text: # -*- coding: utf-8 -*-
  """Main IPython class."""
  
  #-----------------------------------------------------------------------------
  #  Copyright (C) 2001 Janko Hauser <jhauser@zscout.de>
  #  Copyright (C) 2001-2007 Fernando Perez. <fperez@colorado.edu>
  #  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 absolute_import
  from __future__ import print_function
  
  import __builtin__ as builtin_mod
  import __future__
  import abc
  import ast
  import atexit
  import functools
  import os
  import re
  import runpy
  import sys
  import tempfile
  import types
  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, check_linecache_ipython
  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.prefilter import PrefilterManager
  from IPython.core.profiledir import ProfileDir
  from IPython.core.prompts import PromptManager
  from IPython.lib.latextools import LaTeXTool
  from IPython.testing.skipdoctest import skip_doctest
  from IPython.utils import PyColorize
  from IPython.utils import io
  from IPython.utils import py3compat
  from IPython.utils import openpy
  from IPython.utils.decorators import undoc
  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
  #-----------------------------------------------------------------------------
  
  @undoc
  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
  
  @undoc
  def no_op(*a, **kw): pass
  
  @undoc
  class NoOpContext(object):
      def __enter__(self): pass
      def __exit__(self, type, value, traceback): pass
  no_op_context = NoOpContext()
  
  class SpaceInInput(Exception): pass
  
  @undoc
  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
      
      ast_transformers = List([], config=True, help=
          """
          A list of ast.NodeTransformer subclass instances, which will be applied
          to user input before code is run.
          """
      )
  
      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 transform input line by line and detect when a block
      # is ready to be executed.
      input_splitter = Instance('IPython.core.inputsplitter.IPythonInputSplitter',
                                (), {'line_input_checker': True})
      
      # This InputSplitter instance is used to transform completed cells before
      # running them. It allows cell magics to contain blank lines.
      input_transformer_manager = Instance('IPython.core.inputsplitter.IPythonInputSplitter',
                                           (), {'line_input_checker': False})
      
      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}".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)
      readline_delims = Unicode() # set by init_readline()
      # 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')
      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, ipython_dir=None, profile_dir=None,
                   user_module=None, user_ns=None,
                   custom_exceptions=((), None), **kwargs):
  
          # This is where traits with a config_key argument are updated
          # from the values on config.
          super(InteractiveShell, self).__init__(**kwargs)
          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_latextool()
          self.init_magics()
          self.init_logstart()
          self.init_pdb()
          self.init_extension_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 = 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' or sys.platform == 'cli') 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, parent=self)
          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(parent=self)
          self.configurables.append(self.display_formatter)
  
      def init_display_pub(self):
          self.display_pub = self.display_pub_class(parent=self)
          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(parent=self)
          self.configurables.append(self.data_pub)
  
      def init_displayhook(self):
          # Initialize displayhook, set in/out prompts and printing system
          self.displayhook = self.displayhook_class(
              parent=self,
              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_latextool(self):
          """Configure LaTeXTool."""
          cfg = LaTeXTool.instance(parent=self)
          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.")
          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, filename):
          """Return a new 'main' module object for user code execution.
          
          ``filename`` should be the path of the script which will be run in the
          module. Requests with the same filename will get the same module, with
          its namespace cleared.
          
          When scripts are executed via %run, we must keep a reference to their
          __main__ module (a FakeModule instance) around so that Python doesn't
          clear it, rendering references to module globals useless.
  
          This method keeps said reference in a private dict, keyed by the
          absolute path of the script. 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.
          """
          filename = os.path.abspath(filename)
          try:
              main_mod = self._main_mod_cache[filename]
          except KeyError:
              main_mod = self._main_mod_cache[filename] = FakeModule()
          else:
              init_fakemod_dict(main_mod)
          
          return main_mod
  
      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]: m = _ip.new_main_mod(IPython.__file__)
  
          In [17]: len(_ip._main_mod_cache) > 0
          Out[17]: True
  
          In [18]: _ip.clear_main_mod_cache()
  
          In [19]: len(_ip._main_mod_cache) == 0
          Out[19]: True
          """
          self._main_mod_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 <aleaxit@yahoo.com>
          # Datum: Freitag 01 Oktober 2004 04:45:34 nachmittags/abends
          # Gruppen: comp.lang.python
  
          # Michael Hohn <hohn@hooknose.lbl.gov> 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_mod_cache = {}
  
          # 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()
          
          # 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] + \
                 [m.__dict__ for m in self._main_mod_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()
  
      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, parent=self)
          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=check_linecache_ipython)
  
          # 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 show_usage_error(self, exc):
          """Show a short message for UsageErrors
          
          These are special exceptions that shouldn't show a traceback.
          """
          self.write_err("UsageError: %s" % exc)
      
      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.show_usage_error(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)
              # Store these so we can restore them if something like rpy2 modifies
              # them.
              self.readline_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):
                  try:
                      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
                  
                  except TypeError:
                      # The history DB can get corrupted so it returns strings
                      # containing null bytes, which readline objects to.
                      continue
  
      @skip_doctest
      def set_next_input(self, s):
          """ Sets the 'default' input string for the next command line.
  
          Requires readline.
  
          Example::
  
              In [1]: _ip.set_next_input("Hello Word")
              In [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,
                                       parent=self,
                                       )
          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,
                                     parent=self,
                                     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.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
          # FIXME: magic aliases should be defined by the Magics classes
          # or in MagicsManager, not here
          mman.register_alias('ed', 'edit')
          mman.register_alias('hist', 'history')
          mman.register_alias('rep', 'recall')
          mman.register_alias('SVG', 'svg', 'cell')
          mman.register_alias('HTML', 'html', 'cell')
          mman.register_alias('file', 'writefile', 'cell')
  
          # 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)
  
      # Defined here so that it's included in the documentation
      @functools.wraps(magic.MagicsManager.register_function)
      def register_magic_function(self, func, magic_kind='line', magic_name=None):
          self.magics_manager.register_function(func,
                                    magic_kind=magic_kind, magic_name=magic_name)
  
      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 `%%{0}` not found{1}."
              extra = '' if lm is None else (' (But line magic `%{0}` exists, '
                              'did you mean that instead?)'.format(magic_name))
              error(etpl.format(magic_name, extra))
          elif cell == '':
              message = '%%{0} is a cell magic, but the cell body is empty.'.format(magic_name)
              if self.find_line_magic(magic_name) is not None:
                  message += ' Did you mean the line magic %{0} (single %)?'.format(magic_name)
              raise UsageError(message)
          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)
              # The high byte is the exit code, the low byte is a signal number
              # that we discard for now. See the docs for os.wait()
              if ec > 255:
                  ec >>= 8
          
          # 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, parent=self)
          self.configurables.append(self.alias_manager)
          self.ns_table['alias'] = self.alias_manager.alias_table,
  
      #-------------------------------------------------------------------------
      # Things related to extensions
      #-------------------------------------------------------------------------
  
      def init_extension_manager(self):
          self.extension_manager = ExtensionManager(shell=self, parent=self)
          self.configurables.append(self.extension_manager)
  
      #-------------------------------------------------------------------------
      # Things related to payloads
      #-------------------------------------------------------------------------
  
      def init_payload(self):
          self.payload_manager = PayloadManager(parent=self)
          self.configurables.append(self.payload_manager)
  
      #-------------------------------------------------------------------------
      # Things related to the prefilter
      #-------------------------------------------------------------------------
  
      def init_prefilter(self):
          self.prefilter_manager = PrefilterManager(shell=self, parent=self)
          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 _user_obj_error(self):
          """return simple exception dict
          
          for use in user_variables / expressions
          """
          
          etype, evalue, tb = self._get_exc_info()
          stb = self.InteractiveTB.get_exception_only(etype, evalue)
          
          exc_info = {
              u'status' : 'error',
              u'traceback' : stb,
              u'ename' : unicode(etype.__name__),
              u'evalue' : py3compat.safe_unicode(evalue),
          }
  
          return exc_info
      
      def _format_user_obj(self, obj):
          """format a user object to display dict
          
          for use in user_expressions / variables
          """
          
          data, md = self.display_formatter.format(obj)
          value = {
              'status' : 'ok',
              'data' : data,
              'metadata' : md,
          }
          return 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 rich mime-type repr(s) of each value.
          Each element will be a sub-dict of the same form as a display_data message.
          """
          out = {}
          user_ns = self.user_ns
          
          for varname in names:
              try:
                  value = self._format_user_obj(user_ns[varname])
              except:
                  value = self._user_obj_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 rich mime-typed
          display_data of each value.
          """
          out = {}
          user_ns = self.user_ns
          global_ns = self.user_global_ns
          
          for key, expr in expressions.iteritems():
              try:
                  value = self._format_user_obj(eval(expr, global_ns, user_ns))
              except:
                  value = self._user_obj_error()
              out[key] = value
          return out
  
      #-------------------------------------------------------------------------
      # Things related to the running of code
      #-------------------------------------------------------------------------
  
      def ex(self, cmd):
          """Execute a normal python statement in user namespace."""
          with self.builtin_trap:
              exec cmd in self.user_global_ns, self.user_ns
  
      def ev(self, expr):
          """Evaluate python expression expr in user namespace.
  
          Returns the result of evaluation
          """
          with self.builtin_trap:
              return eval(expr, self.user_global_ns, self.user_ns)
  
      def safe_execfile(self, fname, *where, **kw):
          """A safe version of the builtin execfile().
  
          This version will never throw an exception, but instead print
          helpful error messages to the screen.  This only works on pure
          Python files with the .py extension.
  
          Parameters
          ----------
          fname : string
              The name of the file to be executed.
          where : tuple
              One or two namespaces, passed to execfile() as (globals,locals).
              If only one is given, it is passed as both.
          exit_ignore : bool (False)
              If True, then silence SystemExit for non-zero status (it is always
              silenced for zero status, as it is so common).
          raise_exceptions : bool (False)
              If True raise exceptions everywhere. Meant for testing.
  
          """
          kw.setdefault('exit_ignore', False)
          kw.setdefault('raise_exceptions', False)
  
          fname = os.path.abspath(os.path.expanduser(fname))
  
          # Make sure we can open the file
          try:
              with open(fname) as thefile:
                  pass
          except:
              warn('Could not open file <%s> for safe execution.' % fname)
              return
  
          # Find things also in current directory.  This is needed to mimic the
          # behavior of running a script from the system command line, where
          # Python inserts the script's directory into sys.path
          dname = os.path.dirname(fname)
  
          with prepended_to_syspath(dname):
              try:
                  py3compat.execfile(fname,*where)
              except SystemExit 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 and not kw['exit_ignore']:
                      self.showtraceback(exception_only=True)
              except:
                  if kw['raise_exceptions']:
                      raise
                  self.showtraceback()
  
      def safe_execfile_ipy(self, fname):
          """Like safe_execfile, but for .ipy files with IPython syntax.
  
          Parameters
          ----------
          fname : str
              The name of the file to execute.  The filename must have a
              .ipy extension.
          """
          fname = os.path.abspath(os.path.expanduser(fname))
  
          # Make sure we can open the file
          try:
              with open(fname) as thefile:
                  pass
          except:
              warn('Could not open file <%s> for safe execution.' % fname)
              return
  
          # Find things also in current directory.  This is needed to mimic the
          # behavior of running a script from the system command line, where
          # Python inserts the script's directory into sys.path
          dname = os.path.dirname(fname)
  
          with prepended_to_syspath(dname):
              try:
                  with open(fname) as thefile:
                      # self.run_cell currently captures all exceptions
                      # raised in user code.  It would be nice if there were
                      # versions of runlines, execfile that did raise, so
                      # we could catch the errors.
                      self.run_cell(thefile.read(), store_history=False, shell_futures=False)
              except:
                  self.showtraceback()
                  warn('Unknown failure executing file: <%s>' % 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.
  
          `SystemExit` exceptions with status code 0 or None are ignored.
  
          Parameters
          ----------
          mod_name : string
              The name of the module to be executed.
          where : dict
              The globals namespace.
          """
          try:
              try:
                  where.update(
                      runpy.run_module(str(mod_name), run_name="__main__",
                                       alter_sys=True)
                      )
              except SystemExit as status:
                  if status.code:
                      raise
          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, shell_futures=True):
          """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.
          shell_futures : bool
            If True, the code will share future statements with the interactive
            shell. It will both be affected by previous __future__ imports, and
            any __future__ imports in the code will affect the shell. If False,
            __future__ imports are not shared in either direction.
          """
          if (not raw_cell) or raw_cell.isspace():
              return
          
          if silent:
              store_history = False
  
          self.input_transformer_manager.push(raw_cell)
          cell = self.input_transformer_manager.source_reset()
  
          # Our own compiler remembers the __future__ environment. If we want to
          # run code with a separate __future__ environment, use the default
          # compiler
          compiler = self.compile if shell_futures else CachingCompiler()
  
          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 = compiler.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
                      
                      code_ast = self.transform_ast(code_ast)
                      
                      interactivity = "none" if silent else self.ast_node_interactivity
                      self.run_ast_nodes(code_ast.body, cell_name,
                                         interactivity=interactivity, compiler=compiler)
                      
                      # 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 transform_ast(self, node):
          """Apply the AST transformations from self.ast_transformers
          
          Parameters
          ----------
          node : ast.Node
            The root node to be transformed. Typically called with the ast.Module
            produced by parsing user input.
          
          Returns
          -------
          An ast.Node corresponding to the node it was called with. Note that it
          may also modify the passed object, so don't rely on references to the
          original AST.
          """
          for transformer in self.ast_transformers:
              try:
                  node = transformer.visit(node)
              except Exception:
                  warn("AST transformer %r threw an error. It will be unregistered." % transformer)
                  self.ast_transformers.remove(transformer)
          
          if self.ast_transformers:
              ast.fix_missing_locations(node)
          return node
                  
  
      def run_ast_nodes(self, nodelist, cell_name, interactivity='last_expr',
                          compiler=compile):
          """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.
          compiler : callable
            A function with the same interface as the built-in compile(), to turn
            the AST nodes into code objects. Default is the built-in compile().
          """
          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 = compiler(mod, cell_name, "exec")
                  if self.run_code(code):
                      return True
  
              for i, node in enumerate(to_run_interactive):
                  mod = ast.Interactive([node])
                  code = compiler(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_matplotlib(self, gui=None):
          """Enable interactive matplotlib and inline figure support.
  
          This takes the following steps:
          
          1. select the appropriate eventloop and matplotlib backend
          2. set up matplotlib for interactive use with that backend
          3. configure formatters for inline figure display
          4. enable the selected gui eventloop
          
          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 import pylabtools as pt
          gui, backend = pt.find_gui_and_backend(gui, self.pylab_gui_select)
  
          gui = 'inline'
  
          if gui != 'inline':
              # If we have our first gui selection, store it
              if self.pylab_gui_select is None:
                  self.pylab_gui_select = gui
              # Otherwise if they are different
              elif gui != self.pylab_gui_select:
                  print ('Warning: Cannot change to a different GUI toolkit: %s.'
                          ' Using %s instead.' % (gui, self.pylab_gui_select))
                  gui, backend = pt.find_gui_and_backend(self.pylab_gui_select)
  
          pt.activate_matplotlib(backend)
          pt.configure_inline_support(self, backend)
  
          # 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 = \
              pt.mpl_runner(self.safe_execfile)
          
          return gui, backend
  
      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 ``gui`` argument.
          
          This method only adds preloading the namespace to InteractiveShell.enable_matplotlib.
  
          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.
          import_all : optional, bool, default: True
            Whether to do `from numpy import *` and `from pylab import *`
            in addition to module imports.
          welcome_message : deprecated
            This argument is ignored, no welcome message will be displayed.
          """
          from IPython.core.pylabtools import import_pylab
          
          gui, backend = self.enable_matplotlib(gui)
          
          # 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 = {}
          import_pylab(ns, import_all)
          # warn about clobbered names
          ignored = set(["__builtins__"])
          both = set(ns).intersection(self.user_ns).difference(ignored)
          clobbered = [ name for name in both if self.user_ns[name] is not ns[name] ]
          self.user_ns.update(ns)
          self.user_ns_hidden.update(ns)
          return gui, backend, clobbered
  
      #-------------------------------------------------------------------------
      # 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 :
                  from urllib import urlopen  # Deferred import
                  response = 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)
              elif os.path.isdir(os.path.expanduser(tgt)):
                  raise ValueError("'%s' is a directory, not a regular file." % 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)
  