Py3k: Octal (0777 -> 0o777)

IPython/core/application.py

@@ -1,336 +1,336 b''
 # encoding: utf-8
 """
 An application for IPython.
 
 All top-level applications should use the classes in this module for
 handling configuration and creating componenets.
 
 The job of an :class:`Application` is to create the master configuration
 object and then create the configurable objects, passing the config to them.
 
 Authors:
 
 * Brian Granger
 * Fernando Perez
 * Min RK
 
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import atexit
 import glob
 import logging
 import os
 import shutil
 import sys
 
 from IPython.config.application import Application, catch_config_error
 from IPython.config.configurable import Configurable
 from IPython.config.loader import Config, ConfigFileNotFound
 from IPython.core import release, crashhandler
 from IPython.core.profiledir import ProfileDir, ProfileDirError
 from IPython.utils.path import get_ipython_dir, get_ipython_package_dir
 from IPython.utils.traitlets import List, Unicode, Type, Bool, Dict
 from IPython.utils import py3compat
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 
 #-----------------------------------------------------------------------------
 # Base Application Class
 #-----------------------------------------------------------------------------
 
 # aliases and flags
 
 base_aliases = {
     'profile' : 'BaseIPythonApplication.profile',
     'ipython-dir' : 'BaseIPythonApplication.ipython_dir',
     'log-level' : 'Application.log_level',
 }
 
 base_flags = dict(
     debug = ({'Application' : {'log_level' : logging.DEBUG}},
             "set log level to logging.DEBUG (maximize logging output)"),
     quiet = ({'Application' : {'log_level' : logging.CRITICAL}},
             "set log level to logging.CRITICAL (minimize logging output)"),
     init = ({'BaseIPythonApplication' : {
                     'copy_config_files' : True,
                     'auto_create' : True}
             }, """Initialize profile with default config files.  This is equivalent
             to running `ipython profile create <profile>` prior to startup.
             """)
 )
 
 
 class BaseIPythonApplication(Application):
 
     name = Unicode(u'ipython')
     description = Unicode(u'IPython: an enhanced interactive Python shell.')
     version = Unicode(release.version)
 
     aliases = Dict(base_aliases)
     flags = Dict(base_flags)
     classes = List([ProfileDir])
 
     # Track whether the config_file has changed,
     # because some logic happens only if we aren't using the default.
     config_file_specified = Bool(False)
 
     config_file_name = Unicode(u'ipython_config.py')
     def _config_file_name_default(self):
         return self.name.replace('-','_') + u'_config.py'
     def _config_file_name_changed(self, name, old, new):
         if new != old:
             self.config_file_specified = True
 
     # The directory that contains IPython's builtin profiles.
     builtin_profile_dir = Unicode(
         os.path.join(get_ipython_package_dir(), u'config', u'profile', u'default')
     )
 
     config_file_paths = List(Unicode)
     def _config_file_paths_default(self):
         return [os.getcwdu()]
 
     profile = Unicode(u'default', config=True,
         help="""The IPython profile to use."""
     )
 
     def _profile_changed(self, name, old, new):
         self.builtin_profile_dir = os.path.join(
                 get_ipython_package_dir(), u'config', u'profile', new
         )
 
     ipython_dir = Unicode(get_ipython_dir(), config=True,
         help="""
         The name of the IPython directory. This directory is used for logging
         configuration (through profiles), history storage, etc. The default
         is usually $HOME/.ipython. This options can also be specified through
         the environment variable IPYTHONDIR.
         """
     )
 
     overwrite = Bool(False, config=True,
         help="""Whether to overwrite existing config files when copying""")
     auto_create = Bool(False, config=True,
         help="""Whether to create profile dir if it doesn't exist""")
 
     config_files = List(Unicode)
     def _config_files_default(self):
         return [u'ipython_config.py']
 
     copy_config_files = Bool(False, config=True,
         help="""Whether to install the default config files into the profile dir.
         If a new profile is being created, and IPython contains config files for that
         profile, then they will be staged into the new directory.  Otherwise,
         default config files will be automatically generated.
         """)
     
     verbose_crash = Bool(False, config=True,
         help="""Create a massive crash report when IPython encounters what may be an
         internal error.  The default is to append a short message to the
         usual traceback""")
 
     # The class to use as the crash handler.
     crash_handler_class = Type(crashhandler.CrashHandler)
 
     def __init__(self, **kwargs):
         super(BaseIPythonApplication, self).__init__(**kwargs)
         # ensure even default IPYTHONDIR exists
         if not os.path.exists(self.ipython_dir):
             self._ipython_dir_changed('ipython_dir', self.ipython_dir, self.ipython_dir)
 
     #-------------------------------------------------------------------------
     # Various stages of Application creation
     #-------------------------------------------------------------------------
 
     def init_crash_handler(self):
         """Create a crash handler, typically setting sys.excepthook to it."""
         self.crash_handler = self.crash_handler_class(self)
         sys.excepthook = self.excepthook
         def unset_crashhandler():
             sys.excepthook = sys.__excepthook__
         atexit.register(unset_crashhandler)
     
     def excepthook(self, etype, evalue, tb):
         """this is sys.excepthook after init_crashhandler
         
         set self.verbose_crash=True to use our full crashhandler, instead of
         a regular traceback with a short message (crash_handler_lite)
         """
         
         if self.verbose_crash:
             return self.crash_handler(etype, evalue, tb)
         else:
             return crashhandler.crash_handler_lite(etype, evalue, tb)
     
     def _ipython_dir_changed(self, name, old, new):
         if old in sys.path:
             sys.path.remove(old)
         sys.path.append(os.path.abspath(new))
         if not os.path.isdir(new):
-            os.makedirs(new, mode=0777)
+            os.makedirs(new, mode=0o777)
         readme = os.path.join(new, 'README')
         if not os.path.exists(readme):
             path = os.path.join(get_ipython_package_dir(), u'config', u'profile')
             shutil.copy(os.path.join(path, 'README'), readme)
         self.log.debug("IPYTHONDIR set to: %s" % new)
 
     def load_config_file(self, suppress_errors=True):
         """Load the config file.
 
         By default, errors in loading config are handled, and a warning
         printed on screen. For testing, the suppress_errors option is set
         to False, so errors will make tests fail.
         """
         self.log.debug("Searching path %s for config files", self.config_file_paths)
         base_config = 'ipython_config.py'
         self.log.debug("Attempting to load config file: %s" %
                        base_config)
         try:
             Application.load_config_file(
                 self,
                 base_config,
                 path=self.config_file_paths
             )
         except ConfigFileNotFound:
             # ignore errors loading parent
             self.log.debug("Config file %s not found", base_config)
             pass
         if self.config_file_name == base_config:
             # don't load secondary config
             return
         self.log.debug("Attempting to load config file: %s" %
                        self.config_file_name)
         try:
             Application.load_config_file(
                 self,
                 self.config_file_name,
                 path=self.config_file_paths
             )
         except ConfigFileNotFound:
             # Only warn if the default config file was NOT being used.
             if self.config_file_specified:
                 msg = self.log.warn
             else:
                 msg = self.log.debug
             msg("Config file not found, skipping: %s", self.config_file_name)
         except:
             # For testing purposes.
             if not suppress_errors:
                 raise
             self.log.warn("Error loading config file: %s" %
                           self.config_file_name, exc_info=True)
 
     def init_profile_dir(self):
         """initialize the profile dir"""
         try:
             # location explicitly specified:
             location = self.config.ProfileDir.location
         except AttributeError:
             # location not specified, find by profile name
             try:
                 p = ProfileDir.find_profile_dir_by_name(self.ipython_dir, self.profile, self.config)
             except ProfileDirError:
                 # not found, maybe create it (always create default profile)
                 if self.auto_create or self.profile=='default':
                     try:
                         p = ProfileDir.create_profile_dir_by_name(self.ipython_dir, self.profile, self.config)
                     except ProfileDirError:
                         self.log.fatal("Could not create profile: %r"%self.profile)
                         self.exit(1)
                     else:
                         self.log.info("Created profile dir: %r"%p.location)
                 else:
                     self.log.fatal("Profile %r not found."%self.profile)
                     self.exit(1)
             else:
                 self.log.info("Using existing profile dir: %r"%p.location)
         else:
             # location is fully specified
             try:
                 p = ProfileDir.find_profile_dir(location, self.config)
             except ProfileDirError:
                 # not found, maybe create it
                 if self.auto_create:
                     try:
                         p = ProfileDir.create_profile_dir(location, self.config)
                     except ProfileDirError:
                         self.log.fatal("Could not create profile directory: %r"%location)
                         self.exit(1)
                     else:
                         self.log.info("Creating new profile dir: %r"%location)
                 else:
                     self.log.fatal("Profile directory %r not found."%location)
                     self.exit(1)
             else:
                 self.log.info("Using existing profile dir: %r"%location)
 
         self.profile_dir = p
         self.config_file_paths.append(p.location)
 
     def init_config_files(self):
         """[optionally] copy default config files into profile dir."""
         # copy config files
         path = self.builtin_profile_dir
         if self.copy_config_files:
             src = self.profile
 
             cfg = self.config_file_name
             if path and os.path.exists(os.path.join(path, cfg)):
                 self.log.warn("Staging %r from %s into %r [overwrite=%s]"%(
                         cfg, src, self.profile_dir.location, self.overwrite)
                 )
                 self.profile_dir.copy_config_file(cfg, path=path, overwrite=self.overwrite)
             else:
                 self.stage_default_config_file()
         else:
             # Still stage *bundled* config files, but not generated ones
             # This is necessary for `ipython profile=sympy` to load the profile
             # on the first go
             files = glob.glob(os.path.join(path, '*.py'))
             for fullpath in files:
                 cfg = os.path.basename(fullpath)
                 if self.profile_dir.copy_config_file(cfg, path=path, overwrite=False):
                     # file was copied
                     self.log.warn("Staging bundled %s from %s into %r"%(
                             cfg, self.profile, self.profile_dir.location)
                     )
 
 
     def stage_default_config_file(self):
         """auto generate default config file, and stage it into the profile."""
         s = self.generate_config_file()
         fname = os.path.join(self.profile_dir.location, self.config_file_name)
         if self.overwrite or not os.path.exists(fname):
             self.log.warn("Generating default config file: %r"%(fname))
             with open(fname, 'w') as f:
                 f.write(s)
 
     @catch_config_error
     def initialize(self, argv=None):
         # don't hook up crash handler before parsing command-line
         self.parse_command_line(argv)
         self.init_crash_handler()
         if self.subapp is not None:
             # stop here if subapp is taking over
             return
         cl_config = self.config
         self.init_profile_dir()
         self.init_config_files()
         self.load_config_file()
         # enforce cl-opts override configfile opts:
         self.update_config(cl_config)
 

IPython/core/extensions.py

@@ -1,157 +1,157 b''
 # encoding: utf-8
 """A class for managing IPython extensions.
 
 Authors:
 
 * Brian Granger
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import os
 from shutil import copyfile
 import sys
 from urllib import urlretrieve
 from urlparse import urlparse
 
 from IPython.config.configurable import Configurable
 from IPython.utils.traitlets import Instance
 
 #-----------------------------------------------------------------------------
 # Main class
 #-----------------------------------------------------------------------------
 
 class ExtensionManager(Configurable):
     """A class to manage IPython extensions.
 
     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.interactiveshell.InteractiveShellABC')
 
     def __init__(self, shell=None, config=None):
         super(ExtensionManager, self).__init__(shell=shell, config=config)
         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)
+            os.makedirs(self.ipython_extension_dir, mode = 0o777)
 
     def load_extension(self, module_str):
         """Load an IPython extension by its module name.
 
         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)
     
     def install_extension(self, url, filename=None):
         """Download and install an IPython extension. 
         
         If filename is given, the file will be so named (inside the extension
         directory). Otherwise, the name from the URL will be used. The file must
         have a .py or .zip extension; otherwise, a ValueError will be raised.
         
         Returns the full path to the installed file.
         """
         # Ensure the extension directory exists
         if not os.path.isdir(self.ipython_extension_dir):
-            os.makedirs(self.ipython_extension_dir, mode = 0777)
+            os.makedirs(self.ipython_extension_dir, mode = 0o777)
         
         if os.path.isfile(url):
             src_filename = os.path.basename(url)
             copy = copyfile
         else:
             src_filename = urlparse(url).path.split('/')[-1]
             copy = urlretrieve
             
         if filename is None:
             filename = src_filename
         if os.path.splitext(filename)[1] not in ('.py', '.zip'):
             raise ValueError("The file must have a .py or .zip extension", filename)
         
         filename = os.path.join(self.ipython_extension_dir, filename)
         copy(url, filename)
         return filename

IPython/core/interactiveshell.py

@@ -1,3024 +1,3024 b''
 # -*- coding: utf-8 -*-
 """Main IPython class."""
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2001 Janko Hauser <[e-mail]>
 #  Copyright (C) 2001-2007 Fernando Perez. <[e-mail]>
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from __future__ import with_statement
 from __future__ import absolute_import
 from __future__ import print_function
 
 import __builtin__ as builtin_mod
 import __future__
 import abc
 import ast
 import atexit
 import os
 import re
 import runpy
 import sys
 import tempfile
 import types
 import urllib
 from io import open as io_open
 
 from IPython.config.configurable import SingletonConfigurable
 from IPython.core import debugger, oinspect
 from IPython.core import magic
 from IPython.core import page
 from IPython.core import prefilter
 from IPython.core import shadowns
 from IPython.core import ultratb
 from IPython.core.alias import AliasManager, AliasError
 from IPython.core.autocall import ExitAutocall
 from IPython.core.builtin_trap import BuiltinTrap
 from IPython.core.compilerop import CachingCompiler
 from IPython.core.display_trap import DisplayTrap
 from IPython.core.displayhook import DisplayHook
 from IPython.core.displaypub import DisplayPublisher
 from IPython.core.error import UsageError
 from IPython.core.extensions import ExtensionManager
 from IPython.core.fakemodule import FakeModule, init_fakemod_dict
 from IPython.core.formatters import DisplayFormatter
 from IPython.core.history import HistoryManager
 from IPython.core.inputsplitter import IPythonInputSplitter, ESC_MAGIC, ESC_MAGIC2
 from IPython.core.logger import Logger
 from IPython.core.macro import Macro
 from IPython.core.payload import PayloadManager
 from IPython.core.plugin import PluginManager
 from IPython.core.prefilter import PrefilterManager
 from IPython.core.profiledir import ProfileDir
 from IPython.core.pylabtools import pylab_activate
 from IPython.core.prompts import PromptManager
 from IPython.lib.latextools import LaTeXTool
 from IPython.utils import PyColorize
 from IPython.utils import io
 from IPython.utils import py3compat
 from IPython.utils import openpy
 from IPython.utils.doctestreload import doctest_reload
 from IPython.utils.io import ask_yes_no
 from IPython.utils.ipstruct import Struct
 from IPython.utils.path import get_home_dir, get_ipython_dir, get_py_filename, unquote_filename
 from IPython.utils.pickleshare import PickleShareDB
 from IPython.utils.process import system, getoutput
 from IPython.utils.strdispatch import StrDispatch
 from IPython.utils.syspathcontext import prepended_to_syspath
 from IPython.utils.text import (format_screen, LSString, SList,
                                 DollarFormatter)
 from IPython.utils.traitlets import (Integer, CBool, CaselessStrEnum, Enum,
                                      List, Unicode, Instance, Type)
 from IPython.utils.warn import warn, error
 import IPython.core.hooks
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 # compiled regexps for autoindent management
 dedent_re = re.compile(r'^\s+raise|^\s+return|^\s+pass')
 
 #-----------------------------------------------------------------------------
 # Utilities
 #-----------------------------------------------------------------------------
 
 def softspace(file, newvalue):
     """Copied from code.py, to remove the dependency"""
 
     oldvalue = 0
     try:
         oldvalue = file.softspace
     except AttributeError:
         pass
     try:
         file.softspace = newvalue
     except (AttributeError, TypeError):
         # "attribute-less object" or "read-only attributes"
         pass
     return oldvalue
 
 
 def no_op(*a, **kw): pass
 
 class NoOpContext(object):
     def __enter__(self): pass
     def __exit__(self, type, value, traceback): pass
 no_op_context = NoOpContext()
 
 class SpaceInInput(Exception): pass
 
 class Bunch: pass
 
 
 def get_default_colors():
     if sys.platform=='darwin':
         return "LightBG"
     elif os.name=='nt':
         return 'Linux'
     else:
         return 'Linux'
 
 
 class SeparateUnicode(Unicode):
     """A Unicode subclass to validate separate_in, separate_out, etc.
 
     This is a Unicode based trait that converts '0'->'' and '\\n'->'\n'.
     """
 
     def validate(self, obj, value):
         if value == '0': value = ''
         value = value.replace('\\n','\n')
         return super(SeparateUnicode, self).validate(obj, value)
 
 
 class ReadlineNoRecord(object):
     """Context manager to execute some code, then reload readline history
     so that interactive input to the code doesn't appear when pressing up."""
     def __init__(self, shell):
         self.shell = shell
         self._nested_level = 0
 
     def __enter__(self):
         if self._nested_level == 0:
             try:
                 self.orig_length = self.current_length()
                 self.readline_tail = self.get_readline_tail()
             except (AttributeError, IndexError):   # Can fail with pyreadline
                 self.orig_length, self.readline_tail = 999999, []
         self._nested_level += 1
 
     def __exit__(self, type, value, traceback):
         self._nested_level -= 1
         if self._nested_level == 0:
             # Try clipping the end if it's got longer
             try:
                 e = self.current_length() - self.orig_length
                 if e > 0:
                     for _ in range(e):
                         self.shell.readline.remove_history_item(self.orig_length)
 
                 # If it still doesn't match, just reload readline history.
                 if self.current_length() != self.orig_length \
                     or self.get_readline_tail() != self.readline_tail:
                     self.shell.refill_readline_hist()
             except (AttributeError, IndexError):
                 pass
         # Returning False will cause exceptions to propagate
         return False
 
     def current_length(self):
         return self.shell.readline.get_current_history_length()
 
     def get_readline_tail(self, n=10):
         """Get the last n items in readline history."""
         end = self.shell.readline.get_current_history_length() + 1
         start = max(end-n, 1)
         ghi = self.shell.readline.get_history_item
         return [ghi(x) for x in range(start, end)]
 
 #-----------------------------------------------------------------------------
 # Main IPython class
 #-----------------------------------------------------------------------------
 
 class InteractiveShell(SingletonConfigurable):
     """An enhanced, interactive shell for Python."""
 
     _instance = None
 
     autocall = Enum((0,1,2), default_value=0, config=True, help=
         """
         Make IPython automatically call any callable object even if you didn't
         type explicit parentheses. For example, 'str 43' becomes 'str(43)'
         automatically. The value can be '0' to disable the feature, '1' for
         'smart' autocall, where it is not applied if there are no more
         arguments on the line, and '2' for 'full' autocall, where all callable
         objects are automatically called (even if no arguments are present).
         """
     )
     # TODO: remove all autoindent logic and put into frontends.
     # We can't do this yet because even runlines uses the autoindent.
     autoindent = CBool(True, config=True, help=
         """
         Autoindent IPython code entered interactively.
         """
     )
     automagic = CBool(True, config=True, help=
         """
         Enable magic commands to be called without the leading %.
         """
     )
     cache_size = Integer(1000, config=True, help=
         """
         Set the size of the output cache.  The default is 1000, you can
         change it permanently in your config file.  Setting it to 0 completely
         disables the caching system, and the minimum value accepted is 20 (if
         you provide a value less than 20, it is reset to 0 and a warning is
         issued).  This limit is defined because otherwise you'll spend more
         time re-flushing a too small cache than working
         """
     )
     color_info = CBool(True, config=True, help=
         """
         Use colors for displaying information about objects. Because this
         information is passed through a pager (like 'less'), and some pagers
         get confused with color codes, this capability can be turned off.
         """
     )
     colors = CaselessStrEnum(('NoColor','LightBG','Linux'),
                              default_value=get_default_colors(), config=True,
         help="Set the color scheme (NoColor, Linux, or LightBG)."
     )
     colors_force = CBool(False, help=
         """
         Force use of ANSI color codes, regardless of OS and readline
         availability.
         """
         # FIXME: This is essentially a hack to allow ZMQShell to show colors
         # without readline on Win32. When the ZMQ formatting system is
         # refactored, this should be removed.
     )
     debug = CBool(False, config=True)
     deep_reload = CBool(False, config=True, help=
         """
         Enable deep (recursive) reloading by default. IPython can use the
         deep_reload module which reloads changes in modules recursively (it
         replaces the reload() function, so you don't need to change anything to
         use it). deep_reload() forces a full reload of modules whose code may
         have changed, which the default reload() function does not.  When
         deep_reload is off, IPython will use the normal reload(), but
         deep_reload will still be available as dreload().
         """
     )
     disable_failing_post_execute = CBool(False, config=True,
         help="Don't call post-execute functions that have failed in the past."
     )
     display_formatter = Instance(DisplayFormatter)
     displayhook_class = Type(DisplayHook)
     display_pub_class = Type(DisplayPublisher)
     data_pub_class = None
 
     exit_now = CBool(False)
     exiter = Instance(ExitAutocall)
     def _exiter_default(self):
         return ExitAutocall(self)
     # Monotonically increasing execution counter
     execution_count = Integer(1)
     filename = Unicode("<ipython console>")
     ipython_dir= Unicode('', config=True) # Set to get_ipython_dir() in __init__
 
     # Input splitter, to split entire cells of input into either individual
     # interactive statements or whole blocks.
     input_splitter = Instance('IPython.core.inputsplitter.IPythonInputSplitter',
                               (), {})
     logstart = CBool(False, config=True, help=
         """
         Start logging to the default log file.
         """
     )
     logfile = Unicode('', config=True, help=
         """
         The name of the logfile to use.
         """
     )
     logappend = Unicode('', config=True, help=
         """
         Start logging to the given file in append mode.
         """
     )
     object_info_string_level = Enum((0,1,2), default_value=0,
                                     config=True)
     pdb = CBool(False, config=True, help=
         """
         Automatically call the pdb debugger after every exception.
         """
     )
     multiline_history = CBool(sys.platform != 'win32', config=True,
         help="Save multi-line entries as one entry in readline history"
     )
 
     # deprecated prompt traits:
     
     prompt_in1 = Unicode('In [\\#]: ', config=True,
         help="Deprecated, use PromptManager.in_template")
     prompt_in2 = Unicode('   .\\D.: ', config=True,
         help="Deprecated, use PromptManager.in2_template")
     prompt_out = Unicode('Out[\\#]: ', config=True,
         help="Deprecated, use PromptManager.out_template")
     prompts_pad_left = CBool(True, config=True,
         help="Deprecated, use PromptManager.justify")
     
     def _prompt_trait_changed(self, name, old, new):
         table = {
             'prompt_in1' : 'in_template',
             'prompt_in2' : 'in2_template',
             'prompt_out' : 'out_template',
             'prompts_pad_left' : 'justify',
         }
         warn("InteractiveShell.{name} is deprecated, use PromptManager.{newname}\n".format(
                 name=name, newname=table[name])
         )
         # protect against weird cases where self.config may not exist:
         if self.config is not None:
             # propagate to corresponding PromptManager trait
             setattr(self.config.PromptManager, table[name], new)
     
     _prompt_in1_changed = _prompt_trait_changed
     _prompt_in2_changed = _prompt_trait_changed
     _prompt_out_changed = _prompt_trait_changed
     _prompt_pad_left_changed = _prompt_trait_changed
     
     show_rewritten_input = CBool(True, config=True,
         help="Show rewritten input, e.g. for autocall."
     )
     
     quiet = CBool(False, config=True)
 
     history_length = Integer(10000, config=True)
 
     # The readline stuff will eventually be moved to the terminal subclass
     # but for now, we can't do that as readline is welded in everywhere.
     readline_use = CBool(True, config=True)
     readline_remove_delims = Unicode('-/~', config=True)
     # don't use \M- bindings by default, because they
     # conflict with 8-bit encodings. See gh-58,gh-88
     readline_parse_and_bind = List([
             'tab: complete',
             '"\C-l": clear-screen',
             'set show-all-if-ambiguous on',
             '"\C-o": tab-insert',
             '"\C-r": reverse-search-history',
             '"\C-s": forward-search-history',
             '"\C-p": history-search-backward',
             '"\C-n": history-search-forward',
             '"\e[A": history-search-backward',
             '"\e[B": history-search-forward',
             '"\C-k": kill-line',
             '"\C-u": unix-line-discard',
         ], allow_none=False, config=True)
 
     ast_node_interactivity = Enum(['all', 'last', 'last_expr', 'none'],
                                   default_value='last_expr', config=True, 
                                   help="""
         'all', 'last', 'last_expr' or 'none', specifying which nodes should be
         run interactively (displaying output from expressions).""")
 
     # TODO: this part of prompt management should be moved to the frontends.
     # Use custom TraitTypes that convert '0'->'' and '\\n'->'\n'
     separate_in = SeparateUnicode('\n', config=True)
     separate_out = SeparateUnicode('', config=True)
     separate_out2 = SeparateUnicode('', config=True)
     wildcards_case_sensitive = CBool(True, config=True)
     xmode = CaselessStrEnum(('Context','Plain', 'Verbose'),
                             default_value='Context', config=True)
 
     # Subcomponents of InteractiveShell
     alias_manager = Instance('IPython.core.alias.AliasManager')
     prefilter_manager = Instance('IPython.core.prefilter.PrefilterManager')
     builtin_trap = Instance('IPython.core.builtin_trap.BuiltinTrap')
     display_trap = Instance('IPython.core.display_trap.DisplayTrap')
     extension_manager = Instance('IPython.core.extensions.ExtensionManager')
     plugin_manager = Instance('IPython.core.plugin.PluginManager')
     payload_manager = Instance('IPython.core.payload.PayloadManager')
     history_manager = Instance('IPython.core.history.HistoryManager')
     magics_manager = Instance('IPython.core.magic.MagicsManager')
 
     profile_dir = Instance('IPython.core.application.ProfileDir')
     @property
     def profile(self):
         if self.profile_dir is not None:
             name = os.path.basename(self.profile_dir.location)
             return name.replace('profile_','')
 
 
     # Private interface
     _post_execute = Instance(dict)
 
     # Tracks any GUI loop loaded for pylab
     pylab_gui_select = None
 
     def __init__(self, config=None, ipython_dir=None, profile_dir=None,
                  user_module=None, user_ns=None,
                  custom_exceptions=((), None)):
 
         # This is where traits with a config_key argument are updated
         # from the values on config.
         super(InteractiveShell, self).__init__(config=config)
         self.configurables = [self]
 
         # These are relatively independent and stateless
         self.init_ipython_dir(ipython_dir)
         self.init_profile_dir(profile_dir)
         self.init_instance_attrs()
         self.init_environment()
         
         # Check if we're in a virtualenv, and set up sys.path.
         self.init_virtualenv()
 
         # Create namespaces (user_ns, user_global_ns, etc.)
         self.init_create_namespaces(user_module, user_ns)
         # This has to be done after init_create_namespaces because it uses
         # something in self.user_ns, but before init_sys_modules, which
         # is the first thing to modify sys.
         # TODO: When we override sys.stdout and sys.stderr before this class
         # is created, we are saving the overridden ones here. Not sure if this
         # is what we want to do.
         self.save_sys_module_state()
         self.init_sys_modules()
 
         # While we're trying to have each part of the code directly access what
         # it needs without keeping redundant references to objects, we have too
         # much legacy code that expects ip.db to exist.
         self.db = PickleShareDB(os.path.join(self.profile_dir.location, 'db'))
 
         self.init_history()
         self.init_encoding()
         self.init_prefilter()
 
         self.init_syntax_highlighting()
         self.init_hooks()
         self.init_pushd_popd_magic()
         # self.init_traceback_handlers use to be here, but we moved it below
         # because it and init_io have to come after init_readline.
         self.init_user_ns()
         self.init_logger()
         self.init_alias()
         self.init_builtins()
 
         # The following was in post_config_initialization
         self.init_inspector()
         # init_readline() must come before init_io(), because init_io uses
         # readline related things.
         self.init_readline()
         # We save this here in case user code replaces raw_input, but it needs
         # to be after init_readline(), because PyPy's readline works by replacing
         # raw_input.
         if py3compat.PY3:
             self.raw_input_original = input
         else:
             self.raw_input_original = raw_input
         # init_completer must come after init_readline, because it needs to
         # know whether readline is present or not system-wide to configure the
         # completers, since the completion machinery can now operate
         # independently of readline (e.g. over the network)
         self.init_completer()
         # TODO: init_io() needs to happen before init_traceback handlers
         # because the traceback handlers hardcode the stdout/stderr streams.
         # This logic in in debugger.Pdb and should eventually be changed.
         self.init_io()
         self.init_traceback_handlers(custom_exceptions)
         self.init_prompts()
         self.init_display_formatter()
         self.init_display_pub()
         self.init_data_pub()
         self.init_displayhook()
         self.init_reload_doctest()
         self.init_latextool()
         self.init_magics()
         self.init_logstart()
         self.init_pdb()
         self.init_extension_manager()
         self.init_plugin_manager()
         self.init_payload()
         self.hooks.late_startup_hook()
         atexit.register(self.atexit_operations)
 
     def get_ipython(self):
         """Return the currently running IPython instance."""
         return self
 
     #-------------------------------------------------------------------------
     # Trait changed handlers
     #-------------------------------------------------------------------------
 
     def _ipython_dir_changed(self, name, new):
         if not os.path.isdir(new):
-            os.makedirs(new, mode = 0777)
+            os.makedirs(new, mode = 0o777)
 
     def set_autoindent(self,value=None):
         """Set the autoindent flag, checking for readline support.
 
         If called with no arguments, it acts as a toggle."""
 
         if value != 0 and not self.has_readline:
             if os.name == 'posix':
                 warn("The auto-indent feature requires the readline library")
             self.autoindent = 0
             return
         if value is None:
             self.autoindent = not self.autoindent
         else:
             self.autoindent = value
 
     #-------------------------------------------------------------------------
     # init_* methods called by __init__
     #-------------------------------------------------------------------------
 
     def init_ipython_dir(self, ipython_dir):
         if ipython_dir is not None:
             self.ipython_dir = ipython_dir
             return
 
         self.ipython_dir = get_ipython_dir()
 
     def init_profile_dir(self, profile_dir):
         if profile_dir is not None:
             self.profile_dir = profile_dir
             return
         self.profile_dir =\
             ProfileDir.create_profile_dir_by_name(self.ipython_dir, 'default')
 
     def init_instance_attrs(self):
         self.more = False
 
         # command compiler
         self.compile = CachingCompiler()
 
         # Make an empty namespace, which extension writers can rely on both
         # existing and NEVER being used by ipython itself.  This gives them a
         # convenient location for storing additional information and state
         # their extensions may require, without fear of collisions with other
         # ipython names that may develop later.
         self.meta = Struct()
 
         # Temporary files used for various purposes.  Deleted at exit.
         self.tempfiles = []
 
         # Keep track of readline usage (later set by init_readline)
         self.has_readline = False
 
         # keep track of where we started running (mainly for crash post-mortem)
         # This is not being used anywhere currently.
         self.starting_dir = os.getcwdu()
 
         # Indentation management
         self.indent_current_nsp = 0
 
         # Dict to track post-execution functions that have been registered
         self._post_execute = {}
 
     def init_environment(self):
         """Any changes we need to make to the user's environment."""
         pass
 
     def init_encoding(self):
         # Get system encoding at startup time.  Certain terminals (like Emacs
         # under Win32 have it set to None, and we need to have a known valid
         # encoding to use in the raw_input() method
         try:
             self.stdin_encoding = sys.stdin.encoding or 'ascii'
         except AttributeError:
             self.stdin_encoding = 'ascii'
 
     def init_syntax_highlighting(self):
         # Python source parser/formatter for syntax highlighting
         pyformat = PyColorize.Parser().format
         self.pycolorize = lambda src: pyformat(src,'str',self.colors)
 
     def init_pushd_popd_magic(self):
         # for pushd/popd management
         self.home_dir = get_home_dir()
 
         self.dir_stack = []
 
     def init_logger(self):
         self.logger = Logger(self.home_dir, logfname='ipython_log.py',
                              logmode='rotate')
 
     def init_logstart(self):
         """Initialize logging in case it was requested at the command line.
         """
         if self.logappend:
             self.magic('logstart %s append' % self.logappend)
         elif self.logfile:
             self.magic('logstart %s' % self.logfile)
         elif self.logstart:
             self.magic('logstart')
 
     def init_builtins(self):
         # A single, static flag that we set to True.  Its presence indicates
         # that an IPython shell has been created, and we make no attempts at
         # removing on exit or representing the existence of more than one
         # IPython at a time.
         builtin_mod.__dict__['__IPYTHON__'] = True
 
         # In 0.11 we introduced '__IPYTHON__active' as an integer we'd try to
         # manage on enter/exit, but with all our shells it's virtually
         # impossible to get all the cases right.  We're leaving the name in for
         # those who adapted their codes to check for this flag, but will
         # eventually remove it after a few more releases.
         builtin_mod.__dict__['__IPYTHON__active'] = \
                                           'Deprecated, check for __IPYTHON__'
 
         self.builtin_trap = BuiltinTrap(shell=self)
 
     def init_inspector(self):
         # Object inspector
         self.inspector = oinspect.Inspector(oinspect.InspectColors,
                                             PyColorize.ANSICodeColors,
                                             'NoColor',
                                             self.object_info_string_level)
 
     def init_io(self):
         # This will just use sys.stdout and sys.stderr. If you want to
         # override sys.stdout and sys.stderr themselves, you need to do that
         # *before* instantiating this class, because io holds onto
         # references to the underlying streams.
         if sys.platform == 'win32' and self.has_readline:
             io.stdout = io.stderr = io.IOStream(self.readline._outputfile)
         else:
             io.stdout = io.IOStream(sys.stdout)
             io.stderr = io.IOStream(sys.stderr)
 
     def init_prompts(self):
         self.prompt_manager = PromptManager(shell=self, config=self.config)
         self.configurables.append(self.prompt_manager)
         # Set system prompts, so that scripts can decide if they are running
         # interactively.
         sys.ps1 = 'In : '
         sys.ps2 = '...: '
         sys.ps3 = 'Out: '
 
     def init_display_formatter(self):
         self.display_formatter = DisplayFormatter(config=self.config)
         self.configurables.append(self.display_formatter)
 
     def init_display_pub(self):
         self.display_pub = self.display_pub_class(config=self.config)
         self.configurables.append(self.display_pub)
 
     def init_data_pub(self):
         if not self.data_pub_class:
             self.data_pub = None
             return
         self.data_pub = self.data_pub_class(config=self.config)
         self.configurables.append(self.data_pub)
 
     def init_displayhook(self):
         # Initialize displayhook, set in/out prompts and printing system
         self.displayhook = self.displayhook_class(
             config=self.config,
             shell=self,
             cache_size=self.cache_size,
         )
         self.configurables.append(self.displayhook)
         # This is a context manager that installs/revmoes the displayhook at
         # the appropriate time.
         self.display_trap = DisplayTrap(hook=self.displayhook)
 
     def init_reload_doctest(self):
         # Do a proper resetting of doctest, including the necessary displayhook
         # monkeypatching
         try:
             doctest_reload()
         except ImportError:
             warn("doctest module does not exist.")
 
     def init_latextool(self):
         """Configure LaTeXTool."""
         cfg = LaTeXTool.instance(config=self.config)
         if cfg not in self.configurables:
             self.configurables.append(cfg)
 
     def init_virtualenv(self):
         """Add a virtualenv to sys.path so the user can import modules from it.
         This isn't perfect: it doesn't use the Python interpreter with which the
         virtualenv was built, and it ignores the --no-site-packages option. A
         warning will appear suggesting the user installs IPython in the
         virtualenv, but for many cases, it probably works well enough.
         
         Adapted from code snippets online.
         
         http://blog.ufsoft.org/2009/1/29/ipython-and-virtualenv
         """
         if 'VIRTUAL_ENV' not in os.environ:
             # Not in a virtualenv
             return
         
         if sys.executable.startswith(os.environ['VIRTUAL_ENV']):
             # Running properly in the virtualenv, don't need to do anything
             return
         
         warn("Attempting to work in a virtualenv. If you encounter problems, please "
              "install IPython inside the virtualenv.\n")
         if sys.platform == "win32":
             virtual_env = os.path.join(os.environ['VIRTUAL_ENV'], 'Lib', 'site-packages') 
         else:
             virtual_env = os.path.join(os.environ['VIRTUAL_ENV'], 'lib',
                        'python%d.%d' % sys.version_info[:2], 'site-packages')
         
         import site
         sys.path.insert(0, virtual_env)
         site.addsitedir(virtual_env)
 
     #-------------------------------------------------------------------------
     # Things related to injections into the sys module
     #-------------------------------------------------------------------------
 
     def save_sys_module_state(self):
         """Save the state of hooks in the sys module.
 
         This has to be called after self.user_module is created.
         """
         self._orig_sys_module_state = {}
         self._orig_sys_module_state['stdin'] = sys.stdin
         self._orig_sys_module_state['stdout'] = sys.stdout
         self._orig_sys_module_state['stderr'] = sys.stderr
         self._orig_sys_module_state['excepthook'] = sys.excepthook
         self._orig_sys_modules_main_name = self.user_module.__name__
         self._orig_sys_modules_main_mod = sys.modules.get(self.user_module.__name__)
 
     def restore_sys_module_state(self):
         """Restore the state of the sys module."""
         try:
             for k, v in self._orig_sys_module_state.iteritems():
                 setattr(sys, k, v)
         except AttributeError:
             pass
         # Reset what what done in self.init_sys_modules
         if self._orig_sys_modules_main_mod is not None:
             sys.modules[self._orig_sys_modules_main_name] = self._orig_sys_modules_main_mod
 
     #-------------------------------------------------------------------------
     # Things related to hooks
     #-------------------------------------------------------------------------
 
     def init_hooks(self):
         # hooks holds pointers used for user-side customizations
         self.hooks = Struct()
 
         self.strdispatchers = {}
 
         # Set all default hooks, defined in the IPython.hooks module.
         hooks = IPython.core.hooks
         for hook_name in hooks.__all__:
             # default hooks have priority 100, i.e. low; user hooks should have
             # 0-100 priority
             self.set_hook(hook_name,getattr(hooks,hook_name), 100)
 
     def set_hook(self,name,hook, priority = 50, str_key = None, re_key = None):
         """set_hook(name,hook) -> sets an internal IPython hook.
 
         IPython exposes some of its internal API as user-modifiable hooks.  By
         adding your function to one of these hooks, you can modify IPython's
         behavior to call at runtime your own routines."""
 
         # At some point in the future, this should validate the hook before it
         # accepts it.  Probably at least check that the hook takes the number
         # of args it's supposed to.
 
         f = types.MethodType(hook,self)
 
         # check if the hook is for strdispatcher first
         if str_key is not None:
             sdp = self.strdispatchers.get(name, StrDispatch())
             sdp.add_s(str_key, f, priority )
             self.strdispatchers[name] = sdp
             return
         if re_key is not None:
             sdp = self.strdispatchers.get(name, StrDispatch())
             sdp.add_re(re.compile(re_key), f, priority )
             self.strdispatchers[name] = sdp
             return
 
         dp = getattr(self.hooks, name, None)
         if name not in IPython.core.hooks.__all__:
             print("Warning! Hook '%s' is not one of %s" % \
                   (name, IPython.core.hooks.__all__ ))
         if not dp:
             dp = IPython.core.hooks.CommandChainDispatcher()
 
         try:
             dp.add(f,priority)
         except AttributeError:
             # it was not commandchain, plain old func - replace
             dp = f
 
         setattr(self.hooks,name, dp)
 
     def register_post_execute(self, func):
         """Register a function for calling after code execution.
         """
         if not callable(func):
             raise ValueError('argument %s must be callable' % func)
         self._post_execute[func] = True
     
     #-------------------------------------------------------------------------
     # Things related to the "main" module
     #-------------------------------------------------------------------------
 
     def new_main_mod(self,ns=None):
         """Return a new 'main' module object for user code execution.
         """
         main_mod = self._user_main_module
         init_fakemod_dict(main_mod,ns)
         return main_mod
 
     def cache_main_mod(self,ns,fname):
         """Cache a main module's namespace.
 
         When scripts are executed via %run, we must keep a reference to the
         namespace of their __main__ module (a FakeModule instance) around so
         that Python doesn't clear it, rendering objects defined therein
         useless.
 
         This method keeps said reference in a private dict, keyed by the
         absolute path of the module object (which corresponds to the script
         path).  This way, for multiple executions of the same script we only
         keep one copy of the namespace (the last one), thus preventing memory
         leaks from old references while allowing the objects from the last
         execution to be accessible.
 
         Note: we can not allow the actual FakeModule instances to be deleted,
         because of how Python tears down modules (it hard-sets all their
         references to None without regard for reference counts).  This method
         must therefore make a *copy* of the given namespace, to allow the
         original module's __dict__ to be cleared and reused.
 
 
         Parameters
         ----------
           ns : a namespace (a dict, typically)
 
           fname : str
             Filename associated with the namespace.
 
         Examples
         --------
 
         In [10]: import IPython
 
         In [11]: _ip.cache_main_mod(IPython.__dict__,IPython.__file__)
 
         In [12]: IPython.__file__ in _ip._main_ns_cache
         Out[12]: True
         """
         self._main_ns_cache[os.path.abspath(fname)] = ns.copy()
 
     def clear_main_mod_cache(self):
         """Clear the cache of main modules.
 
         Mainly for use by utilities like %reset.
 
         Examples
         --------
 
         In [15]: import IPython
 
         In [16]: _ip.cache_main_mod(IPython.__dict__,IPython.__file__)
 
         In [17]: len(_ip._main_ns_cache) > 0
         Out[17]: True
 
         In [18]: _ip.clear_main_mod_cache()
 
         In [19]: len(_ip._main_ns_cache) == 0
         Out[19]: True
         """
         self._main_ns_cache.clear()
 
     #-------------------------------------------------------------------------
     # Things related to debugging
     #-------------------------------------------------------------------------
 
     def init_pdb(self):
         # Set calling of pdb on exceptions
         # self.call_pdb is a property
         self.call_pdb = self.pdb
 
     def _get_call_pdb(self):
         return self._call_pdb
 
     def _set_call_pdb(self,val):
 
         if val not in (0,1,False,True):
             raise ValueError('new call_pdb value must be boolean')
 
         # store value in instance
         self._call_pdb = val
 
         # notify the actual exception handlers
         self.InteractiveTB.call_pdb = val
 
     call_pdb = property(_get_call_pdb,_set_call_pdb,None,
                         'Control auto-activation of pdb at exceptions')
 
     def debugger(self,force=False):
         """Call the pydb/pdb debugger.
 
         Keywords:
 
           - force(False): by default, this routine checks the instance call_pdb
           flag and does not actually invoke the debugger if the flag is false.
           The 'force' option forces the debugger to activate even if the flag
           is false.
         """
 
         if not (force or self.call_pdb):
             return
 
         if not hasattr(sys,'last_traceback'):
             error('No traceback has been produced, nothing to debug.')
             return
 
         # use pydb if available
         if debugger.has_pydb:
             from pydb import pm
         else:
             # fallback to our internal debugger
             pm = lambda : self.InteractiveTB.debugger(force=True)
 
         with self.readline_no_record:
             pm()
 
     #-------------------------------------------------------------------------
     # Things related to IPython's various namespaces
     #-------------------------------------------------------------------------
     default_user_namespaces = True
 
     def init_create_namespaces(self, user_module=None, user_ns=None):
         # Create the namespace where the user will operate.  user_ns is
         # normally the only one used, and it is passed to the exec calls as
         # the locals argument.  But we do carry a user_global_ns namespace
         # given as the exec 'globals' argument,  This is useful in embedding
         # situations where the ipython shell opens in a context where the
         # distinction between locals and globals is meaningful.  For
         # non-embedded contexts, it is just the same object as the user_ns dict.
 
         # FIXME. For some strange reason, __builtins__ is showing up at user
         # level as a dict instead of a module. This is a manual fix, but I
         # should really track down where the problem is coming from. Alex
         # Schmolck reported this problem first.
 
         # A useful post by Alex Martelli on this topic:
         # Re: inconsistent value from __builtins__
         # Von: Alex Martelli <[e-mail]>
         # Datum: Freitag 01 Oktober 2004 04:45:34 nachmittags/abends
         # Gruppen: comp.lang.python
 
         # Michael Hohn <[e-mail]> wrote:
         # > >>> print type(builtin_check.get_global_binding('__builtins__'))
         # > <type 'dict'>
         # > >>> print type(__builtins__)
         # > <type 'module'>
         # > Is this difference in return value intentional?
 
         # Well, it's documented that '__builtins__' can be either a dictionary
         # or a module, and it's been that way for a long time. Whether it's
         # intentional (or sensible), I don't know. In any case, the idea is
         # that if you need to access the built-in namespace directly, you
         # should start with "import __builtin__" (note, no 's') which will
         # definitely give you a module. Yeah, it's somewhat confusing:-(.
 
         # These routines return a properly built module and dict as needed by
         # the rest of the code, and can also be used by extension writers to
         # generate properly initialized namespaces.
         if (user_ns is not None) or (user_module is not None):
             self.default_user_namespaces = False
         self.user_module, self.user_ns = self.prepare_user_module(user_module, user_ns)
 
         # A record of hidden variables we have added to the user namespace, so
         # we can list later only variables defined in actual interactive use.
         self.user_ns_hidden = set()
 
         # Now that FakeModule produces a real module, we've run into a nasty
         # problem: after script execution (via %run), the module where the user
         # code ran is deleted.  Now that this object is a true module (needed
         # so docetst and other tools work correctly), the Python module
         # teardown mechanism runs over it, and sets to None every variable
         # present in that module.  Top-level references to objects from the
         # script survive, because the user_ns is updated with them.  However,
         # calling functions defined in the script that use other things from
         # the script will fail, because the function's closure had references
         # to the original objects, which are now all None.  So we must protect
         # these modules from deletion by keeping a cache.
         #
         # To avoid keeping stale modules around (we only need the one from the
         # last run), we use a dict keyed with the full path to the script, so
         # only the last version of the module is held in the cache.  Note,
         # however, that we must cache the module *namespace contents* (their
         # __dict__).  Because if we try to cache the actual modules, old ones
         # (uncached) could be destroyed while still holding references (such as
         # those held by GUI objects that tend to be long-lived)>
         #
         # The %reset command will flush this cache.  See the cache_main_mod()
         # and clear_main_mod_cache() methods for details on use.
 
         # This is the cache used for 'main' namespaces
         self._main_ns_cache = {}
         # And this is the single instance of FakeModule whose __dict__ we keep
         # copying and clearing for reuse on each %run
         self._user_main_module = FakeModule()
 
         # A table holding all the namespaces IPython deals with, so that
         # introspection facilities can search easily.
         self.ns_table = {'user_global':self.user_module.__dict__,
                          'user_local':self.user_ns,
                          'builtin':builtin_mod.__dict__
                          }
     
     @property
     def user_global_ns(self):
         return self.user_module.__dict__
 
     def prepare_user_module(self, user_module=None, user_ns=None):
         """Prepare the module and namespace in which user code will be run.
         
         When IPython is started normally, both parameters are None: a new module
         is created automatically, and its __dict__ used as the namespace.
         
         If only user_module is provided, its __dict__ is used as the namespace.
         If only user_ns is provided, a dummy module is created, and user_ns
         becomes the global namespace. If both are provided (as they may be
         when embedding), user_ns is the local namespace, and user_module
         provides the global namespace.
 
         Parameters
         ----------
         user_module : module, optional
             The current user module in which IPython is being run. If None,
             a clean module will be created.
         user_ns : dict, optional
             A namespace in which to run interactive commands.
 
         Returns
         -------
         A tuple of user_module and user_ns, each properly initialised.
         """
         if user_module is None and user_ns is not None:
             user_ns.setdefault("__name__", "__main__")
             class DummyMod(object):
                 "A dummy module used for IPython's interactive namespace."
                 pass
             user_module = DummyMod()
             user_module.__dict__ = user_ns
             
         if user_module is None:
             user_module = types.ModuleType("__main__",
                 doc="Automatically created module for IPython interactive environment")
         
         # We must ensure that __builtin__ (without the final 's') is always
         # available and pointing to the __builtin__ *module*.  For more details:
         # http://mail.python.org/pipermail/python-dev/2001-April/014068.html
         user_module.__dict__.setdefault('__builtin__', builtin_mod)
         user_module.__dict__.setdefault('__builtins__', builtin_mod)
         
         if user_ns is None:
             user_ns = user_module.__dict__
 
         return user_module, user_ns
 
     def init_sys_modules(self):
         # We need to insert into sys.modules something that looks like a
         # module but which accesses the IPython namespace, for shelve and
         # pickle to work interactively. Normally they rely on getting
         # everything out of __main__, but for embedding purposes each IPython
         # instance has its own private namespace, so we can't go shoving
         # everything into __main__.
 
         # note, however, that we should only do this for non-embedded
         # ipythons, which really mimic the __main__.__dict__ with their own
         # namespace.  Embedded instances, on the other hand, should not do
         # this because they need to manage the user local/global namespaces
         # only, but they live within a 'normal' __main__ (meaning, they
         # shouldn't overtake the execution environment of the script they're
         # embedded in).
 
         # This is overridden in the InteractiveShellEmbed subclass to a no-op.
         main_name = self.user_module.__name__
         sys.modules[main_name] = self.user_module
 
     def init_user_ns(self):
         """Initialize all user-visible namespaces to their minimum defaults.
 
         Certain history lists are also initialized here, as they effectively
         act as user namespaces.
 
         Notes
         -----
         All data structures here are only filled in, they are NOT reset by this
         method.  If they were not empty before, data will simply be added to
         therm.
         """
         # This function works in two parts: first we put a few things in
         # user_ns, and we sync that contents into user_ns_hidden so that these
         # initial variables aren't shown by %who.  After the sync, we add the
         # rest of what we *do* want the user to see with %who even on a new
         # session (probably nothing, so theye really only see their own stuff)
 
         # The user dict must *always* have a __builtin__ reference to the
         # Python standard __builtin__ namespace,  which must be imported.
         # This is so that certain operations in prompt evaluation can be
         # reliably executed with builtins.  Note that we can NOT use
         # __builtins__ (note the 's'),  because that can either be a dict or a
         # module, and can even mutate at runtime, depending on the context
         # (Python makes no guarantees on it).  In contrast, __builtin__ is
         # always a module object, though it must be explicitly imported.
 
         # For more details:
         # http://mail.python.org/pipermail/python-dev/2001-April/014068.html
         ns = dict()
         
         # Put 'help' in the user namespace
         try:
             from site import _Helper
             ns['help'] = _Helper()
         except ImportError:
             warn('help() not available - check site.py')
 
         # make global variables for user access to the histories
         ns['_ih'] = self.history_manager.input_hist_parsed
         ns['_oh'] = self.history_manager.output_hist
         ns['_dh'] = self.history_manager.dir_hist
 
         ns['_sh'] = shadowns
 
         # user aliases to input and output histories.  These shouldn't show up
         # in %who, as they can have very large reprs.
         ns['In']  = self.history_manager.input_hist_parsed
         ns['Out'] = self.history_manager.output_hist
 
         # Store myself as the public api!!!
         ns['get_ipython'] = self.get_ipython
         
         ns['exit'] = self.exiter
         ns['quit'] = self.exiter
 
         # Sync what we've added so far to user_ns_hidden so these aren't seen
         # by %who
         self.user_ns_hidden.update(ns)
 
         # Anything put into ns now would show up in %who.  Think twice before
         # putting anything here, as we really want %who to show the user their
         # stuff, not our variables.
 
         # Finally, update the real user's namespace
         self.user_ns.update(ns)
     
     @property
     def all_ns_refs(self):
         """Get a list of references to all the namespace dictionaries in which
         IPython might store a user-created object.
         
         Note that this does not include the displayhook, which also caches
         objects from the output."""
         return [self.user_ns, self.user_global_ns,
                 self._user_main_module.__dict__] + self._main_ns_cache.values()
 
     def reset(self, new_session=True):
         """Clear all internal namespaces, and attempt to release references to
         user objects.
 
         If new_session is True, a new history session will be opened.
         """
         # Clear histories
         self.history_manager.reset(new_session)
         # Reset counter used to index all histories
         if new_session:
             self.execution_count = 1
 
         # Flush cached output items
         if self.displayhook.do_full_cache:
             self.displayhook.flush()
 
         # The main execution namespaces must be cleared very carefully,
         # skipping the deletion of the builtin-related keys, because doing so
         # would cause errors in many object's __del__ methods.
         if self.user_ns is not self.user_global_ns:
             self.user_ns.clear()
         ns = self.user_global_ns
         drop_keys = set(ns.keys())
         drop_keys.discard('__builtin__')
         drop_keys.discard('__builtins__')
         drop_keys.discard('__name__')
         for k in drop_keys:
             del ns[k]
         
         self.user_ns_hidden.clear()
         
         # Restore the user namespaces to minimal usability
         self.init_user_ns()
 
         # Restore the default and user aliases
         self.alias_manager.clear_aliases()
         self.alias_manager.init_aliases()
 
         # Flush the private list of module references kept for script
         # execution protection
         self.clear_main_mod_cache()
 
         # Clear out the namespace from the last %run
         self.new_main_mod()
 
     def del_var(self, varname, by_name=False):
         """Delete a variable from the various namespaces, so that, as
         far as possible, we're not keeping any hidden references to it.
 
         Parameters
         ----------
         varname : str
             The name of the variable to delete.
         by_name : bool
             If True, delete variables with the given name in each
             namespace. If False (default), find the variable in the user
             namespace, and delete references to it.
         """
         if varname in ('__builtin__', '__builtins__'):
             raise ValueError("Refusing to delete %s" % varname)
 
         ns_refs = self.all_ns_refs
         
         if by_name:                    # Delete by name
             for ns in ns_refs:
                 try:
                     del ns[varname]
                 except KeyError:
                     pass
         else:                         # Delete by object
             try:
                 obj = self.user_ns[varname]
             except KeyError:
                 raise NameError("name '%s' is not defined" % varname)
             # Also check in output history
             ns_refs.append(self.history_manager.output_hist)
             for ns in ns_refs:
                 to_delete = [n for n, o in ns.iteritems() if o is obj]
                 for name in to_delete:
                     del ns[name]
 
             # displayhook keeps extra references, but not in a dictionary
             for name in ('_', '__', '___'):
                 if getattr(self.displayhook, name) is obj:
                     setattr(self.displayhook, name, None)
 
     def reset_selective(self, regex=None):
         """Clear selective variables from internal namespaces based on a
         specified regular expression.
 
         Parameters
         ----------
         regex : string or compiled pattern, optional
             A regular expression pattern that will be used in searching
             variable names in the users namespaces.
         """
         if regex is not None:
             try:
                 m = re.compile(regex)
             except TypeError:
                 raise TypeError('regex must be a string or compiled pattern')
             # Search for keys in each namespace that match the given regex
             # If a match is found, delete the key/value pair.
             for ns in self.all_ns_refs:
                 for var in ns:
                     if m.search(var):
                         del ns[var]
 
     def push(self, variables, interactive=True):
         """Inject a group of variables into the IPython user namespace.
 
         Parameters
         ----------
         variables : dict, str or list/tuple of str
             The variables to inject into the user's namespace.  If a dict, a
             simple update is done.  If a str, the string is assumed to have
             variable names separated by spaces.  A list/tuple of str can also
             be used to give the variable names.  If just the variable names are
             give (list/tuple/str) then the variable values looked up in the
             callers frame.
         interactive : bool
             If True (default), the variables will be listed with the ``who``
             magic.
         """
         vdict = None
 
         # We need a dict of name/value pairs to do namespace updates.
         if isinstance(variables, dict):
             vdict = variables
         elif isinstance(variables, (basestring, list, tuple)):
             if isinstance(variables, basestring):
                 vlist = variables.split()
             else:
                 vlist = variables
             vdict = {}
             cf = sys._getframe(1)
             for name in vlist:
                 try:
                     vdict[name] = eval(name, cf.f_globals, cf.f_locals)
                 except:
                     print('Could not get variable %s from %s' %
                            (name,cf.f_code.co_name))
         else:
             raise ValueError('variables must be a dict/str/list/tuple')
 
         # Propagate variables to user namespace
         self.user_ns.update(vdict)
 
         # And configure interactive visibility
         user_ns_hidden = self.user_ns_hidden
         if interactive:
             user_ns_hidden.difference_update(vdict)
         else:
             user_ns_hidden.update(vdict)
     
     def drop_by_id(self, variables):
         """Remove a dict of variables from the user namespace, if they are the
         same as the values in the dictionary.
         
         This is intended for use by extensions: variables that they've added can
         be taken back out if they are unloaded, without removing any that the
         user has overwritten.
         
         Parameters
         ----------
         variables : dict
           A dictionary mapping object names (as strings) to the objects.
         """
         for name, obj in variables.iteritems():
             if name in self.user_ns and self.user_ns[name] is obj:
                 del self.user_ns[name]
                 self.user_ns_hidden.discard(name)
 
     #-------------------------------------------------------------------------
     # Things related to object introspection
     #-------------------------------------------------------------------------
 
     def _ofind(self, oname, namespaces=None):
         """Find an object in the available namespaces.
 
         self._ofind(oname) -> dict with keys: found,obj,ospace,ismagic
 
         Has special code to detect magic functions.
         """
         oname = oname.strip()
         #print '1- oname: <%r>' % oname  # dbg
         if not oname.startswith(ESC_MAGIC) and \
             not oname.startswith(ESC_MAGIC2) and \
             not py3compat.isidentifier(oname, dotted=True):
             return dict(found=False)
 
         alias_ns = None
         if namespaces is None:
             # Namespaces to search in:
             # Put them in a list. The order is important so that we
             # find things in the same order that Python finds them.
             namespaces = [ ('Interactive', self.user_ns),
                            ('Interactive (global)', self.user_global_ns),
                            ('Python builtin', builtin_mod.__dict__),
                            ('Alias', self.alias_manager.alias_table),
                            ]
             alias_ns = self.alias_manager.alias_table
 
         # initialize results to 'null'
         found = False; obj = None;  ospace = None;  ds = None;
         ismagic = False; isalias = False; parent = None
 
         # We need to special-case 'print', which as of python2.6 registers as a
         # function but should only be treated as one if print_function was
         # loaded with a future import.  In this case, just bail.
         if (oname == 'print' and not py3compat.PY3 and not \
             (self.compile.compiler_flags & __future__.CO_FUTURE_PRINT_FUNCTION)):
             return {'found':found, 'obj':obj, 'namespace':ospace,
                     'ismagic':ismagic, 'isalias':isalias, 'parent':parent}
 
         # Look for the given name by splitting it in parts.  If the head is
         # found, then we look for all the remaining parts as members, and only
         # declare success if we can find them all.
         oname_parts = oname.split('.')
         oname_head, oname_rest = oname_parts[0],oname_parts[1:]
         for nsname,ns in namespaces:
             try:
                 obj = ns[oname_head]
             except KeyError:
                 continue
             else:
                 #print 'oname_rest:', oname_rest  # dbg
                 for part in oname_rest:
                     try:
                         parent = obj
                         obj = getattr(obj,part)
                     except:
                         # Blanket except b/c some badly implemented objects
                         # allow __getattr__ to raise exceptions other than
                         # AttributeError, which then crashes IPython.
                         break
                 else:
                     # If we finish the for loop (no break), we got all members
                     found = True
                     ospace = nsname
                     if ns == alias_ns:
                         isalias = True
                     break  # namespace loop
 
         # Try to see if it's magic
         if not found:
             obj = None
             if oname.startswith(ESC_MAGIC2):
                 oname = oname.lstrip(ESC_MAGIC2)
                 obj = self.find_cell_magic(oname)
             elif oname.startswith(ESC_MAGIC):
                 oname = oname.lstrip(ESC_MAGIC)
                 obj = self.find_line_magic(oname)
             else:
                 # search without prefix, so run? will find %run?
                 obj = self.find_line_magic(oname)
                 if obj is None:
                     obj = self.find_cell_magic(oname)
             if obj is not None:
                 found = True
                 ospace = 'IPython internal'
                 ismagic = True
 
         # Last try: special-case some literals like '', [], {}, etc:
         if not found and oname_head in ["''",'""','[]','{}','()']:
             obj = eval(oname_head)
             found = True
             ospace = 'Interactive'
 
         return {'found':found, 'obj':obj, 'namespace':ospace,
                 'ismagic':ismagic, 'isalias':isalias, 'parent':parent}
 
     def _ofind_property(self, oname, info):
         """Second part of object finding, to look for property details."""
         if info.found:
             # Get the docstring of the class property if it exists.
             path = oname.split('.')
             root = '.'.join(path[:-1])
             if info.parent is not None:
                 try:
                     target = getattr(info.parent, '__class__')
                     # The object belongs to a class instance.
                     try:
                         target = getattr(target, path[-1])
                         # The class defines the object.
                         if isinstance(target, property):
                             oname = root + '.__class__.' + path[-1]
                             info = Struct(self._ofind(oname))
                     except AttributeError: pass
                 except AttributeError: pass
 
         # We return either the new info or the unmodified input if the object
         # hadn't been found
         return info
 
     def _object_find(self, oname, namespaces=None):
         """Find an object and return a struct with info about it."""
         inf = Struct(self._ofind(oname, namespaces))
         return Struct(self._ofind_property(oname, inf))
 
     def _inspect(self, meth, oname, namespaces=None, **kw):
         """Generic interface to the inspector system.
 
         This function is meant to be called by pdef, pdoc & friends."""
         info = self._object_find(oname, namespaces)
         if info.found:
             pmethod = getattr(self.inspector, meth)
             formatter = format_screen if info.ismagic else None
             if meth == 'pdoc':
                 pmethod(info.obj, oname, formatter)
             elif meth == 'pinfo':
                 pmethod(info.obj, oname, formatter, info, **kw)
             else:
                 pmethod(info.obj, oname)
         else:
             print('Object `%s` not found.' % oname)
             return 'not found'  # so callers can take other action
 
     def object_inspect(self, oname, detail_level=0):
         with self.builtin_trap:
             info = self._object_find(oname)
             if info.found:
                 return self.inspector.info(info.obj, oname, info=info,
                             detail_level=detail_level
                 )
             else:
                 return oinspect.object_info(name=oname, found=False)
 
     #-------------------------------------------------------------------------
     # Things related to history management
     #-------------------------------------------------------------------------
 
     def init_history(self):
         """Sets up the command history, and starts regular autosaves."""
         self.history_manager = HistoryManager(shell=self, config=self.config)
         self.configurables.append(self.history_manager)
 
     #-------------------------------------------------------------------------
     # Things related to exception handling and tracebacks (not debugging)
     #-------------------------------------------------------------------------
 
     def init_traceback_handlers(self, custom_exceptions):
         # Syntax error handler.
         self.SyntaxTB = ultratb.SyntaxTB(color_scheme='NoColor')
 
         # The interactive one is initialized with an offset, meaning we always
         # want to remove the topmost item in the traceback, which is our own
         # internal code. Valid modes: ['Plain','Context','Verbose']
         self.InteractiveTB = ultratb.AutoFormattedTB(mode = 'Plain',
                                                      color_scheme='NoColor',
                                                      tb_offset = 1,
                                    check_cache=self.compile.check_cache)
 
         # The instance will store a pointer to the system-wide exception hook,
         # so that runtime code (such as magics) can access it.  This is because
         # during the read-eval loop, it may get temporarily overwritten.
         self.sys_excepthook = sys.excepthook
 
         # and add any custom exception handlers the user may have specified
         self.set_custom_exc(*custom_exceptions)
 
         # Set the exception mode
         self.InteractiveTB.set_mode(mode=self.xmode)
 
     def set_custom_exc(self, exc_tuple, handler):
         """set_custom_exc(exc_tuple,handler)
 
         Set a custom exception handler, which will be called if any of the
         exceptions in exc_tuple occur in the mainloop (specifically, in the
         run_code() method).
 
         Parameters
         ----------
 
         exc_tuple : tuple of exception classes
             A *tuple* of exception classes, for which to call the defined
             handler.  It is very important that you use a tuple, and NOT A
             LIST here, because of the way Python's except statement works.  If
             you only want to trap a single exception, use a singleton tuple::
 
                 exc_tuple == (MyCustomException,)
 
         handler : callable
             handler must have the following signature::
 
                 def my_handler(self, etype, value, tb, tb_offset=None):
                     ...
                     return structured_traceback
 
             Your handler must return a structured traceback (a list of strings),
             or None.
 
             This will be made into an instance method (via types.MethodType)
             of IPython itself, and it will be called if any of the exceptions
             listed in the exc_tuple are caught. If the handler is None, an
             internal basic one is used, which just prints basic info.
 
             To protect IPython from crashes, if your handler ever raises an
             exception or returns an invalid result, it will be immediately
             disabled.
 
         WARNING: by putting in your own exception handler into IPython's main
         execution loop, you run a very good chance of nasty crashes.  This
         facility should only be used if you really know what you are doing."""
 
         assert type(exc_tuple)==type(()) , \
                "The custom exceptions must be given AS A TUPLE."
 
         def dummy_handler(self,etype,value,tb,tb_offset=None):
             print('*** Simple custom exception handler ***')
             print('Exception type :',etype)
             print('Exception value:',value)
             print('Traceback      :',tb)
             #print 'Source code    :','\n'.join(self.buffer)
         
         def validate_stb(stb):
             """validate structured traceback return type
             
             return type of CustomTB *should* be a list of strings, but allow
             single strings or None, which are harmless.
             
             This function will *always* return a list of strings,
             and will raise a TypeError if stb is inappropriate.
             """
             msg = "CustomTB must return list of strings, not %r" % stb
             if stb is None:
                 return []
             elif isinstance(stb, basestring):
                 return [stb]
             elif not isinstance(stb, list):
                 raise TypeError(msg)
             # it's a list
             for line in stb:
                 # check every element
                 if not isinstance(line, basestring):
                     raise TypeError(msg)
             return stb
 
         if handler is None:
             wrapped = dummy_handler
         else:
             def wrapped(self,etype,value,tb,tb_offset=None):
                 """wrap CustomTB handler, to protect IPython from user code
                 
                 This makes it harder (but not impossible) for custom exception
                 handlers to crash IPython.
                 """
                 try:
                     stb = handler(self,etype,value,tb,tb_offset=tb_offset)
                     return validate_stb(stb)
                 except:
                     # clear custom handler immediately
                     self.set_custom_exc((), None)
                     print("Custom TB Handler failed, unregistering", file=io.stderr)
                     # show the exception in handler first
                     stb = self.InteractiveTB.structured_traceback(*sys.exc_info())
                     print(self.InteractiveTB.stb2text(stb), file=io.stdout)
                     print("The original exception:", file=io.stdout)
                     stb = self.InteractiveTB.structured_traceback(
                                             (etype,value,tb), tb_offset=tb_offset
                     )
                 return stb
 
         self.CustomTB = types.MethodType(wrapped,self)
         self.custom_exceptions = exc_tuple
 
     def excepthook(self, etype, value, tb):
       """One more defense for GUI apps that call sys.excepthook.
 
       GUI frameworks like wxPython trap exceptions and call
       sys.excepthook themselves.  I guess this is a feature that
       enables them to keep running after exceptions that would
       otherwise kill their mainloop. This is a bother for IPython
       which excepts to catch all of the program exceptions with a try:
       except: statement.
 
       Normally, IPython sets sys.excepthook to a CrashHandler instance, so if
       any app directly invokes sys.excepthook, it will look to the user like
       IPython crashed.  In order to work around this, we can disable the
       CrashHandler and replace it with this excepthook instead, which prints a
       regular traceback using our InteractiveTB.  In this fashion, apps which
       call sys.excepthook will generate a regular-looking exception from
       IPython, and the CrashHandler will only be triggered by real IPython
       crashes.
 
       This hook should be used sparingly, only in places which are not likely
       to be true IPython errors.
       """
       self.showtraceback((etype,value,tb),tb_offset=0)
 
     def _get_exc_info(self, exc_tuple=None):
         """get exc_info from a given tuple, sys.exc_info() or sys.last_type etc.
         
         Ensures sys.last_type,value,traceback hold the exc_info we found,
         from whichever source.
         
         raises ValueError if none of these contain any information
         """
         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
         
         if etype is None:
             raise ValueError("No exception to find")
         
         # Now store the exception info in sys.last_type etc.
         # 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
         
         return etype, value, tb
     
 
     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:
             try:
                 etype, value, tb = self._get_exc_info(exc_tuple)
             except ValueError:
                 self.write_err('No traceback available to show.\n')
                 return
             
             if issubclass(etype, SyntaxError):
                 # Though this won't be called by syntax errors in the input
                 # line, there may be SyntaxError cases with imported code.
                 self.showsyntaxerror(filename)
             elif etype is UsageError:
                 self.write_err("UsageError: %s" % value)
             else:
                 if exception_only:
                     stb = ['An exception has occurred, use %tb to see '
                            'the full traceback.\n']
                     stb.extend(self.InteractiveTB.get_exception_only(etype,
                                                                      value))
                 else:
                     try:
                         # Exception classes can customise their traceback - we
                         # use this in IPython.parallel for exceptions occurring
                         # in the engines. This should return a list of strings.
                         stb = value._render_traceback_()
                     except Exception:
                         stb = self.InteractiveTB.structured_traceback(etype,
                                             value, tb, tb_offset=tb_offset)
 
                     self._showtraceback(etype, value, stb)
                     if self.call_pdb:
                         # drop into debugger
                         self.debugger(force=True)
                     return
 
                 # Actually show the traceback
                 self._showtraceback(etype, value, stb)
 
         except KeyboardInterrupt:
             self.write_err("\nKeyboardInterrupt\n")
 
     def _showtraceback(self, etype, evalue, stb):
         """Actually show a traceback.
 
         Subclasses may override this method to put the traceback on a different
         place, like a side channel.
         """
         print(self.InteractiveTB.stb2text(stb), file=io.stdout)
 
     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 = self._get_exc_info()
 
         if filename and issubclass(etype, SyntaxError):
             try:
                 value.filename = filename
             except:
                 # Not the format we expect; leave it alone
                 pass
         
         stb = self.SyntaxTB.structured_traceback(etype, value, [])
         self._showtraceback(etype, value, stb)
 
     # This is overridden in TerminalInteractiveShell to show a message about
     # the %paste magic.
     def showindentationerror(self):
         """Called by run_cell when there's an IndentationError in code entered
         at the prompt.
 
         This is overridden in TerminalInteractiveShell to show a message about
         the %paste magic."""
         self.showsyntaxerror()
 
     #-------------------------------------------------------------------------
     # Things related to readline
     #-------------------------------------------------------------------------
 
     def init_readline(self):
         """Command history completion/saving/reloading."""
 
         if self.readline_use:
             import IPython.utils.rlineimpl as readline
 
         self.rl_next_input = None
         self.rl_do_indent = False
 
         if not self.readline_use or not readline.have_readline:
             self.has_readline = False
             self.readline = None
             # Set a number of methods that depend on readline to be no-op
             self.readline_no_record = no_op_context
             self.set_readline_completer = no_op
             self.set_custom_completer = no_op
             if self.readline_use:
                 warn('Readline services not available or not loaded.')
         else:
             self.has_readline = True
             self.readline = readline
             sys.modules['readline'] = readline
 
             # Platform-specific configuration
             if os.name == 'nt':
                 # FIXME - check with Frederick to see if we can harmonize
                 # naming conventions with pyreadline to avoid this
                 # platform-dependent check
                 self.readline_startup_hook = readline.set_pre_input_hook
             else:
                 self.readline_startup_hook = readline.set_startup_hook
 
             # Load user's initrc file (readline config)
             # Or if libedit is used, load editrc.
             inputrc_name = os.environ.get('INPUTRC')
             if inputrc_name is None:
                 inputrc_name = '.inputrc'
                 if readline.uses_libedit:
                     inputrc_name = '.editrc'
                 inputrc_name = os.path.join(self.home_dir, inputrc_name)
             if os.path.isfile(inputrc_name):
                 try:
                     readline.read_init_file(inputrc_name)
                 except:
                     warn('Problems reading readline initialization file <%s>'
                          % inputrc_name)
 
             # Configure readline according to user's prefs
             # This is only done if GNU readline is being used.  If libedit
             # is being used (as on Leopard) the readline config is
             # not run as the syntax for libedit is different.
             if not readline.uses_libedit:
                 for rlcommand in self.readline_parse_and_bind:
                     #print "loading rl:",rlcommand  # dbg
                     readline.parse_and_bind(rlcommand)
 
             # Remove some chars from the delimiters list.  If we encounter
             # unicode chars, discard them.
             delims = readline.get_completer_delims()
             if not py3compat.PY3:
                 delims = delims.encode("ascii", "ignore")
             for d in self.readline_remove_delims:
                 delims = delims.replace(d, "")
             delims = delims.replace(ESC_MAGIC, '')
             readline.set_completer_delims(delims)
             # otherwise we end up with a monster history after a while:
             readline.set_history_length(self.history_length)
 
             self.refill_readline_hist()
             self.readline_no_record = ReadlineNoRecord(self)
 
         # Configure auto-indent for all platforms
         self.set_autoindent(self.autoindent)
 
     def refill_readline_hist(self):
         # Load the last 1000 lines from history
         self.readline.clear_history()
         stdin_encoding = sys.stdin.encoding or "utf-8"
         last_cell = u""
         for _, _, cell in self.history_manager.get_tail(1000,
                                                         include_latest=True):
             # Ignore blank lines and consecutive duplicates
             cell = cell.rstrip()
             if cell and (cell != last_cell):
                 if self.multiline_history:
                       self.readline.add_history(py3compat.unicode_to_str(cell,
                                                                 stdin_encoding))
                 else:
                     for line in cell.splitlines():
                         self.readline.add_history(py3compat.unicode_to_str(line,
                                                                 stdin_encoding))
                 last_cell = cell
 
     def set_next_input(self, s):
         """ Sets the 'default' input string for the next command line.
 
         Requires readline.
 
         Example:
 
         [D:\ipython]|1> _ip.set_next_input("Hello Word")
         [D:\ipython]|2> Hello Word_  # cursor is here
         """
         self.rl_next_input = py3compat.cast_bytes_py2(s)
 
     # Maybe move this to the terminal subclass?
     def pre_readline(self):
         """readline hook to be used at the start of each line.
 
         Currently it handles auto-indent only."""
 
         if self.rl_do_indent:
             self.readline.insert_text(self._indent_current_str())
         if self.rl_next_input is not None:
             self.readline.insert_text(self.rl_next_input)
             self.rl_next_input = None
 
     def _indent_current_str(self):
         """return the current level of indentation as a string"""
         return self.input_splitter.indent_spaces * ' '
 
     #-------------------------------------------------------------------------
     # Things related to text completion
     #-------------------------------------------------------------------------
 
     def init_completer(self):
         """Initialize the completion machinery.
 
         This creates completion machinery that can be used by client code,
         either interactively in-process (typically triggered by the readline
         library), programatically (such as in test suites) or out-of-prcess
         (typically over the network by remote frontends).
         """
         from IPython.core.completer import IPCompleter
         from IPython.core.completerlib import (module_completer,
                 magic_run_completer, cd_completer, reset_completer)
 
         self.Completer = IPCompleter(shell=self,
                                      namespace=self.user_ns,
                                      global_namespace=self.user_global_ns,
                                      alias_table=self.alias_manager.alias_table,
                                      use_readline=self.has_readline,
                                      config=self.config,
                                      )
         self.configurables.append(self.Completer)
 
         # Add custom completers to the basic ones built into IPCompleter
         sdisp = self.strdispatchers.get('complete_command', StrDispatch())
         self.strdispatchers['complete_command'] = sdisp
         self.Completer.custom_completers = sdisp
 
         self.set_hook('complete_command', module_completer, str_key = 'import')
         self.set_hook('complete_command', module_completer, str_key = 'from')
         self.set_hook('complete_command', magic_run_completer, str_key = '%run')
         self.set_hook('complete_command', cd_completer, str_key = '%cd')
         self.set_hook('complete_command', reset_completer, str_key = '%reset')
 
         # Only configure readline if we truly are using readline.  IPython can
         # do tab-completion over the network, in GUIs, etc, where readline
         # itself may be absent
         if self.has_readline:
             self.set_readline_completer()
 
     def complete(self, text, line=None, cursor_pos=None):
         """Return the completed text and a list of completions.
 
         Parameters
         ----------
 
            text : string
              A string of text to be completed on.  It can be given as empty and
              instead a line/position pair are given.  In this case, the
              completer itself will split the line like readline does.
 
            line : string, optional
              The complete line that text is part of.
 
            cursor_pos : int, optional
              The position of the cursor on the input line.
 
         Returns
         -------
           text : string
             The actual text that was completed.
 
           matches : list
             A sorted list with all possible completions.
 
         The optional arguments allow the completion to take more context into
         account, and are part of the low-level completion API.
 
         This is a wrapper around the completion mechanism, similar to what
         readline does at the command line when the TAB key is hit.  By
         exposing it as a method, it can be used by other non-readline
         environments (such as GUIs) for text completion.
 
         Simple usage example:
 
         In [1]: x = 'hello'
 
         In [2]: _ip.complete('x.l')
         Out[2]: ('x.l', ['x.ljust', 'x.lower', 'x.lstrip'])
         """
 
         # Inject names into __builtin__ so we can complete on the added names.
         with self.builtin_trap:
             return self.Completer.complete(text, line, cursor_pos)
 
     def set_custom_completer(self, completer, pos=0):
         """Adds a new custom completer function.
 
         The position argument (defaults to 0) is the index in the completers
         list where you want the completer to be inserted."""
 
         newcomp = types.MethodType(completer,self.Completer)
         self.Completer.matchers.insert(pos,newcomp)
 
     def set_readline_completer(self):
         """Reset readline's completer to be our own."""
         self.readline.set_completer(self.Completer.rlcomplete)
 
     def set_completer_frame(self, frame=None):
         """Set the frame of the completer."""
         if frame:
             self.Completer.namespace = frame.f_locals
             self.Completer.global_namespace = frame.f_globals
         else:
             self.Completer.namespace = self.user_ns
             self.Completer.global_namespace = self.user_global_ns
 
     #-------------------------------------------------------------------------
     # Things related to magics
     #-------------------------------------------------------------------------
 
     def init_magics(self):
         from IPython.core import magics as m
         self.magics_manager = magic.MagicsManager(shell=self,
                                    confg=self.config,
                                    user_magics=m.UserMagics(self))
         self.configurables.append(self.magics_manager)
 
         # Expose as public API from the magics manager
         self.register_magics = self.magics_manager.register
         self.register_magic_function = self.magics_manager.register_function
         self.define_magic = self.magics_manager.define_magic
 
         self.register_magics(m.AutoMagics, m.BasicMagics, m.CodeMagics,
             m.ConfigMagics, m.DeprecatedMagics, m.DisplayMagics, m.ExecutionMagics,
             m.ExtensionMagics, m.HistoryMagics, m.LoggingMagics,
             m.NamespaceMagics, m.OSMagics, m.PylabMagics, m.ScriptMagics,
         )
 
         # Register Magic Aliases
         mman = self.magics_manager
         mman.register_alias('ed', 'edit')
         mman.register_alias('hist', 'history')
         mman.register_alias('rep', 'recall')
 
         # FIXME: Move the color initialization to the DisplayHook, which
         # should be split into a prompt manager and displayhook. We probably
         # even need a centralize colors management object.
         self.magic('colors %s' % self.colors)
 
     def run_line_magic(self, magic_name, line):
         """Execute the given line magic.
 
         Parameters
         ----------
         magic_name : str
           Name of the desired magic function, without '%' prefix.
 
         line : str
           The rest of the input line as a single string.
         """
         fn = self.find_line_magic(magic_name)
         if fn is None:
             cm = self.find_cell_magic(magic_name)
             etpl = "Line magic function `%%%s` not found%s."
             extra = '' if cm is None else (' (But cell magic `%%%%%s` exists, '
                                     'did you mean that instead?)' % magic_name )
             error(etpl % (magic_name, extra))
         else:
             # Note: this is the distance in the stack to the user's frame.
             # This will need to be updated if the internal calling logic gets
             # refactored, or else we'll be expanding the wrong variables.
             stack_depth = 2
             magic_arg_s = self.var_expand(line, stack_depth)
             # Put magic args in a list so we can call with f(*a) syntax
             args = [magic_arg_s]
             kwargs = {}
             # Grab local namespace if we need it:
             if getattr(fn, "needs_local_scope", False):
                 kwargs['local_ns'] = sys._getframe(stack_depth).f_locals
             with self.builtin_trap:
                 result = fn(*args,**kwargs)
             return result
 
     def run_cell_magic(self, magic_name, line, cell):
         """Execute the given cell magic.
         
         Parameters
         ----------
         magic_name : str
           Name of the desired magic function, without '%' prefix.
 
         line : str
           The rest of the first input line as a single string.
 
         cell : str
           The body of the cell as a (possibly multiline) string.
         """
         fn = self.find_cell_magic(magic_name)
         if fn is None:
             lm = self.find_line_magic(magic_name)
             etpl = "Cell magic function `%%%%%s` not found%s."
             extra = '' if lm is None else (' (But line magic `%%%s` exists, '
                                     'did you mean that instead?)' % magic_name )
             error(etpl % (magic_name, extra))
         else:
             # Note: this is the distance in the stack to the user's frame.
             # This will need to be updated if the internal calling logic gets
             # refactored, or else we'll be expanding the wrong variables.
             stack_depth = 2
             magic_arg_s = self.var_expand(line, stack_depth)
             with self.builtin_trap:
                 result = fn(magic_arg_s, cell)
             return result
 
     def find_line_magic(self, magic_name):
         """Find and return a line magic by name.
 
         Returns None if the magic isn't found."""
         return self.magics_manager.magics['line'].get(magic_name)
 
     def find_cell_magic(self, magic_name):
         """Find and return a cell magic by name.
 
         Returns None if the magic isn't found."""
         return self.magics_manager.magics['cell'].get(magic_name)
 
     def find_magic(self, magic_name, magic_kind='line'):
         """Find and return a magic of the given type by name.
 
         Returns None if the magic isn't found."""
         return self.magics_manager.magics[magic_kind].get(magic_name)
 
     def magic(self, arg_s):
         """DEPRECATED. Use run_line_magic() instead.
 
         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.
         """
         # TODO: should we issue a loud deprecation warning here?
         magic_name, _, magic_arg_s = arg_s.partition(' ')
         magic_name = magic_name.lstrip(prefilter.ESC_MAGIC)
         return self.run_line_magic(magic_name, magic_arg_s)
 
     #-------------------------------------------------------------------------
     # Things related to macros
     #-------------------------------------------------------------------------
 
     def define_macro(self, name, themacro):
         """Define a new macro
 
         Parameters
         ----------
         name : str
             The name of the macro.
         themacro : str or Macro
             The action to do upon invoking the macro.  If a string, a new
             Macro object is created by passing the string to it.
         """
 
         from IPython.core import macro
 
         if isinstance(themacro, basestring):
             themacro = macro.Macro(themacro)
         if not isinstance(themacro, macro.Macro):
             raise ValueError('A macro must be a string or a Macro instance.')
         self.user_ns[name] = themacro
 
     #-------------------------------------------------------------------------
     # Things related to the running of system commands
     #-------------------------------------------------------------------------
 
     def system_piped(self, cmd):
         """Call the given cmd in a subprocess, piping stdout/err
 
         Parameters
         ----------
         cmd : str
           Command to execute (can not end in '&', as background processes are
           not supported.  Should not be a command that expects input
           other than simple text.
         """
         if cmd.rstrip().endswith('&'):
             # this is *far* from a rigorous test
             # We do not support backgrounding processes because we either use
             # pexpect or pipes to read from.  Users can always just call
             # os.system() or use ip.system=ip.system_raw
             # if they really want a background process.
             raise OSError("Background processes not supported.")
 
         # we explicitly do NOT return the subprocess status code, because
         # a non-None value would trigger :func:`sys.displayhook` calls.
         # Instead, we store the exit_code in user_ns.
         self.user_ns['_exit_code'] = system(self.var_expand(cmd, depth=1))
 
     def system_raw(self, cmd):
         """Call the given cmd in a subprocess using os.system
 
         Parameters
         ----------
         cmd : str
           Command to execute.
         """
         cmd = self.var_expand(cmd, depth=1)
         # protect os.system from UNC paths on Windows, which it can't handle:
         if sys.platform == 'win32':
             from IPython.utils._process_win32 import AvoidUNCPath
             with AvoidUNCPath() as path:
                 if path is not None:
                     cmd = '"pushd %s &&"%s' % (path, cmd)
                 cmd = py3compat.unicode_to_str(cmd)
                 ec = os.system(cmd)
         else:
             cmd = py3compat.unicode_to_str(cmd)
             ec = os.system(cmd)
         
         # We explicitly do NOT return the subprocess status code, because
         # a non-None value would trigger :func:`sys.displayhook` calls.
         # Instead, we store the exit_code in user_ns.
         self.user_ns['_exit_code'] = ec
 
     # use piped system by default, because it is better behaved
     system = system_piped
 
     def getoutput(self, cmd, split=True, depth=0):
         """Get output (possibly including stderr) from a subprocess.
 
         Parameters
         ----------
         cmd : str
           Command to execute (can not end in '&', as background processes are
           not supported.
         split : bool, optional
           If True, split the output into an IPython SList.  Otherwise, an
           IPython LSString is returned.  These are objects similar to normal
           lists and strings, with a few convenience attributes for easier
           manipulation of line-based output.  You can use '?' on them for
           details.
         depth : int, optional
           How many frames above the caller are the local variables which should
           be expanded in the command string? The default (0) assumes that the
           expansion variables are in the stack frame calling this function.
         """
         if cmd.rstrip().endswith('&'):
             # this is *far* from a rigorous test
             raise OSError("Background processes not supported.")
         out = getoutput(self.var_expand(cmd, depth=depth+1))
         if split:
             out = SList(out.splitlines())
         else:
             out = LSString(out)
         return out
 
     #-------------------------------------------------------------------------
     # Things related to aliases
     #-------------------------------------------------------------------------
 
     def init_alias(self):
         self.alias_manager = AliasManager(shell=self, config=self.config)
         self.configurables.append(self.alias_manager)
         self.ns_table['alias'] = self.alias_manager.alias_table,
 
     #-------------------------------------------------------------------------
     # Things related to extensions and plugins
     #-------------------------------------------------------------------------
 
     def init_extension_manager(self):
         self.extension_manager = ExtensionManager(shell=self, config=self.config)
         self.configurables.append(self.extension_manager)
 
     def init_plugin_manager(self):
         self.plugin_manager = PluginManager(config=self.config)
         self.configurables.append(self.plugin_manager)
         
 
     #-------------------------------------------------------------------------
     # Things related to payloads
     #-------------------------------------------------------------------------
 
     def init_payload(self):
         self.payload_manager = PayloadManager(config=self.config)
         self.configurables.append(self.payload_manager)
 
     #-------------------------------------------------------------------------
     # Things related to the prefilter
     #-------------------------------------------------------------------------
 
     def init_prefilter(self):
         self.prefilter_manager = PrefilterManager(shell=self, config=self.config)
         self.configurables.append(self.prefilter_manager)
         # Ultimately this will be refactored in the new interpreter code, but
         # for now, we should expose the main prefilter method (there's legacy
         # code out there that may rely on this).
         self.prefilter = self.prefilter_manager.prefilter_lines
 
     def auto_rewrite_input(self, cmd):
         """Print to the screen the rewritten form of the user's command.
 
         This shows visual feedback by rewriting input lines that cause
         automatic calling to kick in, like::
 
           /f x
 
         into::
 
           ------> f(x)
 
         after the user's input prompt.  This helps the user understand that the
         input line was transformed automatically by IPython.
         """
         if not self.show_rewritten_input:
             return
         
         rw = self.prompt_manager.render('rewrite') + cmd
 
         try:
             # plain ascii works better w/ pyreadline, on some machines, so
             # we use it and only print uncolored rewrite if we have unicode
             rw = str(rw)
             print(rw, file=io.stdout)
         except UnicodeEncodeError:
             print("------> " + cmd)
 
     #-------------------------------------------------------------------------
     # Things related to extracting values/expressions from kernel and user_ns
     #-------------------------------------------------------------------------
 
     def _simple_error(self):
         etype, value = sys.exc_info()[:2]
         return u'[ERROR] {e.__name__}: {v}'.format(e=etype, v=value)
 
     def user_variables(self, names):
         """Get a list of variable names from the user's namespace.
 
         Parameters
         ----------
         names : list of strings
           A list of names of variables to be read from the user namespace.
 
         Returns
         -------
         A dict, keyed by the input names and with the repr() of each value.
         """
         out = {}
         user_ns = self.user_ns
         for varname in names:
             try:
                 value = repr(user_ns[varname])
             except:
                 value = self._simple_error()
             out[varname] = value
         return out
 
     def user_expressions(self, expressions):
         """Evaluate a dict of expressions in the user's namespace.
 
         Parameters
         ----------
         expressions : dict
           A dict with string keys and string values.  The expression values
           should be valid Python expressions, each of which will be evaluated
           in the user namespace.
 
         Returns
         -------
         A dict, keyed like the input expressions dict, with the repr() of each
         value.
         """
         out = {}
         user_ns = self.user_ns
         global_ns = self.user_global_ns
         for key, expr in expressions.iteritems():
             try:
                 value = repr(eval(expr, global_ns, user_ns))
             except:
                 value = self._simple_error()
             out[key] = value
         return out
 
     #-------------------------------------------------------------------------
     # Things related to the running of code
     #-------------------------------------------------------------------------
 
     def ex(self, cmd):
         """Execute a normal python statement in user namespace."""
         with self.builtin_trap:
             exec cmd in self.user_global_ns, self.user_ns
 
     def ev(self, expr):
         """Evaluate python expression expr in user namespace.
 
         Returns the result of evaluation
         """
         with self.builtin_trap:
             return eval(expr, self.user_global_ns, self.user_ns)
 
     def safe_execfile(self, fname, *where, **kw):
         """A safe version of the builtin execfile().
 
         This version will never throw an exception, but instead print
         helpful error messages to the screen.  This only works on pure
         Python files with the .py extension.
 
         Parameters
         ----------
         fname : string
             The name of the file to be executed.
         where : tuple
             One or two namespaces, passed to execfile() as (globals,locals).
             If only one is given, it is passed as both.
         exit_ignore : bool (False)
             If True, then silence SystemExit for non-zero status (it is always
             silenced for zero status, as it is so common).
         raise_exceptions : bool (False)
             If True raise exceptions everywhere. Meant for testing.
 
         """
         kw.setdefault('exit_ignore', False)
         kw.setdefault('raise_exceptions', False)
 
         fname = os.path.abspath(os.path.expanduser(fname))
 
         # Make sure we can open the file
         try:
             with open(fname) as thefile:
                 pass
         except:
             warn('Could not open file <%s> for safe execution.' % fname)
             return
 
         # Find things also in current directory.  This is needed to mimic the
         # behavior of running a script from the system command line, where
         # Python inserts the script's directory into sys.path
         dname = os.path.dirname(fname)
 
         with prepended_to_syspath(dname):
             # Ensure that __file__ is always defined to match Python behavior
             save_fname = self.user_ns.get('__file__',None)
             self.user_ns['__file__'] = fname
             try:
                 py3compat.execfile(fname,*where)
             except SystemExit as status:
                 # If the call was made with 0 or None exit status (sys.exit(0)
                 # or sys.exit() ), don't bother showing a traceback, as both of
                 # these are considered normal by the OS:
                 # > python -c'import sys;sys.exit(0)'; echo $?
                 # 0
                 # > python -c'import sys;sys.exit()'; echo $?
                 # 0
                 # For other exit status, we show the exception unless
                 # explicitly silenced, but only in short form.
                 if kw['raise_exceptions']:
                     raise
                 if status.code not in (0, None) and not kw['exit_ignore']:
                     self.showtraceback(exception_only=True)
             except:
                 if kw['raise_exceptions']:
                     raise
                 self.showtraceback()
             finally:
                 self.user_ns['__file__'] = save_fname
 
     def safe_execfile_ipy(self, fname):
         """Like safe_execfile, but for .ipy files with IPython syntax.
 
         Parameters
         ----------
         fname : str
             The name of the file to execute.  The filename must have a
             .ipy extension.
         """
         fname = os.path.abspath(os.path.expanduser(fname))
 
         # Make sure we can open the file
         try:
             with open(fname) as thefile:
                 pass
         except:
             warn('Could not open file <%s> for safe execution.' % fname)
             return
 
         # Find things also in current directory.  This is needed to mimic the
         # behavior of running a script from the system command line, where
         # Python inserts the script's directory into sys.path
         dname = os.path.dirname(fname)
 
         with prepended_to_syspath(dname):
             # Ensure that __file__ is always defined to match Python behavior
             save_fname = self.user_ns.get('__file__',None)
             self.user_ns['__file__'] = fname
             try:
                 with open(fname) as thefile:
                     # self.run_cell currently captures all exceptions
                     # raised in user code.  It would be nice if there were
                     # versions of runlines, execfile that did raise, so
                     # we could catch the errors.
                     self.run_cell(thefile.read(), store_history=False)
             except:
                 self.showtraceback()
                 warn('Unknown failure executing file: <%s>' % fname)
             finally:
                 self.user_ns['__file__'] = save_fname
 
     def safe_run_module(self, mod_name, where):
         """A safe version of runpy.run_module().
 
         This version will never throw an exception, but instead print
         helpful error messages to the screen.
 
         Parameters
         ----------
         mod_name : string
             The name of the module to be executed.
         where : dict
             The globals namespace.
         """
         try:
             where.update(
                 runpy.run_module(str(mod_name), run_name="__main__",
                                  alter_sys=True)
                 )
         except:
             self.showtraceback()
             warn('Unknown failure executing module: <%s>' % mod_name)
 
     def _run_cached_cell_magic(self, magic_name, line):
         """Special method to call a cell magic with the data stored in self.
         """
         cell = self._current_cell_magic_body
         self._current_cell_magic_body = None
         return self.run_cell_magic(magic_name, line, cell)
 
     def run_cell(self, raw_cell, store_history=False, silent=False):
         """Run a complete IPython cell.
 
         Parameters
         ----------
         raw_cell : str
           The code (including IPython code such as %magic functions) to run.
         store_history : bool
           If True, the raw and translated cell will be stored in IPython's
           history. For user code calling back into IPython's machinery, this
           should be set to False.
         silent : bool
           If True, avoid side-effects, such as implicit displayhooks and
           and logging.  silent=True forces store_history=False.
         """
         if (not raw_cell) or raw_cell.isspace():
             return
         
         if silent:
             store_history = False
 
         self.input_splitter.push(raw_cell)
 
         # Check for cell magics, which leave state behind.  This interface is
         # ugly, we need to do something cleaner later...  Now the logic is
         # simply that the input_splitter remembers if there was a cell magic,
         # and in that case we grab the cell body.
         if self.input_splitter.cell_magic_parts:
             self._current_cell_magic_body = \
                                ''.join(self.input_splitter.cell_magic_parts)
         cell = self.input_splitter.source_reset()
 
         with self.builtin_trap:
             prefilter_failed = False
             if len(cell.splitlines()) == 1:
                 try:
                     # use prefilter_lines to handle trailing newlines
                     # restore trailing newline for ast.parse
                     cell = self.prefilter_manager.prefilter_lines(cell) + '\n'
                 except AliasError as e:
                     error(e)
                     prefilter_failed = True
                 except Exception:
                     # don't allow prefilter errors to crash IPython
                     self.showtraceback()
                     prefilter_failed = True
 
             # Store raw and processed history
             if store_history:
                 self.history_manager.store_inputs(self.execution_count,
                                                   cell, raw_cell)
             if not silent:
                 self.logger.log(cell, raw_cell)
 
             if not prefilter_failed:
                 # don't run if prefilter failed
                 cell_name = self.compile.cache(cell, self.execution_count)
 
                 with self.display_trap:
                     try:
                         code_ast = self.compile.ast_parse(cell,
                                                           filename=cell_name)
                     except IndentationError:
                         self.showindentationerror()
                         if store_history:
                             self.execution_count += 1
                         return None
                     except (OverflowError, SyntaxError, ValueError, TypeError,
                             MemoryError):
                         self.showsyntaxerror()
                         if store_history:
                             self.execution_count += 1
                         return None
                     
                     interactivity = "none" if silent else self.ast_node_interactivity
                     self.run_ast_nodes(code_ast.body, cell_name,
                                        interactivity=interactivity)
                     
                     # Execute any registered post-execution functions.
                     # unless we are silent
                     post_exec = [] if silent else self._post_execute.iteritems()
                     
                     for func, status in post_exec:
                         if self.disable_failing_post_execute and not status:
                             continue
                         try:
                             func()
                         except KeyboardInterrupt:
                             print("\nKeyboardInterrupt", file=io.stderr)
                         except Exception:
                             # register as failing:
                             self._post_execute[func] = False
                             self.showtraceback()
                             print('\n'.join([
                                 "post-execution function %r produced an error." % func,
                                 "If this problem persists, you can disable failing post-exec functions with:",
                                 "",
                                 "    get_ipython().disable_failing_post_execute = True"
                             ]), file=io.stderr)
 
         if store_history:
             # Write output to the database. Does nothing unless
             # history output logging is enabled.
             self.history_manager.store_output(self.execution_count)
             # Each cell is a *single* input, regardless of how many lines it has
             self.execution_count += 1
 
     def run_ast_nodes(self, nodelist, cell_name, interactivity='last_expr'):
         """Run a sequence of AST nodes. The execution mode depends on the
         interactivity parameter.
 
         Parameters
         ----------
         nodelist : list
           A sequence of AST nodes to run.
         cell_name : str
           Will be passed to the compiler as the filename of the cell. Typically
           the value returned by ip.compile.cache(cell).
         interactivity : str
           'all', 'last', 'last_expr' or 'none', specifying which nodes should be
           run interactively (displaying output from expressions). 'last_expr'
           will run the last node interactively only if it is an expression (i.e.
           expressions in loops or other blocks are not displayed. Other values
           for this parameter will raise a ValueError.
         """
         if not nodelist:
             return
 
         if interactivity == 'last_expr':
             if isinstance(nodelist[-1], ast.Expr):
                 interactivity = "last"
             else:
                 interactivity = "none"
 
         if interactivity == 'none':
             to_run_exec, to_run_interactive = nodelist, []
         elif interactivity == 'last':
             to_run_exec, to_run_interactive = nodelist[:-1], nodelist[-1:]
         elif interactivity == 'all':
             to_run_exec, to_run_interactive = [], nodelist
         else:
             raise ValueError("Interactivity was %r" % interactivity)
 
         exec_count = self.execution_count
 
         try:
             for i, node in enumerate(to_run_exec):
                 mod = ast.Module([node])
                 code = self.compile(mod, cell_name, "exec")
                 if self.run_code(code):
                     return True
 
             for i, node in enumerate(to_run_interactive):
                 mod = ast.Interactive([node])
                 code = self.compile(mod, cell_name, "single")
                 if self.run_code(code):
                     return True
 
             # Flush softspace
             if softspace(sys.stdout, 0):
                 print()
 
         except:
             # It's possible to have exceptions raised here, typically by
             # compilation of odd code (such as a naked 'return' outside a
             # function) that did parse but isn't valid. Typically the exception
             # is a SyntaxError, but it's safest just to catch anything and show
             # the user a traceback.
 
             # We do only one try/except outside the loop to minimize the impact
             # on runtime, and also because if any node in the node list is
             # broken, we should stop execution completely.
             self.showtraceback()
 
         return False
 
     def run_code(self, code_obj):
         """Execute a code object.
 
         When an exception occurs, self.showtraceback() is called to display a
         traceback.
 
         Parameters
         ----------
         code_obj : code object
           A compiled code object, to be executed
 
         Returns
         -------
         False : successful execution.
         True : an error occurred.
         """
 
         # Set our own excepthook in case the user code tries to call it
         # directly, so that the IPython crash handler doesn't get triggered
         old_excepthook,sys.excepthook = sys.excepthook, self.excepthook
 
         # we save the original sys.excepthook in the instance, in case config
         # code (such as magics) needs access to it.
         self.sys_excepthook = old_excepthook
         outflag = 1  # happens in more places, so it's easier as default
         try:
             try:
                 self.hooks.pre_run_code_hook()
                 #rprint('Running code', repr(code_obj)) # dbg
                 exec code_obj in self.user_global_ns, self.user_ns
             finally:
                 # Reset our crash handler in place
                 sys.excepthook = old_excepthook
         except SystemExit:
             self.showtraceback(exception_only=True)
             warn("To exit: use 'exit', 'quit', or Ctrl-D.", level=1)
         except self.custom_exceptions:
             etype,value,tb = sys.exc_info()
             self.CustomTB(etype,value,tb)
         except:
             self.showtraceback()
         else:
             outflag = 0
         return outflag
 
     # For backwards compatibility
     runcode = run_code
 
     #-------------------------------------------------------------------------
     # Things related to GUI support and pylab
     #-------------------------------------------------------------------------
 
     def enable_gui(self, gui=None):
         raise NotImplementedError('Implement enable_gui in a subclass')
 
     def enable_pylab(self, gui=None, import_all=True, welcome_message=False):
         """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 correctly
         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, 'qt', 'osx', 'tk',
           'gtk', 'wx' or 'inline'), otherwise we use the default chosen by
           matplotlib (as dictated by the matplotlib build-time options plus the
           user's matplotlibrc configuration file).  Note that not all backends
           make sense in all contexts, for example a terminal ipython can't
           display figures inline.
         """
         from IPython.core.pylabtools import mpl_runner
         # 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 = {}
         try:
             gui = pylab_activate(ns, gui, import_all, self, welcome_message=welcome_message)
         except KeyError:
             error("Backend %r not supported" % gui)
             return
         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
         self.enable_gui(gui)
         self.magics_manager.registry['ExecutionMagics'].default_runner = \
         mpl_runner(self.safe_execfile)
 
     #-------------------------------------------------------------------------
     # Utilities
     #-------------------------------------------------------------------------
 
     def var_expand(self, cmd, depth=0, formatter=DollarFormatter()):
         """Expand python variables in a string.
 
         The depth argument indicates how many frames above the caller should
         be walked to look for the local namespace where to expand variables.
 
         The global namespace for expansion is always the user's interactive
         namespace.
         """
         ns = self.user_ns.copy()
         ns.update(sys._getframe(depth+1).f_locals)
         try:
             # We have to use .vformat() here, because 'self' is a valid and common
             # name, and expanding **ns for .format() would make it collide with
             # the 'self' argument of the method.
             cmd = formatter.vformat(cmd, args=[], kwargs=ns)
         except Exception:
             # if formatter couldn't format, just let it go untransformed
             pass
         return cmd
 
     def mktempfile(self, data=None, prefix='ipython_edit_'):
         """Make a new tempfile and return its filename.
 
         This makes a call to tempfile.mktemp, but it registers the created
         filename internally so ipython cleans it up at exit time.
 
         Optional inputs:
 
           - data(None): if data is given, it gets written out to the temp file
           immediately, and the file is closed again."""
 
         filename = tempfile.mktemp('.py', prefix)
         self.tempfiles.append(filename)
 
         if data:
             tmp_file = open(filename,'w')
             tmp_file.write(data)
             tmp_file.close()
         return filename
 
     # TODO:  This should be removed when Term is refactored.
     def write(self,data):
         """Write a string to the default output"""
         io.stdout.write(data)
 
     # TODO:  This should be removed when Term is refactored.
     def write_err(self,data):
         """Write a string to the default error output"""
         io.stderr.write(data)
 
     def ask_yes_no(self, prompt, default=None):
         if self.quiet:
             return True
         return ask_yes_no(prompt,default)
 
     def show_usage(self):
         """Show a usage message"""
         page.page(IPython.core.usage.interactive_usage)
 
     def extract_input_lines(self, range_str, raw=False):
         """Return as a string a set of input history slices.
 
         Parameters
         ----------
         range_str : string
             The set of slices is given as a string, like "~5/6-~4/2 4:8 9",
             since this function is for use by magic functions which get their
             arguments as strings. The number before the / is the session
             number: ~n goes n back from the current session.
 
         Optional Parameters:
           - raw(False): by default, the processed input is used.  If this is
           true, the raw input history is used instead.
 
         Note that slices can be called with two notations:
 
         N:M -> standard python form, means including items N...(M-1).
 
         N-M -> include items N..M (closed endpoint)."""
         lines = self.history_manager.get_range_by_str(range_str, raw=raw)
         return "\n".join(x for _, _, x in lines)
 
     def find_user_code(self, target, raw=True, py_only=False, skip_encoding_cookie=True):
         """Get a code string from history, file, url, or a string or macro.
 
         This is mainly used by magic functions.
 
         Parameters
         ----------
 
         target : str
 
           A string specifying code to retrieve. This will be tried respectively
           as: ranges of input history (see %history for syntax), url,
           correspnding .py file, filename, or an expression evaluating to a
           string or Macro in the user namespace.
 
         raw : bool
           If true (default), retrieve raw history. Has no effect on the other
           retrieval mechanisms.
 
         py_only : bool (default False)
           Only try to fetch python code, do not try alternative methods to decode file
           if unicode fails.
 
         Returns
         -------
         A string of code.
 
         ValueError is raised if nothing is found, and TypeError if it evaluates
         to an object of another type. In each case, .args[0] is a printable
         message.
         """
         code = self.extract_input_lines(target, raw=raw)  # Grab history
         if code:
             return code
         utarget = unquote_filename(target)
         try:
             if utarget.startswith(('http://', 'https://')):
                 return openpy.read_py_url(utarget, skip_encoding_cookie=skip_encoding_cookie)
         except UnicodeDecodeError:
             if not py_only :
                 response = urllib.urlopen(target)
                 return response.read().decode('latin1')
             raise ValueError(("'%s' seem to be unreadable.") % utarget)
 
         potential_target = [target]
         try :
             potential_target.insert(0,get_py_filename(target))
         except IOError:
             pass
 
         for tgt in potential_target :
             if os.path.isfile(tgt):                        # Read file
                 try :
                     return openpy.read_py_file(tgt, skip_encoding_cookie=skip_encoding_cookie)
                 except UnicodeDecodeError :
                     if not py_only :
                         with io_open(tgt,'r', encoding='latin1') as f :
                             return f.read()
                     raise ValueError(("'%s' seem to be unreadable.") % target)
 
         try:                                              # User namespace
             codeobj = eval(target, self.user_ns)
         except Exception:
             raise ValueError(("'%s' was not found in history, as a file, url, "
                                 "nor in the user namespace.") % target)
         if isinstance(codeobj, basestring):
             return codeobj
         elif isinstance(codeobj, Macro):
             return codeobj.value
 
         raise TypeError("%s is neither a string nor a macro." % target,
                         codeobj)
 
     #-------------------------------------------------------------------------
     # Things related to IPython exiting
     #-------------------------------------------------------------------------
     def atexit_operations(self):
         """This will be executed at the time of exit.
 
         Cleanup operations and saving of persistent data that is done
         unconditionally by IPython should be performed here.
 
         For things that may depend on startup flags or platform specifics (such
         as having readline or not), register a separate atexit function in the
         code that has the appropriate information, rather than trying to
         clutter
         """
         # Close the history session (this stores the end time and line count)
         # this must be *before* the tempfile cleanup, in case of temporary
         # history db
         self.history_manager.end_session()
 
         # Cleanup all tempfiles left around
         for tfile in self.tempfiles:
             try:
                 os.unlink(tfile)
             except OSError:
                 pass
 
         # Clear all user namespaces to release all references cleanly.
         self.reset(new_session=False)
 
         # Run user hooks
         self.hooks.shutdown_hook()
 
     def cleanup(self):
         self.restore_sys_module_state()
 
 
 class InteractiveShellABC(object):
     """An abstract base class for InteractiveShell."""
     __metaclass__ = abc.ABCMeta
 
 InteractiveShellABC.register(InteractiveShell)

IPython/core/profiledir.py

@@ -1,228 +1,228 b''
 # encoding: utf-8
 """
 An object for managing IPython profile directories.
 
 Authors:
 
 * Brian Granger
 * Fernando Perez
 * Min RK
 
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import os
 import shutil
 import sys
 
 from IPython.config.configurable import LoggingConfigurable
 from IPython.config.loader import Config
 from IPython.utils.path import get_ipython_package_dir, expand_path
 from IPython.utils.traitlets import List, Unicode, Bool
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 
 #-----------------------------------------------------------------------------
 # Module errors
 #-----------------------------------------------------------------------------
 
 class ProfileDirError(Exception):
     pass
 
 
 #-----------------------------------------------------------------------------
 # Class for managing profile directories
 #-----------------------------------------------------------------------------
 
 class ProfileDir(LoggingConfigurable):
     """An object to manage the profile directory and its resources.
 
     The profile directory is used by all IPython applications, to manage
     configuration, logging and security.
 
     This object knows how to find, create and manage these directories. This
     should be used by any code that wants to handle profiles.
     """
 
     security_dir_name = Unicode('security')
     log_dir_name = Unicode('log')
     startup_dir_name = Unicode('startup')
     pid_dir_name = Unicode('pid')
     security_dir = Unicode(u'')
     log_dir = Unicode(u'')
     startup_dir = Unicode(u'')
     pid_dir = Unicode(u'')
 
     location = Unicode(u'', config=True,
         help="""Set the profile location directly. This overrides the logic used by the
         `profile` option.""",
         )
 
     _location_isset = Bool(False) # flag for detecting multiply set location
 
     def _location_changed(self, name, old, new):
         if self._location_isset:
             raise RuntimeError("Cannot set profile location more than once.")
         self._location_isset = True
         if not os.path.isdir(new):
             os.makedirs(new)
         
         # ensure config files exist:
         self.security_dir = os.path.join(new, self.security_dir_name)
         self.log_dir = os.path.join(new, self.log_dir_name)
         self.startup_dir = os.path.join(new, self.startup_dir_name)
         self.pid_dir = os.path.join(new, self.pid_dir_name)
         self.check_dirs()
 
     def _log_dir_changed(self, name, old, new):
         self.check_log_dir()
 
     def check_log_dir(self):
         if not os.path.isdir(self.log_dir):
             os.mkdir(self.log_dir)
 
     def _startup_dir_changed(self, name, old, new):
         self.check_startup_dir()
 
     def check_startup_dir(self):
         if not os.path.isdir(self.startup_dir):
             os.mkdir(self.startup_dir)
         readme = os.path.join(self.startup_dir, 'README')
         src = os.path.join(get_ipython_package_dir(), u'config', u'profile', u'README_STARTUP')
         if not os.path.exists(readme):
             shutil.copy(src, readme)
 
     def _security_dir_changed(self, name, old, new):
         self.check_security_dir()
 
     def check_security_dir(self):
         if not os.path.isdir(self.security_dir):
-            os.mkdir(self.security_dir, 0700)
+            os.mkdir(self.security_dir, 0o700)
         else:
             try:
-                os.chmod(self.security_dir, 0700)
+                os.chmod(self.security_dir, 0o700)
             except OSError:
                 self.log.warn("Could not set security dir permissions to private.")
 
     def _pid_dir_changed(self, name, old, new):
         self.check_pid_dir()
 
     def check_pid_dir(self):
         if not os.path.isdir(self.pid_dir):
-            os.mkdir(self.pid_dir, 0700)
+            os.mkdir(self.pid_dir, 0o700)
         else:
             try:
-                os.chmod(self.pid_dir, 0700)
+                os.chmod(self.pid_dir, 0o700)
             except OSError:
                 self.log.warn("Could not set pid dir permissions to private.")
 
     def check_dirs(self):
         self.check_security_dir()
         self.check_log_dir()
         self.check_pid_dir()
         self.check_startup_dir()
 
     def copy_config_file(self, config_file, path=None, overwrite=False):
         """Copy a default config file into the active profile directory.
 
         Default configuration files are kept in :mod:`IPython.config.default`.
         This function moves these from that location to the working profile
         directory.
         """
         dst = os.path.join(self.location, config_file)
         if os.path.isfile(dst) and not overwrite:
             return False
         if path is None:
             path = os.path.join(get_ipython_package_dir(), u'config', u'profile', u'default')
         src = os.path.join(path, config_file)
         shutil.copy(src, dst)
         return True
 
     @classmethod
     def create_profile_dir(cls, profile_dir, config=None):
         """Create a new profile directory given a full path.
 
         Parameters
         ----------
         profile_dir : str
             The full path to the profile directory.  If it does exist, it will
             be used.  If not, it will be created.
         """
         return cls(location=profile_dir, config=config)
 
     @classmethod
     def create_profile_dir_by_name(cls, path, name=u'default', config=None):
         """Create a profile dir by profile name and path.
 
         Parameters
         ----------
         path : unicode
             The path (directory) to put the profile directory in.
         name : unicode
             The name of the profile.  The name of the profile directory will
             be "profile_<profile>".
         """
         if not os.path.isdir(path):
             raise ProfileDirError('Directory not found: %s' % path)
         profile_dir = os.path.join(path, u'profile_' + name)
         return cls(location=profile_dir, config=config)
 
     @classmethod
     def find_profile_dir_by_name(cls, ipython_dir, name=u'default', config=None):
         """Find an existing profile dir by profile name, return its ProfileDir.
 
         This searches through a sequence of paths for a profile dir.  If it
         is not found, a :class:`ProfileDirError` exception will be raised.
 
         The search path algorithm is:
         1. ``os.getcwdu()``
         2. ``ipython_dir``
 
         Parameters
         ----------
         ipython_dir : unicode or str
             The IPython directory to use.
         name : unicode or str
             The name of the profile.  The name of the profile directory
             will be "profile_<profile>".
         """
         dirname = u'profile_' + name
         paths = [os.getcwdu(), ipython_dir]
         for p in paths:
             profile_dir = os.path.join(p, dirname)
             if os.path.isdir(profile_dir):
                 return cls(location=profile_dir, config=config)
         else:
             raise ProfileDirError('Profile directory not found in paths: %s' % dirname)
 
     @classmethod
     def find_profile_dir(cls, profile_dir, config=None):
         """Find/create a profile dir and return its ProfileDir.
 
         This will create the profile directory if it doesn't exist.
 
         Parameters
         ----------
         profile_dir : unicode or str
             The path of the profile directory.  This is expanded using
             :func:`IPython.utils.genutils.expand_path`.
         """
         profile_dir = expand_path(profile_dir)
         if not os.path.isdir(profile_dir):
             raise ProfileDirError('Profile directory not found: %s' % profile_dir)
         return cls(location=profile_dir, config=config)
 
 

IPython/external/path/_path.py

@@ -1,947 +1,947 b''
 """ path.py - An object representing a path to a file or directory.
 
 Example:
 
 from IPython.external.path import path
 d = path('/home/guido/bin')
 for f in d.files('*.py'):
     f.chmod(0755)
 
 This module requires Python 2.5 or later.
 
 
 URL:     http://pypi.python.org/pypi/path.py
 Author:  Jason Orendorff <jason.orendorff\x40gmail\x2ecom> (and others - see the url!)
 Date:    9 Mar 2007
 """
 
 
 # TODO
 #   - Tree-walking functions don't avoid symlink loops.  Matt Harrison
 #     sent me a patch for this.
 #   - Bug in write_text().  It doesn't support Universal newline mode.
 #   - Better error message in listdir() when self isn't a
 #     directory. (On Windows, the error message really sucks.)
 #   - Make sure everything has a good docstring.
 #   - Add methods for regex find and replace.
 #   - guess_content_type() method?
 #   - Perhaps support arguments to touch().
 
 from __future__ import generators
 
 import sys, warnings, os, fnmatch, glob, shutil, codecs
 from hashlib import md5
 
 __version__ = '2.2'
 __all__ = ['path']
 
 # Platform-specific support for path.owner
 if os.name == 'nt':
     try:
         import win32security
     except ImportError:
         win32security = None
 else:
     try:
         import pwd
     except ImportError:
         pwd = None
 
 
 class TreeWalkWarning(Warning):
     pass
 
 class path(unicode):
     """ Represents a filesystem path.
 
     For documentation on individual methods, consult their
     counterparts in os.path.
     """
 
     # --- Special Python methods.
 
     def __repr__(self):
         return 'path(%s)' % unicode.__repr__(self)
 
     # Adding a path and a string yields a path.
     def __add__(self, more):
         try:
             resultStr = unicode.__add__(self, more)
         except TypeError:  #Python bug
             resultStr = NotImplemented
         if resultStr is NotImplemented:
             return resultStr
         return self.__class__(resultStr)
 
     def __radd__(self, other):
         if isinstance(other, basestring):
             return self.__class__(other.__add__(self))
         else:
             return NotImplemented
 
     # The / operator joins paths.
     def __div__(self, rel):
         """ fp.__div__(rel) == fp / rel == fp.joinpath(rel)
 
         Join two path components, adding a separator character if
         needed.
         """
         return self.__class__(os.path.join(self, rel))
 
     # Make the / operator work even when true division is enabled.
     __truediv__ = __div__
 
     def getcwd(cls):
         """ Return the current working directory as a path object. """
         return cls(os.getcwdu())
     getcwd = classmethod(getcwd)
 
 
     # --- Operations on path strings.
 
     def isabs(s): return os.path.isabs(s)
     def abspath(self):       return self.__class__(os.path.abspath(self))
     def normcase(self):      return self.__class__(os.path.normcase(self))
     def normpath(self):      return self.__class__(os.path.normpath(self))
     def realpath(self):      return self.__class__(os.path.realpath(self))
     def expanduser(self):    return self.__class__(os.path.expanduser(self))
     def expandvars(self):    return self.__class__(os.path.expandvars(self))
     def dirname(self):       return self.__class__(os.path.dirname(self))
     def basename(s): return os.path.basename(s)
 
     def expand(self):
         """ Clean up a filename by calling expandvars(),
         expanduser(), and normpath() on it.
 
         This is commonly everything needed to clean up a filename
         read from a configuration file, for example.
         """
         return self.expandvars().expanduser().normpath()
 
     def _get_namebase(self):
         base, ext = os.path.splitext(self.name)
         return base
 
     def _get_ext(self):
         f, ext = os.path.splitext(unicode(self))
         return ext
 
     def _get_drive(self):
         drive, r = os.path.splitdrive(self)
         return self.__class__(drive)
 
     parent = property(
         dirname, None, None,
         """ This path's parent directory, as a new path object.
 
         For example, path('/usr/local/lib/libpython.so').parent == path('/usr/local/lib')
         """)
 
     name = property(
         basename, None, None,
         """ The name of this file or directory without the full path.
 
         For example, path('/usr/local/lib/libpython.so').name == 'libpython.so'
         """)
 
     namebase = property(
         _get_namebase, None, None,
         """ The same as path.name, but with one file extension stripped off.
 
         For example, path('/home/guido/python.tar.gz').name     == 'python.tar.gz',
         but          path('/home/guido/python.tar.gz').namebase == 'python.tar'
         """)
 
     ext = property(
         _get_ext, None, None,
         """ The file extension, for example '.py'. """)
 
     drive = property(
         _get_drive, None, None,
         """ The drive specifier, for example 'C:'.
         This is always empty on systems that don't use drive specifiers.
         """)
 
     def splitpath(self):
         """ p.splitpath() -> Return (p.parent, p.name). """
         parent, child = os.path.split(self)
         return self.__class__(parent), child
 
     def splitdrive(self):
         """ p.splitdrive() -> Return (p.drive, <the rest of p>).
 
         Split the drive specifier from this path.  If there is
         no drive specifier, p.drive is empty, so the return value
         is simply (path(''), p).  This is always the case on Unix.
         """
         drive, rel = os.path.splitdrive(self)
         return self.__class__(drive), rel
 
     def splitext(self):
         """ p.splitext() -> Return (p.stripext(), p.ext).
 
         Split the filename extension from this path and return
         the two parts.  Either part may be empty.
 
         The extension is everything from '.' to the end of the
         last path segment.  This has the property that if
         (a, b) == p.splitext(), then a + b == p.
         """
         filename, ext = os.path.splitext(self)
         return self.__class__(filename), ext
 
     def stripext(self):
         """ p.stripext() -> Remove one file extension from the path.
 
         For example, path('/home/guido/python.tar.gz').stripext()
         returns path('/home/guido/python.tar').
         """
         return self.splitext()[0]
 
     if hasattr(os.path, 'splitunc'):
         def splitunc(self):
             unc, rest = os.path.splitunc(self)
             return self.__class__(unc), rest
 
         def _get_uncshare(self):
             unc, r = os.path.splitunc(self)
             return self.__class__(unc)
 
         uncshare = property(
             _get_uncshare, None, None,
             """ The UNC mount point for this path.
             This is empty for paths on local drives. """)
 
     def joinpath(self, *args):
         """ Join two or more path components, adding a separator
         character (os.sep) if needed.  Returns a new path
         object.
         """
         return self.__class__(os.path.join(self, *args))
 
     def splitall(self):
         r""" Return a list of the path components in this path.
 
         The first item in the list will be a path.  Its value will be
         either os.curdir, os.pardir, empty, or the root directory of
         this path (for example, '/' or 'C:\\').  The other items in
         the list will be strings.
 
         path.path.joinpath(*result) will yield the original path.
         """
         parts = []
         loc = self
         while loc != os.curdir and loc != os.pardir:
             prev = loc
             loc, child = prev.splitpath()
             if loc == prev:
                 break
             parts.append(child)
         parts.append(loc)
         parts.reverse()
         return parts
 
     def relpath(self):
         """ Return this path as a relative path,
         based from the current working directory.
         """
         cwd = self.__class__(os.getcwdu())
         return cwd.relpathto(self)
 
     def relpathto(self, dest):
         """ Return a relative path from self to dest.
 
         If there is no relative path from self to dest, for example if
         they reside on different drives in Windows, then this returns
         dest.abspath().
         """
         origin = self.abspath()
         dest = self.__class__(dest).abspath()
 
         orig_list = origin.normcase().splitall()
         # Don't normcase dest!  We want to preserve the case.
         dest_list = dest.splitall()
 
         if orig_list[0] != os.path.normcase(dest_list[0]):
             # Can't get here from there.
             return dest
 
         # Find the location where the two paths start to differ.
         i = 0
         for start_seg, dest_seg in zip(orig_list, dest_list):
             if start_seg != os.path.normcase(dest_seg):
                 break
             i += 1
 
         # Now i is the point where the two paths diverge.
         # Need a certain number of "os.pardir"s to work up
         # from the origin to the point of divergence.
         segments = [os.pardir] * (len(orig_list) - i)
         # Need to add the diverging part of dest_list.
         segments += dest_list[i:]
         if len(segments) == 0:
             # If they happen to be identical, use os.curdir.
             relpath = os.curdir
         else:
             relpath = os.path.join(*segments)
         return self.__class__(relpath)
 
     # --- Listing, searching, walking, and matching
 
     def listdir(self, pattern=None):
         """ D.listdir() -> List of items in this directory.
 
         Use D.files() or D.dirs() instead if you want a listing
         of just files or just subdirectories.
 
         The elements of the list are path objects.
 
         With the optional 'pattern' argument, this only lists
         items whose names match the given pattern.
         """
         names = os.listdir(self)
         if pattern is not None:
             names = fnmatch.filter(names, pattern)
         return [self / child for child in names]
 
     def dirs(self, pattern=None):
         """ D.dirs() -> List of this directory's subdirectories.
 
         The elements of the list are path objects.
         This does not walk recursively into subdirectories
         (but see path.walkdirs).
 
         With the optional 'pattern' argument, this only lists
         directories whose names match the given pattern.  For
         example, d.dirs('build-*').
         """
         return [p for p in self.listdir(pattern) if p.isdir()]
 
     def files(self, pattern=None):
         """ D.files() -> List of the files in this directory.
 
         The elements of the list are path objects.
         This does not walk into subdirectories (see path.walkfiles).
 
         With the optional 'pattern' argument, this only lists files
         whose names match the given pattern.  For example,
         d.files('*.pyc').
         """
         
         return [p for p in self.listdir(pattern) if p.isfile()]
 
     def walk(self, pattern=None, errors='strict'):
         """ D.walk() -> iterator over files and subdirs, recursively.
 
         The iterator yields path objects naming each child item of
         this directory and its descendants.  This requires that
         D.isdir().
 
         This performs a depth-first traversal of the directory tree.
         Each directory is returned just before all its children.
 
         The errors= keyword argument controls behavior when an
         error occurs.  The default is 'strict', which causes an
         exception.  The other allowed values are 'warn', which
         reports the error via warnings.warn(), and 'ignore'.
         """
         if errors not in ('strict', 'warn', 'ignore'):
             raise ValueError("invalid errors parameter")
 
         try:
             childList = self.listdir()
         except Exception:
             if errors == 'ignore':
                 return
             elif errors == 'warn':
                 warnings.warn(
                     "Unable to list directory '%s': %s"
                     % (self, sys.exc_info()[1]),
                     TreeWalkWarning)
                 return
             else:
                 raise
 
         for child in childList:
             if pattern is None or child.fnmatch(pattern):
                 yield child
             try:
                 isdir = child.isdir()
             except Exception:
                 if errors == 'ignore':
                     isdir = False
                 elif errors == 'warn':
                     warnings.warn(
                         "Unable to access '%s': %s"
                         % (child, sys.exc_info()[1]),
                         TreeWalkWarning)
                     isdir = False
                 else:
                     raise
 
             if isdir:
                 for item in child.walk(pattern, errors):
                     yield item
 
     def walkdirs(self, pattern=None, errors='strict'):
         """ D.walkdirs() -> iterator over subdirs, recursively.
 
         With the optional 'pattern' argument, this yields only
         directories whose names match the given pattern.  For
         example, mydir.walkdirs('*test') yields only directories
         with names ending in 'test'.
 
         The errors= keyword argument controls behavior when an
         error occurs.  The default is 'strict', which causes an
         exception.  The other allowed values are 'warn', which
         reports the error via warnings.warn(), and 'ignore'.
         """
         if errors not in ('strict', 'warn', 'ignore'):
             raise ValueError("invalid errors parameter")
 
         try:
             dirs = self.dirs()
         except Exception:
             if errors == 'ignore':
                 return
             elif errors == 'warn':
                 warnings.warn(
                     "Unable to list directory '%s': %s"
                     % (self, sys.exc_info()[1]),
                     TreeWalkWarning)
                 return
             else:
                 raise
 
         for child in dirs:
             if pattern is None or child.fnmatch(pattern):
                 yield child
             for subsubdir in child.walkdirs(pattern, errors):
                 yield subsubdir
 
     def walkfiles(self, pattern=None, errors='strict'):
         """ D.walkfiles() -> iterator over files in D, recursively.
 
         The optional argument, pattern, limits the results to files
         with names that match the pattern.  For example,
         mydir.walkfiles('*.tmp') yields only files with the .tmp
         extension.
         """
         if errors not in ('strict', 'warn', 'ignore'):
             raise ValueError("invalid errors parameter")
 
         try:
             childList = self.listdir()
         except Exception:
             if errors == 'ignore':
                 return
             elif errors == 'warn':
                 warnings.warn(
                     "Unable to list directory '%s': %s"
                     % (self, sys.exc_info()[1]),
                     TreeWalkWarning)
                 return
             else:
                 raise
 
         for child in childList:
             try:
                 isfile = child.isfile()
                 isdir = not isfile and child.isdir()
             except:
                 if errors == 'ignore':
                     continue
                 elif errors == 'warn':
                     warnings.warn(
                         "Unable to access '%s': %s"
                         % (self, sys.exc_info()[1]),
                         TreeWalkWarning)
                     continue
                 else:
                     raise
 
             if isfile:
                 if pattern is None or child.fnmatch(pattern):
                     yield child
             elif isdir:
                 for f in child.walkfiles(pattern, errors):
                     yield f
 
     def fnmatch(self, pattern):
         """ Return True if self.name matches the given pattern.
 
         pattern - A filename pattern with wildcards,
             for example '*.py'.
         """
         return fnmatch.fnmatch(self.name, pattern)
 
     def glob(self, pattern):
         """ Return a list of path objects that match the pattern.
 
         pattern - a path relative to this directory, with wildcards.
 
         For example, path('/users').glob('*/bin/*') returns a list
         of all the files users have in their bin directories.
         """
         cls = self.__class__
         return [cls(s) for s in glob.glob(unicode(self / pattern))]
 
 
     # --- Reading or writing an entire file at once.
 
     def open(self, mode='r'):
         """ Open this file.  Return a file object. """
         return open(self, mode)
 
     def bytes(self):
         """ Open this file, read all bytes, return them as a string. """
         f = self.open('rb')
         try:
             return f.read()
         finally:
             f.close()
 
     def write_bytes(self, bytes, append=False):
         """ Open this file and write the given bytes to it.
 
         Default behavior is to overwrite any existing file.
         Call p.write_bytes(bytes, append=True) to append instead.
         """
         if append:
             mode = 'ab'
         else:
             mode = 'wb'
         f = self.open(mode)
         try:
             f.write(bytes)
         finally:
             f.close()
 
     def text(self, encoding=None, errors='strict'):
         r""" Open this file, read it in, return the content as a string.
 
         This uses 'U' mode in Python 2.3 and later, so '\r\n' and '\r'
         are automatically translated to '\n'.
 
         Optional arguments:
 
         encoding - The Unicode encoding (or character set) of
             the file.  If present, the content of the file is
             decoded and returned as a unicode object; otherwise
             it is returned as an 8-bit str.
         errors - How to handle Unicode errors; see help(str.decode)
             for the options.  Default is 'strict'.
         """
         if encoding is None:
             # 8-bit
             f = self.open('U')
             try:
                 return f.read()
             finally:
                 f.close()
         else:
             # Unicode
             f = codecs.open(self, 'r', encoding, errors)
             # (Note - Can't use 'U' mode here, since codecs.open
             # doesn't support 'U' mode, even in Python 2.3.)
             try:
                 t = f.read()
             finally:
                 f.close()
             return (t.replace(u'\r\n', u'\n')
                      .replace(u'\r\x85', u'\n')
                      .replace(u'\r', u'\n')
                      .replace(u'\x85', u'\n')
                      .replace(u'\u2028', u'\n'))
 
     def write_text(self, text, encoding=None, errors='strict', linesep=os.linesep, append=False):
         r""" Write the given text to this file.
 
         The default behavior is to overwrite any existing file;
         to append instead, use the 'append=True' keyword argument.
 
         There are two differences between path.write_text() and
         path.write_bytes(): newline handling and Unicode handling.
         See below.
 
         Parameters:
 
           - text - str/unicode - The text to be written.
 
           - encoding - str - The Unicode encoding that will be used.
             This is ignored if 'text' isn't a Unicode string.
 
           - errors - str - How to handle Unicode encoding errors.
             Default is 'strict'.  See help(unicode.encode) for the
             options.  This is ignored if 'text' isn't a Unicode
             string.
 
           - linesep - keyword argument - str/unicode - The sequence of
             characters to be used to mark end-of-line.  The default is
             os.linesep.  You can also specify None; this means to
             leave all newlines as they are in 'text'.
 
           - append - keyword argument - bool - Specifies what to do if
             the file already exists (True: append to the end of it;
             False: overwrite it.)  The default is False.
 
 
         --- Newline handling.
 
         write_text() converts all standard end-of-line sequences
         ('\n', '\r', and '\r\n') to your platform's default end-of-line
         sequence (see os.linesep; on Windows, for example, the
         end-of-line marker is '\r\n').
 
         If you don't like your platform's default, you can override it
         using the 'linesep=' keyword argument.  If you specifically want
         write_text() to preserve the newlines as-is, use 'linesep=None'.
 
         This applies to Unicode text the same as to 8-bit text, except
         there are three additional standard Unicode end-of-line sequences:
         u'\x85', u'\r\x85', and u'\u2028'.
 
         (This is slightly different from when you open a file for
         writing with fopen(filename, "w") in C or open(filename, 'w')
         in Python.)
 
 
         --- Unicode
 
         If 'text' isn't Unicode, then apart from newline handling, the
         bytes are written verbatim to the file.  The 'encoding' and
         'errors' arguments are not used and must be omitted.
 
         If 'text' is Unicode, it is first converted to bytes using the
         specified 'encoding' (or the default encoding if 'encoding'
         isn't specified).  The 'errors' argument applies only to this
         conversion.
 
         """
         if isinstance(text, unicode):
             if linesep is not None:
                 # Convert all standard end-of-line sequences to
                 # ordinary newline characters.
                 text = (text.replace(u'\r\n', u'\n')
                             .replace(u'\r\x85', u'\n')
                             .replace(u'\r', u'\n')
                             .replace(u'\x85', u'\n')
                             .replace(u'\u2028', u'\n'))
                 text = text.replace(u'\n', linesep)
             if encoding is None:
                 encoding = sys.getdefaultencoding()
             bytes = text.encode(encoding, errors)
         else:
             # It is an error to specify an encoding if 'text' is
             # an 8-bit string.
             assert encoding is None
 
             if linesep is not None:
                 text = (text.replace('\r\n', '\n')
                             .replace('\r', '\n'))
                 bytes = text.replace('\n', linesep)
 
         self.write_bytes(bytes, append)
 
     def lines(self, encoding=None, errors='strict', retain=True):
         r""" Open this file, read all lines, return them in a list.
 
         Optional arguments:
             encoding - The Unicode encoding (or character set) of
                 the file.  The default is None, meaning the content
                 of the file is read as 8-bit characters and returned
                 as a list of (non-Unicode) str objects.
             errors - How to handle Unicode errors; see help(str.decode)
                 for the options.  Default is 'strict'
             retain - If true, retain newline characters; but all newline
                 character combinations ('\r', '\n', '\r\n') are
                 translated to '\n'.  If false, newline characters are
                 stripped off.  Default is True.
 
         This uses 'U' mode in Python 2.3 and later.
         """
         if encoding is None and retain:
             f = self.open('U')
             try:
                 return f.readlines()
             finally:
                 f.close()
         else:
             return self.text(encoding, errors).splitlines(retain)
 
     def write_lines(self, lines, encoding=None, errors='strict',
                     linesep=os.linesep, append=False):
         r""" Write the given lines of text to this file.
 
         By default this overwrites any existing file at this path.
 
         This puts a platform-specific newline sequence on every line.
         See 'linesep' below.
 
         lines - A list of strings.
 
         encoding - A Unicode encoding to use.  This applies only if
             'lines' contains any Unicode strings.
 
         errors - How to handle errors in Unicode encoding.  This
             also applies only to Unicode strings.
 
         linesep - The desired line-ending.  This line-ending is
             applied to every line.  If a line already has any
             standard line ending ('\r', '\n', '\r\n', u'\x85',
             u'\r\x85', u'\u2028'), that will be stripped off and
             this will be used instead.  The default is os.linesep,
             which is platform-dependent ('\r\n' on Windows, '\n' on
             Unix, etc.)  Specify None to write the lines as-is,
             like file.writelines().
 
         Use the keyword argument append=True to append lines to the
         file.  The default is to overwrite the file.  Warning:
         When you use this with Unicode data, if the encoding of the
         existing data in the file is different from the encoding
         you specify with the encoding= parameter, the result is
         mixed-encoding data, which can really confuse someone trying
         to read the file later.
         """
         if append:
             mode = 'ab'
         else:
             mode = 'wb'
         f = self.open(mode)
         try:
             for line in lines:
                 isUnicode = isinstance(line, unicode)
                 if linesep is not None:
                     # Strip off any existing line-end and add the
                     # specified linesep string.
                     if isUnicode:
                         if line[-2:] in (u'\r\n', u'\x0d\x85'):
                             line = line[:-2]
                         elif line[-1:] in (u'\r', u'\n',
                                            u'\x85', u'\u2028'):
                             line = line[:-1]
                     else:
                         if line[-2:] == '\r\n':
                             line = line[:-2]
                         elif line[-1:] in ('\r', '\n'):
                             line = line[:-1]
                     line += linesep
                 if isUnicode:
                     if encoding is None:
                         encoding = sys.getdefaultencoding()
                     line = line.encode(encoding, errors)
                 f.write(line)
         finally:
             f.close()
 
     def read_md5(self):
         """ Calculate the md5 hash for this file.
 
         This reads through the entire file.
         """
         f = self.open('rb')
         try:
             m = md5()
             while True:
                 d = f.read(8192)
                 if not d:
                     break
                 m.update(d)
         finally:
             f.close()
         return m.digest()
 
     # --- Methods for querying the filesystem.
     # N.B. We can't assign the functions directly, because they may on some
     # platforms be implemented in C, and compiled functions don't get bound.
     # See gh-737 for discussion of this.
 
     def exists(s): return os.path.exists(s)
     def isdir(s): return os.path.isdir(s)
     def isfile(s): return os.path.isfile(s)
     def islink(s): return os.path.islink(s)
     def ismount(s): return os.path.ismount(s)
 
     if hasattr(os.path, 'samefile'):
         def samefile(s, o): return os.path.samefile(s, o)
 
     def getatime(s): return os.path.getatime(s)
     atime = property(
         getatime, None, None,
         """ Last access time of the file. """)
 
     def getmtime(s): return os.path.getmtime(s)
     mtime = property(
         getmtime, None, None,
         """ Last-modified time of the file. """)
 
     if hasattr(os.path, 'getctime'):
         def getctime(s): return os.path.getctime(s)
         ctime = property(
             getctime, None, None,
             """ Creation time of the file. """)
 
     def getsize(s): return os.path.getsize(s)
     size = property(
         getsize, None, None,
         """ Size of the file, in bytes. """)
 
     if hasattr(os, 'access'):
         def access(self, mode):
             """ Return true if current user has access to this path.
 
             mode - One of the constants os.F_OK, os.R_OK, os.W_OK, os.X_OK
             """
             return os.access(self, mode)
 
     def stat(self):
         """ Perform a stat() system call on this path. """
         return os.stat(self)
 
     def lstat(self):
         """ Like path.stat(), but do not follow symbolic links. """
         return os.lstat(self)
 
     def get_owner(self):
         r""" Return the name of the owner of this file or directory.
 
         This follows symbolic links.
 
         On Windows, this returns a name of the form ur'DOMAIN\User Name'.
         On Windows, a group can own a file or directory.
         """
         if os.name == 'nt':
             if win32security is None:
                 raise Exception("path.owner requires win32all to be installed")
             desc = win32security.GetFileSecurity(
                 self, win32security.OWNER_SECURITY_INFORMATION)
             sid = desc.GetSecurityDescriptorOwner()
             account, domain, typecode = win32security.LookupAccountSid(None, sid)
             return domain + u'\\' + account
         else:
             if pwd is None:
                 raise NotImplementedError("path.owner is not implemented on this platform.")
             st = self.stat()
             return pwd.getpwuid(st.st_uid).pw_name
 
     owner = property(
         get_owner, None, None,
         """ Name of the owner of this file or directory. """)
 
     if hasattr(os, 'statvfs'):
         def statvfs(self):
             """ Perform a statvfs() system call on this path. """
             return os.statvfs(self)
 
     if hasattr(os, 'pathconf'):
         def pathconf(self, name):
             return os.pathconf(self, name)
 
 
     # --- Modifying operations on files and directories
 
     def utime(self, times):
         """ Set the access and modified times of this file. """
         os.utime(self, times)
 
     def chmod(self, mode):
         os.chmod(self, mode)
 
     if hasattr(os, 'chown'):
         def chown(self, uid, gid):
             os.chown(self, uid, gid)
 
     def rename(self, new):
         os.rename(self, new)
 
     def renames(self, new):
         os.renames(self, new)
 
 
     # --- Create/delete operations on directories
 
-    def mkdir(self, mode=0777):
+    def mkdir(self, mode=0o777):
         os.mkdir(self, mode)
 
-    def makedirs(self, mode=0777):
+    def makedirs(self, mode=0o777):
         os.makedirs(self, mode)
 
     def rmdir(self):
         os.rmdir(self)
 
     def removedirs(self):
         os.removedirs(self)
 
 
     # --- Modifying operations on files
 
     def touch(self):
         """ Set the access/modified times of this file to the current time.
         Create the file if it does not exist.
         """
-        fd = os.open(self, os.O_WRONLY | os.O_CREAT, 0666)
+        fd = os.open(self, os.O_WRONLY | os.O_CREAT, 0o666)
         os.close(fd)
         os.utime(self, None)
 
     def remove(self):
         os.remove(self)
 
     def unlink(self):
         os.unlink(self)
 
 
     # --- Links
 
     if hasattr(os, 'link'):
         def link(self, newpath):
             """ Create a hard link at 'newpath', pointing to this file. """
             os.link(self, newpath)
 
     if hasattr(os, 'symlink'):
         def symlink(self, newlink):
             """ Create a symbolic link at 'newlink', pointing here. """
             os.symlink(self, newlink)
 
     if hasattr(os, 'readlink'):
         def readlink(self):
             """ Return the path to which this symbolic link points.
 
             The result may be an absolute or a relative path.
             """
             return self.__class__(os.readlink(self))
 
         def readlinkabs(self):
             """ Return the path to which this symbolic link points.
 
             The result is always an absolute path.
             """
             p = self.readlink()
             if p.isabs():
                 return p
             else:
                 return (self.parent / p).abspath()
 
 
     # --- High-level functions from shutil
 
     copyfile = shutil.copyfile
     copymode = shutil.copymode
     copystat = shutil.copystat
     copy = shutil.copy
     copy2 = shutil.copy2
     copytree = shutil.copytree
     if hasattr(shutil, 'move'):
         move = shutil.move
     rmtree = shutil.rmtree
 
 
     # --- Special stuff from os
 
     if hasattr(os, 'chroot'):
         def chroot(self):
             os.chroot(self)
 
     if hasattr(os, 'startfile'):
         def startfile(self):
             os.startfile(self)