Remove Pydb integration as Pydb is unmaintained and not ion PyPI

Closes # 9482

docs/source/whatsnew/pr/incompat-remove-pydb.rst

@@ -0,0 +1,1 b''
+Integration with pydb has been removed since pydb development has been stopped since 2012, and pydb is not installable from PyPI

IPython/core/completer.py

@@ -1,1325 +1,1324 b''
 # encoding: utf-8
 """Word completion for IPython.
 
 This module is a fork of the rlcompleter module in the Python standard
 library.  The original enhancements made to rlcompleter have been sent
 upstream and were accepted as of Python 2.3, but we need a lot more
 functionality specific to IPython, so this module will continue to live as an
 IPython-specific utility.
 
 Original rlcompleter documentation:
 
 This requires the latest extension to the readline module (the
 completes keywords, built-ins and globals in __main__; when completing
 NAME.NAME..., it evaluates (!) the expression up to the last dot and
 completes its attributes.
 
 It's very cool to do "import string" type "string.", hit the
 completion key (twice), and see the list of names defined by the
 string module!
 
 Tip: to use the tab key as the completion key, call
 
     readline.parse_and_bind("tab: complete")
 
 Notes:
 
 - Exceptions raised by the completer function are *ignored* (and
   generally cause the completion to fail).  This is a feature -- since
   readline sets the tty device in raw (or cbreak) mode, printing a
   traceback wouldn't work well without some complicated hoopla to save,
   reset and restore the tty state.
 
 - The evaluation of the NAME.NAME... form may cause arbitrary
   application defined code to be executed if an object with a
   ``__getattr__`` hook is found.  Since it is the responsibility of the
   application (or the user) to enable this feature, I consider this an
   acceptable risk.  More complicated expressions (e.g. function calls or
   indexing operations) are *not* evaluated.
 
 - GNU readline is also used by the built-in functions input() and
   raw_input(), and thus these also benefit/suffer from the completer
   features.  Clearly an interactive application can benefit by
   specifying its own completer function and using raw_input() for all
   its input.
 
 - When the original stdin is not a tty device, GNU readline is never
   used, and this module (and the readline module) are silently inactive.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 #
 # Some of this code originated from rlcompleter in the Python standard library
 # Copyright (C) 2001 Python Software Foundation, www.python.org
 
 from __future__ import print_function
 
 import __main__
 import glob
 import inspect
 import itertools
 import keyword
 import os
 import re
 import sys
 import unicodedata
 import string
 
 from traitlets.config.configurable import Configurable
 from IPython.core.error import TryNext
 from IPython.core.inputsplitter import ESC_MAGIC
 from IPython.core.latex_symbols import latex_symbols, reverse_latex_symbol
 from IPython.utils import generics
 from IPython.utils.decorators import undoc
 from IPython.utils.dir2 import dir2, get_real_method
 from IPython.utils.process import arg_split
 from IPython.utils.py3compat import builtin_mod, string_types, PY3, cast_unicode_py2
 from traitlets import Bool, Enum, observe
 
 import jedi
 import jedi.api.helpers
 import jedi.parser.user_context
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 # Public API
 __all__ = ['Completer','IPCompleter']
 
 if sys.platform == 'win32':
     PROTECTABLES = ' '
 else:
     PROTECTABLES = ' ()[]{}?=\\|;:\'#*"^&'
 
 
 #-----------------------------------------------------------------------------
 # Main functions and classes
 #-----------------------------------------------------------------------------
 
 def has_open_quotes(s):
     """Return whether a string has open quotes.
 
     This simply counts whether the number of quote characters of either type in
     the string is odd.
 
     Returns
     -------
     If there is an open quote, the quote character is returned.  Else, return
     False.
     """
     # We check " first, then ', so complex cases with nested quotes will get
     # the " to take precedence.
     if s.count('"') % 2:
         return '"'
     elif s.count("'") % 2:
         return "'"
     else:
         return False
 
 
 def protect_filename(s):
     """Escape a string to protect certain characters."""
 
     return "".join([(ch in PROTECTABLES and '\\' + ch or ch)
                     for ch in s])
 
 def expand_user(path):
     """Expand '~'-style usernames in strings.
 
     This is similar to :func:`os.path.expanduser`, but it computes and returns
     extra information that will be useful if the input was being used in
     computing completions, and you wish to return the completions with the
     original '~' instead of its expanded value.
 
     Parameters
     ----------
     path : str
       String to be expanded.  If no ~ is present, the output is the same as the
       input.
 
     Returns
     -------
     newpath : str
       Result of ~ expansion in the input path.
     tilde_expand : bool
       Whether any expansion was performed or not.
     tilde_val : str
       The value that ~ was replaced with.
     """
     # Default values
     tilde_expand = False
     tilde_val = ''
     newpath = path
 
     if path.startswith('~'):
         tilde_expand = True
         rest = len(path)-1
         newpath = os.path.expanduser(path)
         if rest:
             tilde_val = newpath[:-rest]
         else:
             tilde_val = newpath
 
     return newpath, tilde_expand, tilde_val
 
 
 def compress_user(path, tilde_expand, tilde_val):
     """Does the opposite of expand_user, with its outputs.
     """
     if tilde_expand:
         return path.replace(tilde_val, '~')
     else:
         return path
 
 
 def completions_sorting_key(word):
     """key for sorting completions
 
     This does several things:
 
     - Lowercase all completions, so they are sorted alphabetically with
       upper and lower case words mingled
     - Demote any completions starting with underscores to the end
     - Insert any %magic and %%cellmagic completions in the alphabetical order
       by their name
     """
     # Case insensitive sort
     word = word.lower()
 
     prio1, prio2 = 0, 0
 
     if word.startswith('__'):
         prio1 = 2
     elif word.startswith('_'):
         prio1 = 1
 
     if word.endswith('='):
         prio1 = -1
 
     if word.startswith('%%'):
         # If there's another % in there, this is something else, so leave it alone
         if not "%" in word[2:]:
             word = word[2:]
             prio2 = 2
     elif word.startswith('%'):
         if not "%" in word[1:]:
             word = word[1:]
             prio2 = 1
 
     return prio1, word, prio2
 
 
 @undoc
 class Bunch(object): pass
 
 
 DELIMS = ' \t\n`!@#$^&*()=+[{]}\\|;:\'",<>?'
 GREEDY_DELIMS = ' =\r\n'
 
 
 class CompletionSplitter(object):
     """An object to split an input line in a manner similar to readline.
 
     By having our own implementation, we can expose readline-like completion in
     a uniform manner to all frontends.  This object only needs to be given the
     line of text to be split and the cursor position on said line, and it
     returns the 'word' to be completed on at the cursor after splitting the
     entire line.
 
     What characters are used as splitting delimiters can be controlled by
     setting the `delims` attribute (this is a property that internally
     automatically builds the necessary regular expression)"""
 
     # Private interface
 
     # A string of delimiter characters.  The default value makes sense for
     # IPython's most typical usage patterns.
     _delims = DELIMS
 
     # The expression (a normal string) to be compiled into a regular expression
     # for actual splitting.  We store it as an attribute mostly for ease of
     # debugging, since this type of code can be so tricky to debug.
     _delim_expr = None
 
     # The regular expression that does the actual splitting
     _delim_re = None
 
     def __init__(self, delims=None):
         delims = CompletionSplitter._delims if delims is None else delims
         self.delims = delims
 
     @property
     def delims(self):
         """Return the string of delimiter characters."""
         return self._delims
 
     @delims.setter
     def delims(self, delims):
         """Set the delimiters for line splitting."""
         expr = '[' + ''.join('\\'+ c for c in delims) + ']'
         self._delim_re = re.compile(expr)
         self._delims = delims
         self._delim_expr = expr
 
     def split_line(self, line, cursor_pos=None):
         """Split a line of text with a cursor at the given position.
         """
         l = line if cursor_pos is None else line[:cursor_pos]
         return self._delim_re.split(l)[-1]
 
 
 class Completer(Configurable):
 
     greedy = Bool(False,
         help="""Activate greedy completion
         PENDING DEPRECTION. this is now mostly taken care of with Jedi.
 
         This will enable completion on elements of lists, results of function calls, etc.,
         but can be unsafe because the code is actually evaluated on TAB.
         """
     ).tag(config=True)
     
 
     def __init__(self, namespace=None, global_namespace=None, **kwargs):
         """Create a new completer for the command line.
 
         Completer(namespace=ns, global_namespace=ns2) -> completer instance.
 
         If unspecified, the default namespace where completions are performed
         is __main__ (technically, __main__.__dict__). Namespaces should be
         given as dictionaries.
 
         An optional second namespace can be given.  This allows the completer
         to handle cases where both the local and global scopes need to be
         distinguished.
 
         Completer instances should be used as the completion mechanism of
         readline via the set_completer() call:
 
         readline.set_completer(Completer(my_namespace).complete)
         """
 
         # Don't bind to namespace quite yet, but flag whether the user wants a
         # specific namespace or to use __main__.__dict__. This will allow us
         # to bind to __main__.__dict__ at completion time, not now.
         if namespace is None:
             self.use_main_ns = 1
         else:
             self.use_main_ns = 0
             self.namespace = namespace
 
         # The global namespace, if given, can be bound directly
         if global_namespace is None:
             self.global_namespace = {}
         else:
             self.global_namespace = global_namespace
 
         super(Completer, self).__init__(**kwargs)
 
     def complete(self, text, state):
         """Return the next possible completion for 'text'.
 
         This is called successively with state == 0, 1, 2, ... until it
         returns None.  The completion should begin with 'text'.
 
         """
         if self.use_main_ns:
             self.namespace = __main__.__dict__
 
         if state == 0:
             if "." in text:
                 self.matches = self.attr_matches(text)
             else:
                 self.matches = self.global_matches(text)
         try:
             return self.matches[state]
         except IndexError:
             return None
 
     def global_matches(self, text):
         """Compute matches when text is a simple name.
 
         Return a list of all keywords, built-in functions and names currently
         defined in self.namespace or self.global_namespace that match.
 
         """
         matches = []
         match_append = matches.append
         n = len(text)
         for lst in [keyword.kwlist,
                     builtin_mod.__dict__.keys(),
                     self.namespace.keys(),
                     self.global_namespace.keys()]:
             for word in lst:
                 if word[:n] == text and word != "__builtins__":
                     match_append(word)
         return [cast_unicode_py2(m) for m in matches]
 
     def attr_matches(self, text):
         """Compute matches when text contains a dot.
 
         Assuming the text is of the form NAME.NAME....[NAME], and is
         evaluatable in self.namespace or self.global_namespace, it will be
         evaluated and its attributes (as revealed by dir()) are used as
         possible completions.  (For class instances, class members are are
         also considered.)
 
         WARNING: this can still invoke arbitrary C code, if an object
         with a __getattr__ hook is evaluated.
 
         """
 
         # Another option, seems to work great. Catches things like ''.<tab>
         m = re.match(r"(\S+(\.\w+)*)\.(\w*)$", text)
     
         if m:
             expr, attr = m.group(1, 3)
         elif self.greedy:
             m2 = re.match(r"(.+)\.(\w*)$", self.line_buffer)
             if not m2:
                 return []
             expr, attr = m2.group(1,2)
         else:
             return []
     
         try:
             obj = eval(expr, self.namespace)
         except:
             try:
                 obj = eval(expr, self.global_namespace)
             except:
                 return []
 
         if self.limit_to__all__ and hasattr(obj, '__all__'):
             words = get__all__entries(obj)
         else: 
             words = dir2(obj)
 
         try:
             words = generics.complete_object(obj, words)
         except TryNext:
             pass
         except Exception:
             # Silence errors from completion function
             #raise # dbg
             pass
         # Build match list to return
         n = len(attr)
         return [u"%s.%s" % (expr, w) for w in words if w[:n] == attr ]
 
 
 def get__all__entries(obj):
     """returns the strings in the __all__ attribute"""
     try:
         words = getattr(obj, '__all__')
     except:
         return []
     
     return [cast_unicode_py2(w) for w in words if isinstance(w, string_types)]
 
 
 def match_dict_keys(keys, prefix, delims):
     """Used by dict_key_matches, matching the prefix to a list of keys"""
     if not prefix:
         return None, 0, [repr(k) for k in keys
                       if isinstance(k, (string_types, bytes))]
     quote_match = re.search('["\']', prefix)
     quote = quote_match.group()
     try:
         prefix_str = eval(prefix + quote, {})
     except Exception:
         return None, 0, []
 
     pattern = '[^' + ''.join('\\' + c for c in delims) + ']*$'
     token_match = re.search(pattern, prefix, re.UNICODE)
     token_start = token_match.start()
     token_prefix = token_match.group()
 
     # TODO: support bytes in Py3k
     matched = []
     for key in keys:
         try:
             if not key.startswith(prefix_str):
                 continue
         except (AttributeError, TypeError, UnicodeError):
             # Python 3+ TypeError on b'a'.startswith('a') or vice-versa
             continue
 
         # reformat remainder of key to begin with prefix
         rem = key[len(prefix_str):]
         # force repr wrapped in '
         rem_repr = repr(rem + '"')
         if rem_repr.startswith('u') and prefix[0] not in 'uU':
             # Found key is unicode, but prefix is Py2 string.
             # Therefore attempt to interpret key as string.
             try:
                 rem_repr = repr(rem.encode('ascii') + '"')
             except UnicodeEncodeError:
                 continue
 
         rem_repr = rem_repr[1 + rem_repr.index("'"):-2]
         if quote == '"':
             # The entered prefix is quoted with ",
             # but the match is quoted with '.
             # A contained " hence needs escaping for comparison:
             rem_repr = rem_repr.replace('"', '\\"')
 
         # then reinsert prefix from start of token
         matched.append('%s%s' % (token_prefix, rem_repr))
     return quote, token_start, matched
 
 
 def _safe_isinstance(obj, module, class_name):
     """Checks if obj is an instance of module.class_name if loaded
     """
     return (module in sys.modules and
             isinstance(obj, getattr(__import__(module), class_name)))
 
 
 def back_unicode_name_matches(text):
     u"""Match unicode characters back to unicode name
     
     This does  ☃ -> \\snowman
 
     Note that snowman is not a valid python3 combining character but will be expanded.
     Though it will not recombine back to the snowman character by the completion machinery.
 
     This will not either back-complete standard sequences like \\n, \\b ...
     
     Used on Python 3 only.
     """
     if len(text)<2:
         return u'', ()
     maybe_slash = text[-2]
     if maybe_slash != '\\':
         return u'', ()
 
     char = text[-1]
     # no expand on quote for completion in strings.
     # nor backcomplete standard ascii keys
     if char in string.ascii_letters or char in ['"',"'"]:
         return u'', ()
     try :
         unic = unicodedata.name(char)
         return '\\'+char,['\\'+unic]
     except KeyError:
         pass
     return u'', ()
 
 def back_latex_name_matches(text):
     u"""Match latex characters back to unicode name
     
     This does  ->\\sqrt
 
     Used on Python 3 only.
     """
     if len(text)<2:
         return u'', ()
     maybe_slash = text[-2]
     if maybe_slash != '\\':
         return u'', ()
 
 
     char = text[-1]
     # no expand on quote for completion in strings.
     # nor backcomplete standard ascii keys
     if char in string.ascii_letters or char in ['"',"'"]:
         return u'', ()
     try :
         latex = reverse_latex_symbol[char]
         # '\\' replace the \ as well
         return '\\'+char,[latex]
     except KeyError:
         pass
     return u'', ()
 
 
 class IPCompleter(Completer):
     """Extension of the completer class with IPython-specific features"""
     
     @observe('greedy')
     def _greedy_changed(self, change):
         """update the splitter and readline delims when greedy is changed"""
         if change['new']:
             self.splitter.delims = GREEDY_DELIMS
         else:
             self.splitter.delims = DELIMS
 
         if self.readline:
             self.readline.set_completer_delims(self.splitter.delims)
     
     merge_completions = Bool(True,
         help="""Whether to merge completion results into a single list
         
         If False, only the completion results from the first non-empty
         completer will be returned.
         """
     ).tag(config=True)
     omit__names = Enum((0,1,2), default_value=2,
         help="""Instruct the completer to omit private method names
         
         Specifically, when completing on ``object.<tab>``.
         
         When 2 [default]: all names that start with '_' will be excluded.
         
         When 1: all 'magic' names (``__foo__``) will be excluded.
         
         When 0: nothing will be excluded.
         """
     ).tag(config=True)
     limit_to__all__ = Bool(False,
         help="""
         DEPRECATED as of version 5.0.
         
         Instruct the completer to use __all__ for the completion
         
         Specifically, when completing on ``object.<tab>``.
         
         When True: only those names in obj.__all__ will be included.
         
         When False [default]: the __all__ attribute is ignored 
         """,
     ).tag(config=True)
 
     def __init__(self, shell=None, namespace=None, global_namespace=None,
                  use_readline=True, config=None, **kwargs):
         """IPCompleter() -> completer
 
         Return a completer object suitable for use by the readline library
         via readline.set_completer().
 
         Inputs:
 
         - shell: a pointer to the ipython shell itself.  This is needed
           because this completer knows about magic functions, and those can
           only be accessed via the ipython instance.
 
         - namespace: an optional dict where completions are performed.
 
         - global_namespace: secondary optional dict for completions, to
           handle cases (such as IPython embedded inside functions) where
           both Python scopes are visible.
 
         use_readline : bool, optional
           If true, use the readline library.  This completer can still function
           without readline, though in that case callers must provide some extra
           information on each call about the current line."""
 
         self.magic_escape = ESC_MAGIC
         self.splitter = CompletionSplitter()
 
         # Readline configuration, only used by the rlcompleter method.
         if use_readline:
             # We store the right version of readline so that later code
             import IPython.utils.rlineimpl as readline
             self.readline = readline
         else:
             self.readline = None
 
         # _greedy_changed() depends on splitter and readline being defined:
         Completer.__init__(self, namespace=namespace, global_namespace=global_namespace,
                             config=config, **kwargs)
 
         # List where completion matches will be stored
         self.matches = []
         self.shell = shell
         # Regexp to split filenames with spaces in them
         self.space_name_re = re.compile(r'([^\\] )')
         # Hold a local ref. to glob.glob for speed
         self.glob = glob.glob
 
         # Determine if we are running on 'dumb' terminals, like (X)Emacs
         # buffers, to avoid completion problems.
         term = os.environ.get('TERM','xterm')
         self.dumb_terminal = term in ['dumb','emacs']
 
         # Special handling of backslashes needed in win32 platforms
         if sys.platform == "win32":
             self.clean_glob = self._clean_glob_win32
         else:
             self.clean_glob = self._clean_glob
 
         #regexp to parse docstring for function signature
         self.docstring_sig_re = re.compile(r'^[\w|\s.]+\(([^)]*)\).*')
         self.docstring_kwd_re = re.compile(r'[\s|\[]*(\w+)(?:\s*=\s*.*)')
         #use this if positional argument name is also needed
         #= re.compile(r'[\s|\[]*(\w+)(?:\s*=?\s*.*)')
 
         # All active matcher routines for completion
         self.matchers = [
                          self.file_matches,
                          self.magic_matches,
                          self.python_func_kw_matches,
                          self.dict_key_matches,
                          ]
 
     def all_completions(self, text):
         """
-        Wrapper around the complete method for the benefit of emacs
-        and pydb.
+        Wrapper around the complete method for the benefit of emacs.
         """
         return self.complete(text)[1]
 
     def _clean_glob(self, text):
         return self.glob("%s*" % text)
 
     def _clean_glob_win32(self,text):
         return [f.replace("\\","/")
                 for f in self.glob("%s*" % text)]
 
     def file_matches(self, text):
         """Match filenames, expanding ~USER type strings.
 
         Most of the seemingly convoluted logic in this completer is an
         attempt to handle filenames with spaces in them.  And yet it's not
         quite perfect, because Python's readline doesn't expose all of the
         GNU readline details needed for this to be done correctly.
 
         For a filename with a space in it, the printed completions will be
         only the parts after what's already been typed (instead of the
         full completions, as is normally done).  I don't think with the
         current (as of Python 2.3) Python readline it's possible to do
         better."""
 
         # chars that require escaping with backslash - i.e. chars
         # that readline treats incorrectly as delimiters, but we
         # don't want to treat as delimiters in filename matching
         # when escaped with backslash
         if text.startswith('!'):
             text = text[1:]
             text_prefix = u'!'
         else:
             text_prefix = u''
 
         text_until_cursor = self.text_until_cursor
         # track strings with open quotes
         open_quotes = has_open_quotes(text_until_cursor)
 
         if '(' in text_until_cursor or '[' in text_until_cursor:
             lsplit = text
         else:
             try:
                 # arg_split ~ shlex.split, but with unicode bugs fixed by us
                 lsplit = arg_split(text_until_cursor)[-1]
             except ValueError:
                 # typically an unmatched ", or backslash without escaped char.
                 if open_quotes:
                     lsplit = text_until_cursor.split(open_quotes)[-1]
                 else:
                     return []
             except IndexError:
                 # tab pressed on empty line
                 lsplit = ""
 
         if not open_quotes and lsplit != protect_filename(lsplit):
             # if protectables are found, do matching on the whole escaped name
             has_protectables = True
             text0,text = text,lsplit
         else:
             has_protectables = False
             text = os.path.expanduser(text)
 
         if text == "":
             return [text_prefix + cast_unicode_py2(protect_filename(f)) for f in self.glob("*")]
 
         # Compute the matches from the filesystem
         m0 = self.clean_glob(text.replace('\\',''))
 
         if has_protectables:
             # If we had protectables, we need to revert our changes to the
             # beginning of filename so that we don't double-write the part
             # of the filename we have so far
             len_lsplit = len(lsplit)
             matches = [text_prefix + text0 +
                        protect_filename(f[len_lsplit:]) for f in m0]
         else:
             if open_quotes:
                 # if we have a string with an open quote, we don't need to
                 # protect the names at all (and we _shouldn't_, as it
                 # would cause bugs when the filesystem call is made).
                 matches = m0
             else:
                 matches = [text_prefix +
                            protect_filename(f) for f in m0]
 
         # Mark directories in input list by appending '/' to their names.
         return [cast_unicode_py2(x+'/') if os.path.isdir(x) else x for x in matches]
 
     def magic_matches(self, text):
         """Match magics"""
         # Get all shell magics now rather than statically, so magics loaded at
         # runtime show up too.
         lsm = self.shell.magics_manager.lsmagic()
         line_magics = lsm['line']
         cell_magics = lsm['cell']
         pre = self.magic_escape
         pre2 = pre+pre
         
         # Completion logic:
         # - user gives %%: only do cell magics
         # - user gives %: do both line and cell magics
         # - no prefix: do both
         # In other words, line magics are skipped if the user gives %% explicitly
         bare_text = text.lstrip(pre)
         comp = [ pre2+m for m in cell_magics if m.startswith(bare_text)]
         if not text.startswith(pre2):
             comp += [ pre+m for m in line_magics if m.startswith(bare_text)]
         return [cast_unicode_py2(c) for c in comp]
 
     def python_jedi_matches(self, text, line_buffer, cursor_pos):
         """Match attributes or global Python names using Jedi."""
         if line_buffer.startswith('aimport ') or line_buffer.startswith('%aimport '):
             return ()
         namespaces = []
         if self.namespace is None:
             import __main__
             namespaces.append(__main__.__dict__)
         else:
             namespaces.append(self.namespace)
         if self.global_namespace is not None:
             namespaces.append(self.global_namespace)
 
         # cursor_pos is an it, jedi wants line and column
 
         interpreter = jedi.Interpreter(line_buffer, namespaces, column=cursor_pos)
         path = jedi.parser.user_context.UserContext(line_buffer, \
                 (1, len(line_buffer))).get_path_until_cursor()
         path, dot, like = jedi.api.helpers.completion_parts(path)
         if text.startswith('.'):
             # text will be `.` on completions like `a[0].<tab>`
             before = dot
         else:
             before = line_buffer[:len(line_buffer) - len(like)]
 
 
         def trim_start(completion):
             """completions need to start with `text`, trim the beginning until it does"""
             ltext = text.lower()
             lcomp  = completion.lower()
             if ltext in lcomp and not (lcomp.startswith(ltext)):
                 start_index = lcomp.index(ltext)
                 if cursor_pos:
                     if start_index >= cursor_pos:
                         start_index = min(start_index, cursor_pos)
                 return completion[start_index:]
             return completion
         
         completions = interpreter.completions()
 
         completion_text = [c.name_with_symbols for c in completions]
 
         if self.omit__names:
             if self.omit__names == 1:
                 # true if txt is _not_ a __ name, false otherwise:
                 no__name = lambda txt: not txt.startswith('__')
             else:
                 # true if txt is _not_ a _ name, false otherwise:
                 no__name = lambda txt: not txt.startswith('_')
             completion_text = filter(no__name, completion_text)
 
 
         return [trim_start(before + c_text) for c_text in completion_text]
 
 
     def python_matches(self, text):
         """Match attributes or global python names"""
         if "." in text:
             try:
                 matches = self.attr_matches(text)
                 if text.endswith('.') and self.omit__names:
                     if self.omit__names == 1:
                         # true if txt is _not_ a __ name, false otherwise:
                         no__name = (lambda txt:
                                     re.match(r'.*\.__.*?__',txt) is None)
                     else:
                         # true if txt is _not_ a _ name, false otherwise:
                         no__name = (lambda txt:
                                     re.match(r'\._.*?',txt[txt.rindex('.'):]) is None)
                     matches = filter(no__name, matches)
             except NameError:
                 # catches <undefined attributes>.<tab>
                 matches = []
         else:
             matches = self.global_matches(text)
         return matches
 
     def _default_arguments_from_docstring(self, doc):
         """Parse the first line of docstring for call signature.
 
         Docstring should be of the form 'min(iterable[, key=func])\n'.
         It can also parse cython docstring of the form
         'Minuit.migrad(self, int ncall=10000, resume=True, int nsplit=1)'.
         """
         if doc is None:
             return []
 
         #care only the firstline
         line = doc.lstrip().splitlines()[0]
 
         #p = re.compile(r'^[\w|\s.]+\(([^)]*)\).*')
         #'min(iterable[, key=func])\n' -> 'iterable[, key=func]'
         sig = self.docstring_sig_re.search(line)
         if sig is None:
             return []
         # iterable[, key=func]' -> ['iterable[' ,' key=func]']
         sig = sig.groups()[0].split(',')
         ret = []
         for s in sig:
             #re.compile(r'[\s|\[]*(\w+)(?:\s*=\s*.*)')
             ret += self.docstring_kwd_re.findall(s)
         return ret
 
     def _default_arguments(self, obj):
         """Return the list of default arguments of obj if it is callable,
         or empty list otherwise."""
         call_obj = obj
         ret = []
         if inspect.isbuiltin(obj):
             pass
         elif not (inspect.isfunction(obj) or inspect.ismethod(obj)):
             if inspect.isclass(obj):
                 #for cython embededsignature=True the constructor docstring
                 #belongs to the object itself not __init__
                 ret += self._default_arguments_from_docstring(
                             getattr(obj, '__doc__', ''))
                 # for classes, check for __init__,__new__
                 call_obj = (getattr(obj, '__init__', None) or
                        getattr(obj, '__new__', None))
             # for all others, check if they are __call__able
             elif hasattr(obj, '__call__'):
                 call_obj = obj.__call__
         ret += self._default_arguments_from_docstring(
                  getattr(call_obj, '__doc__', ''))
 
         if PY3:
             _keeps = (inspect.Parameter.KEYWORD_ONLY,
                       inspect.Parameter.POSITIONAL_OR_KEYWORD)
             signature = inspect.signature
         else:
             import IPython.utils.signatures
             _keeps = (IPython.utils.signatures.Parameter.KEYWORD_ONLY,
                       IPython.utils.signatures.Parameter.POSITIONAL_OR_KEYWORD)
             signature = IPython.utils.signatures.signature
 
         try:
             sig = signature(call_obj)
             ret.extend(k for k, v in sig.parameters.items() if
                        v.kind in _keeps)
         except ValueError:
             pass
 
         return list(set(ret))
 
     def python_func_kw_matches(self,text):
         """Match named parameters (kwargs) of the last open function"""
 
         if "." in text: # a parameter cannot be dotted
             return []
         try: regexp = self.__funcParamsRegex
         except AttributeError:
             regexp = self.__funcParamsRegex = re.compile(r'''
                 '.*?(?<!\\)' |    # single quoted strings or
                 ".*?(?<!\\)" |    # double quoted strings or
                 \w+          |    # identifier
                 \S                # other characters
                 ''', re.VERBOSE | re.DOTALL)
         # 1. find the nearest identifier that comes before an unclosed
         # parenthesis before the cursor
         # e.g. for "foo (1+bar(x), pa<cursor>,a=1)", the candidate is "foo"
         tokens = regexp.findall(self.text_until_cursor)
         tokens.reverse()
         iterTokens = iter(tokens); openPar = 0
 
         for token in iterTokens:
             if token == ')':
                 openPar -= 1
             elif token == '(':
                 openPar += 1
                 if openPar > 0:
                     # found the last unclosed parenthesis
                     break
         else:
             return []
         # 2. Concatenate dotted names ("foo.bar" for "foo.bar(x, pa" )
         ids = []
         isId = re.compile(r'\w+$').match
 
         while True:
             try:
                 ids.append(next(iterTokens))
                 if not isId(ids[-1]):
                     ids.pop(); break
                 if not next(iterTokens) == '.':
                     break
             except StopIteration:
                 break
         # lookup the candidate callable matches either using global_matches
         # or attr_matches for dotted names
         if len(ids) == 1:
             callableMatches = self.global_matches(ids[0])
         else:
             callableMatches = self.attr_matches('.'.join(ids[::-1]))
         argMatches = []
         for callableMatch in callableMatches:
             try:
                 namedArgs = self._default_arguments(eval(callableMatch,
                                                         self.namespace))
             except:
                 continue
 
             for namedArg in namedArgs:
                 if namedArg.startswith(text):
                     argMatches.append(u"%s=" %namedArg)
         return argMatches
 
     def dict_key_matches(self, text):
         "Match string keys in a dictionary, after e.g. 'foo[' "
         def get_keys(obj):
             # Objects can define their own completions by defining an
             # _ipy_key_completions_() method.
             method = get_real_method(obj, '_ipython_key_completions_')
             if method is not None:
                 return method()
 
             # Special case some common in-memory dict-like types
             if isinstance(obj, dict) or\
                _safe_isinstance(obj, 'pandas', 'DataFrame'):
                 try:
                     return list(obj.keys())
                 except Exception:
                     return []
             elif _safe_isinstance(obj, 'numpy', 'ndarray') or\
                  _safe_isinstance(obj, 'numpy', 'void'):
                 return obj.dtype.names or []
             return []
 
         try:
             regexps = self.__dict_key_regexps
         except AttributeError:
             dict_key_re_fmt = r'''(?x)
             (  # match dict-referring expression wrt greedy setting
                 %s
             )
             \[   # open bracket
             \s*  # and optional whitespace
             ([uUbB]?  # string prefix (r not handled)
                 (?:   # unclosed string
                     '(?:[^']|(?<!\\)\\')*
                 |
                     "(?:[^"]|(?<!\\)\\")*
                 )
             )?
             $
             '''
             regexps = self.__dict_key_regexps = {
                 False: re.compile(dict_key_re_fmt % '''
                                   # identifiers separated by .
                                   (?!\d)\w+
                                   (?:\.(?!\d)\w+)*
                                   '''),
                 True: re.compile(dict_key_re_fmt % '''
                                  .+
                                  ''')
             }
 
         match = regexps[self.greedy].search(self.text_until_cursor)
         if match is None:
             return []
 
         expr, prefix = match.groups()
         try:
             obj = eval(expr, self.namespace)
         except Exception:
             try:
                 obj = eval(expr, self.global_namespace)
             except Exception:
                 return []
 
         keys = get_keys(obj)
         if not keys:
             return keys
         closing_quote, token_offset, matches = match_dict_keys(keys, prefix, self.splitter.delims)
         if not matches:
             return matches
         
         # get the cursor position of
         # - the text being completed
         # - the start of the key text
         # - the start of the completion
         text_start = len(self.text_until_cursor) - len(text)
         if prefix:
             key_start = match.start(2)
             completion_start = key_start + token_offset
         else:
             key_start = completion_start = match.end()
         
         # grab the leading prefix, to make sure all completions start with `text`
         if text_start > key_start:
             leading = ''
         else:
             leading = text[text_start:completion_start]
         
         # the index of the `[` character
         bracket_idx = match.end(1)
 
         # append closing quote and bracket as appropriate
         # this is *not* appropriate if the opening quote or bracket is outside
         # the text given to this method
         suf = ''
         continuation = self.line_buffer[len(self.text_until_cursor):]
         if key_start > text_start and closing_quote:
             # quotes were opened inside text, maybe close them
             if continuation.startswith(closing_quote):
                 continuation = continuation[len(closing_quote):]
             else:
                 suf += closing_quote
         if bracket_idx > text_start:
             # brackets were opened inside text, maybe close them
             if not continuation.startswith(']'):
                 suf += ']'
         
         return [leading + k + suf for k in matches]
 
     def unicode_name_matches(self, text):
         u"""Match Latex-like syntax for unicode characters base 
         on the name of the character.
         
         This does  \\GREEK SMALL LETTER ETA -> η
 
         Works only on valid python 3 identifier, or on combining characters that 
         will combine to form a valid identifier.
         
         Used on Python 3 only.
         """
         slashpos = text.rfind('\\')
         if slashpos > -1:
             s = text[slashpos+1:]
             try :
                 unic = unicodedata.lookup(s)
                 # allow combining chars
                 if ('a'+unic).isidentifier():
                     return '\\'+s,[unic]
             except KeyError:
                 pass
         return u'', []
 
 
 
 
     def latex_matches(self, text):
         u"""Match Latex syntax for unicode characters.
         
         This does both \\alp -> \\alpha and \\alpha -> α
         
         Used on Python 3 only.
         """
         slashpos = text.rfind('\\')
         if slashpos > -1:
             s = text[slashpos:]
             if s in latex_symbols:
                 # Try to complete a full latex symbol to unicode
                 # \\alpha -> α
                 return s, [latex_symbols[s]]
             else:
                 # If a user has partially typed a latex symbol, give them
                 # a full list of options \al -> [\aleph, \alpha]
                 matches = [k for k in latex_symbols if k.startswith(s)]
                 return s, matches
         return u'', []
 
     def dispatch_custom_completer(self, text):
         line = self.line_buffer
         if not line.strip():
             return None
 
         # Create a little structure to pass all the relevant information about
         # the current completion to any custom completer.
         event = Bunch()
         event.line = line
         event.symbol = text
         cmd = line.split(None,1)[0]
         event.command = cmd
         event.text_until_cursor = self.text_until_cursor
 
         # for foo etc, try also to find completer for %foo
         if not cmd.startswith(self.magic_escape):
             try_magic = self.custom_completers.s_matches(
                 self.magic_escape + cmd)
         else:
             try_magic = []
 
         for c in itertools.chain(self.custom_completers.s_matches(cmd),
                  try_magic,
                  self.custom_completers.flat_matches(self.text_until_cursor)):
             try:
                 res = c(event)
                 if res:
                     # first, try case sensitive match
                     withcase = [cast_unicode_py2(r) for r in res if r.startswith(text)]
                     if withcase:
                         return withcase
                     # if none, then case insensitive ones are ok too
                     text_low = text.lower()
                     return [cast_unicode_py2(r) for r in res if r.lower().startswith(text_low)]
             except TryNext:
                 pass
 
         return None
 
     def complete(self, text=None, line_buffer=None, cursor_pos=None):
         """Find completions for the given text and line context.
 
         Note that both the text and the line_buffer are optional, but at least
         one of them must be given.
 
         Parameters
         ----------
           text : string, optional
             Text to perform the completion on.  If not given, the line buffer
             is split using the instance's CompletionSplitter object.
 
           line_buffer : string, optional
             If not given, the completer attempts to obtain the current line
             buffer via readline.  This keyword allows clients which are
             requesting for text completions in non-readline contexts to inform
             the completer of the entire text.
 
           cursor_pos : int, optional
             Index of the cursor in the full line buffer.  Should be provided by
             remote frontends where kernel has no access to frontend state.
 
         Returns
         -------
         text : str
           Text that was actually used in the completion.
 
         matches : list
           A list of completion matches.
         """
         # if the cursor position isn't given, the only sane assumption we can
         # make is that it's at the end of the line (the common case)
         if cursor_pos is None:
             cursor_pos = len(line_buffer) if text is None else len(text)
 
         if PY3:
 
             base_text = text if not line_buffer else line_buffer[:cursor_pos]
             latex_text, latex_matches = self.latex_matches(base_text)
             if latex_matches:
                  return latex_text, latex_matches
             name_text = ''
             name_matches = []
             for meth in (self.unicode_name_matches, back_latex_name_matches, back_unicode_name_matches):
                 name_text, name_matches = meth(base_text)
                 if name_text:
                     return name_text, name_matches
         
         # if text is either None or an empty string, rely on the line buffer
         if not text:
             text = self.splitter.split_line(line_buffer, cursor_pos)
 
         # If no line buffer is given, assume the input text is all there was
         if line_buffer is None:
             line_buffer = text
 
         self.line_buffer = line_buffer
         self.text_until_cursor = self.line_buffer[:cursor_pos]
 
         # Start with a clean slate of completions
         self.matches[:] = []
         custom_res = self.dispatch_custom_completer(text)
         if custom_res is not None:
             # did custom completers produce something?
             self.matches = custom_res
         else:
             # Extend the list of completions with the results of each
             # matcher, so we return results to the user from all
             # namespaces.
             if self.merge_completions:
                 self.matches = []
                 for matcher in self.matchers:
                     try:
                         self.matches.extend(matcher(text))
                     except:
                         # Show the ugly traceback if the matcher causes an
                         # exception, but do NOT crash the kernel!
                         sys.excepthook(*sys.exc_info())
             else:
                 for matcher in self.matchers:
                     self.matches = matcher(text)
                     if self.matches:
                         break
         # FIXME: we should extend our api to return a dict with completions for
         # different types of objects.  The rlcomplete() method could then
         # simply collapse the dict into a list for readline, but we'd have
         # richer completion semantics in other evironments.
         self.matches.extend(self.python_jedi_matches(text, line_buffer, cursor_pos))
 
         self.matches = sorted(set(self.matches), key=completions_sorting_key)
 
         return text, self.matches
 
     def rlcomplete(self, text, state):
         """Return the state-th possible completion for 'text'.
 
         This is called successively with state == 0, 1, 2, ... until it
         returns None.  The completion should begin with 'text'.
 
         Parameters
         ----------
           text : string
             Text to perform the completion on.
 
           state : int
             Counter used by readline.
         """
         if state==0:
 
             self.line_buffer = line_buffer = self.readline.get_line_buffer()
             cursor_pos = self.readline.get_endidx()
 
             #io.rprint("\nRLCOMPLETE: %r %r %r" %
             #          (text, line_buffer, cursor_pos) ) # dbg
 
             # if there is only a tab on a line with only whitespace, instead of
             # the mostly useless 'do you want to see all million completions'
             # message, just do the right thing and give the user his tab!
             # Incidentally, this enables pasting of tabbed text from an editor
             # (as long as autoindent is off).
 
             # It should be noted that at least pyreadline still shows file
             # completions - is there a way around it?
 
             # don't apply this on 'dumb' terminals, such as emacs buffers, so
             # we don't interfere with their own tab-completion mechanism.
             if not (self.dumb_terminal or line_buffer.strip()):
                 self.readline.insert_text('\t')
                 sys.stdout.flush()
                 return None
 
             # Note: debugging exceptions that may occur in completion is very
             # tricky, because readline unconditionally silences them.  So if
             # during development you suspect a bug in the completion code, turn
             # this flag on temporarily by uncommenting the second form (don't
             # flip the value in the first line, as the '# dbg' marker can be
             # automatically detected and is used elsewhere).
             DEBUG = False
             #DEBUG = True # dbg
             if DEBUG:
                 try:
                     self.complete(text, line_buffer, cursor_pos)
                 except:
                     import traceback; traceback.print_exc()
             else:
                 # The normal production version is here
 
                 # This method computes the self.matches array
                 self.complete(text, line_buffer, cursor_pos)
 
         try:
             return self.matches[state]
         except IndexError:
             return None
 

IPython/core/debugger.py

@@ -1,637 +1,591 b''
 # -*- coding: utf-8 -*-
 """
 Pdb debugger class.
 
 Modified from the standard pdb.Pdb class to avoid including readline, so that
 the command line completion of other programs which include this isn't
 damaged.
 
 In the future, this class will be expanded with improvements over the standard
 pdb.
 
 The code in this file is mainly lifted out of cmd.py in Python 2.2, with minor
 changes. Licensing should therefore be under the standard Python terms.  For
 details on the PSF (Python Software Foundation) standard license, see:
 
 http://www.python.org/2.2.3/license.html"""
 
 #*****************************************************************************
 #
 #       This file is licensed under the PSF license.
 #
 #       Copyright (C) 2001 Python Software Foundation, www.python.org
 #       Copyright (C) 2005-2006 Fernando Perez. <[e-mail]>
 #
 #
 #*****************************************************************************
 from __future__ import print_function
 
 import bdb
 import functools
 import inspect
 import sys
 
 from IPython import get_ipython
 from IPython.utils import PyColorize, ulinecache
 from IPython.utils import coloransi, py3compat
 from IPython.core.excolors import exception_colors
 from IPython.testing.skipdoctest import skip_doctest
 
-# See if we can use pydb.
-has_pydb = False
 prompt = 'ipdb> '
+
 #We have to check this directly from sys.argv, config struct not yet available
-if '--pydb' in sys.argv:
-    try:
-        import pydb
-        if hasattr(pydb.pydb, "runl") and pydb.version>'1.17':
-            # Version 1.17 is broken, and that's what ships with Ubuntu Edgy, so we
-            # better protect against it.
-            has_pydb = True
-    except ImportError:
-        print("Pydb (http://bashdb.sourceforge.net/pydb/) does not seem to be available")
-
-if has_pydb:
-    from pydb import Pdb as OldPdb
-    prompt = 'ipydb> '
-else:
-    from pdb import Pdb as OldPdb
+from pdb import Pdb as OldPdb
 
 # Allow the set_trace code to operate outside of an ipython instance, even if
 # it does so with some limitations.  The rest of this support is implemented in
 # the Tracer constructor.
 
 def make_arrow(pad):
     """generate the leading arrow in front of traceback or debugger"""
     if pad >= 2:
         return '-'*(pad-2) + '> '
     elif pad == 1:
         return '>'
     return ''
 
 
 def BdbQuit_excepthook(et, ev, tb, excepthook=None):
     """Exception hook which handles `BdbQuit` exceptions.
 
     All other exceptions are processed using the `excepthook`
     parameter.
     """
     if et==bdb.BdbQuit:
         print('Exiting Debugger.')
     elif excepthook is not None:
         excepthook(et, ev, tb)
     else:
         # Backwards compatibility. Raise deprecation warning?
         BdbQuit_excepthook.excepthook_ori(et,ev,tb)
 
 def BdbQuit_IPython_excepthook(self,et,ev,tb,tb_offset=None):
     print('Exiting Debugger.')
 
 
 class Tracer(object):
     """Class for local debugging, similar to pdb.set_trace.
 
     Instances of this class, when called, behave like pdb.set_trace, but
     providing IPython's enhanced capabilities.
 
     This is implemented as a class which must be initialized in your own code
     and not as a standalone function because we need to detect at runtime
     whether IPython is already active or not.  That detection is done in the
     constructor, ensuring that this code plays nicely with a running IPython,
     while functioning acceptably (though with limitations) if outside of it.
     """
 
     @skip_doctest
     def __init__(self, colors=None):
         """Create a local debugger instance.
 
         Parameters
         ----------
 
         colors : str, optional
             The name of the color scheme to use, it must be one of IPython's
             valid color schemes.  If not given, the function will default to
             the current IPython scheme when running inside IPython, and to
             'NoColor' otherwise.
 
         Examples
         --------
         ::
 
             from IPython.core.debugger import Tracer; debug_here = Tracer()
 
         Later in your code::
 
             debug_here()  # -> will open up the debugger at that point.
 
         Once the debugger activates, you can use all of its regular commands to
         step through code, set breakpoints, etc.  See the pdb documentation
         from the Python standard library for usage details.
         """
 
         ip = get_ipython()
         if ip is None:
             # Outside of ipython, we set our own exception hook manually
             sys.excepthook = functools.partial(BdbQuit_excepthook,
                                                excepthook=sys.excepthook)
             def_colors = 'NoColor'
             try:
                 # Limited tab completion support
                 import readline
                 readline.parse_and_bind('tab: complete')
             except ImportError:
                 pass
         else:
             # In ipython, we use its custom exception handler mechanism
             def_colors = ip.colors
             ip.set_custom_exc((bdb.BdbQuit,), BdbQuit_IPython_excepthook)
 
         if colors is None:
             colors = def_colors
 
         # The stdlib debugger internally uses a modified repr from the `repr`
         # module, that limits the length of printed strings to a hardcoded
         # limit of 30 characters.  That much trimming is too aggressive, let's
         # at least raise that limit to 80 chars, which should be enough for
         # most interactive uses.
         try:
             try:
                 from reprlib import aRepr  # Py 3
             except ImportError:
                 from repr import aRepr  # Py 2
             aRepr.maxstring = 80
         except:
             # This is only a user-facing convenience, so any error we encounter
             # here can be warned about but can be otherwise ignored.  These
             # printouts will tell us about problems if this API changes
             import traceback
             traceback.print_exc()
 
         self.debugger = Pdb(colors)
 
     def __call__(self):
         """Starts an interactive debugger at the point where called.
 
         This is similar to the pdb.set_trace() function from the std lib, but
         using IPython's enhanced debugger."""
 
         self.debugger.set_trace(sys._getframe().f_back)
 
 
 def decorate_fn_with_doc(new_fn, old_fn, additional_text=""):
     """Make new_fn have old_fn's doc string. This is particularly useful
     for the ``do_...`` commands that hook into the help system.
     Adapted from from a comp.lang.python posting
     by Duncan Booth."""
     def wrapper(*args, **kw):
         return new_fn(*args, **kw)
     if old_fn.__doc__:
         wrapper.__doc__ = old_fn.__doc__ + additional_text
     return wrapper
 
 
 def _file_lines(fname):
     """Return the contents of a named file as a list of lines.
 
     This function never raises an IOError exception: if the file can't be
     read, it simply returns an empty list."""
 
     try:
         outfile = open(fname)
     except IOError:
         return []
     else:
         out = outfile.readlines()
         outfile.close()
         return out
 
 
 class Pdb(OldPdb):
     """Modified Pdb class, does not load readline."""
 
     def __init__(self,color_scheme='NoColor',completekey=None,
                  stdin=None, stdout=None, context=5):
 
         # Parent constructor:
         try:
             self.context=int(context)
             if self.context <= 0:
                 raise ValueError("Context must be a positive integer")
         except (TypeError, ValueError):
                 raise ValueError("Context must be a positive integer")
 
-        if has_pydb and completekey is None:
-            OldPdb.__init__(self,stdin=stdin,stdout=sys.stdout)
-        else:
-            OldPdb.__init__(self,completekey,stdin,stdout)
+        OldPdb.__init__(self,completekey,stdin,stdout)
 
         # IPython changes...
-        self.is_pydb = has_pydb
-
         self.shell = get_ipython()
 
         if self.shell is None:
             # No IPython instance running, we must create one
             from IPython.terminal.interactiveshell import \
                 TerminalInteractiveShell
             self.shell = TerminalInteractiveShell.instance()
 
-        if self.is_pydb:
-
-            # interactiveshell.py's ipalias seems to want pdb's checkline
-            # which located in pydb.fn
-            import pydb.fns
-            self.checkline = lambda filename, lineno: \
-                             pydb.fns.checkline(self, filename, lineno)
-
-            self.curframe = None
-            self.do_restart = self.new_do_restart
-
-            self.old_all_completions = self.shell.Completer.all_completions
-            self.shell.Completer.all_completions=self.all_completions
-
-            self.do_list = decorate_fn_with_doc(self.list_command_pydb,
-                                                OldPdb.do_list)
-            self.do_l     = self.do_list
-            self.do_frame = decorate_fn_with_doc(self.new_do_frame,
-                                                 OldPdb.do_frame)
-
         self.aliases = {}
 
         # Create color table: we copy the default one from the traceback
         # module and add a few attributes needed for debugging
         self.color_scheme_table = exception_colors()
 
         # shorthands
         C = coloransi.TermColors
         cst = self.color_scheme_table
 
         cst['NoColor'].colors.prompt = C.NoColor
         cst['NoColor'].colors.breakpoint_enabled = C.NoColor
         cst['NoColor'].colors.breakpoint_disabled = C.NoColor
 
         cst['Linux'].colors.prompt = C.Green
         cst['Linux'].colors.breakpoint_enabled = C.LightRed
         cst['Linux'].colors.breakpoint_disabled = C.Red
 
         cst['LightBG'].colors.prompt = C.Blue
         cst['LightBG'].colors.breakpoint_enabled = C.LightRed
         cst['LightBG'].colors.breakpoint_disabled = C.Red
 
         self.set_colors(color_scheme)
 
         # Add a python parser so we can syntax highlight source while
         # debugging.
         self.parser = PyColorize.Parser()
 
         # Set the prompt - the default prompt is '(Pdb)'
         Colors = cst.active_colors
         if color_scheme == 'NoColor':
             self.prompt = prompt
         else:
             # The colour markers are wrapped by bytes 01 and 02 so that readline
             # can calculate the width.
             self.prompt = u'\x01%s\x02%s\x01%s\x02' % (Colors.prompt, prompt, Colors.Normal)
 
     def set_colors(self, scheme):
         """Shorthand access to the color table scheme selector method."""
         self.color_scheme_table.set_active_scheme(scheme)
 
     def interaction(self, frame, traceback):
         self.shell.set_completer_frame(frame)
         while True:
             try:
                 OldPdb.interaction(self, frame, traceback)
                 break
             except KeyboardInterrupt:
                 self.shell.write('\n' + self.shell.get_exception_only())
                 break
             finally:
                 # Pdb sets readline delimiters, so set them back to our own
                 if self.shell.readline is not None:
                     self.shell.readline.set_completer_delims(self.shell.readline_delims)
 
     def new_do_up(self, arg):
         OldPdb.do_up(self, arg)
         self.shell.set_completer_frame(self.curframe)
     do_u = do_up = decorate_fn_with_doc(new_do_up, OldPdb.do_up)
 
     def new_do_down(self, arg):
         OldPdb.do_down(self, arg)
         self.shell.set_completer_frame(self.curframe)
 
     do_d = do_down = decorate_fn_with_doc(new_do_down, OldPdb.do_down)
 
     def new_do_frame(self, arg):
         OldPdb.do_frame(self, arg)
         self.shell.set_completer_frame(self.curframe)
 
     def new_do_quit(self, arg):
 
         if hasattr(self, 'old_all_completions'):
             self.shell.Completer.all_completions=self.old_all_completions
 
         return OldPdb.do_quit(self, arg)
 
     do_q = do_quit = decorate_fn_with_doc(new_do_quit, OldPdb.do_quit)
 
     def new_do_restart(self, arg):
         """Restart command. In the context of ipython this is exactly the same
         thing as 'quit'."""
         self.msg("Restart doesn't make sense here. Using 'quit' instead.")
         return self.do_quit(arg)
 
     def postloop(self):
         self.shell.set_completer_frame(None)
 
     def print_stack_trace(self, context=None):
         if context is None:
             context = self.context
         try:
             context=int(context)
             if context <= 0:
                 raise ValueError("Context must be a positive integer")
         except (TypeError, ValueError):
                 raise ValueError("Context must be a positive integer")
         try:
             for frame_lineno in self.stack:
                 self.print_stack_entry(frame_lineno, context=context)
         except KeyboardInterrupt:
             pass
 
     def print_stack_entry(self,frame_lineno,prompt_prefix='\n-> ',
                           context=None):
         if context is None:
             context = self.context
         try:
             context=int(context)
             if context <= 0:
                 raise ValueError("Context must be a positive integer")
         except (TypeError, ValueError):
                 raise ValueError("Context must be a positive integer")
         print(self.format_stack_entry(frame_lineno, '', context))
 
         # vds: >>
         frame, lineno = frame_lineno
         filename = frame.f_code.co_filename
         self.shell.hooks.synchronize_with_editor(filename, lineno, 0)
         # vds: <<
 
     def format_stack_entry(self, frame_lineno, lprefix=': ', context=None):
         if context is None:
             context = self.context
         try:
             context=int(context)
             if context <= 0:
                 print("Context must be a positive integer")
         except (TypeError, ValueError):
                 print("Context must be a positive integer")
         try:
             import reprlib  # Py 3
         except ImportError:
             import repr as reprlib  # Py 2
 
         ret = []
 
         Colors = self.color_scheme_table.active_colors
         ColorsNormal = Colors.Normal
         tpl_link = u'%s%%s%s' % (Colors.filenameEm, ColorsNormal)
         tpl_call = u'%s%%s%s%%s%s' % (Colors.vName, Colors.valEm, ColorsNormal)
         tpl_line = u'%%s%s%%s %s%%s' % (Colors.lineno, ColorsNormal)
         tpl_line_em = u'%%s%s%%s %s%%s%s' % (Colors.linenoEm, Colors.line,
                                             ColorsNormal)
 
         frame, lineno = frame_lineno
 
         return_value = ''
         if '__return__' in frame.f_locals:
             rv = frame.f_locals['__return__']
             #return_value += '->'
             return_value += reprlib.repr(rv) + '\n'
         ret.append(return_value)
 
         #s = filename + '(' + `lineno` + ')'
         filename = self.canonic(frame.f_code.co_filename)
         link = tpl_link % py3compat.cast_unicode(filename)
 
         if frame.f_code.co_name:
             func = frame.f_code.co_name
         else:
             func = "<lambda>"
 
         call = ''
         if func != '?':
             if '__args__' in frame.f_locals:
                 args = reprlib.repr(frame.f_locals['__args__'])
             else:
                 args = '()'
             call = tpl_call % (func, args)
 
         # The level info should be generated in the same format pdb uses, to
         # avoid breaking the pdbtrack functionality of python-mode in *emacs.
         if frame is self.curframe:
             ret.append('> ')
         else:
             ret.append('  ')
         ret.append(u'%s(%s)%s\n' % (link,lineno,call))
 
         start = lineno - 1 - context//2
         lines = ulinecache.getlines(filename)
         start = min(start, len(lines) - context)
         start = max(start, 0)
         lines = lines[start : start + context]
 
         for i,line in enumerate(lines):
             show_arrow = (start + 1 + i == lineno)
             linetpl = (frame is self.curframe or show_arrow) \
                       and tpl_line_em \
                       or tpl_line
             ret.append(self.__format_line(linetpl, filename,
                                           start + 1 + i, line,
                                           arrow = show_arrow) )
         return ''.join(ret)
 
     def __format_line(self, tpl_line, filename, lineno, line, arrow = False):
         bp_mark = ""
         bp_mark_color = ""
 
         scheme = self.color_scheme_table.active_scheme_name
         new_line, err = self.parser.format2(line, 'str', scheme)
         if not err: line = new_line
 
         bp = None
         if lineno in self.get_file_breaks(filename):
             bps = self.get_breaks(filename, lineno)
             bp = bps[-1]
 
         if bp:
             Colors = self.color_scheme_table.active_colors
             bp_mark = str(bp.number)
             bp_mark_color = Colors.breakpoint_enabled
             if not bp.enabled:
                 bp_mark_color = Colors.breakpoint_disabled
 
         numbers_width = 7
         if arrow:
             # This is the line with the error
             pad = numbers_width - len(str(lineno)) - len(bp_mark)
             num = '%s%s' % (make_arrow(pad), str(lineno))
         else:
             num = '%*s' % (numbers_width - len(bp_mark), str(lineno))
 
         return tpl_line % (bp_mark_color + bp_mark, num, line)
 
 
-    def list_command_pydb(self, arg):
-        """List command to use if we have a newer pydb installed"""
-        filename, first, last = OldPdb.parse_list_cmd(self, arg)
-        if filename is not None:
-            self.print_list_lines(filename, first, last)
-
     def print_list_lines(self, filename, first, last):
         """The printing (as opposed to the parsing part of a 'list'
         command."""
         try:
             Colors = self.color_scheme_table.active_colors
             ColorsNormal = Colors.Normal
             tpl_line = '%%s%s%%s %s%%s' % (Colors.lineno, ColorsNormal)
             tpl_line_em = '%%s%s%%s %s%%s%s' % (Colors.linenoEm, Colors.line, ColorsNormal)
             src = []
             if filename == "<string>" and hasattr(self, "_exec_filename"):
                 filename = self._exec_filename
 
             for lineno in range(first, last+1):
                 line = ulinecache.getline(filename, lineno)
                 if not line:
                     break
 
                 if lineno == self.curframe.f_lineno:
                     line = self.__format_line(tpl_line_em, filename, lineno, line, arrow = True)
                 else:
                     line = self.__format_line(tpl_line, filename, lineno, line, arrow = False)
 
                 src.append(line)
                 self.lineno = lineno
 
             print(''.join(src))
 
         except KeyboardInterrupt:
             pass
 
     def do_list(self, arg):
         self.lastcmd = 'list'
         last = None
         if arg:
             try:
                 x = eval(arg, {}, {})
                 if type(x) == type(()):
                     first, last = x
                     first = int(first)
                     last = int(last)
                     if last < first:
                         # Assume it's a count
                         last = first + last
                 else:
                     first = max(1, int(x) - 5)
             except:
                 print('*** Error in argument:', repr(arg))
                 return
         elif self.lineno is None:
             first = max(1, self.curframe.f_lineno - 5)
         else:
             first = self.lineno + 1
         if last is None:
             last = first + 10
         self.print_list_lines(self.curframe.f_code.co_filename, first, last)
 
         # vds: >>
         lineno = first
         filename = self.curframe.f_code.co_filename
         self.shell.hooks.synchronize_with_editor(filename, lineno, 0)
         # vds: <<
 
     do_l = do_list
 
     def getsourcelines(self, obj):
         lines, lineno = inspect.findsource(obj)
         if inspect.isframe(obj) and obj.f_globals is obj.f_locals:
             # must be a module frame: do not try to cut a block out of it
             return lines, 1
         elif inspect.ismodule(obj):
             return lines, 1
         return inspect.getblock(lines[lineno:]), lineno+1
 
     def do_longlist(self, arg):
         self.lastcmd = 'longlist'
         try:
             lines, lineno = self.getsourcelines(self.curframe)
         except OSError as err:
             self.error(err)
             return
         last = lineno + len(lines)
         self.print_list_lines(self.curframe.f_code.co_filename, lineno, last)
     do_ll = do_longlist
 
     def do_pdef(self, arg):
         """Print the call signature for any callable object.
 
         The debugger interface to %pdef"""
         namespaces = [('Locals', self.curframe.f_locals),
                       ('Globals', self.curframe.f_globals)]
         self.shell.find_line_magic('pdef')(arg, namespaces=namespaces)
 
     def do_pdoc(self, arg):
         """Print the docstring for an object.
 
         The debugger interface to %pdoc."""
         namespaces = [('Locals', self.curframe.f_locals),
                       ('Globals', self.curframe.f_globals)]
         self.shell.find_line_magic('pdoc')(arg, namespaces=namespaces)
 
     def do_pfile(self, arg):
         """Print (or run through pager) the file where an object is defined.
 
         The debugger interface to %pfile.
         """
         namespaces = [('Locals', self.curframe.f_locals),
                       ('Globals', self.curframe.f_globals)]
         self.shell.find_line_magic('pfile')(arg, namespaces=namespaces)
 
     def do_pinfo(self, arg):
         """Provide detailed information about an object.
 
         The debugger interface to %pinfo, i.e., obj?."""
         namespaces = [('Locals', self.curframe.f_locals),
                       ('Globals', self.curframe.f_globals)]
         self.shell.find_line_magic('pinfo')(arg, namespaces=namespaces)
 
     def do_pinfo2(self, arg):
         """Provide extra detailed information about an object.
 
         The debugger interface to %pinfo2, i.e., obj??."""
         namespaces = [('Locals', self.curframe.f_locals),
                       ('Globals', self.curframe.f_globals)]
         self.shell.find_line_magic('pinfo2')(arg, namespaces=namespaces)
 
     def do_psource(self, arg):
         """Print (or run through pager) the source code for an object."""
         namespaces = [('Locals', self.curframe.f_locals),
                       ('Globals', self.curframe.f_globals)]
         self.shell.find_line_magic('psource')(arg, namespaces=namespaces)
 
     if sys.version_info > (3, ):
         def do_where(self, arg):
             """w(here)
             Print a stack trace, with the most recent frame at the bottom.
             An arrow indicates the "current frame", which determines the
             context of most commands. 'bt' is an alias for this command.
 
             Take a number as argument as an (optional) number of context line to
             print"""
             if arg:
                 context = int(arg)
                 self.print_stack_trace(context)
             else:
                 self.print_stack_trace()
 
         do_w = do_where

IPython/core/interactiveshell.py

@@ -1,3246 +1,3240 b''
 # -*- coding: utf-8 -*-
 """Main IPython class."""
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2001 Janko Hauser <[e-mail]>
 #  Copyright (C) 2001-2007 Fernando Perez. <[e-mail]>
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 from __future__ import absolute_import, print_function
 
 import __future__
 import abc
 import ast
 import atexit
 import functools
 import os
 import re
 import runpy
 import sys
 import tempfile
 import traceback
 import types
 import subprocess
 import warnings
 from io import open as io_open
 
 from pickleshare import PickleShareDB
 
 from traitlets.config.configurable import SingletonConfigurable
-from IPython.core import debugger, oinspect
+from IPython.core import 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 Alias, AliasManager
 from IPython.core.autocall import ExitAutocall
 from IPython.core.builtin_trap import BuiltinTrap
 from IPython.core.events import EventManager, available_events
 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 InputRejected, UsageError
 from IPython.core.extensions import ExtensionManager
 from IPython.core.formatters import DisplayFormatter
 from IPython.core.history import HistoryManager
 from IPython.core.inputsplitter import 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.core.usage import default_banner
 from IPython.testing.skipdoctest import skip_doctest_py2, 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.contexts import NoOpContext
 from IPython.utils.decorators import undoc
 from IPython.utils.io import ask_yes_no
 from IPython.utils.ipstruct import Struct
 from IPython.paths import get_ipython_dir
 from IPython.utils.path import get_home_dir, get_py_filename, unquote_filename, ensure_dir_exists
 from IPython.utils.process import system, getoutput
 from IPython.utils.py3compat import (builtin_mod, unicode_type, string_types,
                                      with_metaclass, iteritems)
 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 traitlets import (
     Integer, Bool, CaselessStrEnum, Enum, List, Dict, Unicode, Instance, Type,
     observe, default,
 )
 from warnings import warn
 from logging import 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
 
 
 class SpaceInInput(Exception): pass
 
 
 def get_default_colors():
     if sys.platform=='darwin':
         return "LightBG"
     elif os.name=='nt':
         return 'Linux'
     else:
         return 'Linux'
 
 
 class SeparateUnicode(Unicode):
     r"""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)
 
 
 @undoc
 class DummyMod(object):
     """A dummy module used for IPython's interactive module when
     a namespace must be assigned to the module's __dict__."""
     pass
 
 
 class ExecutionResult(object):
     """The result of a call to :meth:`InteractiveShell.run_cell`
 
     Stores information about what took place.
     """
     execution_count = None
     error_before_exec = None
     error_in_exec = None
     result = None
 
     @property
     def success(self):
         return (self.error_before_exec is None) and (self.error_in_exec is None)
 
     def raise_error(self):
         """Reraises error if `success` is `False`, otherwise does nothing"""
         if self.error_before_exec is not None:
             raise self.error_before_exec
         if self.error_in_exec is not None:
             raise self.error_in_exec
 
 
 class InteractiveShell(SingletonConfigurable):
     """An enhanced, interactive shell for Python."""
 
     _instance = None
     
     ast_transformers = List([], help=
         """
         A list of ast.NodeTransformer subclass instances, which will be applied
         to user input before code is run.
         """
     ).tag(config=True)
 
     autocall = Enum((0,1,2), default_value=0, 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).
         """
     ).tag(config=True)
     # TODO: remove all autoindent logic and put into frontends.
     # We can't do this yet because even runlines uses the autoindent.
     autoindent = Bool(True, help=
         """
         Autoindent IPython code entered interactively.
         """
     ).tag(config=True)
     automagic = Bool(True, help=
         """
         Enable magic commands to be called without the leading %.
         """
     ).tag(config=True)
     
     banner1 = Unicode(default_banner,
         help="""The part of the banner to be printed before the profile"""
     ).tag(config=True)
     banner2 = Unicode('',
         help="""The part of the banner to be printed after the profile"""
     ).tag(config=True)
 
     cache_size = Integer(1000, 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
         """
     ).tag(config=True)
     color_info = Bool(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.
         """
     ).tag(config=True)
     colors = CaselessStrEnum(('NoColor','LightBG','Linux'),
                              default_value=get_default_colors(),
         help="Set the color scheme (NoColor, Linux, or LightBG)."
     ).tag(config=True)
     colors_force = Bool(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 = Bool(False).tag(config=True)
     deep_reload = Bool(False, help=
         """
         **Deprecated**
 
         Will be removed in IPython 6.0
 
         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().
         """
     ).tag(config=True)
     disable_failing_post_execute = Bool(False,
         help="Don't call post-execute functions that have failed in the past."
     ).tag(config=True)
     display_formatter = Instance(DisplayFormatter, allow_none=True)
     displayhook_class = Type(DisplayHook)
     display_pub_class = Type(DisplayPublisher)
     data_pub_class = None
 
     exit_now = Bool(False)
     exiter = Instance(ExitAutocall)
     @default('exiter')
     def _exiter_default(self):
         return ExitAutocall(self)
     # Monotonically increasing execution counter
     execution_count = Integer(1)
     filename = Unicode("<ipython console>")
     ipython_dir= Unicode('').tag(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 = Bool(False, help=
         """
         Start logging to the default log file in overwrite mode.
         Use `logappend` to specify a log file to **append** logs to.
         """
     ).tag(config=True)
     logfile = Unicode('', help=
         """
         The name of the logfile to use.
         """
     ).tag(config=True)
     logappend = Unicode('', help=
         """
         Start logging to the given file in append mode.
         Use `logfile` to specify a log file to **overwrite** logs to.
         """
     ).tag(config=True)
     object_info_string_level = Enum((0,1,2), default_value=0,
     ).tag(config=True)
     pdb = Bool(False, help=
         """
         Automatically call the pdb debugger after every exception.
         """
     ).tag(config=True)
     multiline_history = Bool(sys.platform != 'win32',
         help="Save multi-line entries as one entry in readline history"
     ).tag(config=True)
     display_page = Bool(False,
         help="""If True, anything that would be passed to the pager
         will be displayed as regular output instead."""
     ).tag(config=True)
 
     # deprecated prompt traits:
     
     prompt_in1 = Unicode('In [\\#]: ',
         help="Deprecated, will be removed in IPython 5.0, use PromptManager.in_template"
     ).tag(config=True)
     prompt_in2 = Unicode('   .\\D.: ',
         help="Deprecated, will be removed in IPython 5.0, use PromptManager.in2_template"
     ).tag(config=True)
     prompt_out = Unicode('Out[\\#]: ',
         help="Deprecated, will be removed in IPython 5.0, use PromptManager.out_template"
     ).tag(config=True)
     prompts_pad_left = Bool(True,
         help="Deprecated, will be removed in IPython 5.0, use PromptManager.justify"
     ).tag(config=True)
     
     @observe('prompt_in1', 'prompt_in2', 'prompt_out', 'prompt_pad_left')
     def _prompt_trait_changed(self, change):
         table = {
             'prompt_in1' : 'in_template',
             'prompt_in2' : 'in2_template',
             'prompt_out' : 'out_template',
             'prompts_pad_left' : 'justify',
         }
         name = change['name']
         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], change['new'])
     
     show_rewritten_input = Bool(True,
         help="Show rewritten input, e.g. for autocall."
     ).tag(config=True)
     
     quiet = Bool(False).tag(config=True)
 
     history_length = Integer(10000,
         help='Total length of command history'
     ).tag(config=True)
 
     history_load_length = Integer(1000, help=
         """
         The number of saved history entries to be loaded
         into the readline buffer at startup.
         """
     ).tag(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 = Bool(True).tag(config=True)
     readline_remove_delims = Unicode('-/~').tag(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',
         ]).tag(config=True)
     
     _custom_readline_config = False
     
     @observe('readline_parse_and_bind')
     def _readline_parse_and_bind_changed(self, change):
         # notice that readline config is customized
         # indicates that it should have higher priority than inputrc
         self._custom_readline_config = True
     
     ast_node_interactivity = Enum(['all', 'last', 'last_expr', 'none'],
                                   default_value='last_expr',
                                   help="""
         'all', 'last', 'last_expr' or 'none', specifying which nodes should be
         run interactively (displaying output from expressions)."""
     ).tag(config=True)
 
     # TODO: this part of prompt management should be moved to the frontends.
     # Use custom TraitTypes that convert '0'->'' and '\\n'->'\n'
     separate_in = SeparateUnicode('\n').tag(config=True)
     separate_out = SeparateUnicode('').tag(config=True)
     separate_out2 = SeparateUnicode('').tag(config=True)
     wildcards_case_sensitive = Bool(True).tag(config=True)
     xmode = CaselessStrEnum(('Context','Plain', 'Verbose'),
                             default_value='Context').tag(config=True)
 
     # Subcomponents of InteractiveShell
     alias_manager = Instance('IPython.core.alias.AliasManager', allow_none=True)
     prefilter_manager = Instance('IPython.core.prefilter.PrefilterManager', allow_none=True)
     builtin_trap = Instance('IPython.core.builtin_trap.BuiltinTrap', allow_none=True)
     display_trap = Instance('IPython.core.display_trap.DisplayTrap', allow_none=True)
     extension_manager = Instance('IPython.core.extensions.ExtensionManager', allow_none=True)
     payload_manager = Instance('IPython.core.payload.PayloadManager', allow_none=True)
     history_manager = Instance('IPython.core.history.HistoryAccessorBase', allow_none=True)
     magics_manager = Instance('IPython.core.magic.MagicsManager', allow_none=True)
 
     profile_dir = Instance('IPython.core.application.ProfileDir', allow_none=True)
     @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 = 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_events()
         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_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_magics()
         self.init_alias()
         self.init_logstart()
         self.init_pdb()
         self.init_extension_manager()
         self.init_payload()
         self.init_deprecation_warnings()
         self.hooks.late_startup_hook()
         self.events.trigger('shell_initialized', self)
         atexit.register(self.atexit_operations)
 
     def get_ipython(self):
         """Return the currently running IPython instance."""
         return self
 
     #-------------------------------------------------------------------------
     # Trait changed handlers
     #-------------------------------------------------------------------------
     @observe('ipython_dir')
     def _ipython_dir_changed(self, change):
         ensure_dir_exists(change['new'])
 
     def set_autoindent(self,value=None):
         """Set the autoindent flag.
 
         If called with no arguments, it acts as a toggle."""
         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 = []
         self.tempdirs = []
 
         # 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 = py3compat.getcwd()
 
         # 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_deprecation_warnings(self):
         """
         register default filter for deprecation warning.
 
         This will allow deprecation warning of function used interactively to show
         warning to users, and still hide deprecation warning from libraries import.
         """
         warnings.filterwarnings("default", category=DeprecationWarning, module=self.user_ns.get("__name__"))
 
     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_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
         
         # venv detection:
         # stdlib venv may symlink sys.executable, so we can't use realpath.
         # but others can symlink *to* the venv Python, so we can't just use sys.executable.
         # So we just check every item in the symlink tree (generally <= 3)
         p = os.path.normcase(sys.executable)
         paths = [p]
         while os.path.islink(p):
             p = os.path.normcase(os.path.join(os.path.dirname(p), os.readlink(p)))
             paths.append(p)
         p_venv = os.path.normcase(os.environ['VIRTUAL_ENV'])
         if any(p.startswith(p_venv) for p in paths):
             # 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 = {'stdin': sys.stdin,
                                        'stdout': sys.stdout,
                                        'stderr': sys.stderr,
                                        '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 iteritems(self._orig_sys_module_state):
                 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 the banner
     #-------------------------------------------------------------------------
     
     @property
     def banner(self):
         banner = self.banner1
         if self.profile and self.profile != 'default':
             banner += '\nIPython profile: %s\n' % self.profile
         if self.banner2:
             banner += '\n' + self.banner2
         return banner
 
     def show_banner(self, banner=None):
         if banner is None:
             banner = self.banner
         sys.stdout.write(banner)
     
     #-------------------------------------------------------------------------
     # 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, _warn_deprecated=False)
         
         if self.display_page:
             self.set_hook('show_in_pager', page.as_hook(page.display_page), 90)
     
     def set_hook(self,name,hook, priority=50, str_key=None, re_key=None,
                  _warn_deprecated=True):
         """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 _warn_deprecated and (name in IPython.core.hooks.deprecated):
             alternative = IPython.core.hooks.deprecated[name]
             warn("Hook {} is deprecated. Use {} instead.".format(name, alternative))
 
         if not dp:
             dp = IPython.core.hooks.CommandChainDispatcher()
 
         try:
             dp.add(f,priority)
         except AttributeError:
             # it was not commandchain, plain old func - replace
             dp = f
 
         setattr(self.hooks,name, dp)
 
     #-------------------------------------------------------------------------
     # Things related to events
     #-------------------------------------------------------------------------
 
     def init_events(self):
         self.events = EventManager(self, available_events)
 
         self.events.register("pre_execute", self._clear_warning_registry)
 
     def register_post_execute(self, func):
         """DEPRECATED: Use ip.events.register('post_run_cell', func)
         
         Register a function for calling after code execution.
         """
         warn("ip.register_post_execute is deprecated, use "
              "ip.events.register('post_run_cell', func) instead.")
         self.events.register('post_run_cell', func)
     
     def _clear_warning_registry(self):
         # clear the warning registry, so that different code blocks with
         # overlapping line number ranges don't cause spurious suppression of
         # warnings (see gh-6611 for details)
         if "__warningregistry__" in self.user_global_ns:
             del self.user_global_ns["__warningregistry__"]
 
     #-------------------------------------------------------------------------
     # Things related to the "main" module
     #-------------------------------------------------------------------------
 
     def new_main_mod(self, filename, modname):
         """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.
         
         ``modname`` should be the module name - normally either '__main__' or
         the basename of the file without the extension.
         
         When scripts are executed via %run, we must keep a reference to their
         __main__ module 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] = types.ModuleType(
                         py3compat.cast_bytes_py2(modname),
                         doc="Module created for script run in IPython")
         else:
             main_mod.__dict__.clear()
             main_mod.__name__ = modname
         
         main_mod.__file__ = filename
         # It seems pydoc (and perhaps others) needs any module instance to
         # implement a __nonzero__ method
         main_mod.__nonzero__ = lambda : True
         
         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__, 'IPython')
 
         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.
+        """Call the 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()
+            self.InteractiveTB.debugger(force=True)
 
     #-------------------------------------------------------------------------
     # Things related to IPython's various namespaces
     #-------------------------------------------------------------------------
     default_user_namespaces = True
 
     def init_create_namespaces(self, user_module=None, user_ns=None):
         # Create the namespace where the user will operate.  user_ns is
         # normally the only one used, and it is passed to the exec calls as
         # the locals argument.  But we do carry a user_global_ns namespace
         # given as the exec 'globals' argument,  This is useful in embedding
         # situations where the ipython shell opens in a context where the
         # distinction between locals and globals is meaningful.  For
         # non-embedded contexts, it is just the same object as the user_ns dict.
 
         # FIXME. For some strange reason, __builtins__ is showing up at user
         # level as a dict instead of a module. This is a manual fix, but I
         # should really track down where the problem is coming from. Alex
         # Schmolck reported this problem first.
 
         # A useful post by Alex Martelli on this topic:
         # Re: inconsistent value from __builtins__
         # Von: Alex Martelli <[e-mail]>
         # Datum: Freitag 01 Oktober 2004 04:45:34 nachmittags/abends
         # Gruppen: comp.lang.python
 
         # Michael Hohn <[e-mail]> wrote:
         # > >>> print type(builtin_check.get_global_binding('__builtins__'))
         # > <type 'dict'>
         # > >>> print type(__builtins__)
         # > <type 'module'>
         # > Is this difference in return value intentional?
 
         # Well, it's documented that '__builtins__' can be either a dictionary
         # or a module, and it's been that way for a long time. Whether it's
         # intentional (or sensible), I don't know. In any case, the idea is
         # that if you need to access the built-in namespace directly, you
         # should start with "import __builtin__" (note, no 's') which will
         # definitely give you a module. Yeah, it's somewhat confusing:-(.
 
         # These routines return a properly built module and dict as needed by
         # the rest of the code, and can also be used by extension writers to
         # generate properly initialized namespaces.
         if (user_ns is not None) or (user_module is not None):
             self.default_user_namespaces = False
         self.user_module, self.user_ns = self.prepare_user_module(user_module, user_ns)
 
         # A record of hidden variables we have added to the user namespace, so
         # we can list later only variables defined in actual interactive use.
         self.user_ns_hidden = {}
 
         # 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 doctest 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__")
             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 they 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, self.user_ns_hidden] + \
                [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 iteritems(ns) 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, string_types+(list, tuple)):
             if isinstance(variables, string_types):
                 vlist = variables.split()
             else:
                 vlist = variables
             vdict = {}
             cf = sys._getframe(1)
             for name in vlist:
                 try:
                     vdict[name] = eval(name, cf.f_globals, cf.f_locals)
                 except:
                     print('Could not get variable %s from %s' %
                            (name,cf.f_code.co_name))
         else:
             raise ValueError('variables must be a dict/str/list/tuple')
 
         # Propagate variables to user namespace
         self.user_ns.update(vdict)
 
         # And configure interactive visibility
         user_ns_hidden = self.user_ns_hidden
         if interactive:
             for name in vdict:
                 user_ns_hidden.pop(name, None)
         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 iteritems(variables):
             if name in self.user_ns and self.user_ns[name] is obj:
                 del self.user_ns[name]
                 self.user_ns_hidden.pop(name, None)
 
     #-------------------------------------------------------------------------
     # 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)
 
         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__),
                            ]
 
         # initialize results to 'null'
         found = False; obj = None;  ospace = 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 idx, part in enumerate(oname_rest):
                     try:
                         parent = obj
                         # The last part is looked up in a special way to avoid
                         # descriptor invocation as it may raise or have side
                         # effects.
                         if idx == len(oname_rest) - 1:
                             obj = self._getattr_property(obj, part)
                         else:
                             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
                     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
                 isalias = isinstance(obj, Alias)
 
         # 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}
 
     @staticmethod
     def _getattr_property(obj, attrname):
         """Property-aware getattr to use in object finding.
 
         If attrname represents a property, return it unevaluated (in case it has
         side effects or raises an error.
 
         """
         if not isinstance(obj, type):
             try:
                 # `getattr(type(obj), attrname)` is not guaranteed to return
                 # `obj`, but does so for property:
                 #
                 # property.__get__(self, None, cls) -> self
                 #
                 # The universal alternative is to traverse the mro manually
                 # searching for attrname in class dicts.
                 attr = getattr(type(obj), attrname)
             except AttributeError:
                 pass
             else:
                 # This relies on the fact that data descriptors (with both
                 # __get__ & __set__ magic methods) take precedence over
                 # instance-level attributes:
                 #
                 #    class A(object):
                 #        @property
                 #        def foobar(self): return 123
                 #    a = A()
                 #    a.__dict__['foobar'] = 345
                 #    a.foobar  # == 123
                 #
                 # So, a property may be returned right away.
                 if isinstance(attr, property):
                     return attr
 
         # Nothing helped, fall back.
         return getattr(obj, attrname)
 
     def _object_find(self, oname, namespaces=None):
         """Find an object and return a struct with info about it."""
         return Struct(self._ofind(oname, namespaces))
 
     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):
         """Get object info about oname"""
         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)
 
     def object_inspect_text(self, oname, detail_level=0):
         """Get object info as formatted text"""
         with self.builtin_trap:
             info = self._object_find(oname)
             if info.found:
                 return self.inspector._format_info(info.obj, oname, info=info,
                             detail_level=detail_level
                 )
             else:
                 raise KeyError(oname)
 
     #-------------------------------------------------------------------------
     # 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, string_types):
                 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, string_types):
                     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=sys.stderr)
                     # show the exception in handler first
                     stb = self.InteractiveTB.structured_traceback(*sys.exc_info())
                     print(self.InteractiveTB.stb2text(stb))
                     print("The original exception:")
                     stb = self.InteractiveTB.structured_traceback(
                                             (etype,value,tb), tb_offset=tb_offset
                     )
                 return stb
 
         self.CustomTB = types.MethodType(wrapped,self)
         self.custom_exceptions = exc_tuple
 
     def excepthook(self, etype, value, tb):
       """One more defense for GUI apps that call sys.excepthook.
 
       GUI frameworks like wxPython trap exceptions and call
       sys.excepthook themselves.  I guess this is a feature that
       enables them to keep running after exceptions that would
       otherwise kill their mainloop. This is a bother for IPython
       which excepts to catch all of the program exceptions with a try:
       except: statement.
 
       Normally, IPython sets sys.excepthook to a CrashHandler instance, so if
       any app directly invokes sys.excepthook, it will look to the user like
       IPython crashed.  In order to work around this, we can disable the
       CrashHandler and replace it with this excepthook instead, which prints a
       regular traceback using our InteractiveTB.  In this fashion, apps which
       call sys.excepthook will generate a regular-looking exception from
       IPython, and the CrashHandler will only be triggered by real IPython
       crashes.
 
       This hook should be used sparingly, only in places which are not likely
       to be true IPython errors.
       """
       self.showtraceback((etype, value, tb), tb_offset=0)
 
     def _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.
         """
         print("UsageError: %s" % exc, file=sys.stderr)
     
     def get_exception_only(self, exc_tuple=None):
         """
         Return as a string (ending with a newline) the exception that
         just occurred, without any traceback.
         """
         etype, value, tb = self._get_exc_info(exc_tuple)
         msg = traceback.format_exception_only(etype, value)
         return ''.join(msg)
 
     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:
                 print('No traceback available to show.', file=sys.stderr)
                 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:
             print('\n' + self.get_exception_only(), file=sys.stderr)
 
     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))
 
     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):
         """Moved to terminal subclass, here only to simplify the init logic."""
         self.readline = None
         # Set a number of methods that depend on readline to be no-op
         self.readline_no_record = NoOpContext()
         self.set_readline_completer = no_op
         self.set_custom_completer = no_op
 
     @skip_doctest
     def set_next_input(self, s, replace=False):
         """ Sets the 'default' input string for the next command line.
 
         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)
 
     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), programmatically (such as in test suites) or out-of-process
         (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,
                                      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', module_completer, str_key = '%aimport')
         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')
 
 
     @skip_doctest_py2
     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_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, string_types):
             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 on Windows or
         subprocess.call using the system shell on other platforms.
 
         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)
                 try:
                     ec = os.system(cmd)
                 except KeyboardInterrupt:
                     print('\n' + self.get_exception_only(), file=sys.stderr)
                     ec = -2
         else:
             cmd = py3compat.unicode_to_str(cmd)
             # For posix the result of the subprocess.call() below is an exit
             # code, which by convention is zero for success, positive for
             # program failure.  Exit codes above 128 are reserved for signals,
             # and the formula for converting a signal to an exit code is usually
             # signal_number+128.  To more easily differentiate between exit
             # codes and signals, ipython uses negative numbers.  For instance
             # since control-c is signal 2 but exit code 130, ipython's
             # _exit_code variable will read -2.  Note that some shells like
             # csh and fish don't follow sh/bash conventions for exit codes.
             executable = os.environ.get('SHELL', None)
             try:
                 # Use env shell instead of default /bin/sh
                 ec = subprocess.call(cmd, shell=True, executable=executable)
             except KeyboardInterrupt:
                 # intercept control-C; a long traceback is not useful here
                 print('\n' + self.get_exception_only(), file=sys.stderr)
                 ec = 130
             if ec > 128:
                 ec = -(ec - 128)
         
         # 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.  Note the semantics
         # of _exit_code: for control-c, _exit_code == -signal.SIGNIT,
         # but raising SystemExit(_exit_code) will give status 254!
         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)
 
     #-------------------------------------------------------------------------
     # 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)
         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_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_type(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
         """
         
         data, md = self.display_formatter.format(obj)
         value = {
             'status' : 'ok',
             'data' : data,
             'metadata' : md,
         }
         return value
     
     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 iteritems(expressions):
             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, 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.
         shell_futures : bool (False)
             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.
 
         """
         kw.setdefault('exit_ignore', False)
         kw.setdefault('raise_exceptions', False)
         kw.setdefault('shell_futures', False)
 
         fname = os.path.abspath(os.path.expanduser(fname))
 
         # Make sure we can open the file
         try:
             with open(fname):
                 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:
                 glob, loc = (where + (None, ))[:2]
                 py3compat.execfile(
                     fname, glob, loc,
                     self.compile if kw['shell_futures'] else None)
             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 status.code:
                     if kw['raise_exceptions']:
                         raise
                     if not kw['exit_ignore']:
                         self.showtraceback(exception_only=True)
             except:
                 if kw['raise_exceptions']:
                     raise
                 # tb offset is 2 because we wrap execfile
                 self.showtraceback(tb_offset=2)
 
     def safe_execfile_ipy(self, fname, shell_futures=False, raise_exceptions=False):
         """Like safe_execfile, but for .ipy or .ipynb files with IPython syntax.
 
         Parameters
         ----------
         fname : str
             The name of the file to execute.  The filename must have a
             .ipy or .ipynb extension.
         shell_futures : bool (False)
             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.
         raise_exceptions : bool (False)
             If True raise exceptions everywhere.  Meant for testing.
         """
         fname = os.path.abspath(os.path.expanduser(fname))
 
         # Make sure we can open the file
         try:
             with open(fname):
                 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)
         
         def get_cells():
             """generator for sequence of code blocks to run"""
             if fname.endswith('.ipynb'):
                 from nbformat import read
                 with io_open(fname) as f:
                     nb = read(f, as_version=4)
                     if not nb.cells:
                         return
                     for cell in nb.cells:
                         if cell.cell_type == 'code':
                             yield cell.source
             else:
                 with open(fname) as f:
                     yield f.read()
 
         with prepended_to_syspath(dname):
             try:
                 for cell in get_cells():
                     result = self.run_cell(cell, silent=True, shell_futures=shell_futures)
                     if raise_exceptions:
                         result.raise_error()
                     elif not result.success:
                         break
             except:
                 if raise_exceptions:
                     raise
                 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_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.
 
         Returns
         -------
         result : :class:`ExecutionResult`
         """
         result = ExecutionResult()
 
         if (not raw_cell) or raw_cell.isspace():
             return result
         
         if silent:
             store_history = False
 
         if store_history:
             result.execution_count = self.execution_count
 
         def error_before_exec(value):
             result.error_before_exec = value
             return result
 
         self.events.trigger('pre_execute')
         if not silent:
             self.events.trigger('pre_run_cell')
 
         # If any of our input transformation (input_transformer_manager or
         # prefilter_manager) raises an exception, we store it in this variable
         # so that we can display the error after logging the input and storing
         # it in the history.
         preprocessing_exc_tuple = None
         try:
             # Static input transformations
             cell = self.input_transformer_manager.transform_cell(raw_cell)
         except SyntaxError:
             preprocessing_exc_tuple = sys.exc_info()
             cell = raw_cell  # cell has to exist so it can be stored/logged
         else:
             if len(cell.splitlines()) == 1:
                 # Dynamic transformations - only applied for single line commands
                 with self.builtin_trap:
                     try:
                         # use prefilter_lines to handle trailing newlines
                         # restore trailing newline for ast.parse
                         cell = self.prefilter_manager.prefilter_lines(cell) + '\n'
                     except Exception:
                         # don't allow prefilter errors to crash IPython
                         preprocessing_exc_tuple = sys.exc_info()
 
         # 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)
 
         # Display the exception if input processing failed.
         if preprocessing_exc_tuple is not None:
             self.showtraceback(preprocessing_exc_tuple)
             if store_history:
                 self.execution_count += 1
             return error_before_exec(preprocessing_exc_tuple[2])
 
         # 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:
             cell_name = self.compile.cache(cell, self.execution_count)
 
             with self.display_trap:
                 # Compile to bytecode
                 try:
                     code_ast = compiler.ast_parse(cell, filename=cell_name)
                 except IndentationError as e:
                     self.showindentationerror()
                     if store_history:
                         self.execution_count += 1
                     return error_before_exec(e)
                 except (OverflowError, SyntaxError, ValueError, TypeError,
                         MemoryError) as e:
                     self.showsyntaxerror()
                     if store_history:
                         self.execution_count += 1
                     return error_before_exec(e)
 
                 # Apply AST transformations
                 try:
                     code_ast = self.transform_ast(code_ast)
                 except InputRejected as e:
                     self.showtraceback()
                     if store_history:
                         self.execution_count += 1
                     return error_before_exec(e)
 
                 # Give the displayhook a reference to our ExecutionResult so it
                 # can fill in the output value.
                 self.displayhook.exec_result = result
 
                 # Execute the user code
                 interactivity = "none" if silent else self.ast_node_interactivity
                 self.run_ast_nodes(code_ast.body, cell_name,
                    interactivity=interactivity, compiler=compiler, result=result)
 
                 # Reset this so later displayed values do not modify the
                 # ExecutionResult
                 self.displayhook.exec_result = None
 
                 self.events.trigger('post_execute')
                 if not silent:
                     self.events.trigger('post_run_cell')
 
         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
 
         return result
     
     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 InputRejected:
                 # User-supplied AST transformers can reject an input by raising
                 # an InputRejected.  Short-circuit in this case so that we
                 # don't unregister the transform.
                 raise
             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, result=None):
         """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().
         result : ExecutionResult, optional
           An object to store exceptions that occur during execution.
 
         Returns
         -------
         True if an exception occurred while running code, False if it finished
         running.
         """
         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)
 
         try:
             for i, node in enumerate(to_run_exec):
                 mod = ast.Module([node])
                 code = compiler(mod, cell_name, "exec")
                 if self.run_code(code, result):
                     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, result):
                     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.
             if result:
                 result.error_before_exec = sys.exc_info()[1]
             self.showtraceback()
             return True
 
         return False
 
     def run_code(self, code_obj, result=None):
         """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
         result : ExecutionResult, optional
           An object to store exceptions that occur during execution.
 
         Returns
         -------
         False : successful execution.
         True : an error occurred.
         """
         # Set our own excepthook in case the user code tries to call it
         # directly, so that the IPython crash handler doesn't get triggered
         old_excepthook, sys.excepthook = sys.excepthook, self.excepthook
 
         # we save the original sys.excepthook in the instance, in case config
         # code (such as magics) needs access to it.
         self.sys_excepthook = old_excepthook
         outflag = 1  # happens in more places, so it's easier as default
         try:
             try:
                 self.hooks.pre_run_code_hook()
                 #rprint('Running code', repr(code_obj)) # dbg
                 exec(code_obj, self.user_global_ns, self.user_ns)
             finally:
                 # Reset our crash handler in place
                 sys.excepthook = old_excepthook
         except SystemExit as e:
             if result is not None:
                 result.error_in_exec = e
             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()
             if result is not None:
                 result.error_in_exec = value
             self.CustomTB(etype, value, tb)
         except:
             if result is not None:
                 result.error_in_exec = sys.exc_info()[1]
             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)
     
         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 = {"__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()
         try:
             frame = sys._getframe(depth+1)
         except ValueError:
             # This is thrown if there aren't that many frames on the stack,
             # e.g. if a script called run_line_magic() directly.
             pass
         else:
             ns.update(frame.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.mkstemp (created in a tempfile.mkdtemp),
         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."""
 
         dirname = tempfile.mkdtemp(prefix=prefix)
         self.tempdirs.append(dirname)
 
         handle, filename = tempfile.mkstemp('.py', prefix, dir=dirname)
         os.close(handle)  # On Windows, there can only be one open handle on a file
         self.tempfiles.append(filename)
 
         if data:
             tmp_file = open(filename,'w')
             tmp_file.write(data)
             tmp_file.close()
         return filename
 
     @undoc
     def write(self,data):
         """DEPRECATED: Write a string to the default output"""
         warn('InteractiveShell.write() is deprecated, use sys.stdout instead',
              DeprecationWarning, stacklevel=2)
         sys.stdout.write(data)
 
     @undoc
     def write_err(self,data):
         """DEPRECATED: Write a string to the default error output"""
         warn('InteractiveShell.write_err() is deprecated, use sys.stderr instead',
              DeprecationWarning, stacklevel=2)
         sys.stderr.write(data)
 
     def ask_yes_no(self, prompt, default=None, interrupt=None):
         if self.quiet:
             return True
         return ask_yes_no(prompt,default,interrupt)
 
     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.
 
         raw : bool, optional
             By default, the processed input is used.  If this is true, the raw
             input history is used instead.
 
         Notes
         -----
 
         Slices can be described 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, search_ns=False):
         """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,
           corresponding .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 :
                 # Deferred import
                 try:
                     from urllib.request import urlopen  # Py3
                 except ImportError:
                     from urllib import urlopen
                 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)
 
         if search_ns:
             # Inspect namespace to load object source
             object_info = self.object_inspect(target, detail_level=1)
             if object_info['found'] and object_info['source']:
                 return object_info['source']
 
         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, string_types):
             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 and folders left around
         for tfile in self.tempfiles:
             try:
                 os.unlink(tfile)
             except OSError:
                 pass
 
         for tdir in self.tempdirs:
             try:
                 os.rmdir(tdir)
             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(with_metaclass(abc.ABCMeta, object)):
     """An abstract base class for InteractiveShell."""
 
 InteractiveShellABC.register(InteractiveShell)

IPython/core/shellapp.py

@@ -1,437 +1,429 b''
 # encoding: utf-8
 """
 A mixin for :class:`~IPython.core.application.Application` classes that
 launch InteractiveShell instances, load extensions, etc.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 from __future__ import absolute_import
 from __future__ import print_function
 
 import glob
 import os
 import sys
 
 from traitlets.config.application import boolean_flag
 from traitlets.config.configurable import Configurable
 from traitlets.config.loader import Config
 from IPython.core import pylabtools
 from IPython.utils import py3compat
 from IPython.utils.contexts import preserve_keys
 from IPython.utils.path import filefind
 from traitlets import (
-    Unicode, Instance, List, Bool, CaselessStrEnum, default, observe,
+    Unicode, Instance, List, Bool, CaselessStrEnum, observe,
 )
 from IPython.lib.inputhook import guis
 
 #-----------------------------------------------------------------------------
 # Aliases and Flags
 #-----------------------------------------------------------------------------
 
 gui_keys = tuple(sorted([ key for key in guis if key is not None ]))
 
 backend_keys = sorted(pylabtools.backends.keys())
 backend_keys.insert(0, 'auto')
 
 shell_flags = {}
 
 addflag = lambda *args: shell_flags.update(boolean_flag(*args))
 addflag('autoindent', 'InteractiveShell.autoindent',
         'Turn on autoindenting.', 'Turn off autoindenting.'
 )
 addflag('automagic', 'InteractiveShell.automagic',
         """Turn on the auto calling of magic commands. Type %%magic at the
         IPython  prompt  for  more information.""",
         'Turn off the auto calling of magic commands.'
 )
 addflag('pdb', 'InteractiveShell.pdb',
     "Enable auto calling the pdb debugger after every exception.",
     "Disable auto calling the pdb debugger after every exception."
 )
-# pydb flag doesn't do any config, as core.debugger switches on import,
-# which is before parsing.  This just allows the flag to be passed.
-shell_flags.update(dict(
-    pydb = ({},
-        """Use the third party 'pydb' package as debugger, instead of pdb.
-        Requires that pydb is installed."""
-    )
-))
 addflag('pprint', 'PlainTextFormatter.pprint',
     "Enable auto pretty printing of results.",
     "Disable auto pretty printing of results."
 )
 addflag('color-info', 'InteractiveShell.color_info',
     """IPython can display information about objects via a set of functions,
     and optionally can use colors for this, syntax highlighting
     source code and various other elements. This is on by default, but can cause
     problems with some pagers. If you see such problems, you can disable the
     colours.""",
     "Disable using colors for info related things."
 )
 addflag('deep-reload', 'InteractiveShell.deep_reload',
     """ **Deprecated** and will be removed in IPython 5.0.
     
     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(). This feature is off
     by default [which means that you have both normal reload() and
     dreload()].""",
     "Disable deep (recursive) reloading by default."
 )
 nosep_config = Config()
 nosep_config.InteractiveShell.separate_in = ''
 nosep_config.InteractiveShell.separate_out = ''
 nosep_config.InteractiveShell.separate_out2 = ''
 
 shell_flags['nosep']=(nosep_config, "Eliminate all spacing between prompts.")
 shell_flags['pylab'] = (
     {'InteractiveShellApp' : {'pylab' : 'auto'}},
     """Pre-load matplotlib and numpy for interactive use with
     the default matplotlib backend."""
 )
 shell_flags['matplotlib'] = (
     {'InteractiveShellApp' : {'matplotlib' : 'auto'}},
     """Configure matplotlib for interactive use with
     the default matplotlib backend."""
 )
 
 # it's possible we don't want short aliases for *all* of these:
 shell_aliases = dict(
     autocall='InteractiveShell.autocall',
     colors='InteractiveShell.colors',
     logfile='InteractiveShell.logfile',
     logappend='InteractiveShell.logappend',
     c='InteractiveShellApp.code_to_run',
     m='InteractiveShellApp.module_to_run',
     ext='InteractiveShellApp.extra_extension',
     gui='InteractiveShellApp.gui',
     pylab='InteractiveShellApp.pylab',
     matplotlib='InteractiveShellApp.matplotlib',
 )
 shell_aliases['cache-size'] = 'InteractiveShell.cache_size'
 
 #-----------------------------------------------------------------------------
 # Main classes and functions
 #-----------------------------------------------------------------------------
 
 class InteractiveShellApp(Configurable):
     """A Mixin for applications that start InteractiveShell instances.
     
     Provides configurables for loading extensions and executing files
     as part of configuring a Shell environment.
 
     The following methods should be called by the :meth:`initialize` method
     of the subclass:
 
       - :meth:`init_path`
       - :meth:`init_shell` (to be implemented by the subclass)
       - :meth:`init_gui_pylab`
       - :meth:`init_extensions`
       - :meth:`init_code`
     """
     extensions = List(Unicode(),
         help="A list of dotted module names of IPython extensions to load."
     ).tag(config=True)
     extra_extension = Unicode('',
         help="dotted module name of an IPython extension to load."
     ).tag(config=True)
 
     reraise_ipython_extension_failures = Bool(False,
         help="Reraise exceptions encountered loading IPython extensions?",
     ).tag(config=True)
 
     # Extensions that are always loaded (not configurable)
     default_extensions = List(Unicode(), [u'storemagic']).tag(config=False)
     
     hide_initial_ns = Bool(True,
         help="""Should variables loaded at startup (by startup files, exec_lines, etc.)
         be hidden from tools like %who?"""
     ).tag(config=True)
 
     exec_files = List(Unicode(),
         help="""List of files to run at IPython startup."""
     ).tag(config=True)
     exec_PYTHONSTARTUP = Bool(True,
         help="""Run the file referenced by the PYTHONSTARTUP environment
         variable at IPython startup."""
     ).tag(config=True)
     file_to_run = Unicode('',
         help="""A file to be run""").tag(config=True)
 
     exec_lines = List(Unicode(),
         help="""lines of code to run at IPython startup."""
     ).tag(config=True)
     code_to_run = Unicode('',
         help="Execute the given command string."
     ).tag(config=True)
     module_to_run = Unicode('',
         help="Run the module as a script."
     ).tag(config=True)
     gui = CaselessStrEnum(gui_keys, allow_none=True,
         help="Enable GUI event loop integration with any of {0}.".format(gui_keys)
     ).tag(config=True)
     matplotlib = CaselessStrEnum(backend_keys, allow_none=True,
         help="""Configure matplotlib for interactive use with
         the default matplotlib backend."""
     ).tag(config=True)
     pylab = CaselessStrEnum(backend_keys, allow_none=True,
         help="""Pre-load matplotlib and numpy for interactive use,
         selecting a particular matplotlib backend and loop integration.
         """
     ).tag(config=True)
     pylab_import_all = Bool(True,
         help="""If true, IPython will populate the user namespace with numpy, pylab, etc.
         and an ``import *`` is done from numpy and pylab, when using pylab mode.
         
         When False, pylab mode should not import any names into the user namespace.
         """
     ).tag(config=True)
     shell = Instance('IPython.core.interactiveshell.InteractiveShellABC',
                      allow_none=True)
     # whether interact-loop should start
     interact = Bool(True)
     
     user_ns = Instance(dict, args=None, allow_none=True)
     @observe('user_ns')
     def _user_ns_changed(self, change):
         if self.shell is not None:
             self.shell.user_ns = change['new']
             self.shell.init_user_ns()
 
     def init_path(self):
         """Add current working directory, '', to sys.path"""
         if sys.path[0] != '':
             sys.path.insert(0, '')
 
     def init_shell(self):
         raise NotImplementedError("Override in subclasses")
 
     def init_gui_pylab(self):
         """Enable GUI event loop integration, taking pylab into account."""
         enable = False
         shell = self.shell
         if self.pylab:
             enable = lambda key: shell.enable_pylab(key, import_all=self.pylab_import_all)
             key = self.pylab
         elif self.matplotlib:
             enable = shell.enable_matplotlib
             key = self.matplotlib
         elif self.gui:
             enable = shell.enable_gui
             key = self.gui
         
         if not enable:
             return
         
         try:
             r = enable(key)
         except ImportError:
             self.log.warning("Eventloop or matplotlib integration failed. Is matplotlib installed?")
             self.shell.showtraceback()
             return
         except Exception:
             self.log.warning("GUI event loop or pylab initialization failed")
             self.shell.showtraceback()
             return
             
         if isinstance(r, tuple):
             gui, backend = r[:2]
             self.log.info("Enabling GUI event loop integration, "
                       "eventloop=%s, matplotlib=%s", gui, backend)
             if key == "auto":
                 print("Using matplotlib backend: %s" % backend)
         else:
             gui = r
             self.log.info("Enabling GUI event loop integration, "
                       "eventloop=%s", gui)
 
     def init_extensions(self):
         """Load all IPython extensions in IPythonApp.extensions.
 
         This uses the :meth:`ExtensionManager.load_extensions` to load all
         the extensions listed in ``self.extensions``.
         """
         try:
             self.log.debug("Loading IPython extensions...")
             extensions = self.default_extensions + self.extensions
             if self.extra_extension:
                 extensions.append(self.extra_extension)
             for ext in extensions:
                 try:
                     self.log.info("Loading IPython extension: %s" % ext)
                     self.shell.extension_manager.load_extension(ext)
                 except:
                     if self.reraise_ipython_extension_failures:
                         raise
                     msg = ("Error in loading extension: {ext}\n"
                            "Check your config files in {location}".format(
                                ext=ext,
                                location=self.profile_dir.location
                            ))
                     self.log.warning(msg, exc_info=True)
         except:
             if self.reraise_ipython_extension_failures:
                 raise
             self.log.warning("Unknown error in loading extensions:", exc_info=True)
 
     def init_code(self):
         """run the pre-flight code, specified via exec_lines"""
         self._run_startup_files()
         self._run_exec_lines()
         self._run_exec_files()
         
         # Hide variables defined here from %who etc.
         if self.hide_initial_ns:
             self.shell.user_ns_hidden.update(self.shell.user_ns)
         
         # command-line execution (ipython -i script.py, ipython -m module)
         # should *not* be excluded from %whos
         self._run_cmd_line_code()
         self._run_module()
         
         # flush output, so itwon't be attached to the first cell
         sys.stdout.flush()
         sys.stderr.flush()
 
     def _run_exec_lines(self):
         """Run lines of code in IPythonApp.exec_lines in the user's namespace."""
         if not self.exec_lines:
             return
         try:
             self.log.debug("Running code from IPythonApp.exec_lines...")
             for line in self.exec_lines:
                 try:
                     self.log.info("Running code in user namespace: %s" %
                                   line)
                     self.shell.run_cell(line, store_history=False)
                 except:
                     self.log.warning("Error in executing line in user "
                                   "namespace: %s" % line)
                     self.shell.showtraceback()
         except:
             self.log.warning("Unknown error in handling IPythonApp.exec_lines:")
             self.shell.showtraceback()
 
     def _exec_file(self, fname, shell_futures=False):
         try:
             full_filename = filefind(fname, [u'.', self.ipython_dir])
-        except IOError as e:
+        except IOError:
             self.log.warning("File not found: %r"%fname)
             return
         # Make sure that the running script gets a proper sys.argv as if it
         # were run from a system shell.
         save_argv = sys.argv
         sys.argv = [full_filename] + self.extra_args[1:]
         # protect sys.argv from potential unicode strings on Python 2:
         if not py3compat.PY3:
             sys.argv = [ py3compat.cast_bytes(a) for a in sys.argv ]
         try:
             if os.path.isfile(full_filename):
                 self.log.info("Running file in user namespace: %s" %
                               full_filename)
                 # Ensure that __file__ is always defined to match Python
                 # behavior.
                 with preserve_keys(self.shell.user_ns, '__file__'):
                     self.shell.user_ns['__file__'] = fname
                     if full_filename.endswith('.ipy'):
                         self.shell.safe_execfile_ipy(full_filename,
                                                      shell_futures=shell_futures)
                     else:
                         # default to python, even without extension
                         self.shell.safe_execfile(full_filename,
                                                  self.shell.user_ns,
                                                  shell_futures=shell_futures,
                                                  raise_exceptions=True)
         finally:
             sys.argv = save_argv
 
     def _run_startup_files(self):
         """Run files from profile startup directory"""
         startup_dir = self.profile_dir.startup_dir
         startup_files = []
         
         if self.exec_PYTHONSTARTUP and os.environ.get('PYTHONSTARTUP', False) and \
                 not (self.file_to_run or self.code_to_run or self.module_to_run):
             python_startup = os.environ['PYTHONSTARTUP']
             self.log.debug("Running PYTHONSTARTUP file %s...", python_startup)
             try:
                 self._exec_file(python_startup)
             except:
                 self.log.warning("Unknown error in handling PYTHONSTARTUP file %s:", python_startup)
                 self.shell.showtraceback()
             finally:
                 # Many PYTHONSTARTUP files set up the readline completions,
                 # but this is often at odds with IPython's own completions.
                 # Do not allow PYTHONSTARTUP to set up readline.
                 if self.shell.has_readline:
                     self.shell.set_readline_completer()
         
         startup_files += glob.glob(os.path.join(startup_dir, '*.py'))
         startup_files += glob.glob(os.path.join(startup_dir, '*.ipy'))
         if not startup_files:
             return
         
         self.log.debug("Running startup files from %s...", startup_dir)
         try:
             for fname in sorted(startup_files):
                 self._exec_file(fname)
         except:
             self.log.warning("Unknown error in handling startup files:")
             self.shell.showtraceback()
 
     def _run_exec_files(self):
         """Run files from IPythonApp.exec_files"""
         if not self.exec_files:
             return
 
         self.log.debug("Running files in IPythonApp.exec_files...")
         try:
             for fname in self.exec_files:
                 self._exec_file(fname)
         except:
             self.log.warning("Unknown error in handling IPythonApp.exec_files:")
             self.shell.showtraceback()
 
     def _run_cmd_line_code(self):
         """Run code or file specified at the command-line"""
         if self.code_to_run:
             line = self.code_to_run
             try:
                 self.log.info("Running code given at command line (c=): %s" %
                               line)
                 self.shell.run_cell(line, store_history=False)
             except:
                 self.log.warning("Error in executing line in user namespace: %s" %
                               line)
                 self.shell.showtraceback()
                 if not self.interact:
                     self.exit(1)
 
         # Like Python itself, ignore the second if the first of these is present
         elif self.file_to_run:
             fname = self.file_to_run
             try:
                 self._exec_file(fname, shell_futures=True)
             except:
                 self.shell.showtraceback(tb_offset=4)
                 if not self.interact:
                     self.exit(1)
 
     def _run_module(self):
         """Run module specified at the command-line."""
         if self.module_to_run:
             # Make sure that the module gets a proper sys.argv as if it were
             # run using `python -m`.
             save_argv = sys.argv
             sys.argv = [sys.executable] + self.extra_args
             try:
                 self.shell.safe_run_module(self.module_to_run,
                                            self.shell.user_ns)
             finally:
                 sys.argv = save_argv