Merge pull request #11128 from Carreau/non-callable-module

Traceback printing change `in <module>()` to `in <module>`.

IPython/core/tests/test_iplib.py

@@ -1,254 +1,254 b''
 """Tests for the key interactiveshell module, where the main ipython class is defined.
 """
 #-----------------------------------------------------------------------------
 # Module imports
 #-----------------------------------------------------------------------------
 
 # third party
 import nose.tools as nt
 
 # our own packages
 from IPython.testing.globalipapp import get_ipython
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 # Get the public instance of IPython
 ip = get_ipython()
 
 #-----------------------------------------------------------------------------
 # Test functions
 #-----------------------------------------------------------------------------
 
 def test_reset():
     """reset must clear most namespaces."""
 
     # Check that reset runs without error
     ip.reset()
 
     # Once we've reset it (to clear of any junk that might have been there from
     # other tests, we can count how many variables are in the user's namespace
     nvars_user_ns = len(ip.user_ns)
     nvars_hidden = len(ip.user_ns_hidden)
 
     # Now add a few variables to user_ns, and check that reset clears them
     ip.user_ns['x'] = 1
     ip.user_ns['y'] = 1
     ip.reset()
     
     # Finally, check that all namespaces have only as many variables as we
     # expect to find in them:
     nt.assert_equal(len(ip.user_ns), nvars_user_ns)
     nt.assert_equal(len(ip.user_ns_hidden), nvars_hidden)
 
 
 # Tests for reporting of exceptions in various modes, handling of SystemExit,
 # and %tb functionality.  This is really a mix of testing ultraTB and interactiveshell.
 
 def doctest_tb_plain():
     """
 In [18]: xmode plain
 Exception reporting mode: Plain
 
 In [19]: run simpleerr.py
 Traceback (most recent call last):
   ...line 32, in <module>
     bar(mode)
   ...line 16, in bar
     div0()
   ...line 8, in div0
     x/y
 ZeroDivisionError: ...
     """
 
 
 def doctest_tb_context():
     """
 In [3]: xmode context
 Exception reporting mode: Context
 
 In [4]: run simpleerr.py
 ---------------------------------------------------------------------------
 ZeroDivisionError                         Traceback (most recent call last)
 <BLANKLINE>
-... in <module>()
+... in <module>
      30         mode = 'div'
      31 
 ---> 32     bar(mode)
 <BLANKLINE>
 ... in bar(mode)
      14     "bar"
      15     if mode=='div':
 ---> 16         div0()
      17     elif mode=='exit':
      18         try:
 <BLANKLINE>
 ... in div0()
       6     x = 1
       7     y = 0
 ----> 8     x/y
       9 
      10 def sysexit(stat, mode):
 <BLANKLINE>
 ZeroDivisionError: ...
 """
 
 
 def doctest_tb_verbose():
     """
 In [5]: xmode verbose
 Exception reporting mode: Verbose
 
 In [6]: run simpleerr.py
 ---------------------------------------------------------------------------
 ZeroDivisionError                         Traceback (most recent call last)
 <BLANKLINE>
-... in <module>()
+... in <module>
      30         mode = 'div'
      31 
 ---> 32     bar(mode)
         global bar = <function bar at ...>
         global mode = 'div'
 <BLANKLINE>
 ... in bar(mode='div')
      14     "bar"
      15     if mode=='div':
 ---> 16         div0()
         global div0 = <function div0 at ...>
      17     elif mode=='exit':
      18         try:
 <BLANKLINE>
 ... in div0()
       6     x = 1
       7     y = 0
 ----> 8     x/y
         x = 1
         y = 0
       9 
      10 def sysexit(stat, mode):
 <BLANKLINE>
 ZeroDivisionError: ...
       """
 
 def doctest_tb_sysexit():
     """
 In [17]: %xmode plain
 Exception reporting mode: Plain
 
 In [18]: %run simpleerr.py exit
 An exception has occurred, use %tb to see the full traceback.
 SystemExit: (1, 'Mode = exit')
 
 In [19]: %run simpleerr.py exit 2
 An exception has occurred, use %tb to see the full traceback.
 SystemExit: (2, 'Mode = exit')
 
 In [20]: %tb
 Traceback (most recent call last):
   File ... in <module>
     bar(mode)
   File ... line 22, in bar
     sysexit(stat, mode)
   File ... line 11, in sysexit
     raise SystemExit(stat, 'Mode = %s' % mode)
 SystemExit: (2, 'Mode = exit')
 
 In [21]: %xmode context
 Exception reporting mode: Context
 
 In [22]: %tb
 ---------------------------------------------------------------------------
 SystemExit                                Traceback (most recent call last)
 <BLANKLINE>
-...<module>()
+...<module>
      30         mode = 'div'
      31 
 ---> 32     bar(mode)
 <BLANKLINE>
 ...bar(mode)
      20         except:
      21             stat = 1
 ---> 22         sysexit(stat, mode)
      23     else:
      24         raise ValueError('Unknown mode')
 <BLANKLINE>
 ...sysexit(stat, mode)
       9 
      10 def sysexit(stat, mode):
 ---> 11     raise SystemExit(stat, 'Mode = %s' % mode)
      12 
      13 def bar(mode):
 <BLANKLINE>
 SystemExit: (2, 'Mode = exit')
 
 In [23]: %xmode verbose
 Exception reporting mode: Verbose
 
 In [24]: %tb
 ---------------------------------------------------------------------------
 SystemExit                                Traceback (most recent call last)
 <BLANKLINE>
-... in <module>()
+... in <module>
      30         mode = 'div'
      31 
 ---> 32     bar(mode)
         global bar = <function bar at ...>
         global mode = 'exit'
 <BLANKLINE>
 ... in bar(mode='exit')
      20         except:
      21             stat = 1
 ---> 22         sysexit(stat, mode)
         global sysexit = <function sysexit at ...>
         stat = 2
         mode = 'exit'
      23     else:
      24         raise ValueError('Unknown mode')
 <BLANKLINE>
 ... in sysexit(stat=2, mode='exit')
       9 
      10 def sysexit(stat, mode):
 ---> 11     raise SystemExit(stat, 'Mode = %s' % mode)
         global SystemExit = undefined
         stat = 2
         mode = 'exit'
      12 
      13 def bar(mode):
 <BLANKLINE>
 SystemExit: (2, 'Mode = exit')
     """
 
 
 def test_run_cell():
     import textwrap
     ip.run_cell('a = 10\na+=1')
     ip.run_cell('assert a == 11\nassert 1')
 
     nt.assert_equal(ip.user_ns['a'], 11)
     complex = textwrap.dedent("""
     if 1:
         print "hello"
         if 1:
             print "world"
         
     if 2:
         print "foo"
 
     if 3:
         print "bar"
 
     if 4:
         print "bar"
     
     """)
     # Simply verifies that this kind of input is run
     ip.run_cell(complex)
     
 
 def test_db():
     """Test the internal database used for variable persistence."""
     ip.db['__unittest_'] = 12
     nt.assert_equal(ip.db['__unittest_'], 12)
     del ip.db['__unittest_']
     assert '__unittest_' not in ip.db

IPython/core/ultratb.py

@@ -1,1458 +1,1460 b''
 # -*- coding: utf-8 -*-
 """
 Verbose and colourful traceback formatting.
 
 **ColorTB**
 
 I've always found it a bit hard to visually parse tracebacks in Python.  The
 ColorTB class is a solution to that problem.  It colors the different parts of a
 traceback in a manner similar to what you would expect from a syntax-highlighting
 text editor.
 
 Installation instructions for ColorTB::
 
     import sys,ultratb
     sys.excepthook = ultratb.ColorTB()
 
 **VerboseTB**
 
 I've also included a port of Ka-Ping Yee's "cgitb.py" that produces all kinds
 of useful info when a traceback occurs.  Ping originally had it spit out HTML
 and intended it for CGI programmers, but why should they have all the fun?  I
 altered it to spit out colored text to the terminal.  It's a bit overwhelming,
 but kind of neat, and maybe useful for long-running programs that you believe
 are bug-free.  If a crash *does* occur in that type of program you want details.
 Give it a shot--you'll love it or you'll hate it.
 
 .. note::
 
   The Verbose mode prints the variables currently visible where the exception
   happened (shortening their strings if too long). This can potentially be
   very slow, if you happen to have a huge data structure whose string
   representation is complex to compute. Your computer may appear to freeze for
   a while with cpu usage at 100%. If this occurs, you can cancel the traceback
   with Ctrl-C (maybe hitting it more than once).
 
   If you encounter this kind of situation often, you may want to use the
   Verbose_novars mode instead of the regular Verbose, which avoids formatting
   variables (but otherwise includes the information and context given by
   Verbose).
 
 .. note::
 
   The verbose mode print all variables in the stack, which means it can
   potentially leak sensitive information like access keys, or unencryted
   password.
 
 Installation instructions for VerboseTB::
 
     import sys,ultratb
     sys.excepthook = ultratb.VerboseTB()
 
 Note:  Much of the code in this module was lifted verbatim from the standard
 library module 'traceback.py' and Ka-Ping Yee's 'cgitb.py'.
 
 Color schemes
 -------------
 
 The colors are defined in the class TBTools through the use of the
 ColorSchemeTable class. Currently the following exist:
 
   - NoColor: allows all of this module to be used in any terminal (the color
     escapes are just dummy blank strings).
 
   - Linux: is meant to look good in a terminal like the Linux console (black
     or very dark background).
 
   - LightBG: similar to Linux but swaps dark/light colors to be more readable
     in light background terminals.
 
   - Neutral: a neutral color scheme that should be readable on both light and
     dark background
 
 You can implement other color schemes easily, the syntax is fairly
 self-explanatory. Please send back new schemes you develop to the author for
 possible inclusion in future releases.
 
 Inheritance diagram:
 
 .. inheritance-diagram:: IPython.core.ultratb
    :parts: 3
 """
 
 #*****************************************************************************
 # Copyright (C) 2001 Nathaniel Gray <[e-mail]>
 # Copyright (C) 2001-2004 Fernando Perez <[e-mail]>
 #
 # Distributed under the terms of the BSD License.  The full license is in
 # the file COPYING, distributed as part of this software.
 #*****************************************************************************
 
 
 import dis
 import inspect
 import keyword
 import linecache
 import os
 import pydoc
 import re
 import sys
 import time
 import tokenize
 import traceback
 
 try:  # Python 2
     generate_tokens = tokenize.generate_tokens
 except AttributeError:  # Python 3
     generate_tokens = tokenize.tokenize
 
 # For purposes of monkeypatching inspect to fix a bug in it.
 from inspect import getsourcefile, getfile, getmodule, \
     ismodule, isclass, ismethod, isfunction, istraceback, isframe, iscode
 
 # IPython's own modules
 from IPython import get_ipython
 from IPython.core import debugger
 from IPython.core.display_trap import DisplayTrap
 from IPython.core.excolors import exception_colors
 from IPython.utils import PyColorize
 from IPython.utils import openpy
 from IPython.utils import path as util_path
 from IPython.utils import py3compat
 from IPython.utils.data import uniq_stable
 from IPython.utils.terminal import get_terminal_size
 
 from logging import info, error, debug
 
 import IPython.utils.colorable as colorable
 
 # Globals
 # amount of space to put line numbers before verbose tracebacks
 INDENT_SIZE = 8
 
 # Default color scheme.  This is used, for example, by the traceback
 # formatter.  When running in an actual IPython instance, the user's rc.colors
 # value is used, but having a module global makes this functionality available
 # to users of ultratb who are NOT running inside ipython.
 DEFAULT_SCHEME = 'NoColor'
 
 # ---------------------------------------------------------------------------
 # Code begins
 
 # Utility functions
 def inspect_error():
     """Print a message about internal inspect errors.
 
     These are unfortunately quite common."""
 
     error('Internal Python error in the inspect module.\n'
           'Below is the traceback from this internal error.\n')
 
 
 # This function is a monkeypatch we apply to the Python inspect module. We have
 # now found when it's needed (see discussion on issue gh-1456), and we have a
 # test case (IPython.core.tests.test_ultratb.ChangedPyFileTest) that fails if
 # the monkeypatch is not applied. TK, Aug 2012.
 def findsource(object):
     """Return the entire source file and starting line number for an object.
 
     The argument may be a module, class, method, function, traceback, frame,
     or code object.  The source code is returned as a list of all the lines
     in the file and the line number indexes a line in that list.  An IOError
     is raised if the source code cannot be retrieved.
 
     FIXED version with which we monkeypatch the stdlib to work around a bug."""
 
     file = getsourcefile(object) or getfile(object)
     # If the object is a frame, then trying to get the globals dict from its
     # module won't work. Instead, the frame object itself has the globals
     # dictionary.
     globals_dict = None
     if inspect.isframe(object):
         # XXX: can this ever be false?
         globals_dict = object.f_globals
     else:
         module = getmodule(object, file)
         if module:
             globals_dict = module.__dict__
     lines = linecache.getlines(file, globals_dict)
     if not lines:
         raise IOError('could not get source code')
 
     if ismodule(object):
         return lines, 0
 
     if isclass(object):
         name = object.__name__
         pat = re.compile(r'^(\s*)class\s*' + name + r'\b')
         # make some effort to find the best matching class definition:
         # use the one with the least indentation, which is the one
         # that's most probably not inside a function definition.
         candidates = []
         for i, line in enumerate(lines):
             match = pat.match(line)
             if match:
                 # if it's at toplevel, it's already the best one
                 if line[0] == 'c':
                     return lines, i
                 # else add whitespace to candidate list
                 candidates.append((match.group(1), i))
         if candidates:
             # this will sort by whitespace, and by line number,
             # less whitespace first
             candidates.sort()
             return lines, candidates[0][1]
         else:
             raise IOError('could not find class definition')
 
     if ismethod(object):
         object = object.__func__
     if isfunction(object):
         object = object.__code__
     if istraceback(object):
         object = object.tb_frame
     if isframe(object):
         object = object.f_code
     if iscode(object):
         if not hasattr(object, 'co_firstlineno'):
             raise IOError('could not find function definition')
         pat = re.compile(r'^(\s*def\s)|(.*(?<!\w)lambda(:|\s))|^(\s*@)')
         pmatch = pat.match
         # fperez - fix: sometimes, co_firstlineno can give a number larger than
         # the length of lines, which causes an error.  Safeguard against that.
         lnum = min(object.co_firstlineno, len(lines)) - 1
         while lnum > 0:
             if pmatch(lines[lnum]):
                 break
             lnum -= 1
 
         return lines, lnum
     raise IOError('could not find code object')
 
 
 # This is a patched version of inspect.getargs that applies the (unmerged)
 # patch for http://bugs.python.org/issue14611 by Stefano Taschini.  This fixes
 # https://github.com/ipython/ipython/issues/8205 and
 # https://github.com/ipython/ipython/issues/8293
 def getargs(co):
     """Get information about the arguments accepted by a code object.
 
     Three things are returned: (args, varargs, varkw), where 'args' is
     a list of argument names (possibly containing nested lists), and
     'varargs' and 'varkw' are the names of the * and ** arguments or None."""
     if not iscode(co):
         raise TypeError('{!r} is not a code object'.format(co))
 
     nargs = co.co_argcount
     names = co.co_varnames
     args = list(names[:nargs])
     step = 0
 
     # The following acrobatics are for anonymous (tuple) arguments.
     for i in range(nargs):
         if args[i][:1] in ('', '.'):
             stack, remain, count = [], [], []
             while step < len(co.co_code):
                 op = ord(co.co_code[step])
                 step = step + 1
                 if op >= dis.HAVE_ARGUMENT:
                     opname = dis.opname[op]
                     value = ord(co.co_code[step]) + ord(co.co_code[step+1])*256
                     step = step + 2
                     if opname in ('UNPACK_TUPLE', 'UNPACK_SEQUENCE'):
                         remain.append(value)
                         count.append(value)
                     elif opname in ('STORE_FAST', 'STORE_DEREF'):
                         if op in dis.haslocal:
                             stack.append(co.co_varnames[value])
                         elif op in dis.hasfree:
                             stack.append((co.co_cellvars + co.co_freevars)[value])
                         # Special case for sublists of length 1: def foo((bar))
                         # doesn't generate the UNPACK_TUPLE bytecode, so if
                         # `remain` is empty here, we have such a sublist.
                         if not remain:
                             stack[0] = [stack[0]]
                             break
                         else:
                             remain[-1] = remain[-1] - 1
                             while remain[-1] == 0:
                                 remain.pop()
                                 size = count.pop()
                                 stack[-size:] = [stack[-size:]]
                                 if not remain:
                                     break
                                 remain[-1] = remain[-1] - 1
                             if not remain:
                                 break
             args[i] = stack[0]
 
     varargs = None
     if co.co_flags & inspect.CO_VARARGS:
         varargs = co.co_varnames[nargs]
         nargs = nargs + 1
     varkw = None
     if co.co_flags & inspect.CO_VARKEYWORDS:
         varkw = co.co_varnames[nargs]
     return inspect.Arguments(args, varargs, varkw)
 
 
 # Monkeypatch inspect to apply our bugfix.
 def with_patch_inspect(f):
     """
     Deprecated since IPython 6.0
     decorator for monkeypatching inspect.findsource
     """
 
     def wrapped(*args, **kwargs):
         save_findsource = inspect.findsource
         save_getargs = inspect.getargs
         inspect.findsource = findsource
         inspect.getargs = getargs
         try:
             return f(*args, **kwargs)
         finally:
             inspect.findsource = save_findsource
             inspect.getargs = save_getargs
 
     return wrapped
 
 
 def fix_frame_records_filenames(records):
     """Try to fix the filenames in each record from inspect.getinnerframes().
 
     Particularly, modules loaded from within zip files have useless filenames
     attached to their code object, and inspect.getinnerframes() just uses it.
     """
     fixed_records = []
     for frame, filename, line_no, func_name, lines, index in records:
         # Look inside the frame's globals dictionary for __file__,
         # which should be better. However, keep Cython filenames since
         # we prefer the source filenames over the compiled .so file.
         if not filename.endswith(('.pyx', '.pxd', '.pxi')):
             better_fn = frame.f_globals.get('__file__', None)
             if isinstance(better_fn, str):
                 # Check the type just in case someone did something weird with
                 # __file__. It might also be None if the error occurred during
                 # import.
                 filename = better_fn
         fixed_records.append((frame, filename, line_no, func_name, lines, index))
     return fixed_records
 
 
 @with_patch_inspect
 def _fixed_getinnerframes(etb, context=1, tb_offset=0):
     LNUM_POS, LINES_POS, INDEX_POS = 2, 4, 5
 
     records = fix_frame_records_filenames(inspect.getinnerframes(etb, context))
     # If the error is at the console, don't build any context, since it would
     # otherwise produce 5 blank lines printed out (there is no file at the
     # console)
     rec_check = records[tb_offset:]
     try:
         rname = rec_check[0][1]
         if rname == '<ipython console>' or rname.endswith('<string>'):
             return rec_check
     except IndexError:
         pass
 
     aux = traceback.extract_tb(etb)
     assert len(records) == len(aux)
     for i, (file, lnum, _, _) in enumerate(aux):
         maybeStart = lnum - 1 - context // 2
         start = max(maybeStart, 0)
         end = start + context
         lines = linecache.getlines(file)[start:end]
         buf = list(records[i])
         buf[LNUM_POS] = lnum
         buf[INDEX_POS] = lnum - 1 - start
         buf[LINES_POS] = lines
         records[i] = tuple(buf)
     return records[tb_offset:]
 
 # Helper function -- largely belongs to VerboseTB, but we need the same
 # functionality to produce a pseudo verbose TB for SyntaxErrors, so that they
 # can be recognized properly by ipython.el's py-traceback-line-re
 # (SyntaxErrors have to be treated specially because they have no traceback)
 
 
 def _format_traceback_lines(lnum, index, lines, Colors, lvals, _line_format):
     """
     Format tracebacks lines with pointing arrow, leading numbers...
 
     Parameters
     ==========
 
     lnum: int
     index: int
     lines: list[string]
     Colors:
         ColorScheme used.
     lvals: bytes
         Values of local variables, already colored, to inject just after the error line.
     _line_format: f (str) -> (str, bool)
         return (colorized version of str, failure to do so)
     """
     numbers_width = INDENT_SIZE - 1
     res = []
 
     for i,line in enumerate(lines, lnum-index):
         line = py3compat.cast_unicode(line)
 
         new_line, err = _line_format(line, 'str')
         if not err:
             line = new_line
 
         if i == lnum:
             # This is the line with the error
             pad = numbers_width - len(str(i))
             num = '%s%s' % (debugger.make_arrow(pad), str(lnum))
             line = '%s%s%s %s%s' % (Colors.linenoEm, num,
                                     Colors.line, line, Colors.Normal)
         else:
             num = '%*s' % (numbers_width, i)
             line = '%s%s%s %s' % (Colors.lineno, num,
                                   Colors.Normal, line)
 
         res.append(line)
         if lvals and i == lnum:
             res.append(lvals + '\n')
     return res
 
 def is_recursion_error(etype, value, records):
     try:
         # RecursionError is new in Python 3.5
         recursion_error_type = RecursionError
     except NameError:
         recursion_error_type = RuntimeError
 
     # The default recursion limit is 1000, but some of that will be taken up
     # by stack frames in IPython itself. >500 frames probably indicates
     # a recursion error.
     return (etype is recursion_error_type) \
            and "recursion" in str(value).lower() \
            and len(records) > 500
 
 def find_recursion(etype, value, records):
     """Identify the repeating stack frames from a RecursionError traceback
 
     'records' is a list as returned by VerboseTB.get_records()
 
     Returns (last_unique, repeat_length)
     """
     # This involves a bit of guesswork - we want to show enough of the traceback
     # to indicate where the recursion is occurring. We guess that the innermost
     # quarter of the traceback (250 frames by default) is repeats, and find the
     # first frame (from in to out) that looks different.
     if not is_recursion_error(etype, value, records):
         return len(records), 0
 
     # Select filename, lineno, func_name to track frames with
     records = [r[1:4] for r in records]
     inner_frames = records[-(len(records)//4):]
     frames_repeated = set(inner_frames)
 
     last_seen_at = {}
     longest_repeat = 0
     i = len(records)
     for frame in reversed(records):
         i -= 1
         if frame not in frames_repeated:
             last_unique = i
             break
 
         if frame in last_seen_at:
             distance = last_seen_at[frame] - i
             longest_repeat = max(longest_repeat, distance)
 
         last_seen_at[frame] = i
     else:
         last_unique = 0 # The whole traceback was recursion
 
     return last_unique, longest_repeat
 
 #---------------------------------------------------------------------------
 # Module classes
 class TBTools(colorable.Colorable):
     """Basic tools used by all traceback printer classes."""
 
     # Number of frames to skip when reporting tracebacks
     tb_offset = 0
 
     def __init__(self, color_scheme='NoColor', call_pdb=False, ostream=None, parent=None, config=None):
         # Whether to call the interactive pdb debugger after printing
         # tracebacks or not
         super(TBTools, self).__init__(parent=parent, config=config)
         self.call_pdb = call_pdb
 
         # Output stream to write to.  Note that we store the original value in
         # a private attribute and then make the public ostream a property, so
         # that we can delay accessing sys.stdout until runtime.  The way
         # things are written now, the sys.stdout object is dynamically managed
         # so a reference to it should NEVER be stored statically.  This
         # property approach confines this detail to a single location, and all
         # subclasses can simply access self.ostream for writing.
         self._ostream = ostream
 
         # Create color table
         self.color_scheme_table = exception_colors()
 
         self.set_colors(color_scheme)
         self.old_scheme = color_scheme  # save initial value for toggles
 
         if call_pdb:
             self.pdb = debugger.Pdb()
         else:
             self.pdb = None
 
     def _get_ostream(self):
         """Output stream that exceptions are written to.
 
         Valid values are:
 
         - None: the default, which means that IPython will dynamically resolve
           to sys.stdout.  This ensures compatibility with most tools, including
           Windows (where plain stdout doesn't recognize ANSI escapes).
 
         - Any object with 'write' and 'flush' attributes.
         """
         return sys.stdout if self._ostream is None else self._ostream
 
     def _set_ostream(self, val):
         assert val is None or (hasattr(val, 'write') and hasattr(val, 'flush'))
         self._ostream = val
 
     ostream = property(_get_ostream, _set_ostream)
 
     def set_colors(self, *args, **kw):
         """Shorthand access to the color table scheme selector method."""
 
         # Set own color table
         self.color_scheme_table.set_active_scheme(*args, **kw)
         # for convenience, set Colors to the active scheme
         self.Colors = self.color_scheme_table.active_colors
         # Also set colors of debugger
         if hasattr(self, 'pdb') and self.pdb is not None:
             self.pdb.set_colors(*args, **kw)
 
     def color_toggle(self):
         """Toggle between the currently active color scheme and NoColor."""
 
         if self.color_scheme_table.active_scheme_name == 'NoColor':
             self.color_scheme_table.set_active_scheme(self.old_scheme)
             self.Colors = self.color_scheme_table.active_colors
         else:
             self.old_scheme = self.color_scheme_table.active_scheme_name
             self.color_scheme_table.set_active_scheme('NoColor')
             self.Colors = self.color_scheme_table.active_colors
 
     def stb2text(self, stb):
         """Convert a structured traceback (a list) to a string."""
         return '\n'.join(stb)
 
     def text(self, etype, value, tb, tb_offset=None, context=5):
         """Return formatted traceback.
 
         Subclasses may override this if they add extra arguments.
         """
         tb_list = self.structured_traceback(etype, value, tb,
                                             tb_offset, context)
         return self.stb2text(tb_list)
 
     def structured_traceback(self, etype, evalue, tb, tb_offset=None,
                              context=5, mode=None):
         """Return a list of traceback frames.
 
         Must be implemented by each class.
         """
         raise NotImplementedError()
 
 
 #---------------------------------------------------------------------------
 class ListTB(TBTools):
     """Print traceback information from a traceback list, with optional color.
 
     Calling requires 3 arguments: (etype, evalue, elist)
     as would be obtained by::
     
       etype, evalue, tb = sys.exc_info()
       if tb:
         elist = traceback.extract_tb(tb)
       else:
         elist = None
 
     It can thus be used by programs which need to process the traceback before
     printing (such as console replacements based on the code module from the
     standard library).
 
     Because they are meant to be called without a full traceback (only a
     list), instances of this class can't call the interactive pdb debugger."""
 
     def __init__(self, color_scheme='NoColor', call_pdb=False, ostream=None, parent=None, config=None):
         TBTools.__init__(self, color_scheme=color_scheme, call_pdb=call_pdb,
                          ostream=ostream, parent=parent,config=config)
 
     def __call__(self, etype, value, elist):
         self.ostream.flush()
         self.ostream.write(self.text(etype, value, elist))
         self.ostream.write('\n')
 
     def structured_traceback(self, etype, value, elist, tb_offset=None,
                              context=5):
         """Return a color formatted string with the traceback info.
 
         Parameters
         ----------
         etype : exception type
           Type of the exception raised.
 
         value : object
           Data stored in the exception
 
         elist : list
           List of frames, see class docstring for details.
 
         tb_offset : int, optional
           Number of frames in the traceback to skip.  If not given, the
           instance value is used (set in constructor).
 
         context : int, optional
           Number of lines of context information to print.
 
         Returns
         -------
         String with formatted exception.
         """
         tb_offset = self.tb_offset if tb_offset is None else tb_offset
         Colors = self.Colors
         out_list = []
         if elist:
 
             if tb_offset and len(elist) > tb_offset:
                 elist = elist[tb_offset:]
 
             out_list.append('Traceback %s(most recent call last)%s:' %
                             (Colors.normalEm, Colors.Normal) + '\n')
             out_list.extend(self._format_list(elist))
         # The exception info should be a single entry in the list.
         lines = ''.join(self._format_exception_only(etype, value))
         out_list.append(lines)
 
         return out_list
 
     def _format_list(self, extracted_list):
         """Format a list of traceback entry tuples for printing.
 
         Given a list of tuples as returned by extract_tb() or
         extract_stack(), return a list of strings ready for printing.
         Each string in the resulting list corresponds to the item with the
         same index in the argument list.  Each string ends in a newline;
         the strings may contain internal newlines as well, for those items
         whose source text line is not None.
 
         Lifted almost verbatim from traceback.py
         """
 
         Colors = self.Colors
         list = []
         for filename, lineno, name, line in extracted_list[:-1]:
             item = '  File %s"%s"%s, line %s%d%s, in %s%s%s\n' % \
                    (Colors.filename, filename, Colors.Normal,
                     Colors.lineno, lineno, Colors.Normal,
                     Colors.name, name, Colors.Normal)
             if line:
                 item += '    %s\n' % line.strip()
             list.append(item)
         # Emphasize the last entry
         filename, lineno, name, line = extracted_list[-1]
         item = '%s  File %s"%s"%s, line %s%d%s, in %s%s%s%s\n' % \
                (Colors.normalEm,
                 Colors.filenameEm, filename, Colors.normalEm,
                 Colors.linenoEm, lineno, Colors.normalEm,
                 Colors.nameEm, name, Colors.normalEm,
                 Colors.Normal)
         if line:
             item += '%s    %s%s\n' % (Colors.line, line.strip(),
                                       Colors.Normal)
         list.append(item)
         return list
 
     def _format_exception_only(self, etype, value):
         """Format the exception part of a traceback.
 
         The arguments are the exception type and value such as given by
         sys.exc_info()[:2]. The return value is a list of strings, each ending
         in a newline.  Normally, the list contains a single string; however,
         for SyntaxError exceptions, it contains several lines that (when
         printed) display detailed information about where the syntax error
         occurred.  The message indicating which exception occurred is the
         always last string in the list.
 
         Also lifted nearly verbatim from traceback.py
         """
         have_filedata = False
         Colors = self.Colors
         list = []
         stype = py3compat.cast_unicode(Colors.excName + etype.__name__ + Colors.Normal)
         if value is None:
             # Not sure if this can still happen in Python 2.6 and above
             list.append(stype + '\n')
         else:
             if issubclass(etype, SyntaxError):
                 have_filedata = True
                 if not value.filename: value.filename = "<string>"
                 if value.lineno:
                     lineno = value.lineno
                     textline = linecache.getline(value.filename, value.lineno)
                 else:
                     lineno = 'unknown'
                     textline = ''
                 list.append('%s  File %s"%s"%s, line %s%s%s\n' % \
                             (Colors.normalEm,
                              Colors.filenameEm, py3compat.cast_unicode(value.filename), Colors.normalEm,
                              Colors.linenoEm, lineno, Colors.Normal  ))
                 if textline == '':
                     textline = py3compat.cast_unicode(value.text, "utf-8")
 
                 if textline is not None:
                     i = 0
                     while i < len(textline) and textline[i].isspace():
                         i += 1
                     list.append('%s    %s%s\n' % (Colors.line,
                                                   textline.strip(),
                                                   Colors.Normal))
                     if value.offset is not None:
                         s = '    '
                         for c in textline[i:value.offset - 1]:
                             if c.isspace():
                                 s += c
                             else:
                                 s += ' '
                         list.append('%s%s^%s\n' % (Colors.caret, s,
                                                    Colors.Normal))
 
             try:
                 s = value.msg
             except Exception:
                 s = self._some_str(value)
             if s:
                 list.append('%s%s:%s %s\n' % (stype, Colors.excName,
                                               Colors.Normal, s))
             else:
                 list.append('%s\n' % stype)
 
         # sync with user hooks
         if have_filedata:
             ipinst = get_ipython()
             if ipinst is not None:
                 ipinst.hooks.synchronize_with_editor(value.filename, value.lineno, 0)
 
         return list
 
     def get_exception_only(self, etype, value):
         """Only print the exception type and message, without a traceback.
 
         Parameters
         ----------
         etype : exception type
         value : exception value
         """
         return ListTB.structured_traceback(self, etype, value, [])
 
     def show_exception_only(self, etype, evalue):
         """Only print the exception type and message, without a traceback.
 
         Parameters
         ----------
         etype : exception type
         value : exception value
         """
         # This method needs to use __call__ from *this* class, not the one from
         # a subclass whose signature or behavior may be different
         ostream = self.ostream
         ostream.flush()
         ostream.write('\n'.join(self.get_exception_only(etype, evalue)))
         ostream.flush()
 
     def _some_str(self, value):
         # Lifted from traceback.py
         try:
             return py3compat.cast_unicode(str(value))
         except:
             return u'<unprintable %s object>' % type(value).__name__
 
 
 #----------------------------------------------------------------------------
 class VerboseTB(TBTools):
     """A port of Ka-Ping Yee's cgitb.py module that outputs color text instead
     of HTML.  Requires inspect and pydoc.  Crazy, man.
 
     Modified version which optionally strips the topmost entries from the
     traceback, to be used with alternate interpreters (because their own code
     would appear in the traceback)."""
 
     def __init__(self, color_scheme='Linux', call_pdb=False, ostream=None,
                  tb_offset=0, long_header=False, include_vars=True,
                  check_cache=None, debugger_cls = None,
                  parent=None, config=None):
         """Specify traceback offset, headers and color scheme.
 
         Define how many frames to drop from the tracebacks. Calling it with
         tb_offset=1 allows use of this handler in interpreters which will have
         their own code at the top of the traceback (VerboseTB will first
         remove that frame before printing the traceback info)."""
         TBTools.__init__(self, color_scheme=color_scheme, call_pdb=call_pdb,
                          ostream=ostream, parent=parent, config=config)
         self.tb_offset = tb_offset
         self.long_header = long_header
         self.include_vars = include_vars
         # By default we use linecache.checkcache, but the user can provide a
         # different check_cache implementation.  This is used by the IPython
         # kernel to provide tracebacks for interactive code that is cached,
         # by a compiler instance that flushes the linecache but preserves its
         # own code cache.
         if check_cache is None:
             check_cache = linecache.checkcache
         self.check_cache = check_cache
 
         self.debugger_cls = debugger_cls or debugger.Pdb
 
     def format_records(self, records, last_unique, recursion_repeat):
         """Format the stack frames of the traceback"""
         frames = []
         for r in records[:last_unique+recursion_repeat+1]:
             #print '*** record:',file,lnum,func,lines,index  # dbg
             frames.append(self.format_record(*r))
 
         if recursion_repeat:
             frames.append('... last %d frames repeated, from the frame below ...\n' % recursion_repeat)
             frames.append(self.format_record(*records[last_unique+recursion_repeat+1]))
 
         return frames
 
     def format_record(self, frame, file, lnum, func, lines, index):
         """Format a single stack frame"""
         Colors = self.Colors  # just a shorthand + quicker name lookup
         ColorsNormal = Colors.Normal  # used a lot
         col_scheme = self.color_scheme_table.active_scheme_name
         indent = ' ' * INDENT_SIZE
         em_normal = '%s\n%s%s' % (Colors.valEm, indent, ColorsNormal)
         undefined = '%sundefined%s' % (Colors.em, ColorsNormal)
         tpl_link = '%s%%s%s' % (Colors.filenameEm, ColorsNormal)
         tpl_call = 'in %s%%s%s%%s%s' % (Colors.vName, Colors.valEm,
                                         ColorsNormal)
         tpl_call_fail = 'in %s%%s%s(***failed resolving arguments***)%s' % \
                         (Colors.vName, Colors.valEm, ColorsNormal)
         tpl_local_var = '%s%%s%s' % (Colors.vName, ColorsNormal)
         tpl_global_var = '%sglobal%s %s%%s%s' % (Colors.em, ColorsNormal,
                                                  Colors.vName, ColorsNormal)
         tpl_name_val = '%%s %s= %%s%s' % (Colors.valEm, ColorsNormal)
 
         if not file:
             file = '?'
         elif file.startswith(str("<")) and file.endswith(str(">")):
             # Not a real filename, no problem...
             pass
         elif not os.path.isabs(file):
             # Try to make the filename absolute by trying all
             # sys.path entries (which is also what linecache does)
             for dirname in sys.path:
                 try:
                     fullname = os.path.join(dirname, file)
                     if os.path.isfile(fullname):
                         file = os.path.abspath(fullname)
                         break
                 except Exception:
                     # Just in case that sys.path contains very
                     # strange entries...
                     pass
 
         file = py3compat.cast_unicode(file, util_path.fs_encoding)
         link = tpl_link % util_path.compress_user(file)
         args, varargs, varkw, locals_ = inspect.getargvalues(frame)
 
         if func == '?':
             call = ''
+        elif func == '<module>':
+            call = tpl_call % (func, '')
         else:
             # Decide whether to include variable details or not
             var_repr = eqrepr if self.include_vars else nullrepr
             try:
                 call = tpl_call % (func, inspect.formatargvalues(args,
                                                                  varargs, varkw,
                                                                  locals_, formatvalue=var_repr))
             except KeyError:
                 # This happens in situations like errors inside generator
                 # expressions, where local variables are listed in the
                 # line, but can't be extracted from the frame.  I'm not
                 # 100% sure this isn't actually a bug in inspect itself,
                 # but since there's no info for us to compute with, the
                 # best we can do is report the failure and move on.  Here
                 # we must *not* call any traceback construction again,
                 # because that would mess up use of %debug later on.  So we
                 # simply report the failure and move on.  The only
                 # limitation will be that this frame won't have locals
                 # listed in the call signature.  Quite subtle problem...
                 # I can't think of a good way to validate this in a unit
                 # test, but running a script consisting of:
                 #  dict( (k,v.strip()) for (k,v) in range(10) )
                 # will illustrate the error, if this exception catch is
                 # disabled.
                 call = tpl_call_fail % func
 
         # Don't attempt to tokenize binary files.
         if file.endswith(('.so', '.pyd', '.dll')):
             return '%s %s\n' % (link, call)
 
         elif file.endswith(('.pyc', '.pyo')):
             # Look up the corresponding source file.
             try:
                 file = openpy.source_from_cache(file)
             except ValueError:
                 # Failed to get the source file for some reason
                 # E.g. https://github.com/ipython/ipython/issues/9486
                 return '%s %s\n' % (link, call)
 
         def linereader(file=file, lnum=[lnum], getline=linecache.getline):
             line = getline(file, lnum[0])
             lnum[0] += 1
             return line
 
         # Build the list of names on this line of code where the exception
         # occurred.
         try:
             names = []
             name_cont = False
 
             for token_type, token, start, end, line in generate_tokens(linereader):
                 # build composite names
                 if token_type == tokenize.NAME and token not in keyword.kwlist:
                     if name_cont:
                         # Continuation of a dotted name
                         try:
                             names[-1].append(token)
                         except IndexError:
                             names.append([token])
                         name_cont = False
                     else:
                         # Regular new names.  We append everything, the caller
                         # will be responsible for pruning the list later.  It's
                         # very tricky to try to prune as we go, b/c composite
                         # names can fool us.  The pruning at the end is easy
                         # to do (or the caller can print a list with repeated
                         # names if so desired.
                         names.append([token])
                 elif token == '.':
                     name_cont = True
                 elif token_type == tokenize.NEWLINE:
                     break
 
         except (IndexError, UnicodeDecodeError, SyntaxError):
             # signals exit of tokenizer
             # SyntaxError can occur if the file is not actually Python
             #  - see gh-6300
             pass
         except tokenize.TokenError as msg:
             # Tokenizing may fail for various reasons, many of which are
             # harmless. (A good example is when the line in question is the
             # close of a triple-quoted string, cf gh-6864). We don't want to
             # show this to users, but want make it available for debugging
             # purposes.
             _m = ("An unexpected error occurred while tokenizing input\n"
                   "The following traceback may be corrupted or invalid\n"
                   "The error message is: %s\n" % msg)
             debug(_m)
 
         # Join composite names (e.g. "dict.fromkeys")
         names = ['.'.join(n) for n in names]
         # prune names list of duplicates, but keep the right order
         unique_names = uniq_stable(names)
 
         # Start loop over vars
         lvals = ''
         lvals_list = []
         if self.include_vars:
             for name_full in unique_names:
                 name_base = name_full.split('.', 1)[0]
                 if name_base in frame.f_code.co_varnames:
                     if name_base in locals_:
                         try:
                             value = repr(eval(name_full, locals_))
                         except:
                             value = undefined
                     else:
                         value = undefined
                     name = tpl_local_var % name_full
                 else:
                     if name_base in frame.f_globals:
                         try:
                             value = repr(eval(name_full, frame.f_globals))
                         except:
                             value = undefined
                     else:
                         value = undefined
                     name = tpl_global_var % name_full
                 lvals_list.append(tpl_name_val % (name, value))
         if lvals_list:
             lvals = '%s%s' % (indent, em_normal.join(lvals_list))
 
         level = '%s %s\n' % (link, call)
 
         if index is None:
             return level
         else:
             _line_format = PyColorize.Parser(style=col_scheme, parent=self).format2
             return '%s%s' % (level, ''.join(
                 _format_traceback_lines(lnum, index, lines, Colors, lvals,
                                          _line_format)))
 
     def prepare_chained_exception_message(self, cause):
         direct_cause = "\nThe above exception was the direct cause of the following exception:\n"
         exception_during_handling = "\nDuring handling of the above exception, another exception occurred:\n"
 
         if cause:
             message = [[direct_cause]]
         else:
             message = [[exception_during_handling]]
         return message
 
     def prepare_header(self, etype, long_version=False):
         colors = self.Colors  # just a shorthand + quicker name lookup
         colorsnormal = colors.Normal  # used a lot
         exc = '%s%s%s' % (colors.excName, etype, colorsnormal)
         width = min(75, get_terminal_size()[0])
         if long_version:
             # Header with the exception type, python version, and date
             pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
             date = time.ctime(time.time())
 
             head = '%s%s%s\n%s%s%s\n%s' % (colors.topline, '-' * width, colorsnormal,
                                            exc, ' ' * (width - len(str(etype)) - len(pyver)),
                                            pyver, date.rjust(width) )
             head += "\nA problem occurred executing Python code.  Here is the sequence of function" \
                     "\ncalls leading up to the error, with the most recent (innermost) call last."
         else:
             # Simplified header
             head = '%s%s' % (exc, 'Traceback (most recent call last)'. \
                              rjust(width - len(str(etype))) )
 
         return head
 
     def format_exception(self, etype, evalue):
         colors = self.Colors  # just a shorthand + quicker name lookup
         colorsnormal = colors.Normal  # used a lot
         # Get (safely) a string form of the exception info
         try:
             etype_str, evalue_str = map(str, (etype, evalue))
         except:
             # User exception is improperly defined.
             etype, evalue = str, sys.exc_info()[:2]
             etype_str, evalue_str = map(str, (etype, evalue))
         # ... and format it
         return ['%s%s%s: %s' % (colors.excName, etype_str,
                                 colorsnormal, py3compat.cast_unicode(evalue_str))]
 
     def format_exception_as_a_whole(self, etype, evalue, etb, number_of_lines_of_context, tb_offset):
         """Formats the header, traceback and exception message for a single exception.
 
         This may be called multiple times by Python 3 exception chaining
         (PEP 3134).
         """
         # some locals
         orig_etype = etype
         try:
             etype = etype.__name__
         except AttributeError:
             pass
 
         tb_offset = self.tb_offset if tb_offset is None else tb_offset
         head = self.prepare_header(etype, self.long_header)
         records = self.get_records(etb, number_of_lines_of_context, tb_offset)
 
         if records is None:
             return ""
 
         last_unique, recursion_repeat = find_recursion(orig_etype, evalue, records)
 
         frames = self.format_records(records, last_unique, recursion_repeat)
 
         formatted_exception = self.format_exception(etype, evalue)
         if records:
             filepath, lnum = records[-1][1:3]
             filepath = os.path.abspath(filepath)
             ipinst = get_ipython()
             if ipinst is not None:
                 ipinst.hooks.synchronize_with_editor(filepath, lnum, 0)
 
         return [[head] + frames + [''.join(formatted_exception[0])]]
 
     def get_records(self, etb, number_of_lines_of_context, tb_offset):
         try:
             # Try the default getinnerframes and Alex's: Alex's fixes some
             # problems, but it generates empty tracebacks for console errors
             # (5 blanks lines) where none should be returned.
             return _fixed_getinnerframes(etb, number_of_lines_of_context, tb_offset)
         except UnicodeDecodeError:
             # This can occur if a file's encoding magic comment is wrong.
             # I can't see a way to recover without duplicating a bunch of code
             # from the stdlib traceback module. --TK
             error('\nUnicodeDecodeError while processing traceback.\n')
             return None
         except:
             # FIXME: I've been getting many crash reports from python 2.3
             # users, traceable to inspect.py.  If I can find a small test-case
             # to reproduce this, I should either write a better workaround or
             # file a bug report against inspect (if that's the real problem).
             # So far, I haven't been able to find an isolated example to
             # reproduce the problem.
             inspect_error()
             traceback.print_exc(file=self.ostream)
             info('\nUnfortunately, your original traceback can not be constructed.\n')
             return None
 
     def get_parts_of_chained_exception(self, evalue):
         def get_chained_exception(exception_value):
             cause = getattr(exception_value, '__cause__', None)
             if cause:
                 return cause
             if getattr(exception_value, '__suppress_context__', False):
                 return None
             return getattr(exception_value, '__context__', None)
 
         chained_evalue = get_chained_exception(evalue)
 
         if chained_evalue:
             return chained_evalue.__class__, chained_evalue, chained_evalue.__traceback__
 
     def structured_traceback(self, etype, evalue, etb, tb_offset=None,
                              number_of_lines_of_context=5):
         """Return a nice text document describing the traceback."""
 
         formatted_exception = self.format_exception_as_a_whole(etype, evalue, etb, number_of_lines_of_context,
                                                                tb_offset)
 
         colors = self.Colors  # just a shorthand + quicker name lookup
         colorsnormal = colors.Normal  # used a lot
         head = '%s%s%s' % (colors.topline, '-' * min(75, get_terminal_size()[0]), colorsnormal)
         structured_traceback_parts = [head]
         chained_exceptions_tb_offset = 0
         lines_of_context = 3
         formatted_exceptions = formatted_exception
         exception = self.get_parts_of_chained_exception(evalue)
         if exception:
             formatted_exceptions += self.prepare_chained_exception_message(evalue.__cause__)
             etype, evalue, etb = exception
         else:
             evalue = None
         chained_exc_ids = set()
         while evalue:
             formatted_exceptions += self.format_exception_as_a_whole(etype, evalue, etb, lines_of_context,
                                                                      chained_exceptions_tb_offset)
             exception = self.get_parts_of_chained_exception(evalue)
 
             if exception and not id(exception[1]) in chained_exc_ids:
                 chained_exc_ids.add(id(exception[1])) # trace exception to avoid infinite 'cause' loop
                 formatted_exceptions += self.prepare_chained_exception_message(evalue.__cause__)
                 etype, evalue, etb = exception
             else:
                 evalue = None
 
         # we want to see exceptions in a reversed order:
         # the first exception should be on top
         for formatted_exception in reversed(formatted_exceptions):
             structured_traceback_parts += formatted_exception
 
         return structured_traceback_parts
 
     def debugger(self, force=False):
         """Call up the pdb debugger if desired, always clean up the tb
         reference.
 
         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 the call_pdb flag is set, the pdb interactive debugger is
         invoked. In all cases, the self.tb reference to the current traceback
         is deleted to prevent lingering references which hamper memory
         management.
 
         Note that each call to pdb() does an 'import readline', so if your app
         requires a special setup for the readline completers, you'll have to
         fix that by hand after invoking the exception handler."""
 
         if force or self.call_pdb:
             if self.pdb is None:
                 self.pdb = self.debugger_cls()
             # the system displayhook may have changed, restore the original
             # for pdb
             display_trap = DisplayTrap(hook=sys.__displayhook__)
             with display_trap:
                 self.pdb.reset()
                 # Find the right frame so we don't pop up inside ipython itself
                 if hasattr(self, 'tb') and self.tb is not None:
                     etb = self.tb
                 else:
                     etb = self.tb = sys.last_traceback
                 while self.tb is not None and self.tb.tb_next is not None:
                     self.tb = self.tb.tb_next
                 if etb and etb.tb_next:
                     etb = etb.tb_next
                 self.pdb.botframe = etb.tb_frame
                 self.pdb.interaction(self.tb.tb_frame, self.tb)
 
         if hasattr(self, 'tb'):
             del self.tb
 
     def handler(self, info=None):
         (etype, evalue, etb) = info or sys.exc_info()
         self.tb = etb
         ostream = self.ostream
         ostream.flush()
         ostream.write(self.text(etype, evalue, etb))
         ostream.write('\n')
         ostream.flush()
 
     # Changed so an instance can just be called as VerboseTB_inst() and print
     # out the right info on its own.
     def __call__(self, etype=None, evalue=None, etb=None):
         """This hook can replace sys.excepthook (for Python 2.1 or higher)."""
         if etb is None:
             self.handler()
         else:
             self.handler((etype, evalue, etb))
         try:
             self.debugger()
         except KeyboardInterrupt:
             print("\nKeyboardInterrupt")
 
 
 #----------------------------------------------------------------------------
 class FormattedTB(VerboseTB, ListTB):
     """Subclass ListTB but allow calling with a traceback.
 
     It can thus be used as a sys.excepthook for Python > 2.1.
 
     Also adds 'Context' and 'Verbose' modes, not available in ListTB.
 
     Allows a tb_offset to be specified. This is useful for situations where
     one needs to remove a number of topmost frames from the traceback (such as
     occurs with python programs that themselves execute other python code,
     like Python shells).  """
 
     def __init__(self, mode='Plain', color_scheme='Linux', call_pdb=False,
                  ostream=None,
                  tb_offset=0, long_header=False, include_vars=False,
                  check_cache=None, debugger_cls=None,
                  parent=None, config=None):
 
         # NEVER change the order of this list. Put new modes at the end:
         self.valid_modes = ['Plain', 'Context', 'Verbose']
         self.verbose_modes = self.valid_modes[1:3]
 
         VerboseTB.__init__(self, color_scheme=color_scheme, call_pdb=call_pdb,
                            ostream=ostream, tb_offset=tb_offset,
                            long_header=long_header, include_vars=include_vars,
                            check_cache=check_cache, debugger_cls=debugger_cls,
                            parent=parent, config=config)
 
         # Different types of tracebacks are joined with different separators to
         # form a single string.  They are taken from this dict
         self._join_chars = dict(Plain='', Context='\n', Verbose='\n')
         # set_mode also sets the tb_join_char attribute
         self.set_mode(mode)
 
     def _extract_tb(self, tb):
         if tb:
             return traceback.extract_tb(tb)
         else:
             return None
 
     def structured_traceback(self, etype, value, tb, tb_offset=None, number_of_lines_of_context=5):
         tb_offset = self.tb_offset if tb_offset is None else tb_offset
         mode = self.mode
         if mode in self.verbose_modes:
             # Verbose modes need a full traceback
             return VerboseTB.structured_traceback(
                 self, etype, value, tb, tb_offset, number_of_lines_of_context
             )
         else:
             # We must check the source cache because otherwise we can print
             # out-of-date source code.
             self.check_cache()
             # Now we can extract and format the exception
             elist = self._extract_tb(tb)
             return ListTB.structured_traceback(
                 self, etype, value, elist, tb_offset, number_of_lines_of_context
             )
 
     def stb2text(self, stb):
         """Convert a structured traceback (a list) to a string."""
         return self.tb_join_char.join(stb)
 
 
     def set_mode(self, mode=None):
         """Switch to the desired mode.
 
         If mode is not specified, cycles through the available modes."""
 
         if not mode:
             new_idx = (self.valid_modes.index(self.mode) + 1 ) % \
                       len(self.valid_modes)
             self.mode = self.valid_modes[new_idx]
         elif mode not in self.valid_modes:
             raise ValueError('Unrecognized mode in FormattedTB: <' + mode + '>\n'
                                                                             'Valid modes: ' + str(self.valid_modes))
         else:
             self.mode = mode
         # include variable details only in 'Verbose' mode
         self.include_vars = (self.mode == self.valid_modes[2])
         # Set the join character for generating text tracebacks
         self.tb_join_char = self._join_chars[self.mode]
 
     # some convenient shortcuts
     def plain(self):
         self.set_mode(self.valid_modes[0])
 
     def context(self):
         self.set_mode(self.valid_modes[1])
 
     def verbose(self):
         self.set_mode(self.valid_modes[2])
 
 
 #----------------------------------------------------------------------------
 class AutoFormattedTB(FormattedTB):
     """A traceback printer which can be called on the fly.
 
     It will find out about exceptions by itself.
 
     A brief example::
 
         AutoTB = AutoFormattedTB(mode = 'Verbose',color_scheme='Linux')
         try:
           ...
         except:
           AutoTB()  # or AutoTB(out=logfile) where logfile is an open file object
     """
 
     def __call__(self, etype=None, evalue=None, etb=None,
                  out=None, tb_offset=None):
         """Print out a formatted exception traceback.
 
         Optional arguments:
           - out: an open file-like object to direct output to.
 
           - tb_offset: the number of frames to skip over in the stack, on a
           per-call basis (this overrides temporarily the instance's tb_offset
           given at initialization time.  """
 
         if out is None:
             out = self.ostream
         out.flush()
         out.write(self.text(etype, evalue, etb, tb_offset))
         out.write('\n')
         out.flush()
         # FIXME: we should remove the auto pdb behavior from here and leave
         # that to the clients.
         try:
             self.debugger()
         except KeyboardInterrupt:
             print("\nKeyboardInterrupt")
 
     def structured_traceback(self, etype=None, value=None, tb=None,
                              tb_offset=None, number_of_lines_of_context=5):
         if etype is None:
             etype, value, tb = sys.exc_info()
         self.tb = tb
         return FormattedTB.structured_traceback(
             self, etype, value, tb, tb_offset, number_of_lines_of_context)
 
 
 #---------------------------------------------------------------------------
 
 # A simple class to preserve Nathan's original functionality.
 class ColorTB(FormattedTB):
     """Shorthand to initialize a FormattedTB in Linux colors mode."""
 
     def __init__(self, color_scheme='Linux', call_pdb=0, **kwargs):
         FormattedTB.__init__(self, color_scheme=color_scheme,
                              call_pdb=call_pdb, **kwargs)
 
 
 class SyntaxTB(ListTB):
     """Extension which holds some state: the last exception value"""
 
     def __init__(self, color_scheme='NoColor', parent=None, config=None):
         ListTB.__init__(self, color_scheme, parent=parent, config=config)
         self.last_syntax_error = None
 
     def __call__(self, etype, value, elist):
         self.last_syntax_error = value
 
         ListTB.__call__(self, etype, value, elist)
 
     def structured_traceback(self, etype, value, elist, tb_offset=None,
                              context=5):
         # If the source file has been edited, the line in the syntax error can
         # be wrong (retrieved from an outdated cache). This replaces it with
         # the current value.
         if isinstance(value, SyntaxError) \
                 and isinstance(value.filename, str) \
                 and isinstance(value.lineno, int):
             linecache.checkcache(value.filename)
             newtext = linecache.getline(value.filename, value.lineno)
             if newtext:
                 value.text = newtext
         self.last_syntax_error = value
         return super(SyntaxTB, self).structured_traceback(etype, value, elist,
                                                           tb_offset=tb_offset, context=context)
 
     def clear_err_state(self):
         """Return the current error state and clear it"""
         e = self.last_syntax_error
         self.last_syntax_error = None
         return e
 
     def stb2text(self, stb):
         """Convert a structured traceback (a list) to a string."""
         return ''.join(stb)
 
 
 # some internal-use functions
 def text_repr(value):
     """Hopefully pretty robust repr equivalent."""
     # this is pretty horrible but should always return *something*
     try:
         return pydoc.text.repr(value)
     except KeyboardInterrupt:
         raise
     except:
         try:
             return repr(value)
         except KeyboardInterrupt:
             raise
         except:
             try:
                 # all still in an except block so we catch
                 # getattr raising
                 name = getattr(value, '__name__', None)
                 if name:
                     # ick, recursion
                     return text_repr(name)
                 klass = getattr(value, '__class__', None)
                 if klass:
                     return '%s instance' % text_repr(klass)
             except KeyboardInterrupt:
                 raise
             except:
                 return 'UNRECOVERABLE REPR FAILURE'
 
 
 def eqrepr(value, repr=text_repr):
     return '=%s' % repr(value)
 
 
 def nullrepr(value, repr=text_repr):
     return ''

IPython/lib/lexers.py

@@ -1,531 +1,531 b''
 # -*- coding: utf-8 -*-
 """
 Defines a variety of Pygments lexers for highlighting IPython code.
 
 This includes:
 
     IPythonLexer, IPython3Lexer
         Lexers for pure IPython (python + magic/shell commands)
 
     IPythonPartialTracebackLexer, IPythonTracebackLexer
         Supports 2.x and 3.x via keyword `python3`.  The partial traceback
         lexer reads everything but the Python code appearing in a traceback.
         The full lexer combines the partial lexer with an IPython lexer.
 
     IPythonConsoleLexer
         A lexer for IPython console sessions, with support for tracebacks.
 
     IPyLexer
         A friendly lexer which examines the first line of text and from it,
         decides whether to use an IPython lexer or an IPython console lexer.
         This is probably the only lexer that needs to be explicitly added
         to Pygments.
 
 """
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013, the IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 # Standard library
 import re
 
 # Third party
 from pygments.lexers import (
     BashLexer, HtmlLexer, JavascriptLexer, RubyLexer, PerlLexer, PythonLexer,
     Python3Lexer, TexLexer)
 from pygments.lexer import (
     Lexer, DelegatingLexer, RegexLexer, do_insertions, bygroups, using,
 )
 from pygments.token import (
     Generic, Keyword, Literal, Name, Operator, Other, Text, Error,
 )
 from pygments.util import get_bool_opt
 
 # Local
 
 line_re = re.compile('.*?\n')
 
 __all__ = ['build_ipy_lexer', 'IPython3Lexer', 'IPythonLexer',
            'IPythonPartialTracebackLexer', 'IPythonTracebackLexer',
            'IPythonConsoleLexer', 'IPyLexer']
 
 
 def build_ipy_lexer(python3):
     """Builds IPython lexers depending on the value of `python3`.
 
     The lexer inherits from an appropriate Python lexer and then adds
     information about IPython specific keywords (i.e. magic commands,
     shell commands, etc.)
 
     Parameters
     ----------
     python3 : bool
         If `True`, then build an IPython lexer from a Python 3 lexer.
 
     """
     # It would be nice to have a single IPython lexer class which takes
     # a boolean `python3`.  But since there are two Python lexer classes,
     # we will also have two IPython lexer classes.
     if python3:
         PyLexer = Python3Lexer
         name = 'IPython3'
         aliases = ['ipython3']
         doc = """IPython3 Lexer"""
     else:
         PyLexer = PythonLexer
         name = 'IPython'
         aliases = ['ipython2', 'ipython']
         doc = """IPython Lexer"""
 
     ipython_tokens = [
        (r'(?s)(\s*)(%%capture)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(PyLexer))),
         (r'(?s)(\s*)(%%debug)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(PyLexer))),
         (r'(?is)(\s*)(%%html)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(HtmlLexer))),
         (r'(?s)(\s*)(%%javascript)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(JavascriptLexer))),
         (r'(?s)(\s*)(%%js)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(JavascriptLexer))),
         (r'(?s)(\s*)(%%latex)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(TexLexer))),
         (r'(?s)(\s*)(%%pypy)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(PerlLexer))),
         (r'(?s)(\s*)(%%prun)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(PyLexer))),
         (r'(?s)(\s*)(%%pypy)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(PyLexer))),
         (r'(?s)(\s*)(%%python)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(PyLexer))),
         (r'(?s)(\s*)(%%python2)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(PythonLexer))),
         (r'(?s)(\s*)(%%python3)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(Python3Lexer))),
         (r'(?s)(\s*)(%%ruby)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(RubyLexer))),
         (r'(?s)(\s*)(%%time)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(PyLexer))),
         (r'(?s)(\s*)(%%timeit)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(PyLexer))),
         (r'(?s)(\s*)(%%writefile)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(PyLexer))),
         (r"(?s)(\s*)(%%)(\w+)(.*)", bygroups(Text, Operator, Keyword, Text)),
         (r'(?s)(^\s*)(%%!)([^\n]*\n)(.*)', bygroups(Text, Operator, Text, using(BashLexer))),
         (r"(%%?)(\w+)(\?\??)$",  bygroups(Operator, Keyword, Operator)),
         (r"\b(\?\??)(\s*)$",  bygroups(Operator, Text)),
         (r'(%)(sx|sc|system)(.*)(\n)', bygroups(Operator, Keyword,
                                                 using(BashLexer), Text)),
         (r'(%)(\w+)(.*\n)', bygroups(Operator, Keyword, Text)),
         (r'^(!!)(.+)(\n)', bygroups(Operator, using(BashLexer), Text)),
         (r'(!)(?!=)(.+)(\n)', bygroups(Operator, using(BashLexer), Text)),
         (r'^(\s*)(\?\??)(\s*%{0,2}[\w\.\*]*)', bygroups(Text, Operator, Text)),
         (r'(\s*%{0,2}[\w\.\*]*)(\?\??)(\s*)$', bygroups(Text, Operator, Text)),
     ]
 
     tokens = PyLexer.tokens.copy()
     tokens['root'] = ipython_tokens + tokens['root']
 
     attrs = {'name': name, 'aliases': aliases, 'filenames': [],
              '__doc__': doc, 'tokens': tokens}
 
     return type(name, (PyLexer,), attrs)
 
 
 IPython3Lexer = build_ipy_lexer(python3=True)
 IPythonLexer = build_ipy_lexer(python3=False)
 
 
 class IPythonPartialTracebackLexer(RegexLexer):
     """
     Partial lexer for IPython tracebacks.
 
     Handles all the non-python output. This works for both Python 2.x and 3.x.
 
     """
     name = 'IPython Partial Traceback'
 
     tokens = {
         'root': [
             # Tracebacks for syntax errors have a different style.
             # For both types of tracebacks, we mark the first line with
             # Generic.Traceback.  For syntax errors, we mark the filename
             # as we mark the filenames for non-syntax tracebacks.
             #
             # These two regexps define how IPythonConsoleLexer finds a
             # traceback.
             #
             ## Non-syntax traceback
             (r'^(\^C)?(-+\n)', bygroups(Error, Generic.Traceback)),
             ## Syntax traceback
             (r'^(  File)(.*)(, line )(\d+\n)',
              bygroups(Generic.Traceback, Name.Namespace,
                       Generic.Traceback, Literal.Number.Integer)),
 
             # (Exception Identifier)(Whitespace)(Traceback Message)
             (r'(?u)(^[^\d\W]\w*)(\s*)(Traceback.*?\n)',
              bygroups(Name.Exception, Generic.Whitespace, Text)),
             # (Module/Filename)(Text)(Callee)(Function Signature)
             # Better options for callee and function signature?
             (r'(.*)( in )(.*)(\(.*\)\n)',
              bygroups(Name.Namespace, Text, Name.Entity, Name.Tag)),
             # Regular line: (Whitespace)(Line Number)(Python Code)
             (r'(\s*?)(\d+)(.*?\n)',
              bygroups(Generic.Whitespace, Literal.Number.Integer, Other)),
             # Emphasized line: (Arrow)(Line Number)(Python Code)
             # Using Exception token so arrow color matches the Exception.
             (r'(-*>?\s?)(\d+)(.*?\n)',
              bygroups(Name.Exception, Literal.Number.Integer, Other)),
             # (Exception Identifier)(Message)
             (r'(?u)(^[^\d\W]\w*)(:.*?\n)',
              bygroups(Name.Exception, Text)),
             # Tag everything else as Other, will be handled later.
             (r'.*\n', Other),
         ],
     }
 
 
 class IPythonTracebackLexer(DelegatingLexer):
     """
     IPython traceback lexer.
 
     For doctests, the tracebacks can be snipped as much as desired with the
     exception to the lines that designate a traceback. For non-syntax error
     tracebacks, this is the line of hyphens. For syntax error tracebacks,
     this is the line which lists the File and line number.
 
     """
     # The lexer inherits from DelegatingLexer.  The "root" lexer is an
     # appropriate IPython lexer, which depends on the value of the boolean
     # `python3`.  First, we parse with the partial IPython traceback lexer.
     # Then, any code marked with the "Other" token is delegated to the root
     # lexer.
     #
     name = 'IPython Traceback'
     aliases = ['ipythontb']
 
     def __init__(self, **options):
         self.python3 = get_bool_opt(options, 'python3', False)
         if self.python3:
             self.aliases = ['ipython3tb']
         else:
             self.aliases = ['ipython2tb', 'ipythontb']
 
         if self.python3:
             IPyLexer = IPython3Lexer
         else:
             IPyLexer = IPythonLexer
 
         DelegatingLexer.__init__(self, IPyLexer,
                                  IPythonPartialTracebackLexer, **options)
 
 class IPythonConsoleLexer(Lexer):
     """
     An IPython console lexer for IPython code-blocks and doctests, such as:
 
     .. code-block:: rst
 
         .. code-block:: ipythonconsole
 
             In [1]: a = 'foo'
 
             In [2]: a
             Out[2]: 'foo'
 
             In [3]: print a
             foo
 
             In [4]: 1 / 0
 
 
     Support is also provided for IPython exceptions:
 
     .. code-block:: rst
 
         .. code-block:: ipythonconsole
 
             In [1]: raise Exception
 
             ---------------------------------------------------------------------------
             Exception                                 Traceback (most recent call last)
-            <ipython-input-1-fca2ab0ca76b> in <module>()
+            <ipython-input-1-fca2ab0ca76b> in <module>
             ----> 1 raise Exception
 
             Exception:
 
     """
     name = 'IPython console session'
     aliases = ['ipythonconsole']
     mimetypes = ['text/x-ipython-console']
 
     # The regexps used to determine what is input and what is output.
     # The default prompts for IPython are:
     #
     #    in           = 'In [#]: '
     #    continuation = '   .D.: '
     #    template     = 'Out[#]: '
     #
     # Where '#' is the 'prompt number' or 'execution count' and 'D' 
     # D is a number of dots  matching the width of the execution count 
     #
     in1_regex = r'In \[[0-9]+\]: '
     in2_regex = r'   \.\.+\.: '
     out_regex = r'Out\[[0-9]+\]: '
 
     #: The regex to determine when a traceback starts.
     ipytb_start = re.compile(r'^(\^C)?(-+\n)|^(  File)(.*)(, line )(\d+\n)')
 
     def __init__(self, **options):
         """Initialize the IPython console lexer.
 
         Parameters
         ----------
         python3 : bool
             If `True`, then the console inputs are parsed using a Python 3
             lexer. Otherwise, they are parsed using a Python 2 lexer.
         in1_regex : RegexObject
             The compiled regular expression used to detect the start
             of inputs. Although the IPython configuration setting may have a
             trailing whitespace, do not include it in the regex. If `None`,
             then the default input prompt is assumed.
         in2_regex : RegexObject
             The compiled regular expression used to detect the continuation
             of inputs. Although the IPython configuration setting may have a
             trailing whitespace, do not include it in the regex. If `None`,
             then the default input prompt is assumed.
         out_regex : RegexObject
             The compiled regular expression used to detect outputs. If `None`,
             then the default output prompt is assumed.
 
         """
         self.python3 = get_bool_opt(options, 'python3', False)
         if self.python3:
             self.aliases = ['ipython3console']
         else:
             self.aliases = ['ipython2console', 'ipythonconsole']
 
         in1_regex = options.get('in1_regex', self.in1_regex)
         in2_regex = options.get('in2_regex', self.in2_regex)
         out_regex = options.get('out_regex', self.out_regex)
 
         # So that we can work with input and output prompts which have been
         # rstrip'd (possibly by editors) we also need rstrip'd variants. If
         # we do not do this, then such prompts will be tagged as 'output'.
         # The reason can't just use the rstrip'd variants instead is because
         # we want any whitespace associated with the prompt to be inserted
         # with the token. This allows formatted code to be modified so as hide
         # the appearance of prompts, with the whitespace included. One example
         # use of this is in copybutton.js from the standard lib Python docs.
         in1_regex_rstrip = in1_regex.rstrip() + '\n'
         in2_regex_rstrip = in2_regex.rstrip() + '\n'
         out_regex_rstrip = out_regex.rstrip() + '\n'
 
         # Compile and save them all.
         attrs = ['in1_regex', 'in2_regex', 'out_regex',
                  'in1_regex_rstrip', 'in2_regex_rstrip', 'out_regex_rstrip']
         for attr in attrs:
             self.__setattr__(attr, re.compile(locals()[attr]))
 
         Lexer.__init__(self, **options)
 
         if self.python3:
             pylexer = IPython3Lexer
             tblexer = IPythonTracebackLexer
         else:
             pylexer = IPythonLexer
             tblexer = IPythonTracebackLexer
 
         self.pylexer = pylexer(**options)
         self.tblexer = tblexer(**options)
 
         self.reset()
 
     def reset(self):
         self.mode = 'output'
         self.index = 0
         self.buffer = u''
         self.insertions = []
 
     def buffered_tokens(self):
         """
         Generator of unprocessed tokens after doing insertions and before
         changing to a new state.
 
         """
         if self.mode == 'output':
             tokens = [(0, Generic.Output, self.buffer)]
         elif self.mode == 'input':
             tokens = self.pylexer.get_tokens_unprocessed(self.buffer)
         else: # traceback
             tokens = self.tblexer.get_tokens_unprocessed(self.buffer)
 
         for i, t, v in do_insertions(self.insertions, tokens):
             # All token indexes are relative to the buffer.
             yield self.index + i, t, v
 
         # Clear it all
         self.index += len(self.buffer)
         self.buffer = u''
         self.insertions = []
 
     def get_mci(self, line):
         """
         Parses the line and returns a 3-tuple: (mode, code, insertion).
 
         `mode` is the next mode (or state) of the lexer, and is always equal
         to 'input', 'output', or 'tb'.
 
         `code` is a portion of the line that should be added to the buffer
         corresponding to the next mode and eventually lexed by another lexer.
         For example, `code` could be Python code if `mode` were 'input'.
 
         `insertion` is a 3-tuple (index, token, text) representing an
         unprocessed "token" that will be inserted into the stream of tokens
         that are created from the buffer once we change modes. This is usually
         the input or output prompt.
 
         In general, the next mode depends on current mode and on the contents
         of `line`.
 
         """
         # To reduce the number of regex match checks, we have multiple
         # 'if' blocks instead of 'if-elif' blocks.
 
         # Check for possible end of input
         in2_match = self.in2_regex.match(line)
         in2_match_rstrip = self.in2_regex_rstrip.match(line)
         if (in2_match and in2_match.group().rstrip() == line.rstrip()) or \
            in2_match_rstrip:
             end_input = True
         else:
             end_input = False
         if end_input and self.mode != 'tb':
             # Only look for an end of input when not in tb mode.
             # An ellipsis could appear within the traceback.
             mode = 'output'
             code = u''
             insertion = (0, Generic.Prompt, line)
             return mode, code, insertion
 
         # Check for output prompt
         out_match = self.out_regex.match(line)
         out_match_rstrip = self.out_regex_rstrip.match(line)
         if out_match or out_match_rstrip:
             mode = 'output'
             if out_match:
                 idx = out_match.end()
             else:
                 idx = out_match_rstrip.end()
             code = line[idx:]
             # Use the 'heading' token for output.  We cannot use Generic.Error
             # since it would conflict with exceptions.
             insertion = (0, Generic.Heading, line[:idx])
             return mode, code, insertion
 
 
         # Check for input or continuation prompt (non stripped version)
         in1_match = self.in1_regex.match(line)
         if in1_match or (in2_match and self.mode != 'tb'):
             # New input or when not in tb, continued input.
             # We do not check for continued input when in tb since it is
             # allowable to replace a long stack with an ellipsis.
             mode = 'input'
             if in1_match:
                 idx = in1_match.end()
             else: # in2_match
                 idx = in2_match.end()
             code = line[idx:]
             insertion = (0, Generic.Prompt, line[:idx])
             return mode, code, insertion
 
         # Check for input or continuation prompt (stripped version)
         in1_match_rstrip = self.in1_regex_rstrip.match(line)
         if in1_match_rstrip or (in2_match_rstrip and self.mode != 'tb'):
             # New input or when not in tb, continued input.
             # We do not check for continued input when in tb since it is
             # allowable to replace a long stack with an ellipsis.
             mode = 'input'
             if in1_match_rstrip:
                 idx = in1_match_rstrip.end()
             else: # in2_match
                 idx = in2_match_rstrip.end()
             code = line[idx:]
             insertion = (0, Generic.Prompt, line[:idx])
             return mode, code, insertion
 
         # Check for traceback
         if self.ipytb_start.match(line):
             mode = 'tb'
             code = line
             insertion = None
             return mode, code, insertion
 
         # All other stuff...
         if self.mode in ('input', 'output'):
             # We assume all other text is output. Multiline input that
             # does not use the continuation marker cannot be detected.
             # For example, the 3 in the following is clearly output:
             #
             #    In [1]: print 3
             #    3
             #
             # But the following second line is part of the input:
             #
             #    In [2]: while True:
             #        print True
             #
             # In both cases, the 2nd line will be 'output'.
             #
             mode = 'output'
         else:
             mode = 'tb'
 
         code = line
         insertion = None
 
         return mode, code, insertion
 
     def get_tokens_unprocessed(self, text):
         self.reset()
         for match in line_re.finditer(text):
             line = match.group()
             mode, code, insertion = self.get_mci(line)
 
             if mode != self.mode:
                 # Yield buffered tokens before transitioning to new mode.
                 for token in self.buffered_tokens():
                     yield token
                 self.mode = mode
 
             if insertion:
                 self.insertions.append((len(self.buffer), [insertion]))
             self.buffer += code
 
         for token in self.buffered_tokens():
             yield token
 
 class IPyLexer(Lexer):
     """
     Primary lexer for all IPython-like code.
 
     This is a simple helper lexer.  If the first line of the text begins with
     "In \[[0-9]+\]:", then the entire text is parsed with an IPython console
     lexer. If not, then the entire text is parsed with an IPython lexer.
 
     The goal is to reduce the number of lexers that are registered
     with Pygments.
 
     """
     name = 'IPy session'
     aliases = ['ipy']
 
     def __init__(self, **options):
         self.python3 = get_bool_opt(options, 'python3', False)
         if self.python3:
             self.aliases = ['ipy3']
         else:
             self.aliases = ['ipy2', 'ipy']
 
         Lexer.__init__(self, **options)
 
         self.IPythonLexer = IPythonLexer(**options)
         self.IPythonConsoleLexer = IPythonConsoleLexer(**options)
 
     def get_tokens_unprocessed(self, text):
         # Search for the input prompt anywhere...this allows code blocks to
         # begin with comments as well.
         if re.match(r'.*(In \[[0-9]+\]:)', text.strip(), re.DOTALL):
             lex = self.IPythonConsoleLexer
         else:
             lex = self.IPythonLexer
         for token in lex.get_tokens_unprocessed(text):
             yield token
 

docs/source/interactive/reference.rst

@@ -1,1037 +1,1037 b''
 =================
 IPython reference
 =================
 
 .. _command_line_options:
 
 Command-line usage
 ==================
 
 You start IPython with the command::
 
     $ ipython [options] files
 
 If invoked with no options, it executes all the files listed in sequence and
 exits. If you add the ``-i`` flag, it drops you into the interpreter while still
 acknowledging any options you may have set in your ``ipython_config.py``. This
 behavior is different from standard Python, which when called as python ``-i``
 will only execute one file and ignore your configuration setup.
 
 Please note that some of the configuration options are not available at the
 command line, simply because they are not practical here. Look into your
 configuration files for details on those. There are separate configuration files
 for each profile, and the files look like :file:`ipython_config.py` or
 :file:`ipython_config_{frontendname}.py`.  Profile directories look like
 :file:`profile_{profilename}` and are typically installed in the
 :envvar:`IPYTHONDIR` directory, which defaults to :file:`$HOME/.ipython`. For
 Windows users, :envvar:`HOME` resolves to :file:`C:\\Users\\{YourUserName}` in
 most instances.
 
 Command-line Options
 --------------------
 
 To see the options IPython accepts, use ``ipython --help`` (and you probably
 should run the output through a pager such as ``ipython --help | less`` for
 more convenient reading).  This shows all the options that have a single-word
 alias to control them, but IPython lets you configure all of its objects from
 the command-line by passing the full class name and a corresponding value; type
 ``ipython --help-all`` to see this full list.  For example::
 
     $ ipython --help-all
     <...snip...>
     --matplotlib=<CaselessStrEnum> (InteractiveShellApp.matplotlib)
         Default: None
         Choices: ['auto', 'gtk', 'gtk3', 'inline', 'nbagg', 'notebook', 'osx', 'qt', 'qt4', 'qt5', 'tk', 'wx']
         Configure matplotlib for interactive use with the default matplotlib
         backend.
     <...snip...>
 
 
 Indicate that the following::
 
    $ ipython --matplotlib qt
 
 
 is equivalent to::
 
    $ ipython --TerminalIPythonApp.matplotlib='qt'
 
 Note that in the second form, you *must* use the equal sign, as the expression
 is evaluated as an actual Python assignment.  While in the above example the
 short form is more convenient, only the most common options have a short form,
 while any configurable variable in IPython can be set at the command-line by
 using the long form.  This long form is the same syntax used in the
 configuration files, if you want to set these options permanently.
 
 
 Interactive use
 ===============
 
 IPython is meant to work as a drop-in replacement for the standard interactive
 interpreter. As such, any code which is valid python should execute normally
 under IPython (cases where this is not true should be reported as bugs). It
 does, however, offer many features which are not available at a standard python
 prompt. What follows is a list of these.
 
 
 Caution for Windows users
 -------------------------
 
 Windows, unfortunately, uses the '\\' character as a path separator. This is a
 terrible choice, because '\\' also represents the escape character in most
 modern programming languages, including Python. For this reason, using '/'
 character is recommended if you have problems with ``\``.  However, in Windows
 commands '/' flags options, so you can not use it for the root directory. This
 means that paths beginning at the root must be typed in a contrived manner
 like: ``%copy \opt/foo/bar.txt \tmp``
 
 .. _magic:
 
 Magic command system
 --------------------
 
 IPython will treat any line whose first character is a % as a special
 call to a 'magic' function. These allow you to control the behavior of
 IPython itself, plus a lot of system-type features. They are all
 prefixed with a % character, but parameters are given without
 parentheses or quotes.
 
 Lines that begin with ``%%`` signal a *cell magic*: they take as arguments not
 only the rest of the current line, but all lines below them as well, in the
 current execution block.  Cell magics can in fact make arbitrary modifications
 to the input they receive, which need not even be valid Python code at all.
 They receive the whole block as a single string.
 
 As a line magic example, the :magic:`cd` magic works just like the OS command of
 the same name::
 
       In [8]: %cd
       /home/fperez
 
 The following uses the builtin :magic:`timeit` in cell mode::
 
   In [10]: %%timeit x = range(10000)
       ...: min(x)
       ...: max(x)
       ...:
   1000 loops, best of 3: 438 us per loop
 
 In this case, ``x = range(10000)`` is called as the line argument, and the
 block with ``min(x)`` and ``max(x)`` is called as the cell body.  The
 :magic:`timeit` magic receives both.
 
 If you have 'automagic' enabled (as it is by default), you don't need to type in
 the single ``%`` explicitly for line magics; IPython will scan its internal
 list of magic functions and call one if it exists. With automagic on you can
 then just type ``cd mydir`` to go to directory 'mydir'::
 
       In [9]: cd mydir
       /home/fperez/mydir
 
 Cell magics *always* require an explicit ``%%`` prefix, automagic
 calling only works for line magics.
 
 The automagic system has the lowest possible precedence in name searches, so
 you can freely use variables with the same names as magic commands. If a magic
 command is 'shadowed' by a variable, you will need the explicit ``%`` prefix to
 use it:
 
 .. sourcecode:: ipython
 
     In [1]: cd ipython     # %cd is called by automagic
     /home/fperez/ipython
 
     In [2]: cd=1 	   # now cd is just a variable
 
     In [3]: cd .. 	   # and doesn't work as a function anymore
     File "<ipython-input-3-9fedb3aff56c>", line 1
       cd ..
           ^
     SyntaxError: invalid syntax
 
 
     In [4]: %cd .. 	   # but %cd always works
     /home/fperez
 
     In [5]: del cd     # if you remove the cd variable, automagic works again
 
     In [6]: cd ipython
 
     /home/fperez/ipython
 
 Line magics, if they return a value, can be assigned to a variable using the
 syntax ``l = %sx ls`` (which in this particular case returns the result of `ls`
 as a python list). See :ref:`below <manual_capture>` for more information.
 
 Type ``%magic`` for more information, including a list of all available magic
 functions at any time and their docstrings. You can also type
 ``%magic_function_name?`` (see :ref:`below <dynamic_object_info>` for
 information on the '?' system) to get information about any particular magic
 function you are interested in.
 
 The API documentation for the :mod:`IPython.core.magic` module contains the full
 docstrings of all currently available magic commands.
 
 .. seealso::
 
    :doc:`magics`
      A list of the line and cell magics available in IPython by default
 
    :ref:`defining_magics`
      How to define and register additional magic functions
 
 
 Access to the standard Python help
 ----------------------------------
 
 Simply type ``help()`` to access Python's standard help system. You can
 also type ``help(object)`` for information about a given object, or
 ``help('keyword')`` for information on a keyword. You may need to configure your
 PYTHONDOCS environment variable for this feature to work correctly.
 
 .. _dynamic_object_info:
 
 Dynamic object information
 --------------------------
 
 Typing ``?word`` or ``word?`` prints detailed information about an object. If
 certain strings in the object are too long (e.g. function signatures) they get
 snipped in the center for brevity. This system gives access variable types and
 values, docstrings, function prototypes and other useful information.
 
 If the information will not fit in the terminal, it is displayed in a pager
 (``less`` if available, otherwise a basic internal pager).
 
 Typing ``??word`` or ``word??`` gives access to the full information, including
 the source code where possible. Long strings are not snipped.
 
 The following magic functions are particularly useful for gathering
 information about your working environment:
 
     * :magic:`pdoc` **<object>**: Print (or run through a pager if too long) the
       docstring for an object. If the given object is a class, it will
       print both the class and the constructor docstrings.
     * :magic:`pdef` **<object>**: Print the call signature for any callable
       object. If the object is a class, print the constructor information.
     * :magic:`psource` **<object>**: Print (or run through a pager if too long)
       the source code for an object.
     * :magic:`pfile` **<object>**: Show the entire source file where an object was
       defined via a pager, opening it at the line where the object
       definition begins.
     * :magic:`who`/:magic:`whos`: These functions give information about identifiers
       you have defined interactively (not things you loaded or defined
       in your configuration files). %who just prints a list of
       identifiers and %whos prints a table with some basic details about
       each identifier.
 
 The dynamic object information functions (?/??, ``%pdoc``,
 ``%pfile``, ``%pdef``, ``%psource``) work on object attributes, as well as
 directly on variables. For example, after doing ``import os``, you can use
 ``os.path.abspath??``.
 
 
 Command line completion
 +++++++++++++++++++++++
 
 At any time, hitting TAB will complete any available python commands or
 variable names, and show you a list of the possible completions if
 there's no unambiguous one. It will also complete filenames in the
 current directory if no python names match what you've typed so far.
 
 
 Search command history
 ++++++++++++++++++++++
 
 IPython provides two ways for searching through previous input and thus
 reduce the need for repetitive typing:
 
    1. Start typing, and then use the up and down arrow keys (or :kbd:`Ctrl-p`
       and :kbd:`Ctrl-n`) to search through only the history items that match
       what you've typed so far.
    2. Hit :kbd:`Ctrl-r`: to open a search prompt. Begin typing and the system
       searches your history for lines that contain what you've typed so
       far, completing as much as it can.
 
 IPython will save your input history when it leaves and reload it next
 time you restart it. By default, the history file is named
 :file:`.ipython/profile_{name}/history.sqlite`.
 
 Autoindent
 ++++++++++
 
 Starting with 5.0, IPython uses `prompt_toolkit` in place of ``readline``,
 it thus can recognize lines ending in ':' and indent the next line,
 while also un-indenting automatically after 'raise' or 'return',
 and support real multi-line editing as well as syntactic coloration
 during edition.
 
 This feature does not use the ``readline`` library anymore, so it will
 not honor your :file:`~/.inputrc` configuration (or whatever
 file your :envvar:`INPUTRC` environment variable points to).
 
 In particular if you want to change the input mode to ``vi``, you will need to
 set the ``TerminalInteractiveShell.editing_mode`` configuration  option of IPython.
 
 Session logging and restoring
 -----------------------------
 
 You can log all input from a session either by starting IPython with the
 command line switch ``--logfile=foo.py`` (see :ref:`here <command_line_options>`)
 or by activating the logging at any moment with the magic function :magic:`logstart`.
 
 Log files can later be reloaded by running them as scripts and IPython
 will attempt to 'replay' the log by executing all the lines in it, thus
 restoring the state of a previous session. This feature is not quite
 perfect, but can still be useful in many cases.
 
 The log files can also be used as a way to have a permanent record of
 any code you wrote while experimenting. Log files are regular text files
 which you can later open in your favorite text editor to extract code or
 to 'clean them up' before using them to replay a session.
 
 The :magic:`logstart` function for activating logging in mid-session is used as
 follows::
 
     %logstart [log_name [log_mode]]
 
 If no name is given, it defaults to a file named 'ipython_log.py' in your
 current working directory, in 'rotate' mode (see below).
 
 '%logstart name' saves to file 'name' in 'backup' mode. It saves your
 history up to that point and then continues logging.
 
 %logstart takes a second optional parameter: logging mode. This can be
 one of (note that the modes are given unquoted):
 
     * [over:] overwrite existing log_name.
     * [backup:] rename (if exists) to log_name~ and start log_name.
     * [append:] well, that says it.
     * [rotate:] create rotating logs log_name.1~, log_name.2~, etc.
 
 The :magic:`logoff` and :magic:`logon` functions allow you to temporarily stop and
 resume logging to a file which had previously been started with
 %logstart. They will fail (with an explanation) if you try to use them
 before logging has been started.
 
 .. _system_shell_access:
 
 System shell access
 -------------------
 
 Any input line beginning with a ``!`` character is passed verbatim (minus
 the ``!``, of course) to the underlying operating system. For example,
 typing ``!ls`` will run 'ls' in the current directory.
 
 .. _manual_capture:
 
 Manual capture of command output and magic output
 -------------------------------------------------
 
 You can assign the result of a system command to a Python variable with the
 syntax ``myfiles = !ls``. Similarly, the result of a magic (as long as it returns
 a value) can be assigned to a variable.  For example, the syntax ``myfiles = %sx ls``
 is equivalent to the above system command example (the :magic:`sx` magic runs a shell command
 and captures the output).  Each of these gets machine
 readable output from stdout (e.g. without colours), and splits on newlines. To
 explicitly get this sort of output without assigning to a variable, use two
 exclamation marks (``!!ls``) or the :magic:`sx` magic command without an assignment.
 (However, ``!!`` commands cannot be assigned to a variable.)
 
 The captured list in this example has some convenience features. ``myfiles.n`` or ``myfiles.s``
 returns a string delimited by newlines or spaces, respectively. ``myfiles.p``
 produces `path objects <http://pypi.python.org/pypi/path.py>`_ from the list items.
 See :ref:`string_lists` for details.
 
 IPython also allows you to expand the value of python variables when
 making system calls. Wrap variables or expressions in {braces}::
 
     In [1]: pyvar = 'Hello world'
     In [2]: !echo "A python variable: {pyvar}"
     A python variable: Hello world
     In [3]: import math
     In [4]: x = 8
     In [5]: !echo {math.factorial(x)}
     40320
 
 For simple cases, you can alternatively prepend $ to a variable name::
 
     In [6]: !echo $sys.argv
     [/home/fperez/usr/bin/ipython]
     In [7]: !echo "A system variable: $$HOME"  # Use $$ for literal $
     A system variable: /home/fperez
 
 Note that `$$` is used to represent a literal `$`.
 
 System command aliases
 ----------------------
 
 The :magic:`alias` magic function allows you to define magic functions which are in fact
 system shell commands. These aliases can have parameters.
 
 ``%alias alias_name cmd`` defines 'alias_name' as an alias for 'cmd'
 
 Then, typing ``alias_name params`` will execute the system command 'cmd
 params' (from your underlying operating system).
 
 You can also define aliases with parameters using ``%s`` specifiers (one per
 parameter). The following example defines the parts function as an
 alias to the command ``echo first %s second %s`` where each ``%s`` will be
 replaced by a positional parameter to the call to %parts::
 
     In [1]: %alias parts echo first %s second %s
     In [2]: parts A B
     first A second B
     In [3]: parts A
     ERROR: Alias <parts> requires 2 arguments, 1 given.
 
 If called with no parameters, :magic:`alias` prints the table of currently
 defined aliases.
 
 The :magic:`rehashx` magic allows you to load your entire $PATH as
 ipython aliases. See its docstring for further details.
 
 
 .. _dreload:
 
 Recursive reload
 ----------------
 
 The :mod:`IPython.lib.deepreload` module allows you to recursively reload a
 module: changes made to any of its dependencies will be reloaded without
 having to exit. To start using it, do::
 
     from IPython.lib.deepreload import reload as dreload
 
 
 Verbose and colored exception traceback printouts
 -------------------------------------------------
 
 IPython provides the option to see very detailed exception tracebacks,
 which can be especially useful when debugging large programs. You can
 run any Python file with the %run function to benefit from these
 detailed tracebacks. Furthermore, both normal and verbose tracebacks can
 be colored (if your terminal supports it) which makes them much easier
 to parse visually.
 
 See the magic :magic:`xmode` and :magic:`colors` functions for details.
 
 These features are basically a terminal version of Ka-Ping Yee's cgitb
 module, now part of the standard Python library.
 
 
 .. _input_caching:
 
 Input caching system
 --------------------
 
 IPython offers numbered prompts (In/Out) with input and output caching
 (also referred to as 'input history'). All input is saved and can be
 retrieved as variables (besides the usual arrow key recall), in
 addition to the :magic:`rep` magic command that brings a history entry
 up for editing on the next command line.
 
 The following variables always exist:
 
 * ``_i``, ``_ii``, ``_iii``: store previous, next previous and next-next
   previous inputs.
 
 * ``In``, ``_ih`` : a list of all inputs; ``_ih[n]`` is the input from line
   ``n``. If you overwrite In with a variable of your own, you can remake the
   assignment to the internal list with a simple ``In=_ih``.
 
 Additionally, global variables named ``_i<n>`` are dynamically created (``<n>``
 being the prompt counter), so ``_i<n> == _ih[<n>] == In[<n>]``.
 
 For example, what you typed at prompt 14 is available as ``_i14``, ``_ih[14]``
 and ``In[14]``.
 
 This allows you to easily cut and paste multi line interactive prompts
 by printing them out: they print like a clean string, without prompt
 characters. You can also manipulate them like regular variables (they
 are strings), modify or exec them.
 
 You can also re-execute multiple lines of input easily by using the magic
 :magic:`rerun` or :magic:`macro` functions. The macro system also allows you to
 re-execute previous lines which include magic function calls (which require
 special processing). Type %macro? for more details on the macro system.
 
 A history function :magic:`history` allows you to see any part of your input
 history by printing a range of the _i variables.
 
 You can also search ('grep') through your history by typing
 ``%hist -g somestring``. This is handy for searching for URLs, IP addresses,
 etc. You can bring history entries listed by '%hist -g' up for editing
 with the %recall command, or run them immediately with :magic:`rerun`.
 
 .. _output_caching:
 
 Output caching system
 ---------------------
 
 For output that is returned from actions, a system similar to the input
 cache exists but using _ instead of _i. Only actions that produce a
 result (NOT assignments, for example) are cached. If you are familiar
 with Mathematica, IPython's _ variables behave exactly like
 Mathematica's % variables.
 
 The following variables always exist:
 
     * [_] (a single underscore): stores previous output, like Python's
       default interpreter.
     * [__] (two underscores): next previous.
     * [___] (three underscores): next-next previous.
 
 Additionally, global variables named _<n> are dynamically created (<n>
 being the prompt counter), such that the result of output <n> is always
 available as _<n> (don't use the angle brackets, just the number, e.g.
 ``_21``).
 
 These variables are also stored in a global dictionary (not a
 list, since it only has entries for lines which returned a result)
 available under the names _oh and Out (similar to _ih and In). So the
 output from line 12 can be obtained as ``_12``, ``Out[12]`` or ``_oh[12]``. If you
 accidentally overwrite the Out variable you can recover it by typing
 ``Out=_oh`` at the prompt.
 
 This system obviously can potentially put heavy memory demands on your
 system, since it prevents Python's garbage collector from removing any
 previously computed results. You can control how many results are kept
 in memory with the configuration option ``InteractiveShell.cache_size``.
 If you set it to 0, output caching is disabled. You can also use the :magic:`reset`
 and :magic:`xdel` magics to clear large items from memory.
 
 Directory history
 -----------------
 
 Your history of visited directories is kept in the global list _dh, and
 the magic :magic:`cd` command can be used to go to any entry in that list. The
 :magic:`dhist` command allows you to view this history. Do ``cd -<TAB>`` to
 conveniently view the directory history.
 
 
 Automatic parentheses and quotes
 --------------------------------
 
 These features were adapted from Nathan Gray's LazyPython. They are
 meant to allow less typing for common situations.
 
 Callable objects (i.e. functions, methods, etc) can be invoked like this
 (notice the commas between the arguments)::
 
     In [1]: callable_ob arg1, arg2, arg3
     ------> callable_ob(arg1, arg2, arg3)
 
 .. note::
    This feature is disabled by default. To enable it, use the ``%autocall``
    magic command. The commands below with special prefixes will always work,
    however.
 
 You can force automatic parentheses by using '/' as the first character
 of a line. For example::
 
     In [2]: /globals # becomes 'globals()'
 
 Note that the '/' MUST be the first character on the line! This won't work::
 
     In [3]: print /globals # syntax error
 
 In most cases the automatic algorithm should work, so you should rarely
 need to explicitly invoke /. One notable exception is if you are trying
 to call a function with a list of tuples as arguments (the parenthesis
 will confuse IPython)::
 
     In [4]: zip (1,2,3),(4,5,6) # won't work
 
 but this will work::
 
     In [5]: /zip (1,2,3),(4,5,6)
     ------> zip ((1,2,3),(4,5,6))
     Out[5]: [(1, 4), (2, 5), (3, 6)]
 
 IPython tells you that it has altered your command line by displaying
 the new command line preceded by ``--->``.
 
 You can force automatic quoting of a function's arguments by using ``,``
 or ``;`` as the first character of a line. For example::
 
     In [1]: ,my_function /home/me  # becomes my_function("/home/me")
 
 If you use ';' the whole argument is quoted as a single string, while ',' splits
 on whitespace::
 
     In [2]: ,my_function a b c    # becomes my_function("a","b","c")
 
     In [3]: ;my_function a b c    # becomes my_function("a b c")
 
 Note that the ',' or ';' MUST be the first character on the line! This
 won't work::
 
     In [4]: x = ,my_function /home/me # syntax error
 
 IPython as your default Python environment
 ==========================================
 
 Python honors the environment variable :envvar:`PYTHONSTARTUP` and will
 execute at startup the file referenced by this variable. If you put the
 following code at the end of that file, then IPython will be your working
 environment anytime you start Python::
 
     import os, IPython
     os.environ['PYTHONSTARTUP'] = ''  # Prevent running this again
     IPython.start_ipython()
     raise SystemExit
 
 The ``raise SystemExit`` is needed to exit Python when
 it finishes, otherwise you'll be back at the normal Python ``>>>``
 prompt.
 
 This is probably useful to developers who manage multiple Python
 versions and don't want to have correspondingly multiple IPython
 versions. Note that in this mode, there is no way to pass IPython any
 command-line options, as those are trapped first by Python itself.
 
 .. _Embedding:
 
 Embedding IPython
 =================
 
 You can start a regular IPython session with
 
 .. sourcecode:: python
 
     import IPython
     IPython.start_ipython(argv=[])
 
 at any point in your program.  This will load IPython configuration,
 startup files, and everything, just as if it were a normal IPython session.
 For information on setting configuration options when running IPython from
 python, see :ref:`configure_start_ipython`.
 
 It is also possible to embed an IPython shell in a namespace in your Python
 code. This allows you to evaluate dynamically the state of your code, operate
 with your variables, analyze them, etc. For example, if you run the following
 code snippet::
 
   import IPython
 
   a = 42
   IPython.embed()
 
 and within the IPython shell, you reassign `a` to `23` to do further testing of 
 some sort, you can then exit::
 
   >>> IPython.embed()
   Python 3.6.2 (default, Jul 17 2017, 16:44:45) 
   Type 'copyright', 'credits' or 'license' for more information
   IPython 6.2.0.dev -- An enhanced Interactive Python. Type '?' for help.
 
   In [1]: a = 23
 
   In [2]: exit()
 
 Once you exit and print `a`, the value 23 will be shown::
 
 
   In: print(a)
   23
 
 It's important to note that the code run in the embedded IPython shell will 
 *not* change the state of your code and variables, **unless** the shell is 
 contained within the global namespace. In the above example, `a` is changed 
 because this is true.
 
 To further exemplify this, consider the following example::
 
   import IPython
   def do():
       a = 42
       print(a)
       IPython.embed()
       print(a)
 
 Now if call the function and complete the state changes as we did above, the
 value `42` will be printed. Again, this is because it's not in the global
 namespace:: 
 
   do()
 
 Running a file with the above code can lead to the following session::
 
   >>> do()
   42
   Python 3.6.2 (default, Jul 17 2017, 16:44:45) 
   Type 'copyright', 'credits' or 'license' for more information
   IPython 6.2.0.dev -- An enhanced Interactive Python. Type '?' for help.
 
   In [1]: a = 23
 
   In [2]: exit()
   42
 
 .. note::
 
   At present, embedding IPython cannot be done from inside IPython.
   Run the code samples below outside IPython.
 
 This feature allows you to easily have a fully functional python
 environment for doing object introspection anywhere in your code with a
 simple function call. In some cases a simple print statement is enough,
 but if you need to do more detailed analysis of a code fragment this
 feature can be very valuable.
 
 It can also be useful in scientific computing situations where it is
 common to need to do some automatic, computationally intensive part and
 then stop to look at data, plots, etc.
 Opening an IPython instance will give you full access to your data and
 functions, and you can resume program execution once you are done with
 the interactive part (perhaps to stop again later, as many times as
 needed).
 
 The following code snippet is the bare minimum you need to include in
 your Python programs for this to work (detailed examples follow later)::
 
     from IPython import embed
 
     embed() # this call anywhere in your program will start IPython
 
 You can also embed an IPython *kernel*, for use with qtconsole, etc. via
 ``IPython.embed_kernel()``. This should function work the same way, but you can
 connect an external frontend (``ipython qtconsole`` or ``ipython console``),
 rather than interacting with it in the terminal.
 
 You can run embedded instances even in code which is itself being run at
 the IPython interactive prompt with '%run <filename>'. Since it's easy
 to get lost as to where you are (in your top-level IPython or in your
 embedded one), it's a good idea in such cases to set the in/out prompts
 to something different for the embedded instances. The code examples
 below illustrate this.
 
 You can also have multiple IPython instances in your program and open
 them separately, for example with different options for data
 presentation. If you close and open the same instance multiple times,
 its prompt counters simply continue from each execution to the next.
 
 Please look at the docstrings in the :mod:`~IPython.frontend.terminal.embed`
 module for more details on the use of this system.
 
 The following sample file illustrating how to use the embedding
 functionality is provided in the examples directory as embed_class_long.py.
 It should be fairly self-explanatory:
 
 .. literalinclude:: ../../../examples/Embedding/embed_class_long.py
     :language: python
 
 Once you understand how the system functions, you can use the following
 code fragments in your programs which are ready for cut and paste:
 
 .. literalinclude:: ../../../examples/Embedding/embed_class_short.py
     :language: python
 
 Using the Python debugger (pdb)
 ===============================
 
 Running entire programs via pdb
 -------------------------------
 
 pdb, the Python debugger, is a powerful interactive debugger which
 allows you to step through code, set breakpoints, watch variables,
 etc.  IPython makes it very easy to start any script under the control
 of pdb, regardless of whether you have wrapped it into a 'main()'
 function or not. For this, simply type ``%run -d myscript`` at an
 IPython prompt. See the :magic:`run` command's documentation for more details, including
 how to control where pdb will stop execution first.
 
 For more information on the use of the pdb debugger, see :ref:`debugger-commands`
 in the Python documentation.
 
 IPython extends the debugger with a few useful additions, like coloring of
 tracebacks. The debugger will adopt the color scheme selected for IPython.
 
 The ``where`` command has also been extended to take as argument the number of
 context line to show. This allows to a many line of context on shallow stack trace:
 
 .. code::
 
     In [5]: def foo(x):
     ...:     1
     ...:     2
     ...:     3
     ...:     return 1/x+foo(x-1)
     ...:     5
     ...:     6
     ...:     7
     ...:
 
     In[6]: foo(1)
     # ...
     ipdb> where 8
-    <ipython-input-6-9e45007b2b59>(1)<module>()
+    <ipython-input-6-9e45007b2b59>(1)<module>
     ----> 1 foo(1)
 
     <ipython-input-5-7baadc3d1465>(5)foo()
         1 def foo(x):
         2     1
         3     2
         4     3
     ----> 5     return 1/x+foo(x-1)
         6     5
         7     6
         8     7
 
     > <ipython-input-5-7baadc3d1465>(5)foo()
         1 def foo(x):
         2     1
         3     2
         4     3
     ----> 5     return 1/x+foo(x-1)
         6     5
         7     6
         8     7
 
 
 And less context on shallower Stack Trace:
 
 .. code::
 
     ipdb> where 1
-    <ipython-input-13-afa180a57233>(1)<module>()
+    <ipython-input-13-afa180a57233>(1)<module>
     ----> 1 foo(7)
 
     <ipython-input-5-7baadc3d1465>(5)foo()
     ----> 5     return 1/x+foo(x-1)
 
     <ipython-input-5-7baadc3d1465>(5)foo()
     ----> 5     return 1/x+foo(x-1)
 
     <ipython-input-5-7baadc3d1465>(5)foo()
     ----> 5     return 1/x+foo(x-1)
 
     <ipython-input-5-7baadc3d1465>(5)foo()
     ----> 5     return 1/x+foo(x-1)
 
 
 Post-mortem debugging
 ---------------------
 
 Going into a debugger when an exception occurs can be
 extremely useful in order to find the origin of subtle bugs, because pdb
 opens up at the point in your code which triggered the exception, and
 while your program is at this point 'dead', all the data is still
 available and you can walk up and down the stack frame and understand
 the origin of the problem.
 
 You can use the :magic:`debug` magic after an exception has occurred to start
 post-mortem debugging. IPython can also call debugger every time your code
 triggers an uncaught exception. This feature can be toggled with the :magic:`pdb` magic
 command, or you can start IPython with the ``--pdb`` option.
 
 For a post-mortem debugger in your programs outside IPython,
 put the following lines toward the top of your 'main' routine::
 
     import sys
     from IPython.core import ultratb
     sys.excepthook = ultratb.FormattedTB(mode='Verbose',
     color_scheme='Linux', call_pdb=1)
 
 The mode keyword can be either 'Verbose' or 'Plain', giving either very
 detailed or normal tracebacks respectively. The color_scheme keyword can
 be one of 'NoColor', 'Linux' (default) or 'LightBG'. These are the same
 options which can be set in IPython with ``--colors`` and ``--xmode``.
 
 This will give any of your programs detailed, colored tracebacks with
 automatic invocation of pdb.
 
 .. _pasting_with_prompts:
 
 Pasting of code starting with Python or IPython prompts
 =======================================================
 
 IPython is smart enough to filter out input prompts, be they plain Python ones
 (``>>>`` and ``...``) or IPython ones (``In [N]:`` and ``...:``).  You can
 therefore copy and paste from existing interactive sessions without worry.
 
 The following is a 'screenshot' of how things work, copying an example from the
 standard Python tutorial::
 
     In [1]: >>> # Fibonacci series:
 
     In [2]: ... # the sum of two elements defines the next
 
     In [3]: ... a, b = 0, 1
 
     In [4]: >>> while b < 10:
        ...:     ...     print(b)
        ...:     ...     a, b = b, a+b
        ...:
     1
     1
     2
     3
     5
     8
 
 And pasting from IPython sessions works equally well::
 
     In [1]: In [5]: def f(x):
        ...:        ...:     "A simple function"
        ...:        ...:     return x**2
        ...:    ...:
 
     In [2]: f(3)
     Out[2]: 9
 
 .. _gui_support:
 
 GUI event loop support
 ======================
 
 IPython has excellent support for working interactively with Graphical User
 Interface (GUI) toolkits, such as wxPython, PyQt4/PySide, PyGTK and Tk. This is
 implemented by running the toolkit's event loop while IPython is waiting for
 input.
 
 For users, enabling GUI event loop integration is simple.  You simple use the
 :magic:`gui` magic as follows::
 
     %gui [GUINAME]
 
 With no arguments, ``%gui`` removes all GUI support.  Valid ``GUINAME``
 arguments include ``wx``, ``qt``, ``qt5``, ``gtk``, ``gtk3`` and ``tk``.
 
 Thus, to use wxPython interactively and create a running :class:`wx.App`
 object, do::
 
     %gui wx
 
 You can also start IPython with an event loop set up using the `--gui`
 flag::
 
     $ ipython --gui=qt
 
 For information on IPython's matplotlib_ integration (and the ``matplotlib``
 mode) see :ref:`this section <matplotlib_support>`.
 
 For developers that want to integrate additional event loops with IPython, see
 :doc:`/config/eventloops`.
 
 When running inside IPython with an integrated event loop, a GUI application
 should *not* start its own event loop. This means that applications that are
 meant to be used both
 in IPython and as standalone apps need to have special code to detects how the
 application is being run. We highly recommend using IPython's support for this.
 Since the details vary slightly between toolkits, we point you to the various
 examples in our source directory :file:`examples/IPython Kernel/gui/` that
 demonstrate these capabilities.
 
 PyQt and PySide
 ---------------
 
 .. attempt at explanation of the complete mess that is Qt support
 
 When you use ``--gui=qt`` or ``--matplotlib=qt``, IPython can work with either
 PyQt4 or PySide.  There are three options for configuration here, because
 PyQt4 has two APIs for QString and QVariant: v1, which is the default on
 Python 2, and the more natural v2, which is the only API supported by PySide.
 v2 is also the default for PyQt4 on Python 3.  IPython's code for the QtConsole
 uses v2, but you can still use any interface in your code, since the
 Qt frontend is in a different process.
 
 The default will be to import PyQt4 without configuration of the APIs, thus
 matching what most applications would expect. It will fall back to PySide if
 PyQt4 is unavailable.
 
 If specified, IPython will respect the environment variable ``QT_API`` used
 by ETS.  ETS 4.0 also works with both PyQt4 and PySide, but it requires
 PyQt4 to use its v2 API.  So if ``QT_API=pyside`` PySide will be used,
 and if ``QT_API=pyqt`` then PyQt4 will be used *with the v2 API* for
 QString and QVariant, so ETS codes like MayaVi will also work with IPython.
 
 If you launch IPython in matplotlib mode with ``ipython --matplotlib=qt``,
 then IPython will ask matplotlib which Qt library to use (only if QT_API is
 *not set*), via the 'backend.qt4' rcParam.  If matplotlib is version 1.0.1 or
 older, then IPython will always use PyQt4 without setting the v2 APIs, since
 neither v2 PyQt nor PySide work.
 
 .. warning::
 
     Note that this means for ETS 4 to work with PyQt4, ``QT_API`` *must* be set
     to work with IPython's qt integration, because otherwise PyQt4 will be
     loaded in an incompatible mode.
 
     It also means that you must *not* have ``QT_API`` set if you want to
     use ``--gui=qt`` with code that requires PyQt4 API v1.
 
 
 .. _matplotlib_support:
 
 Plotting with matplotlib
 ========================
 
 matplotlib_ provides high quality 2D and 3D plotting for Python. matplotlib_
 can produce plots on screen using a variety of GUI toolkits, including Tk,
 PyGTK, PyQt4 and wxPython. It also provides a number of commands useful for
 scientific computing, all with a syntax compatible with that of the popular
 Matlab program.
 
 To start IPython with matplotlib support, use the ``--matplotlib`` switch. If
 IPython is already running, you can run the :magic:`matplotlib` magic.  If no
 arguments are given, IPython will automatically detect your choice of
 matplotlib backend.  You can also request a specific backend with
 ``%matplotlib backend``, where ``backend`` must be one of: 'tk', 'qt', 'wx',
 'gtk', 'osx'.  In the web notebook and Qt console, 'inline' is also a valid
 backend value, which produces static figures inlined inside the application
 window instead of matplotlib's interactive figures that live in separate
 windows.
 
 .. _interactive_demos:
 
 Interactive demos with IPython
 ==============================
 
 IPython ships with a basic system for running scripts interactively in
 sections, useful when presenting code to audiences. A few tags embedded
 in comments (so that the script remains valid Python code) divide a file
 into separate blocks, and the demo can be run one block at a time, with
 IPython printing (with syntax highlighting) the block before executing
 it, and returning to the interactive prompt after each block. The
 interactive namespace is updated after each block is run with the
 contents of the demo's namespace.
 
 This allows you to show a piece of code, run it and then execute
 interactively commands based on the variables just created. Once you
 want to continue, you simply execute the next block of the demo. The
 following listing shows the markup necessary for dividing a script into
 sections for execution as a demo:
 
 .. literalinclude:: ../../../examples/IPython Kernel/example-demo.py
     :language: python
 
 In order to run a file as a demo, you must first make a Demo object out
 of it. If the file is named myscript.py, the following code will make a
 demo::
 
     from IPython.lib.demo import Demo
 
     mydemo = Demo('myscript.py')
 
 This creates the mydemo object, whose blocks you run one at a time by
 simply calling the object with no arguments. Then call it to run each step
 of the demo::
 
     mydemo()
 
 Demo objects can be
 restarted, you can move forward or back skipping blocks, re-execute the
 last block, etc. See the :mod:`IPython.lib.demo` module and the
 :class:`~IPython.lib.demo.Demo` class for details.
 
 Limitations: These demos are limited to
 fairly simple uses. In particular, you cannot break up sections within
 indented code (loops, if statements, function definitions, etc.)
 Supporting something like this would basically require tracking the
 internal execution state of the Python interpreter, so only top-level
 divisions are allowed. If you want to be able to open an IPython
 instance at an arbitrary point in a program, you can use IPython's
 :ref:`embedding facilities <Embedding>`.
 
 .. include:: ../links.txt