warning, these cannot be changed unless various regular expressions
 # are updated in a number of places.  Not great, but at least we told you.
 ESC_SHELL  = '!'
 ESC_SH_CAP = '!!'
 ESC_HELP   = '?'
 ESC_MAGIC  = '%'
 ESC_QUOTE  = ','
 ESC_QUOTE2 = ';'
 ESC_PAREN  = '/'
 
 
 class PrefilterError(Exception):
     pass
 
 
 # RegExp to identify potential function names
 re_fun_name = re.compile(r'[a-zA-Z_]([a-zA-Z0-9_.]*) *$')
 
 # RegExp to exclude strings with this start from autocalling.  In
 # particular, all binary operators should be excluded, so that if foo is
 # callable, foo OP bar doesn't become foo(OP bar), which is invalid.  The
 # characters '!=()' don't need to be checked for, as the checkPythonChars
 # routine explicitely does so, to catch direct calls and rebindings of
 # existing names.
 
 # Warning: the '-' HAS TO BE AT THE END of the first group, otherwise
 # it affects the rest of the group in square brackets.
 re_exclude_auto = re.compile(r'^[,&^\|\*/\+-]'
                              r'|^is |^not |^in |^and |^or ')
 
 # try to catch also methods for stuff in lists/tuples/dicts: off
 # (experimental). For this to work, the line_split regexp would need
 # to be modified so it wouldn't break things at '['. That line is
 # nasty enough that I shouldn't change it until I can test it _well_.
 #self.re_fun_name = re.compile (r'[a-zA-Z_]([a-zA-Z0-9_.\[\]]*) ?$')
 
 
 # Handler Check Utilities
 def is_shadowed(identifier, ip):
     """Is the given identifier defined in one of the namespaces which shadow
     the alias and magic namespaces?  Note that an identifier is different
     than ifun, because it can not contain a '.' character."""
     # This is much safer than calling ofind, which can change state
     return (identifier in ip.user_ns \
             or identifier in ip.internal_ns \
             or identifier in ip.ns_table['builtin'])
 
 
 #-----------------------------------------------------------------------------
 # The LineInfo class used throughout
 #-----------------------------------------------------------------------------
 
 
 class LineInfo(object):
     """A single line of input and associated info.
 
     Includes the following as properties: 
 
     line
       The original, raw line
     
     continue_prompt
       Is this line a continuation in a sequence of multiline input?
     
     pre
       The initial esc character or whitespace.
     
     pre_char
       The escape character(s) in pre or the empty string if there isn't one.
       Note that '!!' is a possible value for pre_char.  Otherwise it will
       always be a single character.
     
     pre_whitespace
       The leading whitespace from pre if it exists.  If there is a pre_char,
       this is just ''.
     
     ifun
       The 'function part', which is basically the maximal initial sequence
       of valid python identifiers and the '.' character.  This is what is
       checked for alias and magic transformations, used for auto-calling,
       etc.
     
     the_rest
       Everything else on the line.
     """
     def __init__(self, line, continue_prompt):
         self.line            = line
         self.continue_prompt = continue_prompt
         self.pre, self.ifun, self.the_rest = split_user_input(line)
 
         self.pre_char       = self.pre.strip()
         if self.pre_char:
             self.pre_whitespace = '' # No whitespace allowd before esc chars
         else: 
             self.pre_whitespace = self.pre
 
         self._oinfo = None
 
     def ofind(self, ip):
         """Do a full, attribute-walking lookup of the ifun in the various
         namespaces for the given IPython InteractiveShell instance.
 
         Return a dict with keys: found,obj,ospace,ismagic
 
         Note: can cause state changes because of calling getattr, but should
         only be run if autocall is on and if the line hasn't matched any
         other, less dangerous handlers.
 
         Does cache the results of the call, so can be called multiple times
         without worrying about *further* damaging state.
         """
         if not self._oinfo:
             # ip.shell._ofind is actually on the Magic class!
             self._oinfo = ip.shell._ofind(self.ifun)
         return self._oinfo
 
     def __str__(self):                                                         
         return "Lineinfo [%s|%s|%s]" %(self.pre, self.ifun, self.the_rest) 
 
 
 #-----------------------------------------------------------------------------
 # Main Prefilter manager
 #-----------------------------------------------------------------------------
 
 
 class PrefilterManager(Configurable):
     """Main prefilter component.
 
     The IPython prefilter is run on all user input before it is run.  The
     prefilter consumes lines of input and produces transformed lines of 
     input.
 
     The iplementation consists of two phases:
 
     1. Transformers
     2. Checkers and handlers
 
     Over time, we plan on deprecating the checkers and handlers and doing
     everything in the transformers.
 
     The transformers are instances of :class:`PrefilterTransformer` and have
     a single method :meth:`transform` that takes a line and returns a
     transformed line.  The transformation can be accomplished using any
     tool, but our current ones use regular expressions for speed.  We also
     ship :mod:`pyparsing` in :mod:`IPython.external` for use in transformers.
 
     After all the transformers have been run, the line is fed to the checkers,
     which are instances of :class:`PrefilterChecker`.  The line is passed to
     the :meth:`check` method, which either returns `None` or a 
     :class:`PrefilterHandler` instance.  If `None` is returned, the other
     checkers are tried.  If an :class:`PrefilterHandler` instance is returned,
     the line is passed to the :meth:`handle` method of the returned
     handler and no further checkers are tried.
     
     Both transformers and checkers have a `priority` attribute, that determines
     the order in which they are called.  Smaller priorities are tried first.
 
     Both transformers and checkers also have `enabled` attribute, which is
     a boolean that determines if the instance is used.
 
     Users or developers can change the priority or enabled attribute of
     transformers or checkers, but they must call the :meth:`sort_checkers`
     or :meth:`sort_transformers` method after changing the priority.
     """
 
     multi_line_specials = CBool(True, config=True)
-    shell = Instance('IPython.core.iplib.InteractiveShell')
+    shell = Instance('IPython.core.iplib.InteractiveShellABC')
 
     def __init__(self, shell, config=None):
         super(PrefilterManager, self).__init__(config=config)
         self.shell = shell
         self.init_transformers()
         self.init_handlers()
         self.init_checkers()
 
     #-------------------------------------------------------------------------
     # API for managing transformers
     #-------------------------------------------------------------------------
 
     def init_transformers(self):
         """Create the default transformers."""
         self._transformers = []
         for transformer_cls in _default_transformers:
             transformer_cls(self.shell, self, config=self.config)
 
     def sort_transformers(self):
         """Sort the transformers by priority.
 
         This must be called after the priority of a transformer is changed.
         The :meth:`register_transformer` method calls this automatically.
         """
         self._transformers.sort(cmp=lambda x,y: x.priority-y.priority)
 
     @property
     def transformers(self):
         """Return a list of checkers, sorted by priority."""
         return self._transformers
 
     def register_transformer(self, transformer):
         """Register a transformer instance."""
         if transformer not in self._transformers:
             self._transformers.append(transformer)
             self.sort_transformers()
 
     def unregister_transformer(self, transformer):
         """Unregister a transformer instance."""
         if transformer in self._transformers:
             self._transformers.remove(transformer)
 
     #-------------------------------------------------------------------------
     # API for managing checkers
     #-------------------------------------------------------------------------
 
     def init_checkers(self):
         """Create the default checkers."""
         self._checkers = []
         for checker in _default_checkers:
             checker(self.shell, self, config=self.config)
 
     def sort_checkers(self):
         """Sort the checkers by priority.
 
         This must be called after the priority of a checker is changed.
         The :meth:`register_checker` method calls this automatically.
         """
         self._checkers.sort(cmp=lambda x,y: x.priority-y.priority)
 
     @property
     def checkers(self):
         """Return a list of checkers, sorted by priority."""
         return self._checkers
 
     def register_checker(self, checker):
         """Register a checker instance."""
         if checker not in self._checkers:
             self._checkers.append(checker)
             self.sort_checkers()
 
     def unregister_checker(self, checker):
         """Unregister a checker instance."""
         if checker in self._checkers:
             self._checkers.remove(checker)
 
     #-------------------------------------------------------------------------
     # API for managing checkers
     #-------------------------------------------------------------------------
 
     def init_handlers(self):
         """Create the default handlers."""
         self._handlers = {}
         self._esc_handlers = {}
         for handler in _default_handlers:
             handler(self.shell, self, config=self.config)
 
     @property
     def handlers(self):
         """Return a dict of all the handlers."""
         return self._handlers
 
     def register_handler(self, name, handler, esc_strings):
         """Register a handler instance by name with esc_strings."""
         self._handlers[name] = handler
         for esc_str in esc_strings:
             self._esc_handlers[esc_str] = handler
 
     def unregister_handler(self, name, handler, esc_strings):
         """Unregister a handler instance by name with esc_strings."""
         try:
             del self._handlers[name]
         except KeyError:
             pass
         for esc_str in esc_strings:
             h = self._esc_handlers.get(esc_str)
             if h is handler:
                 del self._esc_handlers[esc_str]
 
     def get_handler_by_name(self, name):
         """Get a handler by its name."""
         return self._handlers.get(name)
 
     def get_handler_by_esc(self, esc_str):
         """Get a handler by its escape string."""
         return self._esc_handlers.get(esc_str)
 
     #-------------------------------------------------------------------------
     # Main prefiltering API
     #-------------------------------------------------------------------------
 
     def prefilter_line_info(self, line_info):
         """Prefilter a line that has been converted to a LineInfo object.
 
         This implements the checker/handler part of the prefilter pipe.
         """
         # print "prefilter_line_info: ", line_info
         handler = self.find_handler(line_info)
         return handler.handle(line_info)
 
     def find_handler(self, line_info):
         """Find a handler for the line_info by trying checkers."""
         for checker in self.checkers:
             if checker.enabled:
                 handler = checker.check(line_info)
                 if handler:
                     return handler
         return self.get_handler_by_name('normal')
 
     def transform_line(self, line, continue_prompt):
         """Calls the enabled transformers in order of increasing priority."""
         for transformer in self.transformers:
             if transformer.enabled:
                 line = transformer.transform(line, continue_prompt)
         return line
 
     def prefilter_line(self, line, continue_prompt=False):
         """Prefilter a single input line as text.
 
         This method prefilters a single line of text by calling the
         transformers and then the checkers/handlers.
         """
 
         # print "prefilter_line: ", line, continue_prompt
         # All handlers *must* return a value, even if it's blank ('').
 
         # Lines are NOT logged here. Handlers should process the line as
         # needed, update the cache AND log it (so that the input cache array
         # stays synced).
 
         # save the line away in case we crash, so the post-mortem handler can
         # record it
         self.shell._last_input_line = line
 
         if not line:
             # Return immediately on purely empty lines, so that if the user
             # previously typed some whitespace that started a continuation
             # prompt, he can break out of that loop with just an empty line.
             # This is how the default python prompt works.
 
             # Only return if the accumulated input buffer was just whitespace!
             if ''.join(self.shell.buffer).isspace():
                 self.shell.buffer[:] = []
             return ''
 
         # At this point, we invoke our transformers.
         if not continue_prompt or (continue_prompt and self.multi_line_specials):
             line = self.transform_line(line, continue_prompt)
 
         # Now we compute line_info for the checkers and handlers
         line_info = LineInfo(line, continue_prompt)
         
         # the input history needs to track even empty lines
         stripped = line.strip()
 
         normal_handler = self.get_handler_by_name('normal')
         if not stripped:
             if not continue_prompt:
                 self.shell.outputcache.prompt_count -= 1
 
             return normal_handler.handle(line_info)
 
         # special handlers are only allowed for single line statements
         if continue_prompt and not self.multi_line_specials:
             return normal_handler.handle(line_info)
 
         prefiltered = self.prefilter_line_info(line_info)
         # print "prefiltered line: %r" % prefiltered
         return prefiltered
 
     def prefilter_lines(self, lines, continue_prompt=False):
         """Prefilter multiple input lines of text.
 
         This is the main entry point for prefiltering multiple lines of
         input.  This simply calls :meth:`prefilter_line` for each line of
         input.
 
         This covers cases where there are multiple lines in the user entry,
         which is the case when the user goes back to a multiline history
         entry and presses enter.
         """
         llines = lines.rstrip('\n').split('\n')
         # We can get multiple lines in one shot, where multiline input 'blends'
         # into one line, in cases like recalling from the readline history
         # buffer.  We need to make sure that in such cases, we correctly
         # communicate downstream which line is first and which are continuation
         # ones.
         if len(llines) > 1:
             out = '\n'.join([self.prefilter_line(line, lnum>0)
                              for lnum, line in enumerate(llines) ])
         else:
             out = self.prefilter_line(llines[0], continue_prompt)
             
         return out
 
 #-----------------------------------------------------------------------------
 # Prefilter transformers
 #-----------------------------------------------------------------------------
 
 
 class PrefilterTransformer(Configurable):
     """Transform a line of user input."""
 
     priority = Int(100, config=True)
     # Transformers don't currently use shell or prefilter_manager, but as we
     # move away from checkers and handlers, they will need them.
-    shell = Instance('IPython.core.iplib.InteractiveShell')
+    shell = Instance('IPython.core.iplib.InteractiveShellABC')
     prefilter_manager = Instance('IPython.core.prefilter.PrefilterManager')
     enabled = Bool(True, config=True)
 
     def __init__(self, shell, prefilter_manager, config=None):
         super(PrefilterTransformer, self).__init__(config=config)
         self.shell = shell
         self.prefilter_manager = prefilter_manager
         self.prefilter_manager.register_transformer(self)
 
     def transform(self, line, continue_prompt):
         """Transform a line, returning the new one."""
         return None
 
     def __repr__(self):
         return "<%s(priority=%r, enabled=%r)>" % (
             self.__class__.__name__, self.priority, self.enabled)
 
 
 _assign_system_re = re.compile(r'(?P<lhs>(\s*)([\w\.]+)((\s*,\s*[\w\.]+)*))'
                                r'\s*=\s*!(?P<cmd>.*)')
 
 
 class AssignSystemTransformer(PrefilterTransformer):
     """Handle the `files = !ls` syntax."""
 
     priority = Int(100, config=True)
 
     def transform(self, line, continue_prompt):
         m = _assign_system_re.match(line)
         if m is not None:
             cmd = m.group('cmd')
             lhs = m.group('lhs')
             expr = make_quoted_expr("sc -l =%s" % cmd)
             new_line = '%s = get_ipython().magic(%s)' % (lhs, expr)
             return new_line
         return line
 
 
 _assign_magic_re = re.compile(r'(?P<lhs>(\s*)([\w\.]+)((\s*,\s*[\w\.]+)*))'
                                r'\s*=\s*%(?P<cmd>.*)')
 
 class AssignMagicTransformer(PrefilterTransformer):
     """Handle the `a = %who` syntax."""
 
     priority = Int(200, config=True)
 
     def transform(self, line, continue_prompt):
         m = _assign_magic_re.match(line)
         if m is not None:
             cmd = m.group('cmd')
             lhs = m.group('lhs')
             expr = make_quoted_expr(cmd)
             new_line = '%s = get_ipython().magic(%s)' % (lhs, expr)
             return new_line
         return line
 
 
 _classic_prompt_re = re.compile(r'(^[ \t]*>>> |^[ \t]*\.\.\. )')
 
 class PyPromptTransformer(PrefilterTransformer):
     """Handle inputs that start with '>>> ' syntax."""
 
     priority = Int(50, config=True)
 
     def transform(self, line, continue_prompt):
 
         if not line or line.isspace() or line.strip() == '...':
             # This allows us to recognize multiple input prompts separated by
             # blank lines and pasted in a single chunk, very common when
             # pasting doctests or long tutorial passages.
             return ''
         m = _classic_prompt_re.match(line)
         if m:
             return line[len(m.group(0)):]
         else:
             return line
 
 
 _ipy_prompt_re = re.compile(r'(^[ \t]*In \[\d+\]: |^[ \t]*\ \ \ \.\.\.+: )')
 
 class IPyPromptTransformer(PrefilterTransformer):
     """Handle inputs that start classic IPython prompt syntax."""
 
     priority = Int(50, config=True)
 
     def transform(self, line, continue_prompt):
 
         if not line or line.isspace() or line.strip() == '...':
             # This allows us to recognize multiple input prompts separated by
             # blank lines and pasted in a single chunk, very common when
             # pasting doctests or long tutorial passages.
             return ''
         m = _ipy_prompt_re.match(line)
         if m:
             return line[len(m.group(0)):]
         else:
             return line
 
 #-----------------------------------------------------------------------------
 # Prefilter checkers
 #-----------------------------------------------------------------------------
 
 
 class PrefilterChecker(Configurable):
     """Inspect an input line and return a handler for that line."""
 
     priority = Int(100, config=True)
-    shell = Instance('IPython.core.iplib.InteractiveShell')
+    shell = Instance('IPython.core.iplib.InteractiveShellABC')
     prefilter_manager = Instance('IPython.core.prefilter.PrefilterManager')
     enabled = Bool(True, config=True)
 
     def __init__(self, shell, prefilter_manager, config=None):
         super(PrefilterChecker, self).__init__(config=config)
         self.shell = shell
         self.prefilter_manager = prefilter_manager
         self.prefilter_manager.register_checker(self)
 
     def check(self, line_info):
         """Inspect line_info and return a handler instance or None."""
         return None
 
     def __repr__(self):
         return "<%s(priority=%r, enabled=%r)>" % (
             self.__class__.__name__, self.priority, self.enabled)
 
 
 class EmacsChecker(PrefilterChecker):
 
     priority = Int(100, config=True)
     enabled = Bool(False, config=True)
 
     def check(self, line_info):
         "Emacs ipython-mode tags certain input lines."
         if line_info.line.endswith('# PYTHON-MODE'):
             return self.prefilter_manager.get_handler_by_name('emacs')
         else:
             return None
 
 
 class ShellEscapeChecker(PrefilterChecker):
 
     priority = Int(200, config=True)
 
     def check(self, line_info):
         if line_info.line.lstrip().startswith(ESC_SHELL):
             return self.prefilter_manager.get_handler_by_name('shell')
 
 
 class IPyAutocallChecker(PrefilterChecker):
 
     priority = Int(300, config=True)
 
     def check(self, line_info):
         "Instances of IPyAutocall in user_ns get autocalled immediately"
         obj = self.shell.user_ns.get(line_info.ifun, None)
         if isinstance(obj, IPyAutocall):
             obj.set_ip(self.shell)
             return self.prefilter_manager.get_handler_by_name('auto')
         else:
             return None
 
 
 class MultiLineMagicChecker(PrefilterChecker):
 
     priority = Int(400, config=True)
 
     def check(self, line_info):
         "Allow ! and !! in multi-line statements if multi_line_specials is on"
         # Note that this one of the only places we check the first character of
         # ifun and *not* the pre_char.  Also note that the below test matches
         # both ! and !!.    
         if line_info.continue_prompt \
             and self.prefilter_manager.multi_line_specials:
                 if line_info.ifun.startswith(ESC_MAGIC):
                     return self.prefilter_manager.get_handler_by_name('magic')
         else:
             return None
 
 
 class EscCharsChecker(PrefilterChecker):
 
     priority = Int(500, config=True)
 
     def check(self, line_info):
         """Check for escape character and return either a handler to handle it,
         or None if there is no escape char."""
         if line_info.line[-1] == ESC_HELP \
                and line_info.pre_char != ESC_SHELL \
                and line_info.pre_char != ESC_SH_CAP:
             # the ? can be at the end, but *not* for either kind of shell escape,
             # because a ? can be a vaild final char in a shell cmd
             return self.prefilter_manager.get_handler_by_name('help')
         else:
             # This returns None like it should if no handler exists
             return self.prefilter_manager.get_handler_by_esc(line_info.pre_char)
 
 
 class AssignmentChecker(PrefilterChecker):
 
     priority = Int(600, config=True)
 
     def check(self, line_info):
         """Check to see if user is assigning to a var for the first time, in
         which case we want to avoid any sort of automagic / autocall games.
     
         This allows users to assign to either alias or magic names true python
         variables (the magic/alias systems always take second seat to true
         python code).  E.g. ls='hi', or ls,that=1,2"""
         if line_info.the_rest:
             if line_info.the_rest[0] in '=,':
                 return self.prefilter_manager.get_handler_by_name('normal')
         else:
             return None
 
 
 class AutoMagicChecker(PrefilterChecker):
 
     priority = Int(700, config=True)
 
     def check(self, line_info):
         """If the ifun is magic, and automagic is on, run it.  Note: normal,
         non-auto magic would already have been triggered via '%' in
         check_esc_chars. This just checks for automagic.  Also, before
         triggering the magic handler, make sure that there is nothing in the
         user namespace which could shadow it."""
         if not self.shell.automagic or not hasattr(self.shell,'magic_'+line_info.ifun):
             return None
 
         # We have a likely magic method.  Make sure we should actually call it.
         if line_info.continue_prompt and not self.prefilter_manager.multi_line_specials:
             return None
 
         head = line_info.ifun.split('.',1)[0]
         if is_shadowed(head, self.shell):
             return None
 
         return self.prefilter_manager.get_handler_by_name('magic')
 
 
 class AliasChecker(PrefilterChecker):
 
     priority = Int(800, config=True)
 
     def check(self, line_info):
         "Check if the initital identifier on the line is an alias."
         # Note: aliases can not contain '.'
         head = line_info.ifun.split('.',1)[0]
         if line_info.ifun not in self.shell.alias_manager \
                or head not in self.shell.alias_manager \
                or is_shadowed(head, self.shell):
             return None
 
         return self.prefilter_manager.get_handler_by_name('alias')
 
 
 class PythonOpsChecker(PrefilterChecker):
 
     priority = Int(900, config=True)
 
     def check(self, line_info):
         """If the 'rest' of the line begins with a function call or pretty much
         any python operator, we should simply execute the line (regardless of
         whether or not there's a possible autocall expansion).  This avoids
         spurious (and very confusing) geattr() accesses."""
         if line_info.the_rest and line_info.the_rest[0] in '!=()<>,+*/%^&|':
             return self.prefilter_manager.get_handler_by_name('normal')
         else:
             return None
 
 
 class AutocallChecker(PrefilterChecker):
 
     priority = Int(1000, config=True)
 
     def check(self, line_info):
         "Check if the initial word/function is callable and autocall is on."
         if not self.shell.autocall:
             return None
 
         oinfo = line_info.ofind(self.shell) # This can mutate state via getattr
         if not oinfo['found']:
             return None
         
         if callable(oinfo['obj']) \
                and (not re_exclude_auto.match(line_info.the_rest)) \
                and re_fun_name.match(line_info.ifun):
             return self.prefilter_manager.get_handler_by_name('auto')
         else:
             return None
 
 
 #-----------------------------------------------------------------------------
 # Prefilter handlers
 #-----------------------------------------------------------------------------
 
 
 class PrefilterHandler(Configurable):
 
     handler_name = Str('normal')
     esc_strings = List([])
-    shell = Instance('IPython.core.iplib.InteractiveShell')
+    shell = Instance('IPython.core.iplib.InteractiveShellABC')
     prefilter_manager = Instance('IPython.core.prefilter.PrefilterManager')
 
     def __init__(self, shell, prefilter_manager, config=None):
         super(PrefilterHandler, self).__init__(config=config)
         self.shell = shell
         self.prefilter_manager = prefilter_manager
         self.prefilter_manager.register_handler(
             self.handler_name,
             self,
             self.esc_strings
         )
 
     def handle(self, line_info):
         # print "normal: ", line_info
         """Handle normal input lines. Use as a template for handlers."""
 
         # With autoindent on, we need some way to exit the input loop, and I
         # don't want to force the user to have to backspace all the way to
         # clear the line.  The rule will be in this case, that either two
         # lines of pure whitespace in a row, or a line of pure whitespace but
         # of a size different to the indent level, will exit the input loop.
         line = line_info.line
         continue_prompt = line_info.continue_prompt
 
         if (continue_prompt and
             self.shell.autoindent and
             line.isspace() and
             
             (0 < abs(len(line) - self.shell.indent_current_nsp) <= 2
              or
              not self.shell.buffer
              or
              (self.shell.buffer[-1]).isspace()
              )
             ):
             line = ''
 
         self.shell.log(line, line, continue_prompt)
         return line
 
     def __str__(self):
         return "<%s(name=%s)>" % (self.__class__.__name__, self.handler_name)
 
 
 class AliasHandler(PrefilterHandler):
 
     handler_name = Str('alias')
 
     def handle(self, line_info):
         """Handle alias input lines. """
         transformed = self.shell.alias_manager.expand_aliases(line_info.ifun,line_info.the_rest)
         # pre is needed, because it carries the leading whitespace.  Otherwise
         # aliases won't work in indented sections.
         line_out = '%sget_ipython().system(%s)' % (line_info.pre_whitespace,
                                          make_quoted_expr(transformed))
         
         self.shell.log(line_info.line, line_out, line_info.continue_prompt)
         return line_out
 
 
 class ShellEscapeHandler(PrefilterHandler):
 
     handler_name = Str('shell')
     esc_strings = List([ESC_SHELL, ESC_SH_CAP])
 
     def handle(self, line_info):
         """Execute the line in a shell, empty return value"""
         magic_handler = self.prefilter_manager.get_handler_by_name('magic')
 
         line = line_info.line
         if line.lstrip().startswith(ESC_SH_CAP):
             # rewrite LineInfo's line, ifun and the_rest to properly hold the
             # call to %sx and the actual command to be executed, so
             # handle_magic can work correctly.  Note that this works even if
             # the line is indented, so it handles multi_line_specials
             # properly.
             new_rest = line.lstrip()[2:]
             line_info.line = '%ssx %s' % (ESC_MAGIC, new_rest)
             line_info.ifun = 'sx'
             line_info.the_rest = new_rest
             return magic_handler.handle(line_info)
         else:
             cmd = line.lstrip().lstrip(ESC_SHELL)
             line_out = '%sget_ipython().system(%s)' % (line_info.pre_whitespace,
                                              make_quoted_expr(cmd))
         # update cache/log and return
         self.shell.log(line, line_out, line_info.continue_prompt)
         return line_out
 
 
 class MagicHandler(PrefilterHandler):
 
     handler_name = Str('magic')
     esc_strings = List([ESC_MAGIC])
 
     def handle(self, line_info):
         """Execute magic functions."""
         ifun    = line_info.ifun
         the_rest = line_info.the_rest
         cmd = '%sget_ipython().magic(%s)' % (line_info.pre_whitespace,
                                    make_quoted_expr(ifun + " " + the_rest))
         self.shell.log(line_info.line, cmd, line_info.continue_prompt)
         return cmd
 
 
 class AutoHandler(PrefilterHandler):
 
     handler_name = Str('auto')
     esc_strings = List([ESC_PAREN, ESC_QUOTE, ESC_QUOTE2])
 
     def handle(self, line_info):
         """Handle lines which can be auto-executed, quoting if requested."""
         line    = line_info.line
         ifun    = line_info.ifun
         the_rest = line_info.the_rest
         pre     = line_info.pre
         continue_prompt = line_info.continue_prompt
         obj = line_info.ofind(self)['obj']
         #print 'pre <%s> ifun <%s> rest <%s>' % (pre,ifun,the_rest)  # dbg
 
         # This should only be active for single-line input!
         if continue_prompt:
             self.shell.log(line,line,continue_prompt)
             return line
 
         force_auto = isinstance(obj, IPyAutocall)
         auto_rewrite = True
         
         if pre == ESC_QUOTE:
             # Auto-quote splitting on whitespace
             newcmd = '%s("%s")' % (ifun,'", "'.join(the_rest.split()) )
         elif pre == ESC_QUOTE2:
             # Auto-quote whole string
             newcmd = '%s("%s")' % (ifun,the_rest)
         elif pre == ESC_PAREN:
             newcmd = '%s(%s)' % (ifun,",".join(the_rest.split()))
         else:
             # Auto-paren.
             # We only apply it to argument-less calls if the autocall
             # parameter is set to 2.  We only need to check that autocall is <
             # 2, since this function isn't called unless it's at least 1.
             if not the_rest and (self.shell.autocall < 2) and not force_auto:
                 newcmd = '%s %s' % (ifun,the_rest)
                 auto_rewrite = False
             else:
                 if not force_auto and the_rest.startswith('['):
                     if hasattr(obj,'__getitem__'):
                         # Don't autocall in this case: item access for an object
                         # which is BOTH callable and implements __getitem__.
                         newcmd = '%s %s' % (ifun,the_rest)
                         auto_rewrite = False
                     else:
                         # if the object doesn't support [] access, go ahead and
                         # autocall
                         newcmd = '%s(%s)' % (ifun.rstrip(),the_rest)
                 elif the_rest.endswith(';'):
                     newcmd = '%s(%s);' % (ifun.rstrip(),the_rest[:-1])
                 else:
                     newcmd = '%s(%s)' % (ifun.rstrip(), the_rest)
 
         if auto_rewrite:
             rw = self.shell.outputcache.prompt1.auto_rewrite() + newcmd
             
             try:
                 # plain ascii works better w/ pyreadline, on some machines, so
                 # we use it and only print uncolored rewrite if we have unicode
                 rw = str(rw)
                 print >>Term.cout, rw
             except UnicodeEncodeError:
                 print "-------------->" + newcmd
             
         # log what is now valid Python, not the actual user input (without the
         # final newline)
         self.shell.log(line,newcmd,continue_prompt)
         return newcmd
 
 
 class HelpHandler(PrefilterHandler):
 
     handler_name = Str('help')
     esc_strings = List([ESC_HELP])
 
     def handle(self, line_info):
         """Try to get some help for the object.
 
         obj? or ?obj   -> basic information.
         obj?? or ??obj -> more details.
         """
         normal_handler = self.prefilter_manager.get_handler_by_name('normal')
         line = line_info.line
         # We need to make sure that we don't process lines which would be
         # otherwise valid python, such as "x=1 # what?"
         try:
             codeop.compile_command(line)
         except SyntaxError:
             # We should only handle as help stuff which is NOT valid syntax
             if line[0]==ESC_HELP:
                 line = line[1:]
             elif line[-1]==ESC_HELP:
                 line = line[:-1]
             self.shell.log(line, '#?'+line, line_info.continue_prompt)
             if line:
                 #print 'line:<%r>' % line  # dbg
                 self.shell.magic_pinfo(line)
             else:
                 page(self.shell.usage, screen_lines=self.shell.usable_screen_length)
             return '' # Empty string is needed here!
         except:
             raise
             # Pass any other exceptions through to the normal handler
             return normal_handler.handle(line_info)
         else:
             # If the code compiles ok, we should handle it normally
             return normal_handler.handle(line_info)
 
 
 class EmacsHandler(PrefilterHandler):
 
     handler_name = Str('emacs')
     esc_strings = List([])
 
     def handle(self, line_info):
         """Handle input lines marked by python-mode."""
 
         # Currently, nothing is done.  Later more functionality can be added
         # here if needed.
 
         # The input cache shouldn't be updated
         return line_info.line
 
 
 #-----------------------------------------------------------------------------
 # Defaults
 #-----------------------------------------------------------------------------
 
 
 _default_transformers = [
     AssignSystemTransformer,
     AssignMagicTransformer,
     PyPromptTransformer,
     IPyPromptTransformer,
 ]
 
 _default_checkers = [
     EmacsChecker,
     ShellEscapeChecker,
     IPyAutocallChecker,
     MultiLineMagicChecker,
     EscCharsChecker,
     AssignmentChecker,
     AutoMagicChecker,
     AliasChecker,
     PythonOpsChecker,
     AutocallChecker
 ]
 
 _default_handlers = [
     PrefilterHandler,
     AliasHandler,
     ShellEscapeHandler,
     MagicHandler,
     AutoHandler,
     HelpHandler,
     EmacsHandler
 ]

IPython/extensions/parallelmagic.py

@@ -1,201 +1,202 b''
 #!/usr/bin/env python
 # encoding: utf-8
 
 """Magic command interface for interactive parallel work."""
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2009  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import new
 
-from IPython.config.configurable import Configurable
+from IPython.core.plugin import Plugin
 from IPython.utils.traitlets import Bool, Any, Instance
 from IPython.utils.autoattr import auto_attr
 from IPython.testing import decorators as testdec
 
 #-----------------------------------------------------------------------------
 # Definitions of magic functions for use with IPython
 #-----------------------------------------------------------------------------
 
 
 NO_ACTIVE_MULTIENGINE_CLIENT = """
 Use activate() on a MultiEngineClient object to activate it for magics.
 """
 
 
-class ParalleMagicComponent(Configurable):
+class ParalleMagic(Plugin):
     """A component to manage the %result, %px and %autopx magics."""
 
     active_multiengine_client = Any()
     verbose = Bool(False, config=True)
-    shell = Instance('IPython.core.iplib.InteractiveShell')
+    shell = Instance('IPython.core.iplib.InteractiveShellABC')
 
     def __init__(self, shell, config=None):
-        super(ParalleMagicComponent, self).__init__(config=config)
+        super(ParalleMagic, self).__init__(config=config)
         self.shell = shell
         self._define_magics()
         # A flag showing if autopx is activated or not
         self.autopx = False
 
     def _define_magics(self):
         """Define the magic functions."""
         self.shell.define_magic('result', self.magic_result)
         self.shell.define_magic('px', self.magic_px)
         self.shell.define_magic('autopx', self.magic_autopx)
 
     @testdec.skip_doctest
     def magic_result(self, ipself, parameter_s=''):
         """Print the result of command i on all engines..
 
         To use this a :class:`MultiEngineClient` instance must be created 
         and then activated by calling its :meth:`activate` method.
 
         Then you can do the following::
 
             In [23]: %result
             Out[23]: 
             <Results List>
             [0] In [6]: a = 10
             [1] In [6]: a = 10
     
             In [22]: %result 6
             Out[22]: 
             <Results List>
             [0] In [6]: a = 10
             [1] In [6]: a = 10
         """
         if self.active_multiengine_client is None:
             print NO_ACTIVE_MULTIENGINE_CLIENT
             return
 
         try:
             index = int(parameter_s)
         except:
             index = None
         result = self.active_multiengine_client.get_result(index)
         return result
 
     @testdec.skip_doctest
     def magic_px(self, ipself, parameter_s=''):
         """Executes the given python command in parallel.
 
         To use this a :class:`MultiEngineClient` instance must be created 
         and then activated by calling its :meth:`activate` method.
         
         Then you can do the following::
 
             In [24]: %px a = 5
             Parallel execution on engines: all
             Out[24]: 
             <Results List>
             [0] In [7]: a = 5
             [1] In [7]: a = 5
         """
 
         if self.active_multiengine_client is None:
             print NO_ACTIVE_MULTIENGINE_CLIENT
             return
         print "Parallel execution on engines: %s" % self.active_multiengine_client.targets
         result = self.active_multiengine_client.execute(parameter_s)
         return result
 
     @testdec.skip_doctest
     def magic_autopx(self, ipself, parameter_s=''):
         """Toggles auto parallel mode.
 
         To use this a :class:`MultiEngineClient` instance must be created 
         and then activated by calling its :meth:`activate` method. Once this
         is called, all commands typed at the command line are send to
         the engines to be executed in parallel. To control which engine
         are used, set the ``targets`` attributed of the multiengine client
         before entering ``%autopx`` mode.
 
         Then you can do the following::
 
             In [25]: %autopx
             %autopx to enabled
 
             In [26]: a = 10
             <Results List>
             [0] In [8]: a = 10
             [1] In [8]: a = 10
 
 
             In [27]: %autopx
             %autopx disabled
         """
         if self.autopx:
             self._disable_autopx()
         else:
             self._enable_autopx()
 
     def _enable_autopx(self):
         """Enable %autopx mode by saving the original runsource and installing 
         pxrunsource.
         """
         if self.active_multiengine_client is None:
             print NO_ACTIVE_MULTIENGINE_CLIENT
             return
 
         self._original_runsource = self.shell.runsource
         self.shell.runsource = new.instancemethod(
             self.pxrunsource, self.shell, self.shell.__class__
         )
         self.autopx = True
         print "%autopx enabled"
     
     def _disable_autopx(self):
         """Disable %autopx by restoring the original InteractiveShell.runsource."""
         if self.autopx:
             self.shell.runsource = self._original_runsource
             self.autopx = False
             print "%autopx disabled"
 
     def pxrunsource(self, ipself, source, filename="<input>", symbol="single"):
         """A parallel replacement for InteractiveShell.runsource."""
 
         try:
             code = ipself.compile(source, filename, symbol)
         except (OverflowError, SyntaxError, ValueError):
             # Case 1
             ipself.showsyntaxerror(filename)
             return None
 
         if code is None:
             # Case 2
             return True
 
         # Case 3
         # Because autopx is enabled, we now call executeAll or disable autopx if
         # %autopx or autopx has been called
         if 'get_ipython().magic("%autopx' in source or 'get_ipython().magic("autopx' in source:
             self._disable_autopx()
             return False
         else:
             try:
                 result = self.active_multiengine_client.execute(source)
             except:
                 ipself.showtraceback()
             else:
                 print result.__repr__()
             return False
 
 
 _loaded = False
 
 
 def load_ipython_extension(ip):
     """Load the extension in IPython."""
     global _loaded
     if not _loaded:
-        prd = ParalleMagicComponent(ip, config=ip.config)
+        plugin = ParalleMagic(ip, config=ip.config)
+        ip.plugin_manager.register_plugin('parallel_magic', plugin)
         _loaded = True
 

IPython/extensions/pretty.py

@@ -1,158 +1,158 b''
 """Use pretty.py for configurable pretty-printing.
 
 To enable this extension in your configuration
 file, add the following to :file:`ipython_config.py`::
 
     c.Global.extensions = ['IPython.extensions.pretty']
     def dict_pprinter(obj, p, cycle):
         return p.text("<dict>")
     c.PrettyResultDisplay.verbose = True
     c.PrettyResultDisplay.defaults_for_type = [
         (dict, dict_pprinter)
     ]
     c.PrettyResultDisplay.defaults_for_type_by_name = [
         ('numpy', 'dtype', 'IPython.extensions.pretty.dtype_pprinter')
     ]
 
 This extension can also be loaded by using the ``%load_ext`` magic::
 
     %load_ext IPython.extensions.pretty
 
 If this extension is enabled, you can always add additional pretty printers
 by doing::
 
     ip = get_ipython()
     prd = ip.get_component('pretty_result_display')
     import numpy
     from IPython.extensions.pretty import dtype_pprinter
     prd.for_type(numpy.dtype, dtype_pprinter)
 
     # If you don't want to have numpy imported until it needs to be:
     prd.for_type_by_name('numpy', 'dtype', dtype_pprinter)
 """
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from IPython.core.error import TryNext
 from IPython.external import pretty
-from IPython.config.configurable import Configurable
+from IPython.core.plugin import Plugin
 from IPython.utils.traitlets import Bool, List, Instance
 from IPython.utils.io import Term
 from IPython.utils.autoattr import auto_attr
 from IPython.utils.importstring import import_item
 
 #-----------------------------------------------------------------------------
 # Code
 #-----------------------------------------------------------------------------
 
 
 _loaded = False
 
 
-class PrettyResultDisplay(Configurable):
+class PrettyResultDisplay(Plugin):
     """A component for pretty printing on steroids."""
 
     verbose = Bool(False, config=True)
-    shell = Instance('IPython.core.iplib.InteractiveShell')
+    shell = Instance('IPython.core.iplib.InteractiveShellABC')
 
     # A list of (type, func_name), like
     # [(dict, 'my_dict_printer')]
     # The final argument can also be a callable
     defaults_for_type = List(default_value=[], config=True)
 
     # A list of (module_name, type_name, func_name), like
     # [('numpy', 'dtype', 'IPython.extensions.pretty.dtype_pprinter')]
     # The final argument can also be a callable
     defaults_for_type_by_name = List(default_value=[], config=True)
 
     def __init__(self, shell, config=None):
         super(PrettyResultDisplay, self).__init__(config=config)
         self.shell = shell
         self._setup_defaults()
 
     def _setup_defaults(self):
         """Initialize the default pretty printers."""
         for typ, func_name in self.defaults_for_type:
             func = self._resolve_func_name(func_name)
             self.for_type(typ, func)
         for type_module, type_name, func_name in self.defaults_for_type_by_name:
             func = self._resolve_func_name(func_name)
             self.for_type_by_name(type_module, type_name, func)
 
     def _resolve_func_name(self, func_name):
         if callable(func_name):
             return func_name
         elif isinstance(func_name, basestring):
             return import_item(func_name)
         else:
             raise TypeError('func_name must be a str or callable, got: %r' % func_name)
 
     def __call__(self, otherself, arg):
         """Uber-pretty-printing display hook.
 
         Called for displaying the result to the user.
         """
         
         if self.shell.pprint:
             out = pretty.pretty(arg, verbose=self.verbose)
             if '\n' in out:
                 # So that multi-line strings line up with the left column of
                 # the screen, instead of having the output prompt mess up
                 # their first line.                
                 Term.cout.write('\n')
             print >>Term.cout, out
         else:
             raise TryNext
 
     def for_type(self, typ, func):
         """Add a pretty printer for a type."""
         return pretty.for_type(typ, func)
 
     def for_type_by_name(self, type_module, type_name, func):
         """Add a pretty printer for a type by its name and module name."""
         return pretty.for_type_by_name(type_module, type_name, func)
 
 
 #-----------------------------------------------------------------------------
 # Initialization code for the extension
 #-----------------------------------------------------------------------------
 
 
 def load_ipython_extension(ip):
     """Load the extension in IPython as a hook."""
     global _loaded
     if not _loaded:
-        prd = PrettyResultDisplay(ip, config=ip.config)
-        ip.set_hook('result_display', prd, priority=99)
+        plugin = PrettyResultDisplay(ip, config=ip.config)
+        ip.set_hook('result_display', plugin, priority=99)
         _loaded = True
-        return prd
+        ip.plugin_manager.register_plugin('pretty_result_display', plugin)
 
 def unload_ipython_extension(ip):
     """Unload the extension."""
     # The hook system does not have a way to remove a hook so this is a pass
     pass
 
 
 #-----------------------------------------------------------------------------
 # Example pretty printers
 #-----------------------------------------------------------------------------
 
 
 def dtype_pprinter(obj, p, cycle):
     """ A pretty-printer for numpy dtype objects.
     """
     if cycle:
         return p.text('dtype(...)')
     if hasattr(obj, 'fields'):
         if obj.fields is None:
             p.text(repr(obj))
         else:
             p.begin_group(7, 'dtype([')
             for i, field in enumerate(obj.descr):
                 if i > 0:
                     p.text(',')
                     p.breakable()
                 p.pretty(field)
             p.end_group(7, '])')

IPython/extensions/tests/test_pretty.py

@@ -1,101 +1,100 b''
 #!/usr/bin/env python
 # encoding: utf-8
 """
 Simple tests for :mod:`IPython.extensions.pretty`.
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2009  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from unittest import TestCase
 
-from IPython.core.component import Component, masquerade_as
-from IPython.core.iplib import InteractiveShell
+from IPython.config.configurable import Configurable
+from IPython.core.iplib import InteractiveShellABC
 from IPython.extensions import pretty as pretty_ext
 from IPython.external import pretty
 from IPython.testing import decorators as dec
 from IPython.testing import tools as tt
 from IPython.utils.traitlets import Bool
 
 #-----------------------------------------------------------------------------
 # Tests
 #-----------------------------------------------------------------------------
 
-class InteractiveShellStub(Component):
+class InteractiveShellStub(Configurable):
     pprint = Bool(True)
 
+InteractiveShellABC.register(InteractiveShellStub)
+
 class A(object):
     pass
 
 def a_pprinter(o, p, c):
     return p.text("<A>")
 
 class TestPrettyResultDisplay(TestCase):
 
     def setUp(self):
-        self.ip = InteractiveShellStub(None)
-        # This allows our stub to be retrieved instead of the real
-        # InteractiveShell
-        masquerade_as(self.ip, InteractiveShell)
-        self.prd = pretty_ext.PrettyResultDisplay(self.ip,
-                                                  name='pretty_result_display')
+        self.ip = InteractiveShellStub()
+        self.prd = pretty_ext.PrettyResultDisplay(self.ip, config=None)
 
     def test_for_type(self):
         self.prd.for_type(A, a_pprinter)
         a = A()
         result = pretty.pretty(a)
         self.assertEquals(result, "<A>")
 
 ipy_src = """
 class A(object):
     def __repr__(self):
         return 'A()'
     
 class B(object):
     def __repr__(self):
         return 'B()'
  
 a = A()
 b = B()
 
 def a_pretty_printer(obj, p, cycle):
     p.text('<A>')
 
 def b_pretty_printer(obj, p, cycle):
     p.text('<B>')
 
 
 a
 b
 
 ip = get_ipython()
-prd = ip.extension_manager.load_extension('pretty')
+ip.extension_manager.load_extension('pretty')
+prd = ip.plugin_manager.get_plugin('pretty_result_display')
 prd.for_type(A, a_pretty_printer)
 prd.for_type_by_name(B.__module__, B.__name__, b_pretty_printer)
 
 a
 b
 """
 ipy_out = """
 A()
 B()
 <A>
 <B>
 """
 
 class TestPrettyInteractively(tt.TempFileMixin):
     
     # XXX Unfortunately, ipexec_validate fails under win32.  If someone helps
     # us write a win32-compatible version, we can reactivate this test.
     @dec.skip_win32
     def test_printers(self):
         self.mktmp(ipy_src, '.ipy')
         tt.ipexec_validate(self.fname, ipy_out)

IPython/testing/globalipapp.py

@@ -1,174 +1,174 b''
 """Global IPython app to support test running.
 
 We must start our own ipython object and heavily muck with it so that all the
 modifications IPython makes to system behavior don't send the doctest machinery
 into a fit.  This code should be considered a gross hack, but it gets the job
 done.
 """
 
 from __future__ import absolute_import
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2009  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import __builtin__
 import commands
 import os
 import sys
 
 from . import tools
 
 #-----------------------------------------------------------------------------
 # Functions
 #-----------------------------------------------------------------------------
 
 # Hack to modify the %run command so we can sync the user's namespace with the
 # test globals.  Once we move over to a clean magic system, this will be done
 # with much less ugliness.
 
 class py_file_finder(object):
     def __init__(self,test_filename):
         self.test_filename = test_filename
         
     def __call__(self,name):
         from IPython.utils.path import get_py_filename
         try:
             return get_py_filename(name)
         except IOError:
             test_dir = os.path.dirname(self.test_filename)
             new_path = os.path.join(test_dir,name)
             return get_py_filename(new_path)
     
 
 def _run_ns_sync(self,arg_s,runner=None):
     """Modified version of %run that syncs testing namespaces.
 
     This is strictly needed for running doctests that call %run.
     """
     #print >> sys.stderr,  'in run_ns_sync', arg_s  # dbg
     
     _ip = get_ipython()
     finder = py_file_finder(arg_s)
     out = _ip.magic_run_ori(arg_s,runner,finder)
     return out
 
 
 class ipnsdict(dict):
     """A special subclass of dict for use as an IPython namespace in doctests.
 
     This subclass adds a simple checkpointing capability so that when testing
     machinery clears it (we use it as the test execution context), it doesn't
     get completely destroyed.
     """
     
     def __init__(self,*a):
         dict.__init__(self,*a)
         self._savedict = {}
         
     def clear(self):
         dict.clear(self)
         self.update(self._savedict)
         
     def _checkpoint(self):
         self._savedict.clear()
         self._savedict.update(self)
 
     def update(self,other):
         self._checkpoint()
         dict.update(self,other)
 
         # If '_' is in the namespace, python won't set it when executing code,
         # and we have examples that test it.  So we ensure that the namespace
         # is always 'clean' of it before it's used for test code execution.
         self.pop('_',None)
 
         # The builtins namespace must *always* be the real __builtin__ module,
         # else weird stuff happens.  The main ipython code does have provisions
         # to ensure this after %run, but since in this class we do some
         # aggressive low-level cleaning of the execution namespace, we need to
         # correct for that ourselves, to ensure consitency with the 'real'
         # ipython.
         self['__builtins__'] = __builtin__
 
 
 def get_ipython():
     # This will get replaced by the real thing once we start IPython below
     return start_ipython()
 
 
 def start_ipython():
     """Start a global IPython shell, which we need for IPython-specific syntax.
     """
     global get_ipython
 
     # This function should only ever run once!
     if hasattr(start_ipython, 'already_called'):
         return
     start_ipython.already_called = True
 
     # Ok,  first time we're called, go ahead
     from IPython.core import iplib
     
     def xsys(cmd):
         """Execute a command and print its output.
 
         This is just a convenience function to replace the IPython system call
         with one that is more doctest-friendly.
         """
         cmd = _ip.var_expand(cmd,depth=1)
         sys.stdout.write(commands.getoutput(cmd))
         sys.stdout.flush()
 
     # Store certain global objects that IPython modifies
     _displayhook = sys.displayhook
     _excepthook = sys.excepthook
     _main = sys.modules.get('__main__')
 
     # Create custom argv and namespaces for our IPython to be test-friendly
     config = tools.default_config()
 
     # Create and initialize our test-friendly IPython instance.
     shell = iplib.InteractiveShell(
-        parent=None, config=config, 
+        config=config, 
         user_ns=ipnsdict(), user_global_ns={}
     )
 
     # A few more tweaks needed for playing nicely with doctests...
     
     # These traps are normally only active for interactive use, set them
     # permanently since we'll be mocking interactive sessions.
     shell.builtin_trap.set()
 
     # Set error printing to stdout so nose can doctest exceptions
     shell.InteractiveTB.out_stream = 'stdout'
     
     # Modify the IPython system call with one that uses getoutput, so that we
     # can capture subcommands and print them to Python's stdout, otherwise the
     # doctest machinery would miss them.
     shell.system = xsys
 
     # IPython is ready, now clean up some global state...
     
     # Deactivate the various python system hooks added by ipython for
     # interactive convenience so we don't confuse the doctest system
     sys.modules['__main__'] = _main
     sys.displayhook = _displayhook
     sys.excepthook = _excepthook
 
     # So that ipython magics and aliases can be doctested (they work by making
     # a call into a global _ip object).  Also make the top-level get_ipython
     # now return this without recursively calling here again.
     _ip = shell
     get_ipython = _ip.get_ipython
     __builtin__._ip = _ip
     __builtin__.get_ipython = get_ipython
 
     return _ip

IPython/utils/traitlets.py

@@ -1,1025 +1,1047 b''
 #!/usr/bin/env python
 # encoding: utf-8
 """
 A lightweight Traits like module.
 
 This is designed to provide a lightweight, simple, pure Python version of
 many of the capabilities of enthought.traits.  This includes:
 
 * Validation
 * Type specification with defaults
 * Static and dynamic notification
 * Basic predefined types
 * An API that is similar to enthought.traits
 
 We don't support:
 
 * Delegation
 * Automatic GUI generation
 * A full set of trait types.  Most importantly, we don't provide container
   traits (list, dict, tuple) that can trigger notifications if their
   contents change.
 * API compatibility with enthought.traits
 
 There are also some important difference in our design:
 
 * enthought.traits does not validate default values.  We do.
 
 We choose to create this module because we need these capabilities, but
 we need them to be pure Python so they work in all Python implementations,
 including Jython and IronPython.
 
 Authors:
 
 * Brian Granger
 * Enthought, Inc.  Some of the code in this file comes from enthought.traits
   and is licensed under the BSD license.  Also, many of the ideas also come
   from enthought.traits even though our implementation is very different.
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2009  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 
 import inspect
 import sys
 import types
 from types import (
     InstanceType, ClassType, FunctionType,
     ListType, TupleType
 )
 
 def import_item(name):
     """Import and return bar given the string foo.bar."""
     package = '.'.join(name.split('.')[0:-1])
     obj = name.split('.')[-1]
     execString = 'from %s import %s' % (package, obj)
     try:
         exec execString
     except SyntaxError:
         raise ImportError("Invalid class specification: %s" % name)
     exec 'temp = %s' % obj
     return temp
 
 
 ClassTypes = (ClassType, type)
 
 SequenceTypes = (ListType, TupleType)
 
 #-----------------------------------------------------------------------------
 # Basic classes
 #-----------------------------------------------------------------------------
 
 
 class NoDefaultSpecified ( object ): pass
 NoDefaultSpecified = NoDefaultSpecified()
 
 
 class Undefined ( object ): pass
 Undefined = Undefined()
 
 class TraitError(Exception):
     pass
 
 #-----------------------------------------------------------------------------
 # Utilities
 #-----------------------------------------------------------------------------
 
 
 def class_of ( object ):
     """ Returns a string containing the class name of an object with the
     correct indefinite article ('a' or 'an') preceding it (e.g., 'an Image',
     'a PlotValue').
     """
     if isinstance( object, basestring ):
         return add_article( object )
 
     return add_article( object.__class__.__name__ )
 
 
 def add_article ( name ):
     """ Returns a string containing the correct indefinite article ('a' or 'an')
     prefixed to the specified string.
     """
     if name[:1].lower() in 'aeiou':
        return 'an ' + name
 
     return 'a ' + name
 
 
 def repr_type(obj):
     """ Return a string representation of a value and its type for readable
     error messages.
     """
     the_type = type(obj)
     if the_type is InstanceType:
         # Old-style class.
         the_type = obj.__class__
     msg = '%r %r' % (obj, the_type)
     return msg
 
 
 def parse_notifier_name(name):
     """Convert the name argument to a list of names.
     
     Examples
     --------
     
     >>> parse_notifier_name('a')
     ['a']
     >>> parse_notifier_name(['a','b'])
     ['a', 'b']
     >>> parse_notifier_name(None)
     ['anytrait']
     """
     if isinstance(name, str):
         return [name]
     elif name is None:
         return ['anytrait']
     elif isinstance(name, (list, tuple)):
         for n in name:
             assert isinstance(n, str), "names must be strings"
         return name
 
 
 class _SimpleTest:
     def __init__ ( self, value ): self.value = value
     def __call__ ( self, test  ):
         return test == self.value
     def __repr__(self):
         return "<SimpleTest(%r)" % self.value
     def __str__(self):
         return self.__repr__()
 
 
 def getmembers(object, predicate=None):
     """A safe version of inspect.getmembers that handles missing attributes.
 
     This is useful when there are descriptor based attributes that for 
     some reason raise AttributeError even though they exist.  This happens
     in zope.inteface with the __provides__ attribute.
     """
     results = []
     for key in dir(object):
         try:
             value = getattr(object, key)
         except AttributeError:
             pass
         else:
             if not predicate or predicate(value):
                 results.append((key, value))
     results.sort()
     return results
 
 
 #-----------------------------------------------------------------------------
 # Base TraitType for all traits
 #-----------------------------------------------------------------------------
 
 
 class TraitType(object):
     """A base class for all trait descriptors.
 
     Notes
     -----
     Our implementation of traits is based on Python's descriptor
     prototol.  This class is the base class for all such descriptors.  The
     only magic we use is a custom metaclass for the main :class:`HasTraits`
     class that does the following:
 
     1. Sets the :attr:`name` attribute of every :class:`TraitType`
        instance in the class dict to the name of the attribute.
     2. Sets the :attr:`this_class` attribute of every :class:`TraitType`
        instance in the class dict to the *class* that declared the trait.
        This is used by the :class:`This` trait to allow subclasses to
        accept superclasses for :class:`This` values.
     """
     
 
     metadata = {}
     default_value = Undefined
     info_text = 'any value'
 
     def __init__(self, default_value=NoDefaultSpecified, **metadata):
         """Create a TraitType.
         """
         if default_value is not NoDefaultSpecified:
             self.default_value = default_value
 
         if len(metadata) > 0:
             if len(self.metadata) > 0:
                 self._metadata = self.metadata.copy()
                 self._metadata.update(metadata)
             else:
                 self._metadata = metadata
         else:
             self._metadata = self.metadata
 
         self.init()
 
     def init(self):
         pass
 
     def get_default_value(self):
         """Create a new instance of the default value."""
         dv = self.default_value
         return dv
 
     def instance_init(self, obj):
         """This is called by :meth:`HasTraits.__new__` to finish init'ing.
 
         Some stages of initialization must be delayed until the parent
         :class:`HasTraits` instance has been created.  This method is
         called in :meth:`HasTraits.__new__` after the instance has been
         created.
 
         This method trigger the creation and validation of default values
         and also things like the resolution of str given class names in 
         :class:`Type` and :class`Instance`.
 
         Parameters
         ----------
         obj : :class:`HasTraits` instance
             The parent :class:`HasTraits` instance that has just been
             created.
         """
         self.set_default_value(obj)
 
     def set_default_value(self, obj):
         """Set the default value on a per instance basis.
 
         This method is called by :meth:`instance_init` to create and
         validate the default value.  The creation and validation of 
         default values must be delayed until the parent :class:`HasTraits`
         class has been instantiated.
         """
         dv = self.get_default_value()
         newdv = self._validate(obj, dv)
         obj._trait_values[self.name] = newdv
 
     def __get__(self, obj, cls=None):
         """Get the value of the trait by self.name for the instance.
 
         Default values are instantiated when :meth:`HasTraits.__new__`
         is called.  Thus by the time this method gets called either the 
         default value or a user defined value (they called :meth:`__set__`)
         is in the :class:`HasTraits` instance.
         """
         if obj is None:
             return self
         else:
             try:
                 value = obj._trait_values[self.name]
             except:
                 # HasTraits should call set_default_value to populate
                 # this.  So this should never be reached.
                 raise TraitError('Unexpected error in TraitType: '
                                     'default value not set properly')
             else:
                 return value
 
     def __set__(self, obj, value):
         new_value = self._validate(obj, value)
         old_value = self.__get__(obj)
         if old_value != new_value:
             obj._trait_values[self.name] = new_value
             obj._notify_trait(self.name, old_value, new_value)
 
     def _validate(self, obj, value):
         if hasattr(self, 'validate'):
             return self.validate(obj, value)
         elif hasattr(self, 'is_valid_for'):
             valid = self.is_valid_for(value)
             if valid:
                 return value
             else:
                 raise TraitError('invalid value for type: %r' % value)
         elif hasattr(self, 'value_for'):
             return self.value_for(value)
         else:
             return value
 
     def info(self):
         return self.info_text
 
     def error(self, obj, value):
         if obj is not None:
             e = "The '%s' trait of %s instance must be %s, but a value of %s was specified." \
                 % (self.name, class_of(obj),
                    self.info(), repr_type(value))
         else:
             e = "The '%s' trait must be %s, but a value of %r was specified." \
                 % (self.name, self.info(), repr_type(value))            
         raise TraitError(e)
 
     def get_metadata(self, key):
         return getattr(self, '_metadata', {}).get(key, None)
 
     def set_metadata(self, key, value):
         getattr(self, '_metadata', {})[key] = value
 
 
 #-----------------------------------------------------------------------------
 # The HasTraits implementation
 #-----------------------------------------------------------------------------
 
 
 class MetaHasTraits(type):
     """A metaclass for HasTraits.
     
     This metaclass makes sure that any TraitType class attributes are
     instantiated and sets their name attribute.
     """
     
     def __new__(mcls, name, bases, classdict):
         """Create the HasTraits class.
         
         This instantiates all TraitTypes in the class dict and sets their
         :attr:`name` attribute.
         """
         # print "MetaHasTraitlets (mcls, name): ", mcls, name
         # print "MetaHasTraitlets (bases): ", bases
         # print "MetaHasTraitlets (classdict): ", classdict
         for k,v in classdict.iteritems():
             if isinstance(v, TraitType):
                 v.name = k
             elif inspect.isclass(v):
                 if issubclass(v, TraitType):
                     vinst = v()
                     vinst.name = k
                     classdict[k] = vinst
         return super(MetaHasTraits, mcls).__new__(mcls, name, bases, classdict)
 
     def __init__(cls, name, bases, classdict):
         """Finish initializing the HasTraits class.
         
         This sets the :attr:`this_class` attribute of each TraitType in the
         class dict to the newly created class ``cls``.
         """
         for k, v in classdict.iteritems():
             if isinstance(v, TraitType):
                 v.this_class = cls
         super(MetaHasTraits, cls).__init__(name, bases, classdict)
 
 class HasTraits(object):
 
     __metaclass__ = MetaHasTraits
 
     def __new__(cls, *args, **kw):
         # This is needed because in Python 2.6 object.__new__ only accepts
         # the cls argument.
         new_meth = super(HasTraits, cls).__new__
         if new_meth is object.__new__:
             inst = new_meth(cls)
         else:
             inst = new_meth(cls, *args, **kw)
         inst._trait_values = {}
         inst._trait_notifiers = {}
         # Here we tell all the TraitType instances to set their default
         # values on the instance. 
         for key in dir(cls):
             # Some descriptors raise AttributeError like zope.interface's
             # __provides__ attributes even though they exist.  This causes
             # AttributeErrors even though they are listed in dir(cls).
             try:
                 value = getattr(cls, key)
             except AttributeError:
                 pass
             else:
                 if isinstance(value, TraitType):
                     value.instance_init(inst)
 
         return inst
 
     # def __init__(self):
     #     self._trait_values = {}
     #     self._trait_notifiers = {}
 
     def _notify_trait(self, name, old_value, new_value):
 
         # First dynamic ones
         callables = self._trait_notifiers.get(name,[])
         more_callables = self._trait_notifiers.get('anytrait',[])
         callables.extend(more_callables)
 
         # Now static ones
         try:
             cb = getattr(self, '_%s_changed' % name)
         except:
             pass
         else:
             callables.append(cb)
 
         # Call them all now
         for c in callables:
             # Traits catches and logs errors here.  I allow them to raise
             if callable(c):
                 argspec = inspect.getargspec(c)
                 nargs = len(argspec[0])
                 # Bound methods have an additional 'self' argument
                 # I don't know how to treat unbound methods, but they
                 # can't really be used for callbacks.
                 if isinstance(c, types.MethodType):
                     offset = -1
                 else:
                     offset = 0
                 if nargs + offset == 0:
                     c()
                 elif nargs + offset == 1:
                     c(name)
                 elif nargs + offset == 2:
                     c(name, new_value)
                 elif nargs + offset == 3:
                     c(name, old_value, new_value)
                 else:
                     raise TraitError('a trait changed callback '
                                         'must have 0-3 arguments.')
             else:
                 raise TraitError('a trait changed callback '
                                     'must be callable.')
                 
 
     def _add_notifiers(self, handler, name):
         if not self._trait_notifiers.has_key(name):
             nlist = []
             self._trait_notifiers[name] = nlist
         else:
             nlist = self._trait_notifiers[name]
         if handler not in nlist:
             nlist.append(handler)
 
     def _remove_notifiers(self, handler, name):
         if self._trait_notifiers.has_key(name):
             nlist = self._trait_notifiers[name]
             try:
                 index = nlist.index(handler)
             except ValueError:
                 pass
             else:
                 del nlist[index]
 
     def on_trait_change(self, handler, name=None, remove=False):
         """Setup a handler to be called when a trait changes.
 
         This is used to setup dynamic notifications of trait changes.
         
         Static handlers can be created by creating methods on a HasTraits
         subclass with the naming convention '_[traitname]_changed'.  Thus,
         to create static handler for the trait 'a', create the method
         _a_changed(self, name, old, new) (fewer arguments can be used, see
         below).
         
         Parameters
         ----------
         handler : callable
             A callable that is called when a trait changes.  Its 
             signature can be handler(), handler(name), handler(name, new)
             or handler(name, old, new).
         name : list, str, None
             If None, the handler will apply to all traits.  If a list
             of str, handler will apply to all names in the list.  If a
             str, the handler will apply just to that name.
         remove : bool
             If False (the default), then install the handler.  If True
             then unintall it.
         """
         if remove:
             names = parse_notifier_name(name)
             for n in names:
                 self._remove_notifiers(handler, n)
         else:
             names = parse_notifier_name(name)
             for n in names:
                 self._add_notifiers(handler, n)
 
     def trait_names(self, **metadata):
         """Get a list of all the names of this classes traits."""
         return self.traits(**metadata).keys()
 
     def traits(self, **metadata):
         """Get a list of all the traits of this class.
 
         The TraitTypes returned don't know anything about the values
         that the various HasTrait's instances are holding.
 
         This follows the same algorithm as traits does and does not allow
         for any simple way of specifying merely that a metadata name
         exists, but has any value.  This is because get_metadata returns
         None if a metadata key doesn't exist.
         """
         traits = dict([memb for memb in getmembers(self.__class__) if \
                      isinstance(memb[1], TraitType)])
 
         if len(metadata) == 0:
             return traits
 
         for meta_name, meta_eval in metadata.items():
             if type(meta_eval) is not FunctionType:
                 metadata[meta_name] = _SimpleTest(meta_eval)
 
         result = {}
         for name, trait in traits.items():
             for meta_name, meta_eval in metadata.items():
                 if not meta_eval(trait.get_metadata(meta_name)):
                     break
             else:
                 result[name] = trait
 
         return result
 
     def trait_metadata(self, traitname, key):
         """Get metadata values for trait by key."""
         try:
             trait = getattr(self.__class__, traitname)
         except AttributeError:
             raise TraitError("Class %s does not have a trait named %s" %
                                 (self.__class__.__name__, traitname))
         else:
             return trait.get_metadata(key)
 
 #-----------------------------------------------------------------------------
 # Actual TraitTypes implementations/subclasses
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # TraitTypes subclasses for handling classes and instances of classes
 #-----------------------------------------------------------------------------
 
 
 class ClassBasedTraitType(TraitType):
     """A trait with error reporting for Type, Instance and This."""
 
     def error(self, obj, value):
         kind = type(value)
         if kind is InstanceType:
             msg = 'class %s' % value.__class__.__name__
         else:
             msg = '%s (i.e. %s)' % ( str( kind )[1:-1], repr( value ) )
 
         super(ClassBasedTraitType, self).error(obj, msg)
 
 
 class Type(ClassBasedTraitType):
     """A trait whose value must be a subclass of a specified class."""
 
     def __init__ (self, default_value=None, klass=None, allow_none=True, **metadata ):
         """Construct a Type trait
 
         A Type trait specifies that its values must be subclasses of
         a particular class.
 
         If only ``default_value`` is given, it is used for the ``klass`` as
         well.
 
         Parameters
         ----------
         default_value : class, str or None
             The default value must be a subclass of klass.  If an str,
             the str must be a fully specified class name, like 'foo.bar.Bah'.
             The string is resolved into real class, when the parent 
             :class:`HasTraits` class is instantiated.
         klass : class, str, None
             Values of this trait must be a subclass of klass.  The klass
             may be specified in a string like: 'foo.bar.MyClass'.
             The string is resolved into real class, when the parent 
             :class:`HasTraits` class is instantiated.
         allow_none : boolean
             Indicates whether None is allowed as an assignable value. Even if
             ``False``, the default value may be ``None``.
         """
         if default_value is None:
             if klass is None:
                 klass = object
         elif klass is None:
             klass = default_value
 
         if not (inspect.isclass(klass) or isinstance(klass, basestring)):
             raise TraitError("A Type trait must specify a class.")
 
         self.klass       = klass
         self._allow_none = allow_none
 
         super(Type, self).__init__(default_value, **metadata)
 
     def validate(self, obj, value):
         """Validates that the value is a valid object instance."""
         try:
             if issubclass(value, self.klass):
                 return value
         except:
             if (value is None) and (self._allow_none):
                 return value
 
         self.error(obj, value)
 
     def info(self):
         """ Returns a description of the trait."""
         if isinstance(self.klass, basestring):
             klass = self.klass
         else:
             klass = self.klass.__name__
         result = 'a subclass of ' + klass
         if self._allow_none:
             return result + ' or None'
         return result
 
     def instance_init(self, obj):
         self._resolve_classes()
         super(Type, self).instance_init(obj)
 
     def _resolve_classes(self):
         if isinstance(self.klass, basestring):
             self.klass = import_item(self.klass)
         if isinstance(self.default_value, basestring):
             self.default_value = import_item(self.default_value)
 
     def get_default_value(self):
         return self.default_value
 
 
 class DefaultValueGenerator(object):
     """A class for generating new default value instances."""
 
     def __init__(self, *args, **kw):
         self.args = args
         self.kw = kw
 
     def generate(self, klass):
         return klass(*self.args, **self.kw)
 
 
 class Instance(ClassBasedTraitType):
     """A trait whose value must be an instance of a specified class.
     
     The value can also be an instance of a subclass of the specified class.
     """
 
     def __init__(self, klass=None, args=None, kw=None, 
                  allow_none=True, **metadata ):
         """Construct an Instance trait.
 
         This trait allows values that are instances of a particular
         class or its sublclasses.  Our implementation is quite different
         from that of enthough.traits as we don't allow instances to be used
         for klass and we handle the ``args`` and ``kw`` arguments differently.
 
         Parameters
         ----------
         klass : class, str
             The class that forms the basis for the trait.  Class names
             can also be specified as strings, like 'foo.bar.Bar'.
         args : tuple
             Positional arguments for generating the default value.
         kw : dict
             Keyword arguments for generating the default value.
         allow_none : bool
             Indicates whether None is allowed as a value.
 
         Default Value
         -------------
         If both ``args`` and ``kw`` are None, then the default value is None.
         If ``args`` is a tuple and ``kw`` is a dict, then the default is
         created as ``klass(*args, **kw)``.  If either ``args`` or ``kw`` is 
         not (but not both), None is replace by ``()`` or ``{}``.
         """
 
         self._allow_none = allow_none
 
         if (klass is None) or (not (inspect.isclass(klass) or isinstance(klass, basestring))):
             raise TraitError('The klass argument must be a class'
                                 ' you gave: %r' % klass)
         self.klass = klass
         
         # self.klass is a class, so handle default_value
         if args is None and kw is None:
             default_value = None
         else:
             if args is None:
                 # kw is not None
                 args = ()
             elif kw is None:
                 # args is not None
                 kw = {}
         
             if not isinstance(kw, dict):
                 raise TraitError("The 'kw' argument must be a dict or None.")
             if not isinstance(args, tuple):
                 raise TraitError("The 'args' argument must be a tuple or None.")
             
             default_value = DefaultValueGenerator(*args, **kw)
 
         super(Instance, self).__init__(default_value, **metadata)
 
     def validate(self, obj, value):
         if value is None:
             if self._allow_none:
                 return value
             self.error(obj, value)
 
         if isinstance(value, self.klass):
             return value
         else:
             self.error(obj, value)
 
     def info(self):
         if isinstance(self.klass, basestring):
             klass = self.klass
         else:
             klass = self.klass.__name__
         result = class_of(klass)
         if self._allow_none:
             return result + ' or None'
 
         return result
 
     def instance_init(self, obj):
         self._resolve_classes()
         super(Instance, self).instance_init(obj)
 
     def _resolve_classes(self):
         if isinstance(self.klass, basestring):
             self.klass = import_item(self.klass)
 
     def get_default_value(self):
         """Instantiate a default value instance.
         
         This is called when the containing HasTraits classes'
         :meth:`__new__` method is called to ensure that a unique instance
         is created for each HasTraits instance.
         """
         dv  = self.default_value
         if isinstance(dv, DefaultValueGenerator):
             return dv.generate(self.klass)
         else:
             return dv
 
 
 class This(ClassBasedTraitType):
     """A trait for instances of the class containing this trait.
 
     Because how how and when class bodies are executed, the ``This``
     trait can only have a default value of None.  This, and because we 
     always validate default values, ``allow_none`` is *always* true.
     """
 
     info_text = 'an instance of the same type as the receiver or None'
 
     def __init__(self, **metadata):
         super(This, self).__init__(None, **metadata)
 
     def validate(self, obj, value):
         # What if value is a superclass of obj.__class__?  This is
         # complicated if it was the superclass that defined the This
         # trait.
         if isinstance(value, self.this_class) or (value is None):
             return value
         else:
             self.error(obj, value)
 
 
 #-----------------------------------------------------------------------------
 # Basic TraitTypes implementations/subclasses
 #-----------------------------------------------------------------------------
 
 
 class Any(TraitType):
     default_value = None
     info_text = 'any value'
 
 
 class Int(TraitType):
     """A integer trait."""
 
     evaluate = int
     default_value = 0
     info_text = 'an integer'
 
     def validate(self, obj, value):
         if isinstance(value, int):
             return value
         self.error(obj, value)
 
 class CInt(Int):
     """A casting version of the int trait."""
 
     def validate(self, obj, value):
         try:
             return int(value)
         except:
             self.error(obj, value)
 
 
 class Long(TraitType):
     """A long integer trait."""
 
     evaluate = long
     default_value = 0L
     info_text = 'a long'
 
     def validate(self, obj, value):
         if isinstance(value, long):
             return value
         if isinstance(value, int):
             return long(value)
         self.error(obj, value)
 
 
 class CLong(Long):
     """A casting version of the long integer trait."""
 
     def validate(self, obj, value):
         try:
             return long(value)
         except:
             self.error(obj, value)
 
 
 class Float(TraitType):
     """A float trait."""
 
     evaluate = float
     default_value = 0.0
     info_text = 'a float'
 
     def validate(self, obj, value):
         if isinstance(value, float):
             return value
         if isinstance(value, int):
             return float(value)
         self.error(obj, value)
 
 
 class CFloat(Float):
     """A casting version of the float trait."""
 
     def validate(self, obj, value):
         try:
             return float(value)
         except:
             self.error(obj, value)
 
 class Complex(TraitType):
     """A trait for complex numbers."""
 
     evaluate = complex
     default_value = 0.0 + 0.0j
     info_text = 'a complex number'
 
     def validate(self, obj, value):
         if isinstance(value, complex):
             return value
         if isinstance(value, (float, int)):
             return complex(value)
         self.error(obj, value)
 
 
 class CComplex(Complex):
     """A casting version of the complex number trait."""
 
     def validate (self, obj, value):
         try:
             return complex(value)
         except:
             self.error(obj, value)
 
 
 class Str(TraitType):
     """A trait for strings."""
 
     evaluate = lambda x: x
     default_value = ''
     info_text = 'a string'
 
     def validate(self, obj, value):
         if isinstance(value, str):
             return value
         self.error(obj, value)
 
 
 class CStr(Str):
     """A casting version of the string trait."""
 
     def validate(self, obj, value):
         try:
             return str(value)
         except:
             try:
                 return unicode(value)
             except:
                 self.error(obj, value)
 
 
 class Unicode(TraitType):
     """A trait for unicode strings."""
 
     evaluate = unicode
     default_value = u''
     info_text = 'a unicode string'
 
     def validate(self, obj, value):
         if isinstance(value, unicode):
             return value
         if isinstance(value, str):
             return unicode(value)
         self.error(obj, value)
 
 
 class CUnicode(Unicode):
     """A casting version of the unicode trait."""
 
     def validate(self, obj, value):
         try:
             return unicode(value)
         except:
             self.error(obj, value)
 
 
 class Bool(TraitType):
     """A boolean (True, False) trait."""
     evaluate = bool
     default_value = False
     info_text = 'a boolean'
 
     def validate(self, obj, value):
         if isinstance(value, bool):
             return value
         self.error(obj, value)
 
 
 class CBool(Bool):
     """A casting version of the boolean trait."""
 
     def validate(self, obj, value):
         try:
             return bool(value)
         except:
             self.error(obj, value)
 
 
 class Enum(TraitType):
     """An enum that whose value must be in a given sequence."""
 
     def __init__(self, values, default_value=None, allow_none=True, **metadata):
         self.values = values
         self._allow_none = allow_none
         super(Enum, self).__init__(default_value, **metadata)
 
     def validate(self, obj, value):
         if value is None:
             if self._allow_none:
                 return value
 
         if value in self.values:
                 return value
         self.error(obj, value)
 
     def info(self):
         """ Returns a description of the trait."""
         result = 'any of ' + repr(self.values)
         if self._allow_none:
             return result + ' or None'
         return result
 
 class CaselessStrEnum(Enum):
     """An enum of strings that are caseless in validate."""
 
     def validate(self, obj, value):
         if value is None:
             if self._allow_none:
                 return value
 
         if not isinstance(value, str):
             self.error(obj, value)
 
         for v in self.values:
             if v.lower() == value.lower():
                 return v
         self.error(obj, value)
 
 
 class List(Instance):
     """An instance of a Python list."""
 
     def __init__(self, default_value=None, allow_none=True, **metadata):
         """Create a list trait type from a list or tuple.
 
         The default value is created by doing ``list(default_value)``, 
         which creates a copy of the ``default_value``.
         """
         if default_value is None:
             args = ((),)
         elif isinstance(default_value, SequenceTypes):
             args = (default_value,)
         else:
             raise TypeError('default value of List was %s' % default_value)
 
         super(List,self).__init__(klass=list, args=args, 
                                   allow_none=allow_none, **metadata)
+
+
+class Dict(Instance):
+    """An instance of a Python dict."""
+
+    def __init__(self, default_value=None, allow_none=True, **metadata):
+        """Create a dict trait type from a dict.
+
+        The default value is created by doing ``dict(default_value)``, 
+        which creates a copy of the ``default_value``.
+        """
+        if default_value is None:
+            args = ((),)
+        elif isinstance(default_value, dict):
+            args = (default_value,)
+        elif isinstance(default_value, SequenceTypes):
+            args = (default_value,)
+        else:
+            raise TypeError('default value of Dict was %s' % default_value)
+
+        super(Dict,self).__init__(klass=dict, args=args, 
+                                  allow_none=allow_none, **metadata)