Rename history retrieval methods, and improve docstrings.

IPython/core/history.py

@@ -1,667 +1,709 b''
 """ History related magics and functionality """
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010 The IPython Development Team.
 #
 #  Distributed under the terms of the BSD License.
 #
 #  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from __future__ import print_function
 
 # Stdlib imports
 import datetime
 import json
 import os
 import re
 import sqlite3
 
 from collections import defaultdict
 
 # Our own packages
 from IPython.config.configurable import Configurable
 import IPython.utils.io
 
 from IPython.testing import decorators as testdec
 from IPython.utils.io import ask_yes_no
 from IPython.utils.traitlets import Bool, Dict, Instance, Int, List, Unicode
 from IPython.utils.warn import warn
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 class HistoryManager(Configurable):
     """A class to organize all history-related functionality in one place.
     """
     # Public interface
 
     # An instance of the IPython shell we are attached to
     shell = Instance('IPython.core.interactiveshell.InteractiveShellABC')
     # Lists to hold processed and raw history. These start with a blank entry
     # so that we can index them starting from 1
     input_hist_parsed = List([""])
     input_hist_raw = List([""])
     # A list of directories visited during session
     dir_hist = List()
     # A dict of output history, keyed with ints from the shell's
     # execution count. If there are several outputs from one command,
     # only the last one is stored.
     output_hist = Dict()
     # Contains all outputs, in lists of reprs.
     output_hist_reprs = Instance(defaultdict)
     
     # String holding the path to the history file
     hist_file = Unicode()
     # The SQLite database
     db = Instance(sqlite3.Connection)
     # The number of the current session in the history database
     session_number = Int()
     # Should we log output to the database? (default no)
     db_log_output = Bool(False, config=True)
     # Write to database every x commands (higher values save disk access & power)
     #  Values of 1 or less effectively disable caching. 
     db_cache_size = Int(0, config=True)
     # The input and output caches
     db_input_cache = List()
     db_output_cache = List()
     
     # Private interface
     # Variables used to store the three last inputs from the user.  On each new
     # history update, we populate the user's namespace with these, shifted as
     # necessary.
     _i00, _i, _ii, _iii = '','','',''
 
     # A set with all forms of the exit command, so that we don't store them in
     # the history (it's annoying to rewind the first entry and land on an exit
     # call).
     _exit_commands = None
     
     def __init__(self, shell, config=None):
         """Create a new history manager associated with a shell instance.
         """
         # We need a pointer back to the shell for various tasks.
         super(HistoryManager, self).__init__(shell=shell, config=config)
 
         # list of visited directories
         try:
             self.dir_hist = [os.getcwd()]
         except OSError:
             self.dir_hist = []
 
         # Now the history file
         if shell.profile:
             histfname = 'history-%s' % shell.profile
         else:
             histfname = 'history'
         self.hist_file = os.path.join(shell.ipython_dir, histfname + '.sqlite')
         self.init_db()
         self.new_session()
     
         self._i00, self._i, self._ii, self._iii = '','','',''
         self.output_hist_reprs = defaultdict(list)
 
         self._exit_commands = set(['Quit', 'quit', 'Exit', 'exit', '%Quit',
                                    '%quit', '%Exit', '%exit'])
         
     def init_db(self):
         """Connect to the database, and create tables if necessary."""
         self.db = sqlite3.connect(self.hist_file)
         self.db.execute("""CREATE TABLE IF NOT EXISTS sessions (session integer
                         primary key autoincrement, start timestamp,
                         end timestamp, num_cmds integer, remark text)""")
         self.db.execute("""CREATE TABLE IF NOT EXISTS history 
                 (session integer, line integer, source text, source_raw text,
                 PRIMARY KEY (session, line))""")
         # Output history is optional, but ensure the table's there so it can be
         # enabled later.
         self.db.execute("""CREATE TABLE IF NOT EXISTS output_history
                         (session integer, line integer, output text,
                         PRIMARY KEY (session, line))""")
         self.db.commit()
     
     def new_session(self):
         """Get a new session number."""
         with self.db:
             cur = self.db.execute("""INSERT INTO sessions VALUES (NULL, ?, NULL,
                             NULL, "") """, (datetime.datetime.now(),))
             self.session_number = cur.lastrowid
             
     def end_session(self):
         """Close the database session, filling in the end time and line count."""
         self.writeout_cache()
         with self.db:
             self.db.execute("""UPDATE sessions SET end=?, num_cmds=? WHERE
                             session==?""", (datetime.datetime.now(),
                             len(self.input_hist_parsed)-1, self.session_number))
         self.session_number = 0
                             
     def name_session(self, name):
         """Give the current session a name in the history database."""
         with self.db:
             self.db.execute("UPDATE sessions SET remark=? WHERE session==?",
                             (name, self.session_number))
                             
     def reset(self, new_session=True):
         """Clear the session history, releasing all object references, and
         optionally open a new session."""
         if self.session_number:
             self.end_session()
         self.input_hist_parsed[:] = [""]
         self.input_hist_raw[:] = [""]
         self.output_hist.clear()
         # The directory history can't be completely empty
         self.dir_hist[:] = [os.getcwd()]
         
         if new_session:
             self.new_session()
     
     ## -------------------------------
     ## Methods for retrieving history:
     ## -------------------------------
-    def _get_hist_sql(self, sql, params, raw=True, output=False):
+    def _run_sql(self, sql, params, raw=True, output=False):
         """Prepares and runs an SQL query for the history database.
         
         Parameters
         ----------
         sql : str
           Any filtering expressions to go after SELECT ... FROM ...
         params : tuple
           Parameters passed to the SQL query (to replace "?")
-        raw : bool
-          If True, get raw input.
-        output : bool
-          If True, include output where available.
+        raw, output : bool
+          See :meth:`get_range`
         
         Returns
         -------
-        An iterator over 3-tuples: (session, line_number, command), or if output
-        is True, (session, line_number, (command, output)).
+        Tuples as :meth:`get_range`
         """
         toget = 'source_raw' if raw else 'source'
         sqlfrom = "history"
         if output:
             sqlfrom = "history LEFT JOIN output_history USING (session, line)"
             toget = "history.%s, output_history.output" % toget
         cur = self.db.execute("SELECT session, line, %s FROM %s " %\
                                 (toget, sqlfrom) + sql, params)
         if output:    # Regroup into 3-tuples, and parse JSON
             loads = lambda out: json.loads(out) if out else None
             return ((ses, lin, (inp, loads(out))) \
                                         for ses, lin, inp, out in cur)
         return cur
         
     
-    def get_hist_tail(self, n=10, raw=True, output=False, include_latest=False):
+    def get_tail(self, n=10, raw=True, output=False, include_latest=False):
         """Get the last n lines from the history database.
         
-        If include_latest is False (default), n+1 lines are fetched, and
-        the latest one is discarded. This is intended to be used where
-        the function is called by a user command, which it should not
-        return."""
+        Parameters
+        ----------
+        n : int
+          The number of lines to get
+        raw, output : bool
+          See :meth:`get_range`
+        include_latest : bool
+          If False (default), n+1 lines are fetched, and the latest one
+          is discarded. This is intended to be used where the function
+          is called by a user command, which it should not return.
+        
+        Returns
+        -------
+        Tuples as :meth:`get_range`
+        """
         self.writeout_cache()
         if not include_latest:
             n += 1
-        cur = self._get_hist_sql("ORDER BY session DESC, line DESC LIMIT ?",
+        cur = self._run_sql("ORDER BY session DESC, line DESC LIMIT ?",
                                 (n,), raw=raw, output=output)
         if not include_latest:
             return reversed(list(cur)[1:])
         return reversed(list(cur))
         
-    def get_hist_search(self, pattern="*", raw=True, search_raw=True,
+    def search(self, pattern="*", raw=True, search_raw=True,
                                                         output=False):
         """Search the database using unix glob-style matching (wildcards
         * and ?).
         
+        Parameters
+        ----------
+        pattern : str
+          The wildcarded pattern to match when searching
+        search_raw : bool
+          If True, search the raw input, otherwise, the parsed input
+        raw, output : bool
+          See :meth:`get_range`
+        
         Returns
         -------
-        An iterator over tuples: (session, line_number, command)
+        Tuples as :meth:`get_range`
         """
         tosearch = "source_raw" if search_raw else "source"
         if output:
             tosearch = "history." + tosearch
         self.writeout_cache()
-        return self._get_hist_sql("WHERE %s GLOB ?" % tosearch, (pattern,),
+        return self._run_sql("WHERE %s GLOB ?" % tosearch, (pattern,),
                                     raw=raw, output=output)
                                 
-    def _get_hist_session(self, start=1, stop=None, raw=True, output=False):
+    def _get_range_session(self, start=1, stop=None, raw=True, output=False):
         """Get input and output history from the current session. Called by
-        get_history, and takes similar parameters."""
+        get_range, and takes similar parameters."""
         input_hist = self.input_hist_raw if raw else self.input_hist_parsed
             
         n = len(input_hist)
         if start < 0:
             start += n
         if not stop:
             stop = n
         elif stop < 0:
             stop += n
         
         for i in range(start, stop):
             if output:
                 line = (input_hist[i], self.output_hist_reprs.get(i))
             else:
                 line = input_hist[i]
             yield (0, i, line)
             
-    def get_history(self, session=0, start=1, stop=None, raw=True,output=False):
+    def get_range(self, session=0, start=1, stop=None, raw=True,output=False):
         """Retrieve input by session.
         
         Parameters
         ----------
         session : int
             Session number to retrieve. The current session is 0, and negative
             numbers count back from current session, so -1 is previous session.
         start : int
             First line to retrieve.
         stop : int
             End of line range (excluded from output itself). If None, retrieve
             to the end of the session.
         raw : bool
             If True, return untranslated input
         output : bool
             If True, attempt to include output. This will be 'real' Python
             objects for the current session, or text reprs from previous
             sessions if db_log_output was enabled at the time. Where no output
             is found, None is used.
             
         Returns
         -------
         An iterator over the desired lines. Each line is a 3-tuple, either
         (session, line, input) if output is False, or
         (session, line, (input, output)) if output is True.
         """
         if session == 0 or session==self.session_number:   # Current session
-            return self._get_hist_session(start, stop, raw, output)
+            return self._get_range_session(start, stop, raw, output)
         if session < 0:
             session += self.session_number
             
         if stop:
             lineclause = "line >= ? AND line < ?"
             params = (session, start, stop)
         else:
             lineclause = "line>=?"
             params = (session, start)
         
-        return self._get_hist_sql("WHERE session==? AND %s""" % lineclause,
+        return self._run_sql("WHERE session==? AND %s""" % lineclause,
                                     params, raw=raw, output=output)
         
-    def get_hist_from_rangestr(self, rangestr, raw=True, output=False):
+    def get_range_by_str(self, rangestr, raw=True, output=False):
         """Get lines of history from a string of ranges, as used by magic
-        commands %hist, %save, %macro, etc."""
+        commands %hist, %save, %macro, etc.
+        
+        Parameters
+        ----------
+        rangestr : str
+          A string specifying ranges, e.g. "5 ~2/1-4". See
+          :func:`magic_history` for full details.
+        raw, output : bool
+          As :meth:`get_range`
+          
+        Returns
+        -------
+        Tuples as :meth:`get_range`
+        """
         for sess, s, e in extract_hist_ranges(rangestr):
-            for line in self.get_history(sess, s, e, raw=raw, output=output):
+            for line in self.get_range(sess, s, e, raw=raw, output=output):
                 yield line
     
     ## ----------------------------
     ## Methods for storing history:
     ## ----------------------------
     def store_inputs(self, line_num, source, source_raw=None):
         """Store source and raw input in history and create input cache
         variables _i*.
         
         Parameters
         ----------
         line_num : int
           The prompt number of this input.
         
         source : str
           Python input.
 
         source_raw : str, optional
           If given, this is the raw input without any IPython transformations
           applied to it.  If not given, ``source`` is used.
         """
         if source_raw is None:
             source_raw = source
         source = source.rstrip('\n')
         source_raw = source_raw.rstrip('\n')
             
         # do not store exit/quit commands
         if source_raw.strip() in self._exit_commands:
             return
         
         self.input_hist_parsed.append(source)
         self.input_hist_raw.append(source_raw)
         
         self.db_input_cache.append((self.session_number, line_num,
                                     source, source_raw))
         # Trigger to flush cache and write to DB.
         if len(self.db_input_cache) >= self.db_cache_size:
             self.writeout_cache()
 
         # update the auto _i variables
         self._iii = self._ii
         self._ii = self._i
         self._i = self._i00
         self._i00 = source_raw
 
         # hackish access to user namespace to create _i1,_i2... dynamically
         new_i = '_i%s' % line_num
         to_main = {'_i': self._i,
                    '_ii': self._ii,
                    '_iii': self._iii,
                    new_i : self._i00 }
         self.shell.user_ns.update(to_main)
         
     def store_output(self, line_num):
         """If database output logging is enabled, this saves all the
         outputs from the indicated prompt number to the database. It's
-        called by run_cell after code has been executed."""
+        called by run_cell after code has been executed.
+        
+        Parameters
+        ----------
+        line_num : int
+          The line number from which to save outputs
+        """
         if (not self.db_log_output) or not self.output_hist_reprs[line_num]:
             return
         output = json.dumps(self.output_hist_reprs[line_num])
         db_row = (self.session_number, line_num, output)
         if self.db_cache_size > 1:
             self.db_output_cache.append(db_row)
         else:
           with self.db:
             self.db.execute("INSERT INTO output_history VALUES (?,?,?)", db_row)
         
     def writeout_cache(self):
         #print(self.db_input_cache)
         with self.db:
             self.db.executemany("INSERT INTO history VALUES (?, ?, ?, ?)",
                                 self.db_input_cache)
             self.db.executemany("INSERT INTO output_history VALUES (?, ?, ?)",
                                 self.db_output_cache)
         self.db_input_cache = []
         self.db_output_cache = []
 
         
 # To match, e.g. ~5/8-~2/3
 range_re = re.compile(r"""
 ((?P<startsess>~?\d+)/)?
 (?P<start>\d+)                    # Only the start line num is compulsory
 ((?P<sep>[\-:])
  ((?P<endsess>~?\d+)/)?
  (?P<end>\d+))?
 """, re.VERBOSE)
 
 def extract_hist_ranges(ranges_str):
     """Turn a string of history ranges into 3-tuples of (session, start, stop).
     
     Examples
     --------
     list(extract_input_ranges("~8/5-~7/4 2"))
     [(-8, 5, None), (-7, 1, 4), (0, 2, 3)]
     """
     for range_str in ranges_str.split():
         rmatch = range_re.match(range_str)
         if not rmatch:
             continue
         start = int(rmatch.group("start"))
         end = rmatch.group("end")
         end = int(end) if end else start+1   # If no end specified, get (a, a+1)
         if rmatch.group("sep") == "-":       # 1-3 == 1:4 --> [1, 2, 3]
             end += 1
         startsess = rmatch.group("startsess") or "0"
         endsess = rmatch.group("endsess") or startsess
         startsess = int(startsess.replace("~","-"))
         endsess = int(endsess.replace("~","-"))
         assert endsess >= startsess
 
         if endsess == startsess:
             yield (startsess, start, end)
             continue
         # Multiple sessions in one range:
         yield (startsess, start, None)
         for sess in range(startsess+1, endsess):
             yield (sess, 1, None)
         yield (endsess, 1, end)
 
 def _format_lineno(session, line):
     """Helper function to format line numbers properly."""
     if session == 0:
         return str(line)
     return "%s#%s" % (session, line)
 
 @testdec.skip_doctest
 def magic_history(self, parameter_s = ''):
     """Print input history (_i<n> variables), with most recent last.
     
     %history       -> print at most 40 inputs (some may be multi-line)\\
     %history n     -> print at most n inputs\\
     %history n1 n2 -> print inputs between n1 and n2 (n2 not included)\\
 
     By default, input history is printed without line numbers so it can be
-    directly pasted into an editor.
-
-    With -n, each input's number <n> is shown, and is accessible as the
-    automatically generated variable _i<n> as well as In[<n>].  Multi-line
-    statements are printed starting at a new line for easy copy/paste.
+    directly pasted into an editor. Use -n to show them.
+
+    Ranges of history can be indicated using the syntax:
+    4      : Line 4, current session
+    4-6    : Lines 4-6, current session
+    243/1-5: Lines 1-5, session 243
+    ~2/7   : Line 7, session 2 before current
+    ~8/1-~6/5 : From the first line of 8 sessions ago, to the fifth line
+                of 6 sessions ago.
+    Multiple ranges can be entered, separated by spaces
+    
+    The same syntax is used by %macro, %save, %edit, %rerun
 
     Options:
 
       -n: print line numbers for each input.
       This feature is only available if numbered prompts are in use.
 
       -o: also print outputs for each input.
 
       -p: print classic '>>>' python prompts before each input.  This is useful
        for making documentation, and in conjunction with -o, for producing
        doctest-ready output.
 
       -r: (default) print the 'raw' history, i.e. the actual commands you typed.
       
       -t: print the 'translated' history, as IPython understands it.  IPython
       filters your input and converts it all into valid Python source before
       executing it (things like magics or aliases are turned into function
       calls, for example). With this option, you'll see the native history
       instead of the user-entered version: '%cd /' will be seen as
       'get_ipython().magic("%cd /")' instead of '%cd /'.
       
       -g: treat the arg as a pattern to grep for in (full) history.
       This includes the saved history (almost all commands ever written).
       Use '%hist -g' to show full saved history (may be very long).
       
       -l: get the last n lines from all sessions. Specify n as a single arg, or
       the default is the last 10 lines.
 
       -f FILENAME: instead of printing the output to the screen, redirect it to
        the given file.  The file is always overwritten, though IPython asks for
        confirmation first if it already exists.
        
     Examples
     --------
     ::
     
       In [6]: %hist -n 4 6
       4:a = 12
       5:print a**2
 
     """
 
     if not self.shell.displayhook.do_full_cache:
         print('This feature is only available if numbered prompts are in use.')
         return
     opts,args = self.parse_options(parameter_s,'noprtglf:',mode='string')
     
     # For brevity
     history_manager = self.shell.history_manager
     
     def _format_lineno(session, line):
         """Helper function to format line numbers properly."""
         if session in (0, history_manager.session_number):
             return str(line)
         return "%s/%s" % (session, line)
 
     # Check if output to specific file was requested.
     try:
         outfname = opts['f']
     except KeyError:
         outfile = IPython.utils.io.Term.cout  # default
         # We don't want to close stdout at the end!
         close_at_end = False
     else:
         if os.path.exists(outfname):
             if not ask_yes_no("File %r exists. Overwrite?" % outfname): 
                 print('Aborting.')
                 return
 
         outfile = open(outfname,'w')
         close_at_end = True
     
     print_nums = 'n' in opts
     get_output = 'o' in opts
     pyprompts = 'p' in opts
     # Raw history is the default
     raw = not('t' in opts)
             
     default_length = 40
     pattern = None
     
     if 'g' in opts:         # Glob search
         pattern = "*" + args + "*" if args else "*"
-        hist = history_manager.get_hist_search(pattern, raw=raw,
-                                                              output=get_output)
+        hist = history_manager.search(pattern, raw=raw, output=get_output)
     elif 'l' in opts:       # Get 'tail'
         try:
             n = int(args)
         except ValueError, IndexError:
             n = 10
-        hist = history_manager.get_hist_tail(n, raw=raw, output=get_output)
+        hist = history_manager.get_tail(n, raw=raw, output=get_output)
     else:
         if args:            # Get history by ranges
-            hist = history_manager.get_hist_from_rangestr(args, raw, get_output)
+            hist = history_manager.get_range_by_str(args, raw, get_output)
         else:               # Just get history for the current session
-            hist = history_manager.get_history(raw=raw, output=get_output)
+            hist = history_manager.get_range(raw=raw, output=get_output)
     
     # We could be displaying the entire history, so let's not try to pull it 
     # into a list in memory. Anything that needs more space will just misalign.
     width = 4
         
     for session, lineno, inline in hist:
         # Print user history with tabs expanded to 4 spaces.  The GUI clients
         # use hard tabs for easier usability in auto-indented code, but we want
         # to produce PEP-8 compliant history for safe pasting into an editor.
         if get_output:
             inline, output = inline
         inline = inline.expandtabs(4).rstrip()
             
         multiline = "\n" in inline
         line_sep = '\n' if multiline else ' '
         if print_nums:
             print('%s:%s' % (_format_lineno(session, lineno).rjust(width),
                     line_sep),  file=outfile, end='')
         if pyprompts:
             print(">>> ", end="", file=outfile)
             if multiline:
                 inline = "\n... ".join(inline.splitlines()) + "\n..."
         print(inline, file=outfile)
         if get_output and output:
             print("\n".join(output), file=outfile)
 
     if close_at_end:
         outfile.close()
 
 
 def magic_rep(self, arg):
     r""" Repeat a command, or get command to input line for editing
 
     - %rep (no arguments):
     
     Place a string version of last computation result (stored in the special '_'
     variable) to the next input prompt. Allows you to create elaborate command
     lines without using copy-paste::
     
          In[1]: l = ["hei", "vaan"]
          In[2]: "".join(l)
         Out[2]: heivaan
          In[3]: %rep
          In[4]: heivaan_ <== cursor blinking
     
     %rep 45
     
     Place history line 45 on the next input prompt. Use %hist to find
     out the number.
     
-    %rep 1-4 6-7 3
+    %rep 1-4
     
     Combine the specified lines into one cell, and place it on the next
-    input prompt. History slice syntax is the same as in %macro and %save.
+    input prompt. See %history for the slice syntax.
     
     %rep foo+bar
     
     If foo+bar can be evaluated in the user namespace, the result is
     placed at the next input prompt. Otherwise, the history is searched
     for lines which contain that substring, and the most recent one is
     placed at the next input prompt.
     """
     if not arg:                 # Last output
         self.set_next_input(str(self.shell.user_ns["_"]))
         return
                                 # Get history range
-    histlines = self.history_manager.get_hist_from_rangestr(arg)
+    histlines = self.history_manager.get_range_by_str(arg)
     cmd = "\n".join(x[2] for x in histlines)
     if cmd:
         self.set_next_input(cmd.rstrip())
         return
 
     try:                        # Variable in user namespace
         cmd = str(eval(arg, self.shell.user_ns))
     except Exception:           # Search for term in history
-        histlines = self.history_manager.get_hist_search("*"+arg+"*")
+        histlines = self.history_manager.search("*"+arg+"*")
         for h in reversed([x[2] for x in histlines]):
             if 'rep' in h:
                 continue
             self.set_next_input(h.rstrip())
             return
     else:
         self.set_next_input(cmd.rstrip())
     print("Couldn't evaluate or find in history:", arg)
         
 def magic_rerun(self, parameter_s=''):
     """Re-run previous input
     
     By default, you can specify ranges of input history to be repeated
-    (as with %hist). With no arguments, it will repeat the last line.
+    (as with %history). With no arguments, it will repeat the last line.
     
     Options:
     
       -l <n> : Repeat the last n lines of input, not including the
       current command.
       
       -g foo : Repeat the most recent line which contains foo
     """
     opts, args = self.parse_options(parameter_s, 'l:g:', mode='string')
     if "l" in opts:         # Last n lines
         n = int(opts['l'])
-        hist = self.history_manager.get_hist_tail(n)
+        hist = self.history_manager.get_tail(n)
     elif "g" in opts:       # Search
         p = "*"+opts['g']+"*"
-        hist = list(self.history_manager.get_hist_search(p))
+        hist = list(self.history_manager.search(p))
         for l in reversed(hist):
             if "rerun" not in l[2]:
                 hist = [l]     # The last match which isn't a %rerun
                 break
         else:
             hist = []          # No matches except %rerun
     elif args:              # Specify history ranges
-        hist = self.history_manager.get_hist_from_rangestr(args)
+        hist = self.history_manager.get_range_by_str(args)
     else:                   # Last line
-        hist = self.history_manager.get_hist_tail(1)
+        hist = self.history_manager.get_tail(1)
     hist = [x[2] for x in hist]
     if not hist:
         print("No lines in history match specification")
         return
     histlines = "\n".join(hist)
     print("=== Executing: ===")
     print(histlines)
     print("=== Output: ===")
     self.run_cell("\n".join(hist), store_history=False)
 
 
 def init_ipython(ip):
     ip.define_magic("rep", magic_rep) 
     ip.define_magic("recall", magic_rep)
     ip.define_magic("rerun", magic_rerun)
     ip.define_magic("hist",magic_history)    # Alternative name
     ip.define_magic("history",magic_history)
 
     # XXX - ipy_completers are in quarantine, need to be updated to new apis
     #import ipy_completers
     #ipy_completers.quick_completer('%hist' ,'-g -t -r -n')

IPython/core/interactiveshell.py

@@ -1,2527 +1,2527 b''
 # -*- coding: utf-8 -*-
 """Main IPython class."""
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2001 Janko Hauser <[e-mail]>
 #  Copyright (C) 2001-2007 Fernando Perez. <[e-mail]>
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from __future__ import with_statement
 from __future__ import absolute_import
 
 import __builtin__
 import __future__
 import abc
 import atexit
 import codeop
 import os
 import re
 import sys
 import tempfile
 import types
 from contextlib import nested
 
 from IPython.config.configurable import Configurable
 from IPython.core import debugger, oinspect
 from IPython.core import history as ipcorehist
 from IPython.core import page
 from IPython.core import prefilter
 from IPython.core import shadowns
 from IPython.core import ultratb
 from IPython.core.alias import AliasManager
 from IPython.core.builtin_trap import BuiltinTrap
 from IPython.core.compilerop import CachingCompiler
 from IPython.core.display_trap import DisplayTrap
 from IPython.core.displayhook import DisplayHook
 from IPython.core.displaypub import DisplayPublisher
 from IPython.core.error import TryNext, UsageError
 from IPython.core.extensions import ExtensionManager
 from IPython.core.fakemodule import FakeModule, init_fakemod_dict
 from IPython.core.formatters import DisplayFormatter
 from IPython.core.history import HistoryManager
 from IPython.core.inputsplitter import IPythonInputSplitter
 from IPython.core.logger import Logger
 from IPython.core.magic import Magic
 from IPython.core.payload import PayloadManager
 from IPython.core.plugin import PluginManager
 from IPython.core.prefilter import PrefilterManager, ESC_MAGIC
 from IPython.external.Itpl import ItplNS
 from IPython.utils import PyColorize
 from IPython.utils import io
 from IPython.utils.doctestreload import doctest_reload
 from IPython.utils.io import ask_yes_no, rprint
 from IPython.utils.ipstruct import Struct
 from IPython.utils.path import get_home_dir, get_ipython_dir, HomeDirError
 from IPython.utils.pickleshare import PickleShareDB
 from IPython.utils.process import system, getoutput
 from IPython.utils.strdispatch import StrDispatch
 from IPython.utils.syspathcontext import prepended_to_syspath
 from IPython.utils.text import num_ini_spaces, format_screen, LSString, SList
 from IPython.utils.traitlets import (Int, Str, CBool, CaselessStrEnum, Enum,
                                      List, Unicode, Instance, Type)
 from IPython.utils.warn import warn, error, fatal
 import IPython.core.hooks
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 # compiled regexps for autoindent management
 dedent_re = re.compile(r'^\s+raise|^\s+return|^\s+pass')
 
 #-----------------------------------------------------------------------------
 # Utilities
 #-----------------------------------------------------------------------------
 
 # store the builtin raw_input globally, and use this always, in case user code
 # overwrites it (like wx.py.PyShell does)
 raw_input_original = raw_input
 
 def softspace(file, newvalue):
     """Copied from code.py, to remove the dependency"""
 
     oldvalue = 0
     try:
         oldvalue = file.softspace
     except AttributeError:
         pass
     try:
         file.softspace = newvalue
     except (AttributeError, TypeError):
         # "attribute-less object" or "read-only attributes"
         pass
     return oldvalue
 
 
 def no_op(*a, **kw): pass
 
 class SpaceInInput(Exception): pass
 
 class Bunch: pass
 
 
 def get_default_colors():
     if sys.platform=='darwin':
         return "LightBG"
     elif os.name=='nt':
         return 'Linux'
     else:
         return 'Linux'
 
 
 class SeparateStr(Str):
     """A Str subclass to validate separate_in, separate_out, etc.
 
     This is a Str based trait that converts '0'->'' and '\\n'->'\n'.
     """
 
     def validate(self, obj, value):
         if value == '0': value = ''
         value = value.replace('\\n','\n')
         return super(SeparateStr, self).validate(obj, value)
 
 class MultipleInstanceError(Exception):
     pass
 
 
 #-----------------------------------------------------------------------------
 # Main IPython class
 #-----------------------------------------------------------------------------
 
 class InteractiveShell(Configurable, Magic):
     """An enhanced, interactive shell for Python."""
 
     _instance = None
     autocall = Enum((0,1,2), default_value=1, config=True)
     # TODO: remove all autoindent logic and put into frontends.
     # We can't do this yet because even runlines uses the autoindent.
     autoindent = CBool(True, config=True)
     automagic = CBool(True, config=True)
     cache_size = Int(1000, config=True)
     color_info = CBool(True, config=True)
     colors = CaselessStrEnum(('NoColor','LightBG','Linux'), 
                              default_value=get_default_colors(), config=True)
     debug = CBool(False, config=True)
     deep_reload = CBool(False, config=True)
     display_formatter = Instance(DisplayFormatter)
     displayhook_class = Type(DisplayHook)
     display_pub_class = Type(DisplayPublisher)
 
     exit_now = CBool(False)
     # Monotonically increasing execution counter
     execution_count = Int(1)
     filename = Str("<ipython console>")
     ipython_dir= Unicode('', config=True) # Set to get_ipython_dir() in __init__
 
     # Input splitter, to split entire cells of input into either individual
     # interactive statements or whole blocks.
     input_splitter = Instance('IPython.core.inputsplitter.IPythonInputSplitter',
                               (), {})
     logstart = CBool(False, config=True)
     logfile = Str('', config=True)
     logappend = Str('', config=True)
     object_info_string_level = Enum((0,1,2), default_value=0,
                                     config=True)
     pdb = CBool(False, config=True)
 
     profile = Str('', config=True)
     prompt_in1 = Str('In [\\#]: ', config=True)
     prompt_in2 = Str('   .\\D.: ', config=True)
     prompt_out = Str('Out[\\#]: ', config=True)
     prompts_pad_left = CBool(True, config=True)
     quiet = CBool(False, config=True)
 
     history_length = Int(10000, config=True)
     
     # The readline stuff will eventually be moved to the terminal subclass
     # but for now, we can't do that as readline is welded in everywhere.
     readline_use = CBool(True, config=True)
     readline_merge_completions = CBool(True, config=True)
     readline_omit__names = Enum((0,1,2), default_value=2, config=True)
     readline_remove_delims = Str('-/~', config=True)
     readline_parse_and_bind = List([
             'tab: complete',
             '"\C-l": clear-screen',
             'set show-all-if-ambiguous on',
             '"\C-o": tab-insert',
             '"\M-i": "    "',
             '"\M-o": "\d\d\d\d"',
             '"\M-I": "\d\d\d\d"',
             '"\C-r": reverse-search-history',
             '"\C-s": forward-search-history',
             '"\C-p": history-search-backward',
             '"\C-n": history-search-forward',
             '"\e[A": history-search-backward',
             '"\e[B": history-search-forward',
             '"\C-k": kill-line',
             '"\C-u": unix-line-discard',
         ], allow_none=False, config=True)
 
     # TODO: this part of prompt management should be moved to the frontends.
     # Use custom TraitTypes that convert '0'->'' and '\\n'->'\n'
     separate_in = SeparateStr('\n', config=True)
     separate_out = SeparateStr('', config=True)
     separate_out2 = SeparateStr('', config=True)
     wildcards_case_sensitive = CBool(True, config=True)
     xmode = CaselessStrEnum(('Context','Plain', 'Verbose'), 
                             default_value='Context', config=True)
 
     # Subcomponents of InteractiveShell
     alias_manager = Instance('IPython.core.alias.AliasManager')
     prefilter_manager = Instance('IPython.core.prefilter.PrefilterManager')
     builtin_trap = Instance('IPython.core.builtin_trap.BuiltinTrap')
     display_trap = Instance('IPython.core.display_trap.DisplayTrap')
     extension_manager = Instance('IPython.core.extensions.ExtensionManager')
     plugin_manager = Instance('IPython.core.plugin.PluginManager')
     payload_manager = Instance('IPython.core.payload.PayloadManager')
     history_manager = Instance('IPython.core.history.HistoryManager')
 
     # Private interface
     _post_execute = set()
 
     def __init__(self, config=None, ipython_dir=None,
                  user_ns=None, user_global_ns=None,
                  custom_exceptions=((), None)):
 
         # This is where traits with a config_key argument are updated
         # from the values on config.
         super(InteractiveShell, self).__init__(config=config)
 
         # These are relatively independent and stateless
         self.init_ipython_dir(ipython_dir)
         self.init_instance_attrs()
         self.init_environment()
 
         # Create namespaces (user_ns, user_global_ns, etc.)
         self.init_create_namespaces(user_ns, user_global_ns)
         # This has to be done after init_create_namespaces because it uses
         # something in self.user_ns, but before init_sys_modules, which
         # is the first thing to modify sys.
         # TODO: When we override sys.stdout and sys.stderr before this class
         # is created, we are saving the overridden ones here. Not sure if this
         # is what we want to do.
         self.save_sys_module_state()
         self.init_sys_modules()
         
         # While we're trying to have each part of the code directly access what
         # it needs without keeping redundant references to objects, we have too
         # much legacy code that expects ip.db to exist.
         self.db = PickleShareDB(os.path.join(self.ipython_dir, 'db'))
 
         self.init_history()
         self.init_encoding()
         self.init_prefilter()
 
         Magic.__init__(self, self)
 
         self.init_syntax_highlighting()
         self.init_hooks()
         self.init_pushd_popd_magic()
         # self.init_traceback_handlers use to be here, but we moved it below
         # because it and init_io have to come after init_readline.
         self.init_user_ns()
         self.init_logger()
         self.init_alias()
         self.init_builtins()
 
         # pre_config_initialization
 
         # The next section should contain everything that was in ipmaker.
         self.init_logstart()
 
         # The following was in post_config_initialization
         self.init_inspector()
         # init_readline() must come before init_io(), because init_io uses
         # readline related things.
         self.init_readline()
         # init_completer must come after init_readline, because it needs to
         # know whether readline is present or not system-wide to configure the
         # completers, since the completion machinery can now operate
         # independently of readline (e.g. over the network)
         self.init_completer()
         # TODO: init_io() needs to happen before init_traceback handlers
         # because the traceback handlers hardcode the stdout/stderr streams.
         # This logic in in debugger.Pdb and should eventually be changed.
         self.init_io()
         self.init_traceback_handlers(custom_exceptions)
         self.init_prompts()
         self.init_display_formatter()
         self.init_display_pub()
         self.init_displayhook()
         self.init_reload_doctest()
         self.init_magics()
         self.init_pdb()
         self.init_extension_manager()
         self.init_plugin_manager()
         self.init_payload()
         self.hooks.late_startup_hook()
         atexit.register(self.atexit_operations)
 
     @classmethod
     def instance(cls, *args, **kwargs):
         """Returns a global InteractiveShell instance."""
         if cls._instance is None:
             inst = cls(*args, **kwargs)
             # Now make sure that the instance will also be returned by
             # the subclasses instance attribute.
             for subclass in cls.mro():
                 if issubclass(cls, subclass) and \
                        issubclass(subclass, InteractiveShell):
                     subclass._instance = inst
                 else:
                     break
         if isinstance(cls._instance, cls):
             return cls._instance
         else:
             raise MultipleInstanceError(
                 'Multiple incompatible subclass instances of '
                 'InteractiveShell are being created.'
             )
 
     @classmethod
     def initialized(cls):
         return hasattr(cls, "_instance")
 
     def get_ipython(self):
         """Return the currently running IPython instance."""
         return self
 
     #-------------------------------------------------------------------------
     # Trait changed handlers
     #-------------------------------------------------------------------------
 
     def _ipython_dir_changed(self, name, new):
         if not os.path.isdir(new):
             os.makedirs(new, mode = 0777)
 
     def set_autoindent(self,value=None):
         """Set the autoindent flag, checking for readline support.
 
         If called with no arguments, it acts as a toggle."""
 
         if not self.has_readline:
             if os.name == 'posix':
                 warn("The auto-indent feature requires the readline library")
             self.autoindent = 0
             return
         if value is None:
             self.autoindent = not self.autoindent
         else:
             self.autoindent = value
 
     #-------------------------------------------------------------------------
     # init_* methods called by __init__
     #-------------------------------------------------------------------------
 
     def init_ipython_dir(self, ipython_dir):
         if ipython_dir is not None:
             self.ipython_dir = ipython_dir
             self.config.Global.ipython_dir = self.ipython_dir
             return
 
         if hasattr(self.config.Global, 'ipython_dir'):
             self.ipython_dir = self.config.Global.ipython_dir
         else:
             self.ipython_dir = get_ipython_dir()
 
         # All children can just read this
         self.config.Global.ipython_dir = self.ipython_dir
 
     def init_instance_attrs(self):
         self.more = False
 
         # command compiler
         self.compile = CachingCompiler()
         
         # User input buffers
         # NOTE: these variables are slated for full removal, once we are 100%
         # sure that the new execution logic is solid.  We will delte runlines,
         # push_line and these buffers, as all input will be managed by the
         # frontends via an inputsplitter instance.
         self.buffer = []
         self.buffer_raw = []
 
         # Make an empty namespace, which extension writers can rely on both
         # existing and NEVER being used by ipython itself.  This gives them a
         # convenient location for storing additional information and state
         # their extensions may require, without fear of collisions with other
         # ipython names that may develop later.
         self.meta = Struct()
 
         # Object variable to store code object waiting execution.  This is
         # used mainly by the multithreaded shells, but it can come in handy in
         # other situations.  No need to use a Queue here, since it's a single
         # item which gets cleared once run.
         self.code_to_run = None
 
         # Temporary files used for various purposes.  Deleted at exit.
         self.tempfiles = []
 
         # Keep track of readline usage (later set by init_readline)
         self.has_readline = False
 
         # keep track of where we started running (mainly for crash post-mortem)
         # This is not being used anywhere currently.
         self.starting_dir = os.getcwd()
 
         # Indentation management
         self.indent_current_nsp = 0
 
     def init_environment(self):
         """Any changes we need to make to the user's environment."""
         pass
 
     def init_encoding(self):
         # Get system encoding at startup time.  Certain terminals (like Emacs
         # under Win32 have it set to None, and we need to have a known valid
         # encoding to use in the raw_input() method
         try:
             self.stdin_encoding = sys.stdin.encoding or 'ascii'
         except AttributeError:
             self.stdin_encoding = 'ascii'
 
     def init_syntax_highlighting(self):
         # Python source parser/formatter for syntax highlighting
         pyformat = PyColorize.Parser().format
         self.pycolorize = lambda src: pyformat(src,'str',self.colors)
 
     def init_pushd_popd_magic(self):
         # for pushd/popd management
         try:
             self.home_dir = get_home_dir()
         except HomeDirError, msg:
             fatal(msg)
 
         self.dir_stack = []
 
     def init_logger(self):
         self.logger = Logger(self.home_dir, logfname='ipython_log.py',
                              logmode='rotate')
 
     def init_logstart(self):
         """Initialize logging in case it was requested at the command line.
         """
         if self.logappend:
             self.magic_logstart(self.logappend + ' append')
         elif self.logfile:
             self.magic_logstart(self.logfile)
         elif self.logstart:
             self.magic_logstart()
 
     def init_builtins(self):
         self.builtin_trap = BuiltinTrap(shell=self)
 
     def init_inspector(self):
         # Object inspector
         self.inspector = oinspect.Inspector(oinspect.InspectColors,
                                             PyColorize.ANSICodeColors,
                                             'NoColor',
                                             self.object_info_string_level)
 
     def init_io(self):
         # This will just use sys.stdout and sys.stderr. If you want to
         # override sys.stdout and sys.stderr themselves, you need to do that
         # *before* instantiating this class, because Term holds onto 
         # references to the underlying streams.
         if sys.platform == 'win32' and self.has_readline:
             Term = io.IOTerm(cout=self.readline._outputfile,
                              cerr=self.readline._outputfile)
         else:
             Term = io.IOTerm()
         io.Term = Term
 
     def init_prompts(self):
         # TODO: This is a pass for now because the prompts are managed inside
         # the DisplayHook. Once there is a separate prompt manager, this 
         # will initialize that object and all prompt related information.
         pass
 
     def init_display_formatter(self):
         self.display_formatter = DisplayFormatter(config=self.config)
 
     def init_display_pub(self):
         self.display_pub = self.display_pub_class(config=self.config)
 
     def init_displayhook(self):
         # Initialize displayhook, set in/out prompts and printing system
         self.displayhook = self.displayhook_class(
             config=self.config,
             shell=self,
             cache_size=self.cache_size,
             input_sep = self.separate_in,
             output_sep = self.separate_out,
             output_sep2 = self.separate_out2,
             ps1 = self.prompt_in1,
             ps2 = self.prompt_in2,
             ps_out = self.prompt_out,
             pad_left = self.prompts_pad_left
         )
         # This is a context manager that installs/revmoes the displayhook at
         # the appropriate time.
         self.display_trap = DisplayTrap(hook=self.displayhook)
 
     def init_reload_doctest(self):
         # Do a proper resetting of doctest, including the necessary displayhook
         # monkeypatching
         try:
             doctest_reload()
         except ImportError:
             warn("doctest module does not exist.")
 
     #-------------------------------------------------------------------------
     # Things related to injections into the sys module
     #-------------------------------------------------------------------------
 
     def save_sys_module_state(self):
         """Save the state of hooks in the sys module.
 
         This has to be called after self.user_ns is created.
         """
         self._orig_sys_module_state = {}
         self._orig_sys_module_state['stdin'] = sys.stdin
         self._orig_sys_module_state['stdout'] = sys.stdout
         self._orig_sys_module_state['stderr'] = sys.stderr
         self._orig_sys_module_state['excepthook'] = sys.excepthook
         try:
             self._orig_sys_modules_main_name = self.user_ns['__name__']
         except KeyError:
             pass
 
     def restore_sys_module_state(self):
         """Restore the state of the sys module."""
         try:
             for k, v in self._orig_sys_module_state.iteritems():
                 setattr(sys, k, v)
         except AttributeError:
             pass
         # Reset what what done in self.init_sys_modules
         try:
             sys.modules[self.user_ns['__name__']] = self._orig_sys_modules_main_name
         except (AttributeError, KeyError):
             pass
 
     #-------------------------------------------------------------------------
     # Things related to hooks
     #-------------------------------------------------------------------------
 
     def init_hooks(self):
         # hooks holds pointers used for user-side customizations
         self.hooks = Struct()
 
         self.strdispatchers = {}
 
         # Set all default hooks, defined in the IPython.hooks module.
         hooks = IPython.core.hooks
         for hook_name in hooks.__all__:
             # default hooks have priority 100, i.e. low; user hooks should have
             # 0-100 priority
             self.set_hook(hook_name,getattr(hooks,hook_name), 100)
 
     def set_hook(self,name,hook, priority = 50, str_key = None, re_key = None):
         """set_hook(name,hook) -> sets an internal IPython hook.
 
         IPython exposes some of its internal API as user-modifiable hooks.  By
         adding your function to one of these hooks, you can modify IPython's 
         behavior to call at runtime your own routines."""
 
         # At some point in the future, this should validate the hook before it
         # accepts it.  Probably at least check that the hook takes the number
         # of args it's supposed to.
         
         f = types.MethodType(hook,self)
 
         # check if the hook is for strdispatcher first
         if str_key is not None:
             sdp = self.strdispatchers.get(name, StrDispatch())
             sdp.add_s(str_key, f, priority )
             self.strdispatchers[name] = sdp
             return
         if re_key is not None:
             sdp = self.strdispatchers.get(name, StrDispatch())
             sdp.add_re(re.compile(re_key), f, priority )
             self.strdispatchers[name] = sdp
             return
             
         dp = getattr(self.hooks, name, None)
         if name not in IPython.core.hooks.__all__:
             print "Warning! Hook '%s' is not one of %s" % \
                   (name, IPython.core.hooks.__all__ )
         if not dp:
             dp = IPython.core.hooks.CommandChainDispatcher()
         
         try:
             dp.add(f,priority)
         except AttributeError:
             # it was not commandchain, plain old func - replace
             dp = f
 
         setattr(self.hooks,name, dp)
 
     def register_post_execute(self, func):
         """Register a function for calling after code execution.
         """
         if not callable(func):
             raise ValueError('argument %s must be callable' % func)
         self._post_execute.add(func)
 
     #-------------------------------------------------------------------------
     # Things related to the "main" module
     #-------------------------------------------------------------------------
 
     def new_main_mod(self,ns=None):
         """Return a new 'main' module object for user code execution.
         """
         main_mod = self._user_main_module
         init_fakemod_dict(main_mod,ns)
         return main_mod
 
     def cache_main_mod(self,ns,fname):
         """Cache a main module's namespace.
 
         When scripts are executed via %run, we must keep a reference to the
         namespace of their __main__ module (a FakeModule instance) around so
         that Python doesn't clear it, rendering objects defined therein
         useless.
 
         This method keeps said reference in a private dict, keyed by the
         absolute path of the module object (which corresponds to the script
         path).  This way, for multiple executions of the same script we only
         keep one copy of the namespace (the last one), thus preventing memory
         leaks from old references while allowing the objects from the last
         execution to be accessible.
 
         Note: we can not allow the actual FakeModule instances to be deleted,
         because of how Python tears down modules (it hard-sets all their
         references to None without regard for reference counts).  This method
         must therefore make a *copy* of the given namespace, to allow the
         original module's __dict__ to be cleared and reused.
 
         
         Parameters
         ----------
           ns : a namespace (a dict, typically)
 
           fname : str
             Filename associated with the namespace.
 
         Examples
         --------
 
         In [10]: import IPython
 
         In [11]: _ip.cache_main_mod(IPython.__dict__,IPython.__file__)
 
         In [12]: IPython.__file__ in _ip._main_ns_cache
         Out[12]: True
         """
         self._main_ns_cache[os.path.abspath(fname)] = ns.copy()
 
     def clear_main_mod_cache(self):
         """Clear the cache of main modules.
 
         Mainly for use by utilities like %reset.
 
         Examples
         --------
 
         In [15]: import IPython
 
         In [16]: _ip.cache_main_mod(IPython.__dict__,IPython.__file__)
 
         In [17]: len(_ip._main_ns_cache) > 0
         Out[17]: True
 
         In [18]: _ip.clear_main_mod_cache()
 
         In [19]: len(_ip._main_ns_cache) == 0
         Out[19]: True
         """
         self._main_ns_cache.clear()
 
     #-------------------------------------------------------------------------
     # Things related to debugging
     #-------------------------------------------------------------------------
 
     def init_pdb(self):
         # Set calling of pdb on exceptions
         # self.call_pdb is a property
         self.call_pdb = self.pdb
 
     def _get_call_pdb(self):
         return self._call_pdb
 
     def _set_call_pdb(self,val):
 
         if val not in (0,1,False,True):
             raise ValueError,'new call_pdb value must be boolean'
 
         # store value in instance
         self._call_pdb = val
 
         # notify the actual exception handlers
         self.InteractiveTB.call_pdb = val
 
     call_pdb = property(_get_call_pdb,_set_call_pdb,None,
                         'Control auto-activation of pdb at exceptions')
 
     def debugger(self,force=False):
         """Call the pydb/pdb debugger.
 
         Keywords:
 
           - force(False): by default, this routine checks the instance call_pdb
           flag and does not actually invoke the debugger if the flag is false.
           The 'force' option forces the debugger to activate even if the flag
           is false.
         """
 
         if not (force or self.call_pdb):
             return
 
         if not hasattr(sys,'last_traceback'):
             error('No traceback has been produced, nothing to debug.')
             return
 
         # use pydb if available
         if debugger.has_pydb:
             from pydb import pm
         else:
             # fallback to our internal debugger
             pm = lambda : self.InteractiveTB.debugger(force=True)
         self.history_saving_wrapper(pm)()
 
     #-------------------------------------------------------------------------
     # Things related to IPython's various namespaces
     #-------------------------------------------------------------------------
 
     def init_create_namespaces(self, user_ns=None, user_global_ns=None):
         # Create the namespace where the user will operate.  user_ns is
         # normally the only one used, and it is passed to the exec calls as
         # the locals argument.  But we do carry a user_global_ns namespace
         # given as the exec 'globals' argument,  This is useful in embedding
         # situations where the ipython shell opens in a context where the
         # distinction between locals and globals is meaningful.  For
         # non-embedded contexts, it is just the same object as the user_ns dict.
 
         # FIXME. For some strange reason, __builtins__ is showing up at user
         # level as a dict instead of a module. This is a manual fix, but I
         # should really track down where the problem is coming from. Alex
         # Schmolck reported this problem first.
 
         # A useful post by Alex Martelli on this topic:
         # Re: inconsistent value from __builtins__
         # Von: Alex Martelli <[e-mail]>
         # Datum: Freitag 01 Oktober 2004 04:45:34 nachmittags/abends
         # Gruppen: comp.lang.python
 
         # Michael Hohn <[e-mail]> wrote:
         # > >>> print type(builtin_check.get_global_binding('__builtins__'))
         # > <type 'dict'>
         # > >>> print type(__builtins__)
         # > <type 'module'>
         # > Is this difference in return value intentional?
 
         # Well, it's documented that '__builtins__' can be either a dictionary
         # or a module, and it's been that way for a long time. Whether it's
         # intentional (or sensible), I don't know. In any case, the idea is
         # that if you need to access the built-in namespace directly, you
         # should start with "import __builtin__" (note, no 's') which will
         # definitely give you a module. Yeah, it's somewhat confusing:-(.
 
         # These routines return properly built dicts as needed by the rest of
         # the code, and can also be used by extension writers to generate
         # properly initialized namespaces.
         user_ns, user_global_ns = self.make_user_namespaces(user_ns,
                                                             user_global_ns)
 
         # Assign namespaces
         # This is the namespace where all normal user variables live
         self.user_ns = user_ns
         self.user_global_ns = user_global_ns
 
         # An auxiliary namespace that checks what parts of the user_ns were
         # loaded at startup, so we can list later only variables defined in
         # actual interactive use.  Since it is always a subset of user_ns, it
         # doesn't need to be separately tracked in the ns_table.
         self.user_ns_hidden = {}
 
         # A namespace to keep track of internal data structures to prevent
         # them from cluttering user-visible stuff.  Will be updated later
         self.internal_ns = {}
 
         # Now that FakeModule produces a real module, we've run into a nasty
         # problem: after script execution (via %run), the module where the user
         # code ran is deleted.  Now that this object is a true module (needed
         # so docetst and other tools work correctly), the Python module
         # teardown mechanism runs over it, and sets to None every variable
         # present in that module.  Top-level references to objects from the
         # script survive, because the user_ns is updated with them.  However,
         # calling functions defined in the script that use other things from
         # the script will fail, because the function's closure had references
         # to the original objects, which are now all None.  So we must protect
         # these modules from deletion by keeping a cache.
         # 
         # To avoid keeping stale modules around (we only need the one from the
         # last run), we use a dict keyed with the full path to the script, so
         # only the last version of the module is held in the cache.  Note,
         # however, that we must cache the module *namespace contents* (their
         # __dict__).  Because if we try to cache the actual modules, old ones
         # (uncached) could be destroyed while still holding references (such as
         # those held by GUI objects that tend to be long-lived)>
         # 
         # The %reset command will flush this cache.  See the cache_main_mod()
         # and clear_main_mod_cache() methods for details on use.
 
         # This is the cache used for 'main' namespaces
         self._main_ns_cache = {}
         # And this is the single instance of FakeModule whose __dict__ we keep
         # copying and clearing for reuse on each %run
         self._user_main_module = FakeModule()
 
         # A table holding all the namespaces IPython deals with, so that
         # introspection facilities can search easily.
         self.ns_table = {'user':user_ns,
                          'user_global':user_global_ns,
                          'internal':self.internal_ns,
                          'builtin':__builtin__.__dict__
                          }
 
         # Similarly, track all namespaces where references can be held and that
         # we can safely clear (so it can NOT include builtin).  This one can be
         # a simple list.  Note that the main execution namespaces, user_ns and
         # user_global_ns, can NOT be listed here, as clearing them blindly
         # causes errors in object __del__ methods.  Instead, the reset() method
         # clears them manually and carefully.
         self.ns_refs_table = [ self.user_ns_hidden,
                                self.internal_ns, self._main_ns_cache ]
 
     def make_user_namespaces(self, user_ns=None, user_global_ns=None):
         """Return a valid local and global user interactive namespaces.
 
         This builds a dict with the minimal information needed to operate as a
         valid IPython user namespace, which you can pass to the various
         embedding classes in ipython. The default implementation returns the
         same dict for both the locals and the globals to allow functions to
         refer to variables in the namespace. Customized implementations can
         return different dicts. The locals dictionary can actually be anything
         following the basic mapping protocol of a dict, but the globals dict
         must be a true dict, not even a subclass. It is recommended that any
         custom object for the locals namespace synchronize with the globals
         dict somehow.
 
         Raises TypeError if the provided globals namespace is not a true dict.
 
         Parameters
         ----------
         user_ns : dict-like, optional
             The current user namespace. The items in this namespace should
             be included in the output. If None, an appropriate blank
             namespace should be created.
         user_global_ns : dict, optional
             The current user global namespace. The items in this namespace
             should be included in the output. If None, an appropriate
             blank namespace should be created.
 
         Returns
         -------
             A pair of dictionary-like object to be used as the local namespace
             of the interpreter and a dict to be used as the global namespace.
         """
 
 
         # We must ensure that __builtin__ (without the final 's') is always
         # available and pointing to the __builtin__ *module*.  For more details:
         # http://mail.python.org/pipermail/python-dev/2001-April/014068.html
 
         if user_ns is None:
             # Set __name__ to __main__ to better match the behavior of the
             # normal interpreter.
             user_ns = {'__name__'     :'__main__',
                        '__builtin__' : __builtin__,
                        '__builtins__' : __builtin__,
                       }
         else:
             user_ns.setdefault('__name__','__main__')
             user_ns.setdefault('__builtin__',__builtin__)
             user_ns.setdefault('__builtins__',__builtin__)
 
         if user_global_ns is None:
             user_global_ns = user_ns
         if type(user_global_ns) is not dict:
             raise TypeError("user_global_ns must be a true dict; got %r"
                 % type(user_global_ns))
 
         return user_ns, user_global_ns
 
     def init_sys_modules(self):
         # We need to insert into sys.modules something that looks like a
         # module but which accesses the IPython namespace, for shelve and
         # pickle to work interactively. Normally they rely on getting
         # everything out of __main__, but for embedding purposes each IPython
         # instance has its own private namespace, so we can't go shoving
         # everything into __main__.
 
         # note, however, that we should only do this for non-embedded
         # ipythons, which really mimic the __main__.__dict__ with their own
         # namespace.  Embedded instances, on the other hand, should not do
         # this because they need to manage the user local/global namespaces
         # only, but they live within a 'normal' __main__ (meaning, they
         # shouldn't overtake the execution environment of the script they're
         # embedded in).
 
         # This is overridden in the InteractiveShellEmbed subclass to a no-op.
 
         try:
             main_name = self.user_ns['__name__']
         except KeyError:
             raise KeyError('user_ns dictionary MUST have a "__name__" key')
         else:
             sys.modules[main_name] = FakeModule(self.user_ns)
 
     def init_user_ns(self):
         """Initialize all user-visible namespaces to their minimum defaults.
 
         Certain history lists are also initialized here, as they effectively
         act as user namespaces.
 
         Notes
         -----
         All data structures here are only filled in, they are NOT reset by this
         method.  If they were not empty before, data will simply be added to
         therm.
         """
         # This function works in two parts: first we put a few things in
         # user_ns, and we sync that contents into user_ns_hidden so that these
         # initial variables aren't shown by %who.  After the sync, we add the
         # rest of what we *do* want the user to see with %who even on a new
         # session (probably nothing, so theye really only see their own stuff)
 
         # The user dict must *always* have a __builtin__ reference to the
         # Python standard __builtin__ namespace,  which must be imported.
         # This is so that certain operations in prompt evaluation can be
         # reliably executed with builtins.  Note that we can NOT use
         # __builtins__ (note the 's'),  because that can either be a dict or a
         # module, and can even mutate at runtime, depending on the context
         # (Python makes no guarantees on it).  In contrast, __builtin__ is
         # always a module object, though it must be explicitly imported.
         
         # For more details:
         # http://mail.python.org/pipermail/python-dev/2001-April/014068.html
         ns = dict(__builtin__ = __builtin__)
         
         # Put 'help' in the user namespace
         try:
             from site import _Helper
             ns['help'] = _Helper()
         except ImportError:
             warn('help() not available - check site.py')
 
         # make global variables for user access to the histories
         ns['_ih'] = self.history_manager.input_hist_parsed
         ns['_oh'] = self.history_manager.output_hist
         ns['_dh'] = self.history_manager.dir_hist
 
         ns['_sh'] = shadowns
 
         # user aliases to input and output histories.  These shouldn't show up
         # in %who, as they can have very large reprs.
         ns['In']  = self.history_manager.input_hist_parsed
         ns['Out'] = self.history_manager.output_hist
 
         # Store myself as the public api!!!
         ns['get_ipython'] = self.get_ipython
 
         # Sync what we've added so far to user_ns_hidden so these aren't seen
         # by %who
         self.user_ns_hidden.update(ns)
 
         # Anything put into ns now would show up in %who.  Think twice before
         # putting anything here, as we really want %who to show the user their
         # stuff, not our variables.
         
         # Finally, update the real user's namespace
         self.user_ns.update(ns)
 
     def reset(self, new_session=True):
         """Clear all internal namespaces.
 
         Note that this is much more aggressive than %reset, since it clears
         fully all namespaces, as well as all input/output lists.
         
         If new_session is True, a new history session will be opened.
         """
         # Clear histories
         self.history_manager.reset(new_session)
 
         # Reset counter used to index all histories
         self.execution_count = 0
         
         # Restore the user namespaces to minimal usability
         for ns in self.ns_refs_table:
             ns.clear()
 
         # The main execution namespaces must be cleared very carefully,
         # skipping the deletion of the builtin-related keys, because doing so
         # would cause errors in many object's __del__ methods.
         for ns in [self.user_ns, self.user_global_ns]:
             drop_keys = set(ns.keys())
             drop_keys.discard('__builtin__')
             drop_keys.discard('__builtins__')
             for k in drop_keys:
                 del ns[k]
                                         
         # Restore the user namespaces to minimal usability
         self.init_user_ns()
 
         # Restore the default and user aliases
         self.alias_manager.clear_aliases()
         self.alias_manager.init_aliases()
 
     def reset_selective(self, regex=None):
         """Clear selective variables from internal namespaces based on a
         specified regular expression.
 
         Parameters
         ----------
         regex : string or compiled pattern, optional
             A regular expression pattern that will be used in searching
             variable names in the users namespaces.
         """
         if regex is not None:
             try:
                 m = re.compile(regex)
             except TypeError:
                 raise TypeError('regex must be a string or compiled pattern')
             # Search for keys in each namespace that match the given regex
             # If a match is found, delete the key/value pair.
             for ns in self.ns_refs_table:
                 for var in ns:
                     if m.search(var):
                         del ns[var]        
         
     def push(self, variables, interactive=True):
         """Inject a group of variables into the IPython user namespace.
 
         Parameters
         ----------
         variables : dict, str or list/tuple of str
             The variables to inject into the user's namespace.  If a dict, a
             simple update is done.  If a str, the string is assumed to have
             variable names separated by spaces.  A list/tuple of str can also
             be used to give the variable names.  If just the variable names are
             give (list/tuple/str) then the variable values looked up in the
             callers frame.
         interactive : bool
             If True (default), the variables will be listed with the ``who``
             magic.
         """
         vdict = None
 
         # We need a dict of name/value pairs to do namespace updates.
         if isinstance(variables, dict):
             vdict = variables
         elif isinstance(variables, (basestring, list, tuple)):
             if isinstance(variables, basestring):
                 vlist = variables.split()
             else:
                 vlist = variables
             vdict = {}
             cf = sys._getframe(1)
             for name in vlist:
                 try:
                     vdict[name] = eval(name, cf.f_globals, cf.f_locals)
                 except:
                     print ('Could not get variable %s from %s' %
                            (name,cf.f_code.co_name))
         else:
             raise ValueError('variables must be a dict/str/list/tuple')
             
         # Propagate variables to user namespace
         self.user_ns.update(vdict)
 
         # And configure interactive visibility
         config_ns = self.user_ns_hidden
         if interactive:
             for name, val in vdict.iteritems():
                 config_ns.pop(name, None)
         else:
             for name,val in vdict.iteritems():
                 config_ns[name] = val
 
     #-------------------------------------------------------------------------
     # Things related to object introspection
     #-------------------------------------------------------------------------
 
     def _ofind(self, oname, namespaces=None):
         """Find an object in the available namespaces.
 
         self._ofind(oname) -> dict with keys: found,obj,ospace,ismagic
 
         Has special code to detect magic functions.
         """
         #oname = oname.strip()
         #print '1- oname: <%r>' % oname  # dbg
         try:
             oname = oname.strip().encode('ascii')
             #print '2- oname: <%r>' % oname  # dbg
         except UnicodeEncodeError:
             print 'Python identifiers can only contain ascii characters.'
             return dict(found=False)
 
         alias_ns = None
         if namespaces is None:
             # Namespaces to search in:
             # Put them in a list. The order is important so that we
             # find things in the same order that Python finds them.
             namespaces = [ ('Interactive', self.user_ns),
                            ('IPython internal', self.internal_ns),
                            ('Python builtin', __builtin__.__dict__),
                            ('Alias', self.alias_manager.alias_table),
                            ]
             alias_ns = self.alias_manager.alias_table
 
         # initialize results to 'null'
         found = False; obj = None;  ospace = None;  ds = None;
         ismagic = False; isalias = False; parent = None
 
         # We need to special-case 'print', which as of python2.6 registers as a
         # function but should only be treated as one if print_function was
         # loaded with a future import.  In this case, just bail.
         if (oname == 'print' and not (self.compile.compiler_flags &
                                       __future__.CO_FUTURE_PRINT_FUNCTION)):
             return {'found':found, 'obj':obj, 'namespace':ospace,
                     'ismagic':ismagic, 'isalias':isalias, 'parent':parent}
 
         # Look for the given name by splitting it in parts.  If the head is
         # found, then we look for all the remaining parts as members, and only
         # declare success if we can find them all.
         oname_parts = oname.split('.')
         oname_head, oname_rest = oname_parts[0],oname_parts[1:]
         for nsname,ns in namespaces:
             try:
                 obj = ns[oname_head]
             except KeyError:
                 continue
             else:
                 #print 'oname_rest:', oname_rest  # dbg
                 for part in oname_rest:
                     try:
                         parent = obj
                         obj = getattr(obj,part)
                     except:
                         # Blanket except b/c some badly implemented objects
                         # allow __getattr__ to raise exceptions other than
                         # AttributeError, which then crashes IPython.
                         break
                 else:
                     # If we finish the for loop (no break), we got all members
                     found = True
                     ospace = nsname
                     if ns == alias_ns:
                         isalias = True
                     break  # namespace loop
 
         # Try to see if it's magic
         if not found:
             if oname.startswith(ESC_MAGIC):
                 oname = oname[1:]
             obj = getattr(self,'magic_'+oname,None)
             if obj is not None:
                 found = True
                 ospace = 'IPython internal'
                 ismagic = True
 
         # Last try: special-case some literals like '', [], {}, etc:
         if not found and oname_head in ["''",'""','[]','{}','()']:
             obj = eval(oname_head)
             found = True
             ospace = 'Interactive'
 
         return {'found':found, 'obj':obj, 'namespace':ospace,
                 'ismagic':ismagic, 'isalias':isalias, 'parent':parent}
 
     def _ofind_property(self, oname, info):
         """Second part of object finding, to look for property details."""
         if info.found:
             # Get the docstring of the class property if it exists.
             path = oname.split('.')
             root = '.'.join(path[:-1])
             if info.parent is not None:
                 try:
                     target = getattr(info.parent, '__class__') 
                     # The object belongs to a class instance. 
                     try: 
                         target = getattr(target, path[-1])
                         # The class defines the object. 
                         if isinstance(target, property):
                             oname = root + '.__class__.' + path[-1]
                             info = Struct(self._ofind(oname))
                     except AttributeError: pass
                 except AttributeError: pass
 
         # We return either the new info or the unmodified input if the object
         # hadn't been found
         return info
 
     def _object_find(self, oname, namespaces=None):
         """Find an object and return a struct with info about it."""
         inf = Struct(self._ofind(oname, namespaces))
         return Struct(self._ofind_property(oname, inf))
         
     def _inspect(self, meth, oname, namespaces=None, **kw):
         """Generic interface to the inspector system.
 
         This function is meant to be called by pdef, pdoc & friends."""
         info = self._object_find(oname)
         if info.found:
             pmethod = getattr(self.inspector, meth)
             formatter = format_screen if info.ismagic else None
             if meth == 'pdoc':
                 pmethod(info.obj, oname, formatter)
             elif meth == 'pinfo':
                 pmethod(info.obj, oname, formatter, info, **kw)
             else:
                 pmethod(info.obj, oname)
         else:
             print 'Object `%s` not found.' % oname
             return 'not found'  # so callers can take other action
 
     def object_inspect(self, oname):
         info = self._object_find(oname)
         if info.found:
             return self.inspector.info(info.obj, oname, info=info)
         else:
             return oinspect.object_info(name=oname, found=False)
 
     #-------------------------------------------------------------------------
     # Things related to history management
     #-------------------------------------------------------------------------
 
     def init_history(self):
         """Sets up the command history, and starts regular autosaves."""
         self.history_manager = HistoryManager(shell=self, config=self.config)
 
     def history_saving_wrapper(self, func):
         """ Wrap func for readline history saving
 
         Convert func into callable that saves & restores
         history around the call """
 
         if self.has_readline:
             from IPython.utils import rlineimpl as readline
         else:
             return func
 
         def wrapper():
             self.save_history()
             try:
                 func()
             finally:
                 self.reload_history()
         return wrapper
     
 
     #-------------------------------------------------------------------------
     # Things related to exception handling and tracebacks (not debugging)
     #-------------------------------------------------------------------------
 
     def init_traceback_handlers(self, custom_exceptions):
         # Syntax error handler.
         self.SyntaxTB = ultratb.SyntaxTB(color_scheme='NoColor')
         
         # The interactive one is initialized with an offset, meaning we always
         # want to remove the topmost item in the traceback, which is our own
         # internal code. Valid modes: ['Plain','Context','Verbose']
         self.InteractiveTB = ultratb.AutoFormattedTB(mode = 'Plain',
                                                      color_scheme='NoColor',
                                                      tb_offset = 1,
                                    check_cache=self.compile.check_cache)
 
         # The instance will store a pointer to the system-wide exception hook,
         # so that runtime code (such as magics) can access it.  This is because
         # during the read-eval loop, it may get temporarily overwritten.
         self.sys_excepthook = sys.excepthook
 
         # and add any custom exception handlers the user may have specified
         self.set_custom_exc(*custom_exceptions)
 
         # Set the exception mode
         self.InteractiveTB.set_mode(mode=self.xmode)
 
     def set_custom_exc(self, exc_tuple, handler):
         """set_custom_exc(exc_tuple,handler)
 
         Set a custom exception handler, which will be called if any of the
         exceptions in exc_tuple occur in the mainloop (specifically, in the
         run_code() method.
 
         Inputs:
 
           - exc_tuple: a *tuple* of valid exceptions to call the defined
           handler for.  It is very important that you use a tuple, and NOT A
           LIST here, because of the way Python's except statement works.  If
           you only want to trap a single exception, use a singleton tuple:
 
             exc_tuple == (MyCustomException,)
 
           - handler: this must be defined as a function with the following
           basic interface::
 
             def my_handler(self, etype, value, tb, tb_offset=None)
                 ...
                 # The return value must be
                 return structured_traceback
 
           This will be made into an instance method (via types.MethodType)
           of IPython itself, and it will be called if any of the exceptions
           listed in the exc_tuple are caught.  If the handler is None, an
           internal basic one is used, which just prints basic info.
 
         WARNING: by putting in your own exception handler into IPython's main
         execution loop, you run a very good chance of nasty crashes.  This
         facility should only be used if you really know what you are doing."""
 
         assert type(exc_tuple)==type(()) , \
                "The custom exceptions must be given AS A TUPLE."
 
         def dummy_handler(self,etype,value,tb):
             print '*** Simple custom exception handler ***'
             print 'Exception type :',etype
             print 'Exception value:',value
             print 'Traceback      :',tb
             print 'Source code    :','\n'.join(self.buffer)
 
         if handler is None: handler = dummy_handler
 
         self.CustomTB = types.MethodType(handler,self)
         self.custom_exceptions = exc_tuple
 
     def excepthook(self, etype, value, tb):
       """One more defense for GUI apps that call sys.excepthook.
 
       GUI frameworks like wxPython trap exceptions and call
       sys.excepthook themselves.  I guess this is a feature that
       enables them to keep running after exceptions that would
       otherwise kill their mainloop. This is a bother for IPython
       which excepts to catch all of the program exceptions with a try:
       except: statement.
 
       Normally, IPython sets sys.excepthook to a CrashHandler instance, so if
       any app directly invokes sys.excepthook, it will look to the user like
       IPython crashed.  In order to work around this, we can disable the
       CrashHandler and replace it with this excepthook instead, which prints a
       regular traceback using our InteractiveTB.  In this fashion, apps which
       call sys.excepthook will generate a regular-looking exception from
       IPython, and the CrashHandler will only be triggered by real IPython
       crashes.
 
       This hook should be used sparingly, only in places which are not likely
       to be true IPython errors.
       """
       self.showtraceback((etype,value,tb),tb_offset=0)
 
     def showtraceback(self,exc_tuple = None,filename=None,tb_offset=None,
                       exception_only=False):
         """Display the exception that just occurred.
 
         If nothing is known about the exception, this is the method which
         should be used throughout the code for presenting user tracebacks,
         rather than directly invoking the InteractiveTB object.
 
         A specific showsyntaxerror() also exists, but this method can take
         care of calling it if needed, so unless you are explicitly catching a
         SyntaxError exception, don't try to analyze the stack manually and
         simply call this method."""
         
         try:
             if exc_tuple is None:
                 etype, value, tb = sys.exc_info()
             else:
                 etype, value, tb = exc_tuple
 
             if etype is None:
                 if hasattr(sys, 'last_type'):
                     etype, value, tb = sys.last_type, sys.last_value, \
                                        sys.last_traceback
                 else:
                     self.write_err('No traceback available to show.\n')
                     return
     
             if etype is SyntaxError:
                 # Though this won't be called by syntax errors in the input
                 # line, there may be SyntaxError cases whith imported code.
                 self.showsyntaxerror(filename)
             elif etype is UsageError:
                 print "UsageError:", value
             else:
                 # WARNING: these variables are somewhat deprecated and not
                 # necessarily safe to use in a threaded environment, but tools
                 # like pdb depend on their existence, so let's set them.  If we
                 # find problems in the field, we'll need to revisit their use.
                 sys.last_type = etype
                 sys.last_value = value
                 sys.last_traceback = tb
     
                 if etype in self.custom_exceptions:
                     # FIXME: Old custom traceback objects may just return a
                     # string, in that case we just put it into a list
                     stb = self.CustomTB(etype, value, tb, tb_offset)
                     if isinstance(ctb, basestring):
                         stb = [stb]
                 else:
                     if exception_only:
                         stb = ['An exception has occurred, use %tb to see '
                                'the full traceback.\n']
                         stb.extend(self.InteractiveTB.get_exception_only(etype,
                                                                          value))
                     else:
                         stb = self.InteractiveTB.structured_traceback(etype,
                                                 value, tb, tb_offset=tb_offset)
                         # FIXME: the pdb calling should be done by us, not by
                         # the code computing the traceback.
                         if self.InteractiveTB.call_pdb:
                             # pdb mucks up readline, fix it back
                             self.set_readline_completer()
 
                 # Actually show the traceback
                 self._showtraceback(etype, value, stb)
                 
         except KeyboardInterrupt:
             self.write_err("\nKeyboardInterrupt\n")
 
     def _showtraceback(self, etype, evalue, stb):
         """Actually show a traceback.
 
         Subclasses may override this method to put the traceback on a different
         place, like a side channel.
         """
         print >> io.Term.cout, self.InteractiveTB.stb2text(stb)
 
     def showsyntaxerror(self, filename=None):
         """Display the syntax error that just occurred.
 
         This doesn't display a stack trace because there isn't one.
 
         If a filename is given, it is stuffed in the exception instead
         of what was there before (because Python's parser always uses
         "<string>" when reading from a string).
         """
         etype, value, last_traceback = sys.exc_info()
 
         # See note about these variables in showtraceback() above
         sys.last_type = etype
         sys.last_value = value
         sys.last_traceback = last_traceback
         
         if filename and etype is SyntaxError:
             # Work hard to stuff the correct filename in the exception
             try:
                 msg, (dummy_filename, lineno, offset, line) = value
             except:
                 # Not the format we expect; leave it alone
                 pass
             else:
                 # Stuff in the right filename
                 try:
                     # Assume SyntaxError is a class exception
                     value = SyntaxError(msg, (filename, lineno, offset, line))
                 except:
                     # If that failed, assume SyntaxError is a string
                     value = msg, (filename, lineno, offset, line)
         stb = self.SyntaxTB.structured_traceback(etype, value, [])
         self._showtraceback(etype, value, stb)
 
     #-------------------------------------------------------------------------
     # Things related to readline
     #-------------------------------------------------------------------------
 
     def init_readline(self):
         """Command history completion/saving/reloading."""
 
         if self.readline_use:
             import IPython.utils.rlineimpl as readline
 
         self.rl_next_input = None
         self.rl_do_indent = False
 
         if not self.readline_use or not readline.have_readline:
             self.has_readline = False
             self.readline = None
             # Set a number of methods that depend on readline to be no-op
             self.set_readline_completer = no_op
             self.set_custom_completer = no_op
             self.set_completer_frame = no_op
             warn('Readline services not available or not loaded.')
         else:
             self.has_readline = True
             self.readline = readline
             sys.modules['readline'] = readline
             
             # Platform-specific configuration
             if os.name == 'nt':
                 # FIXME - check with Frederick to see if we can harmonize
                 # naming conventions with pyreadline to avoid this
                 # platform-dependent check
                 self.readline_startup_hook = readline.set_pre_input_hook
             else:
                 self.readline_startup_hook = readline.set_startup_hook
 
             # Load user's initrc file (readline config)
             # Or if libedit is used, load editrc.
             inputrc_name = os.environ.get('INPUTRC')
             if inputrc_name is None:
                 home_dir = get_home_dir()
                 if home_dir is not None:
                     inputrc_name = '.inputrc'
                     if readline.uses_libedit:
                         inputrc_name = '.editrc'
                     inputrc_name = os.path.join(home_dir, inputrc_name)
             if os.path.isfile(inputrc_name):
                 try:
                     readline.read_init_file(inputrc_name)
                 except:
                     warn('Problems reading readline initialization file <%s>'
                          % inputrc_name)
             
             # Configure readline according to user's prefs
             # This is only done if GNU readline is being used.  If libedit
             # is being used (as on Leopard) the readline config is
             # not run as the syntax for libedit is different.
             if not readline.uses_libedit:
                 for rlcommand in self.readline_parse_and_bind:
                     #print "loading rl:",rlcommand  # dbg
                     readline.parse_and_bind(rlcommand)
 
             # Remove some chars from the delimiters list.  If we encounter
             # unicode chars, discard them.
             delims = readline.get_completer_delims().encode("ascii", "ignore")
             delims = delims.translate(None, self.readline_remove_delims)
             delims = delims.replace(ESC_MAGIC, '')
             readline.set_completer_delims(delims)
             # otherwise we end up with a monster history after a while:
             readline.set_history_length(self.history_length)
             
             # Load the last 1000 lines from history
-            for _, _, cell in self.history_manager.get_hist_tail(1000,
+            for _, _, cell in self.history_manager.get_tail(1000,
                                                 include_latest=True):
                 if cell.strip(): # Ignore blank lines
                     for line in cell.splitlines():
                         readline.add_history(line)
 
         # Configure auto-indent for all platforms
         self.set_autoindent(self.autoindent)
 
     def set_next_input(self, s):
         """ Sets the 'default' input string for the next command line.
         
         Requires readline.
         
         Example:
         
         [D:\ipython]|1> _ip.set_next_input("Hello Word")
         [D:\ipython]|2> Hello Word_  # cursor is here        
         """
 
         self.rl_next_input = s
 
     # Maybe move this to the terminal subclass?
     def pre_readline(self):
         """readline hook to be used at the start of each line.
 
         Currently it handles auto-indent only."""
 
         if self.rl_do_indent:
             self.readline.insert_text(self._indent_current_str())
         if self.rl_next_input is not None:
             self.readline.insert_text(self.rl_next_input)
             self.rl_next_input = None
 
     def _indent_current_str(self):
         """return the current level of indentation as a string"""
         return self.input_splitter.indent_spaces * ' '
 
     #-------------------------------------------------------------------------
     # Things related to text completion
     #-------------------------------------------------------------------------
 
     def init_completer(self):
         """Initialize the completion machinery.
 
         This creates completion machinery that can be used by client code,
         either interactively in-process (typically triggered by the readline
         library), programatically (such as in test suites) or out-of-prcess
         (typically over the network by remote frontends).
         """
         from IPython.core.completer import IPCompleter
         from IPython.core.completerlib import (module_completer,
                                                magic_run_completer, cd_completer)
         
         self.Completer = IPCompleter(self,
                                      self.user_ns,
                                      self.user_global_ns,
                                      self.readline_omit__names,
                                      self.alias_manager.alias_table,
                                      self.has_readline)
         
         # Add custom completers to the basic ones built into IPCompleter
         sdisp = self.strdispatchers.get('complete_command', StrDispatch())
         self.strdispatchers['complete_command'] = sdisp
         self.Completer.custom_completers = sdisp
 
         self.set_hook('complete_command', module_completer, str_key = 'import')
         self.set_hook('complete_command', module_completer, str_key = 'from')
         self.set_hook('complete_command', magic_run_completer, str_key = '%run')
         self.set_hook('complete_command', cd_completer, str_key = '%cd')
 
         # Only configure readline if we truly are using readline.  IPython can
         # do tab-completion over the network, in GUIs, etc, where readline
         # itself may be absent
         if self.has_readline:
             self.set_readline_completer()
 
     def complete(self, text, line=None, cursor_pos=None):
         """Return the completed text and a list of completions.
 
         Parameters
         ----------
 
            text : string
              A string of text to be completed on.  It can be given as empty and
              instead a line/position pair are given.  In this case, the
              completer itself will split the line like readline does.
 
            line : string, optional
              The complete line that text is part of.
 
            cursor_pos : int, optional
              The position of the cursor on the input line.
 
         Returns
         -------
           text : string
             The actual text that was completed.
 
           matches : list
             A sorted list with all possible completions.
 
         The optional arguments allow the completion to take more context into
         account, and are part of the low-level completion API.
         
         This is a wrapper around the completion mechanism, similar to what
         readline does at the command line when the TAB key is hit.  By
         exposing it as a method, it can be used by other non-readline
         environments (such as GUIs) for text completion.
 
         Simple usage example:
 
         In [1]: x = 'hello'
 
         In [2]: _ip.complete('x.l')
         Out[2]: ('x.l', ['x.ljust', 'x.lower', 'x.lstrip'])
         """
 
         # Inject names into __builtin__ so we can complete on the added names.
         with self.builtin_trap:
             return self.Completer.complete(text, line, cursor_pos)
 
     def set_custom_completer(self, completer, pos=0):
         """Adds a new custom completer function.
 
         The position argument (defaults to 0) is the index in the completers
         list where you want the completer to be inserted."""
 
         newcomp = types.MethodType(completer,self.Completer)
         self.Completer.matchers.insert(pos,newcomp)
 
     def set_readline_completer(self):
         """Reset readline's completer to be our own."""
         self.readline.set_completer(self.Completer.rlcomplete)
 
     def set_completer_frame(self, frame=None):
         """Set the frame of the completer."""
         if frame:
             self.Completer.namespace = frame.f_locals
             self.Completer.global_namespace = frame.f_globals
         else:
             self.Completer.namespace = self.user_ns
             self.Completer.global_namespace = self.user_global_ns
 
     #-------------------------------------------------------------------------
     # Things related to magics
     #-------------------------------------------------------------------------
 
     def init_magics(self):
         # FIXME: Move the color initialization to the DisplayHook, which
         # should be split into a prompt manager and displayhook. We probably
         # even need a centralize colors management object.
         self.magic_colors(self.colors)
         # History was moved to a separate module
         from . import history
         history.init_ipython(self)
 
     def magic(self,arg_s):
         """Call a magic function by name.
 
         Input: a string containing the name of the magic function to call and
         any additional arguments to be passed to the magic.
 
         magic('name -opt foo bar') is equivalent to typing at the ipython
         prompt:
 
         In[1]: %name -opt foo bar
 
         To call a magic without arguments, simply use magic('name').
 
         This provides a proper Python function to call IPython's magics in any
         valid Python code you can type at the interpreter, including loops and
         compound statements.
         """
         args = arg_s.split(' ',1)
         magic_name = args[0]
         magic_name = magic_name.lstrip(prefilter.ESC_MAGIC)
 
         try:
             magic_args = args[1]
         except IndexError:
             magic_args = ''
         fn = getattr(self,'magic_'+magic_name,None)
         if fn is None:
             error("Magic function `%s` not found." % magic_name)
         else:
             magic_args = self.var_expand(magic_args,1)
             with nested(self.builtin_trap,):
                 result = fn(magic_args)
                 return result
 
     def define_magic(self, magicname, func):
         """Expose own function as magic function for ipython 
     
         def foo_impl(self,parameter_s=''):
             'My very own magic!. (Use docstrings, IPython reads them).'
             print 'Magic function. Passed parameter is between < >:'
             print '<%s>' % parameter_s
             print 'The self object is:',self
     
         self.define_magic('foo',foo_impl)
         """
         
         import new
         im = types.MethodType(func,self)
         old = getattr(self, "magic_" + magicname, None)
         setattr(self, "magic_" + magicname, im)
         return old
 
     #-------------------------------------------------------------------------
     # Things related to macros
     #-------------------------------------------------------------------------
 
     def define_macro(self, name, themacro):
         """Define a new macro
 
         Parameters
         ----------
         name : str
             The name of the macro.
         themacro : str or Macro
             The action to do upon invoking the macro.  If a string, a new 
             Macro object is created by passing the string to it.
         """
         
         from IPython.core import macro
 
         if isinstance(themacro, basestring):
             themacro = macro.Macro(themacro)
         if not isinstance(themacro, macro.Macro):
             raise ValueError('A macro must be a string or a Macro instance.')
         self.user_ns[name] = themacro
 
     #-------------------------------------------------------------------------
     # Things related to the running of system commands
     #-------------------------------------------------------------------------
 
     def system(self, cmd):
         """Call the given cmd in a subprocess.
 
         Parameters
         ----------
         cmd : str
           Command to execute (can not end in '&', as bacground processes are
           not supported.
         """
         # We do not support backgrounding processes because we either use
         # pexpect or pipes to read from.  Users can always just call
         # os.system() if they really want a background process.
         if cmd.endswith('&'):
             raise OSError("Background processes not supported.")
 
         return system(self.var_expand(cmd, depth=2))
 
     def getoutput(self, cmd, split=True):
         """Get output (possibly including stderr) from a subprocess.
 
         Parameters
         ----------
         cmd : str
           Command to execute (can not end in '&', as background processes are
           not supported.
         split : bool, optional
         
           If True, split the output into an IPython SList.  Otherwise, an
           IPython LSString is returned.  These are objects similar to normal
           lists and strings, with a few convenience attributes for easier
           manipulation of line-based output.  You can use '?' on them for
           details.
           """
         if cmd.endswith('&'):
             raise OSError("Background processes not supported.")
         out = getoutput(self.var_expand(cmd, depth=2))
         if split:
             out = SList(out.splitlines())
         else:
             out = LSString(out)
         return out
 
     #-------------------------------------------------------------------------
     # Things related to aliases
     #-------------------------------------------------------------------------
 
     def init_alias(self):
         self.alias_manager = AliasManager(shell=self, config=self.config)
         self.ns_table['alias'] = self.alias_manager.alias_table,
 
     #-------------------------------------------------------------------------
     # Things related to extensions and plugins
     #-------------------------------------------------------------------------
 
     def init_extension_manager(self):
         self.extension_manager = ExtensionManager(shell=self, config=self.config)
 
     def init_plugin_manager(self):
         self.plugin_manager = PluginManager(config=self.config)
 
     #-------------------------------------------------------------------------
     # Things related to payloads
     #-------------------------------------------------------------------------
 
     def init_payload(self):
         self.payload_manager = PayloadManager(config=self.config)
 
     #-------------------------------------------------------------------------
     # Things related to the prefilter
     #-------------------------------------------------------------------------
 
     def init_prefilter(self):
         self.prefilter_manager = PrefilterManager(shell=self, config=self.config)
         # Ultimately this will be refactored in the new interpreter code, but
         # for now, we should expose the main prefilter method (there's legacy
         # code out there that may rely on this).
         self.prefilter = self.prefilter_manager.prefilter_lines
 
     def auto_rewrite_input(self, cmd):
         """Print to the screen the rewritten form of the user's command.
 
         This shows visual feedback by rewriting input lines that cause
         automatic calling to kick in, like::
 
           /f x
 
         into::
 
           ------> f(x)
           
         after the user's input prompt.  This helps the user understand that the
         input line was transformed automatically by IPython.
         """
         rw = self.displayhook.prompt1.auto_rewrite() + cmd
 
         try:
             # plain ascii works better w/ pyreadline, on some machines, so
             # we use it and only print uncolored rewrite if we have unicode
             rw = str(rw)
             print >> IPython.utils.io.Term.cout, rw
         except UnicodeEncodeError:
             print "------> " + cmd
             
     #-------------------------------------------------------------------------
     # Things related to extracting values/expressions from kernel and user_ns
     #-------------------------------------------------------------------------
 
     def _simple_error(self):
         etype, value = sys.exc_info()[:2]
         return u'[ERROR] {e.__name__}: {v}'.format(e=etype, v=value)
 
     def user_variables(self, names):
         """Get a list of variable names from the user's namespace.
 
         Parameters
         ----------
         names : list of strings
           A list of names of variables to be read from the user namespace.
 
         Returns
         -------
         A dict, keyed by the input names and with the repr() of each value.
         """
         out = {}
         user_ns = self.user_ns
         for varname in names:
             try:
                 value = repr(user_ns[varname])
             except:
                 value = self._simple_error()
             out[varname] = value
         return out
         
     def user_expressions(self, expressions):
         """Evaluate a dict of expressions in the user's namespace.
 
         Parameters
         ----------
         expressions : dict
           A dict with string keys and string values.  The expression values
           should be valid Python expressions, each of which will be evaluated
           in the user namespace.
         
         Returns
         -------
         A dict, keyed like the input expressions dict, with the repr() of each
         value.
         """
         out = {}
         user_ns = self.user_ns
         global_ns = self.user_global_ns
         for key, expr in expressions.iteritems():
             try:
                 value = repr(eval(expr, global_ns, user_ns))
             except:
                 value = self._simple_error()
             out[key] = value
         return out
 
     #-------------------------------------------------------------------------
     # Things related to the running of code
     #-------------------------------------------------------------------------
 
     def ex(self, cmd):
         """Execute a normal python statement in user namespace."""
         with nested(self.builtin_trap,):
             exec cmd in self.user_global_ns, self.user_ns
 
     def ev(self, expr):
         """Evaluate python expression expr in user namespace.
 
         Returns the result of evaluation
         """
         with nested(self.builtin_trap,):
             return eval(expr, self.user_global_ns, self.user_ns)
 
     def safe_execfile(self, fname, *where, **kw):
         """A safe version of the builtin execfile().
 
         This version will never throw an exception, but instead print
         helpful error messages to the screen.  This only works on pure
         Python files with the .py extension.
 
         Parameters
         ----------
         fname : string
             The name of the file to be executed.
         where : tuple
             One or two namespaces, passed to execfile() as (globals,locals).
             If only one is given, it is passed as both.
         exit_ignore : bool (False)
             If True, then silence SystemExit for non-zero status (it is always
             silenced for zero status, as it is so common).
         """
         kw.setdefault('exit_ignore', False)
 
         fname = os.path.abspath(os.path.expanduser(fname))
 
         # Make sure we have a .py file
         if not fname.endswith('.py'):
             warn('File must end with .py to be run using execfile: <%s>' % fname)
 
         # Make sure we can open the file
         try:
             with open(fname) as thefile:
                 pass
         except:
             warn('Could not open file <%s> for safe execution.' % fname)
             return
 
         # Find things also in current directory.  This is needed to mimic the
         # behavior of running a script from the system command line, where
         # Python inserts the script's directory into sys.path
         dname = os.path.dirname(fname)
 
         with prepended_to_syspath(dname):
             try:
                 execfile(fname,*where)
             except SystemExit, status:
                 # If the call was made with 0 or None exit status (sys.exit(0)
                 # or sys.exit() ), don't bother showing a traceback, as both of
                 # these are considered normal by the OS:
                 # > python -c'import sys;sys.exit(0)'; echo $?
                 # 0
                 # > python -c'import sys;sys.exit()'; echo $?
                 # 0
                 # For other exit status, we show the exception unless
                 # explicitly silenced, but only in short form.
                 if status.code not in (0, None) and not kw['exit_ignore']:
                     self.showtraceback(exception_only=True)
             except:
                 self.showtraceback()
 
     def safe_execfile_ipy(self, fname):
         """Like safe_execfile, but for .ipy files with IPython syntax.
 
         Parameters
         ----------
         fname : str
             The name of the file to execute.  The filename must have a
             .ipy extension.
         """
         fname = os.path.abspath(os.path.expanduser(fname))
 
         # Make sure we have a .py file
         if not fname.endswith('.ipy'):
             warn('File must end with .py to be run using execfile: <%s>' % fname)
 
         # Make sure we can open the file
         try:
             with open(fname) as thefile:
                 pass
         except:
             warn('Could not open file <%s> for safe execution.' % fname)
             return
 
         # Find things also in current directory.  This is needed to mimic the
         # behavior of running a script from the system command line, where
         # Python inserts the script's directory into sys.path
         dname = os.path.dirname(fname)
 
         with prepended_to_syspath(dname):
             try:
                 with open(fname) as thefile:
                     # self.run_cell currently captures all exceptions
                     # raised in user code.  It would be nice if there were
                     # versions of runlines, execfile that did raise, so
                     # we could catch the errors.
                     self.run_cell(thefile.read())
             except:
                 self.showtraceback()
                 warn('Unknown failure executing file: <%s>' % fname)
 
     def run_cell(self, cell, store_history=True):
         """Run the contents of an entire multiline 'cell' of code, and store it
         in the history.
 
         The cell is split into separate blocks which can be executed
         individually.  Then, based on how many blocks there are, they are
         executed as follows:
 
         - A single block: 'single' mode. If it is also a single line, dynamic
         transformations, including automagic and macros, will be applied.
 
         If there's more than one block, it depends:
 
         - if the last one is no more than two lines long, run all but the last
         in 'exec' mode and the very last one in 'single' mode.  This makes it
         easy to type simple expressions at the end to see computed values.  -
         otherwise (last one is also multiline), run all in 'exec' mode
 
         When code is executed in 'single' mode, :func:`sys.displayhook` fires,
         results are displayed and output prompts are computed.  In 'exec' mode,
         no results are displayed unless :func:`print` is called explicitly;
         this mode is more akin to running a script.
 
         Parameters
         ----------
         cell : str
           A single or multiline string.
         """
         # Store the untransformed code
         raw_cell = cell
         
         # We only do dynamic transforms on a single line. We need to do this
         # first, because a macro can be expanded to several lines, which then
         # need to be split into blocks again.
         if len(cell.splitlines()) <= 1:
             temp = self.input_splitter.split_blocks(cell)
             cell = self.prefilter_manager.prefilter_line(temp[0])
         
         # We need to break up the input into executable blocks that can be run
         # in 'single' mode, to provide comfortable user behavior.
         blocks = self.input_splitter.split_blocks(cell)
         
         if not blocks:
             return
 
         # Store the 'ipython' version of the cell as well, since that's what
         # needs to go into the translated history and get executed (the
         # original cell may contain non-python syntax).
         cell = ''.join(blocks)
 
         # Store raw and processed history
         if store_history:
             self.history_manager.store_inputs(self.execution_count, 
                                                         cell, raw_cell)
 
         self.logger.log(cell, raw_cell)
 
         # All user code execution must happen with our context managers active
         with nested(self.builtin_trap, self.display_trap):
 
             # Single-block input should behave like an interactive prompt
             if len(blocks) == 1:
                 out = self.run_source(blocks[0])
                 # Write output to the database. Does nothing unless
                 # history output logging is enabled.
                 if store_history:
                     self.history_manager.store_output(self.execution_count)
                     # since we return here, we need to update the execution count
                     self.execution_count += 1
                 return out
 
             # In multi-block input, if the last block is a simple (one-two
             # lines) expression, run it in single mode so it produces output.
             # Otherwise just run it all in 'exec' mode.  This seems like a
             # reasonable usability design.
             last = blocks[-1]
             last_nlines = len(last.splitlines())
             
             if last_nlines < 2:
                 # Here we consider the cell split between 'body' and 'last',
                 # store all history and execute 'body', and if successful, then
                 # proceed to execute 'last'.
 
                 # Get the main body to run as a cell
                 ipy_body = ''.join(blocks[:-1])
                 retcode = self.run_source(ipy_body, symbol='exec',
                                           post_execute=False)
                 if retcode==0:
                     # Last expression compiled as 'single' so it produces output
                     self.run_source(last)
             else:
                 # Run the whole cell as one entity, storing both raw and
                 # processed input in history
                 self.run_source(ipy_cell, symbol='exec')
 
         # Write output to the database. Does nothing unless
         # history output logging is enabled.
         if store_history:
             self.history_manager.store_output(self.execution_count)
             # Each cell is a *single* input, regardless of how many lines it has
             self.execution_count += 1
 
     # PENDING REMOVAL: this method is slated for deletion, once our new
     # input logic has been 100% moved to frontends and is stable.
     def runlines(self, lines, clean=False):
         """Run a string of one or more lines of source.
 
         This method is capable of running a string containing multiple source
         lines, as if they had been entered at the IPython prompt.  Since it
         exposes IPython's processing machinery, the given strings can contain
         magic calls (%magic), special shell access (!cmd), etc.
         """
         
         if not isinstance(lines, (list, tuple)):
             lines = lines.splitlines()
 
         if clean:
             lines = self._cleanup_ipy_script(lines)
 
         # We must start with a clean buffer, in case this is run from an
         # interactive IPython session (via a magic, for example).
         self.reset_buffer()
 
         # Since we will prefilter all lines, store the user's raw input too
         # before we apply any transformations
         self.buffer_raw[:] = [ l+'\n' for l in lines]
         
         more = False
         prefilter_lines = self.prefilter_manager.prefilter_lines
         with nested(self.builtin_trap, self.display_trap):
             for line in lines:
                 # skip blank lines so we don't mess up the prompt counter, but
                 # do NOT skip even a blank line if we are in a code block (more
                 # is true)
             
                 if line or more:
                     more = self.push_line(prefilter_lines(line, more))
                     # IPython's run_source returns None if there was an error
                     # compiling the code.  This allows us to stop processing
                     # right away, so the user gets the error message at the
                     # right place.
                     if more is None:
                         break
             # final newline in case the input didn't have it, so that the code
             # actually does get executed
             if more:
                 self.push_line('\n')
 
     def run_source(self, source, filename=None,
                    symbol='single', post_execute=True):
         """Compile and run some source in the interpreter.
 
         Arguments are as for compile_command().
 
         One several things can happen:
 
         1) The input is incorrect; compile_command() raised an
         exception (SyntaxError or OverflowError).  A syntax traceback
         will be printed by calling the showsyntaxerror() method.
 
         2) The input is incomplete, and more input is required;
         compile_command() returned None.  Nothing happens.
 
         3) The input is complete; compile_command() returned a code
         object.  The code is executed by calling self.run_code() (which
         also handles run-time exceptions, except for SystemExit).
 
         The return value is:
 
           - True in case 2
 
           - False in the other cases, unless an exception is raised, where
           None is returned instead.  This can be used by external callers to
           know whether to continue feeding input or not.
 
         The return value can be used to decide whether to use sys.ps1 or
         sys.ps2 to prompt the next line."""
 
         # We need to ensure that the source is unicode from here on.
         if type(source)==str:
             usource = source.decode(self.stdin_encoding)
         else:
             usource = source
 
         if 0:  # dbg
             print 'Source:', repr(source)  # dbg
             print 'USource:', repr(usource)  # dbg
             print 'type:', type(source) # dbg
             print 'encoding', self.stdin_encoding  # dbg
         
         try:
             code = self.compile(usource, symbol, self.execution_count)
         except (OverflowError, SyntaxError, ValueError, TypeError, MemoryError):
             # Case 1
             self.showsyntaxerror(filename)
             return None
 
         if code is None:
             # Case 2
             return True
 
         # Case 3
         # We store the code object so that threaded shells and
         # custom exception handlers can access all this info if needed.
         # The source corresponding to this can be obtained from the
         # buffer attribute as '\n'.join(self.buffer).
         self.code_to_run = code
         # now actually execute the code object
         if self.run_code(code, post_execute) == 0:
             return False
         else:
             return None
 
     # For backwards compatibility
     runsource = run_source
     
     def run_code(self, code_obj, post_execute=True):
         """Execute a code object.
 
         When an exception occurs, self.showtraceback() is called to display a
         traceback.
 
         Return value: a flag indicating whether the code to be run completed
         successfully:
 
           - 0: successful execution.
           - 1: an error occurred.
         """
 
         # Set our own excepthook in case the user code tries to call it
         # directly, so that the IPython crash handler doesn't get triggered
         old_excepthook,sys.excepthook = sys.excepthook, self.excepthook
 
         # we save the original sys.excepthook in the instance, in case config
         # code (such as magics) needs access to it.
         self.sys_excepthook = old_excepthook
         outflag = 1  # happens in more places, so it's easier as default
         try:
             try:
                 self.hooks.pre_run_code_hook()
                 #rprint('Running code', repr(code_obj)) # dbg
                 exec code_obj in self.user_global_ns, self.user_ns
             finally:
                 # Reset our crash handler in place
                 sys.excepthook = old_excepthook
         except SystemExit:
             self.reset_buffer()
             self.showtraceback(exception_only=True)
             warn("To exit: use any of 'exit', 'quit', %Exit or Ctrl-D.", level=1)
         except self.custom_exceptions:
             etype,value,tb = sys.exc_info()
             self.CustomTB(etype,value,tb)
         except:
             self.showtraceback()
         else:
             outflag = 0
             if softspace(sys.stdout, 0):
                 print
 
         # Execute any registered post-execution functions.  Here, any errors
         # are reported only minimally and just on the terminal, because the
         # main exception channel may be occupied with a user traceback.
         # FIXME: we need to think this mechanism a little more carefully.
         if post_execute:
             for func in self._post_execute:
                 try:
                     func()
                 except:
                     head = '[ ERROR ] Evaluating post_execute function: %s' % \
                            func
                     print >> io.Term.cout, head
                     print >> io.Term.cout, self._simple_error()
                     print >> io.Term.cout, 'Removing from post_execute'
                     self._post_execute.remove(func)
 
         # Flush out code object which has been run (and source)
         self.code_to_run = None
         return outflag
         
     # For backwards compatibility
     runcode = run_code
 
     # PENDING REMOVAL: this method is slated for deletion, once our new
     # input logic has been 100% moved to frontends and is stable.
     def push_line(self, line):
         """Push a line to the interpreter.
 
         The line should not have a trailing newline; it may have
         internal newlines.  The line is appended to a buffer and the
         interpreter's run_source() method is called with the
         concatenated contents of the buffer as source.  If this
         indicates that the command was executed or invalid, the buffer
         is reset; otherwise, the command is incomplete, and the buffer
         is left as it was after the line was appended.  The return
         value is 1 if more input is required, 0 if the line was dealt
         with in some way (this is the same as run_source()).
         """
 
         # autoindent management should be done here, and not in the
         # interactive loop, since that one is only seen by keyboard input.  We
         # need this done correctly even for code run via runlines (which uses
         # push).
 
         #print 'push line: <%s>' % line  # dbg
         self.buffer.append(line)
         full_source = '\n'.join(self.buffer)
         more = self.run_source(full_source, self.filename)
         if not more:
             self.history_manager.store_inputs(self.execution_count,
                                         '\n'.join(self.buffer_raw), full_source)
             self.reset_buffer()
             self.execution_count += 1
         return more
 
     def reset_buffer(self):
         """Reset the input buffer."""
         self.buffer[:] = []
         self.buffer_raw[:] = []
         self.input_splitter.reset()
 
     # For backwards compatibility
     resetbuffer = reset_buffer
 
     def _is_secondary_block_start(self, s):
         if not s.endswith(':'):
             return False
         if (s.startswith('elif') or 
             s.startswith('else') or 
             s.startswith('except') or
             s.startswith('finally')):
             return True
 
     def _cleanup_ipy_script(self, script):
         """Make a script safe for self.runlines()
 
         Currently, IPython is lines based, with blocks being detected by
         empty lines.  This is a problem for block based scripts that may
         not have empty lines after blocks.  This script adds those empty
         lines to make scripts safe for running in the current line based
         IPython.
         """
         res = []
         lines = script.splitlines()
         level = 0
 
         for l in lines:
             lstripped = l.lstrip()
             stripped = l.strip()                
             if not stripped:
                 continue
             newlevel = len(l) - len(lstripped)                    
             if level > 0 and newlevel == 0 and \
                    not self._is_secondary_block_start(stripped): 
                 # add empty line
                 res.append('')
             res.append(l)
             level = newlevel
 
         return '\n'.join(res) + '\n'
 
     #-------------------------------------------------------------------------
     # Things related to GUI support and pylab
     #-------------------------------------------------------------------------
 
     def enable_pylab(self, gui=None):
         raise NotImplementedError('Implement enable_pylab in a subclass')
 
     #-------------------------------------------------------------------------
     # Utilities
     #-------------------------------------------------------------------------
 
     def var_expand(self,cmd,depth=0):
         """Expand python variables in a string.
 
         The depth argument indicates how many frames above the caller should
         be walked to look for the local namespace where to expand variables.
 
         The global namespace for expansion is always the user's interactive
         namespace.
         """
 
         return str(ItplNS(cmd,
                           self.user_ns,  # globals
                           # Skip our own frame in searching for locals:
                           sys._getframe(depth+1).f_locals # locals
                           ))
 
     def mktempfile(self, data=None, prefix='ipython_edit_'):
         """Make a new tempfile and return its filename.
 
         This makes a call to tempfile.mktemp, but it registers the created
         filename internally so ipython cleans it up at exit time.
 
         Optional inputs:
 
           - data(None): if data is given, it gets written out to the temp file
           immediately, and the file is closed again."""
 
         filename = tempfile.mktemp('.py', prefix)
         self.tempfiles.append(filename)
         
         if data:
             tmp_file = open(filename,'w')
             tmp_file.write(data)
             tmp_file.close()
         return filename
 
     # TODO:  This should be removed when Term is refactored.
     def write(self,data):
         """Write a string to the default output"""
         io.Term.cout.write(data)
 
     # TODO:  This should be removed when Term is refactored.
     def write_err(self,data):
         """Write a string to the default error output"""
         io.Term.cerr.write(data)
 
     def ask_yes_no(self,prompt,default=True):
         if self.quiet:
             return True
         return ask_yes_no(prompt,default)
     
     def show_usage(self):
         """Show a usage message"""
         page.page(IPython.core.usage.interactive_usage)
 
     #-------------------------------------------------------------------------
     # Things related to IPython exiting
     #-------------------------------------------------------------------------
     def atexit_operations(self):
         """This will be executed at the time of exit.
 
         Cleanup operations and saving of persistent data that is done
         unconditionally by IPython should be performed here.
 
         For things that may depend on startup flags or platform specifics (such
         as having readline or not), register a separate atexit function in the
         code that has the appropriate information, rather than trying to
         clutter 
         """
         # Cleanup all tempfiles left around
         for tfile in self.tempfiles:
             try:
                 os.unlink(tfile)
             except OSError:
                 pass
         
         # Close the history session (this stores the end time and line count)
         self.history_manager.end_session()
         
         # Clear all user namespaces to release all references cleanly.
         self.reset(new_session=False)
 
         # Run user hooks
         self.hooks.shutdown_hook()
 
     def cleanup(self):
         self.restore_sys_module_state()
 
 
 class InteractiveShellABC(object):
     """An abstract base class for InteractiveShell."""
     __metaclass__ = abc.ABCMeta
 
 InteractiveShellABC.register(InteractiveShell)

IPython/core/tests/test_history.py

@@ -1,109 +1,109 b''
 """Tests for the IPython tab-completion machinery.
 """
 #-----------------------------------------------------------------------------
 # Module imports
 #-----------------------------------------------------------------------------
 
 # stdlib
 import os
 import sys
 import unittest
 
 # third party
 import nose.tools as nt
 
 # our own packages
 from IPython.utils.tempdir import TemporaryDirectory
 from IPython.core.history import HistoryManager, extract_hist_ranges
 
 def test_history():
 
     ip = get_ipython()
     with TemporaryDirectory() as tmpdir:
         #tmpdir = '/software/temp'
         histfile = os.path.realpath(os.path.join(tmpdir, 'history.sqlite'))
         # Ensure that we restore the history management that we mess with in
         # this test doesn't affect the IPython instance used by the test suite
         # beyond this test.
         hist_manager_ori = ip.history_manager
         try:
             ip.history_manager = HistoryManager(shell=ip)
             ip.history_manager.hist_file = histfile
             ip.history_manager.init_db()  # Has to be called after changing file
             ip.history_manager.reset()
             print 'test',histfile
             hist = ['a=1', 'def f():\n    test = 1\n    return test', 'b=2']
             for i, h in enumerate(hist, start=1):
                 ip.history_manager.store_inputs(i, h)
             
             ip.history_manager.db_log_output = True
             # Doesn't match the input, but we'll just check it's stored.
             ip.history_manager.output_hist_reprs[3].append("spam")
             ip.history_manager.store_output(3)
             
             nt.assert_equal(ip.history_manager.input_hist_raw, [''] + hist)
             
             # Check lines were written to DB
             c = ip.history_manager.db.execute("SELECT source_raw FROM history")
             nt.assert_equal([x for x, in c], hist)
               
             # New session
             ip.history_manager.reset()
             newcmds = ["z=5","class X(object):\n    pass", "k='p'"]
             for i, cmd in enumerate(newcmds, start=1):
                 ip.history_manager.store_inputs(i, cmd)
-            gothist = ip.history_manager.get_history(start=1, stop=4)
+            gothist = ip.history_manager.get_range(start=1, stop=4)
             nt.assert_equal(list(gothist), zip([0,0,0],[1,2,3], newcmds))
             # Previous session:
-            gothist = ip.history_manager.get_history(-1, 1, 4)
+            gothist = ip.history_manager.get_range(-1, 1, 4)
             nt.assert_equal(list(gothist), zip([1,1,1],[1,2,3], hist))
             
             # Check get_hist_tail
-            gothist = ip.history_manager.get_hist_tail(4, output=True,
+            gothist = ip.history_manager.get_tail(4, output=True,
                                                     include_latest=True)
             expected = [(1, 3, (hist[-1], ["spam"])),
                         (2, 1, (newcmds[0], None)),
                         (2, 2, (newcmds[1], None)),
                         (2, 3, (newcmds[2], None)),]
             nt.assert_equal(list(gothist), expected)
             
-            gothist = ip.history_manager.get_hist_tail(2)
+            gothist = ip.history_manager.get_tail(2)
             expected = [(2, 1, newcmds[0]),
                         (2, 2, newcmds[1])]
             nt.assert_equal(list(gothist), expected)
             
             # Check get_hist_search
-            gothist = ip.history_manager.get_hist_search("*test*")
+            gothist = ip.history_manager.search("*test*")
             nt.assert_equal(list(gothist), [(1,2,hist[1])] )
-            gothist = ip.history_manager.get_hist_search("b*", output=True)
+            gothist = ip.history_manager.search("b*", output=True)
             nt.assert_equal(list(gothist), [(1,3,(hist[2],["spam"]))] )
             
             # Cross testing: check that magic %save can get previous session.
             testfilename = os.path.realpath(os.path.join(tmpdir, "test.py"))
             ip.magic_save(testfilename + " ~1/1-3")
             testfile = open(testfilename, "r")
             nt.assert_equal(testfile.read(), "\n".join(hist))
         finally:
             # Restore history manager
             ip.history_manager = hist_manager_ori
 
 def test_extract_hist_ranges():
     instr = "1 2/3 ~4/5-6 ~4/7-~4/9 ~9/2-~7/5"
     expected = [(0, 1, 2),  # 0 == current session
                 (2, 3, 4),
                 (-4, 5, 7),
                 (-4, 7, 10),
                 (-9, 2, None),  # None == to end
                 (-8, 1, None),
                 (-7, 1, 6)]
     actual = list(extract_hist_ranges(instr))
     nt.assert_equal(actual, expected)
     
 def test_magic_rerun():
     """Simple test for %rerun (no args -> rerun last line)"""
     ip = get_ipython()
     ip.run_cell("a = 10")
     ip.run_cell("a += 1")
     nt.assert_equal(ip.user_ns["a"], 11)
     ip.run_cell("%rerun")
     nt.assert_equal(ip.user_ns["a"], 12)

IPython/zmq/ipkernel.py

@@ -1,643 +1,643 b''
 #!/usr/bin/env python
 """A simple interactive kernel that talks to a frontend over 0MQ.
 
 Things to do:
 
 * Implement `set_parent` logic. Right before doing exec, the Kernel should
   call set_parent on all the PUB objects with the message about to be executed.
 * Implement random port and security key logic.
 * Implement control messages.
 * Implement event loop and poll version.
 """
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from __future__ import print_function
 
 # Standard library imports.
 import __builtin__
 import atexit
 import sys
 import time
 import traceback
 import logging
 # System library imports.
 import zmq
 
 # Local imports.
 from IPython.config.configurable import Configurable
 from IPython.utils import io
 from IPython.utils.jsonutil import json_clean
 from IPython.lib import pylabtools
 from IPython.utils.traitlets import Instance, Float
 from entry_point import (base_launch_kernel, make_argument_parser, make_kernel,
                          start_kernel)
 from iostream import OutStream
 from session import Session, Message
 from zmqshell import ZMQInteractiveShell
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 # Module-level logger
 logger = logging.getLogger(__name__)
 
 #-----------------------------------------------------------------------------
 # Main kernel class
 #-----------------------------------------------------------------------------
 
 class Kernel(Configurable):
 
     #---------------------------------------------------------------------------
     # Kernel interface
     #---------------------------------------------------------------------------
 
     shell = Instance('IPython.core.interactiveshell.InteractiveShellABC')
     session = Instance(Session)
     reply_socket = Instance('zmq.Socket')
     pub_socket = Instance('zmq.Socket')
     req_socket = Instance('zmq.Socket')
 
     # Private interface
 
     # Time to sleep after flushing the stdout/err buffers in each execute
     # cycle.  While this introduces a hard limit on the minimal latency of the
     # execute cycle, it helps prevent output synchronization problems for
     # clients.
     # Units are in seconds.  The minimum zmq latency on local host is probably
     # ~150 microseconds, set this to 500us for now.  We may need to increase it
     # a little if it's not enough after more interactive testing.
     _execute_sleep = Float(0.0005, config=True)
 
     # Frequency of the kernel's event loop.
     # Units are in seconds, kernel subclasses for GUI toolkits may need to
     # adapt to milliseconds.
     _poll_interval = Float(0.05, config=True)
 
     # If the shutdown was requested over the network, we leave here the
     # necessary reply message so it can be sent by our registered atexit
     # handler.  This ensures that the reply is only sent to clients truly at
     # the end of our shutdown process (which happens after the underlying
     # IPython shell's own shutdown).
     _shutdown_message = None
 
     # This is a dict of port number that the kernel is listening on. It is set
     # by record_ports and used by connect_request.
     _recorded_ports = None
 
 
     def __init__(self, **kwargs):
         super(Kernel, self).__init__(**kwargs)
 
         # Before we even start up the shell, register *first* our exit handlers
         # so they come before the shell's
         atexit.register(self._at_shutdown)
 
         # Initialize the InteractiveShell subclass
         self.shell = ZMQInteractiveShell.instance()
         self.shell.displayhook.session = self.session
         self.shell.displayhook.pub_socket = self.pub_socket
         self.shell.display_pub.session = self.session
         self.shell.display_pub.pub_socket = self.pub_socket
 
         # TMP - hack while developing
         self.shell._reply_content = None
 
         # Build dict of handlers for message types
         msg_types = [ 'execute_request', 'complete_request', 
                       'object_info_request', 'history_tail_request',
                       'connect_request', 'shutdown_request']
         self.handlers = {}
         for msg_type in msg_types:
             self.handlers[msg_type] = getattr(self, msg_type)
 
     def do_one_iteration(self):
         """Do one iteration of the kernel's evaluation loop.
         """
         ident,msg = self.session.recv(self.reply_socket, zmq.NOBLOCK)
         if msg is None:
             return
         
         # This assert will raise in versions of zeromq 2.0.7 and lesser.
         # We now require 2.0.8 or above, so we can uncomment for safety.
         # print(ident,msg, file=sys.__stdout__)
         assert ident is not None, "Missing message part."
         
         # Print some info about this message and leave a '--->' marker, so it's
         # easier to trace visually the message chain when debugging.  Each
         # handler prints its message at the end.
         # Eventually we'll move these from stdout to a logger.
         logger.debug('\n*** MESSAGE TYPE:'+str(msg['msg_type'])+'***')
         logger.debug('   Content: '+str(msg['content'])+'\n   --->\n   ')
 
         # Find and call actual handler for message
         handler = self.handlers.get(msg['msg_type'], None)
         if handler is None:
             logger.error("UNKNOWN MESSAGE TYPE:" +str(msg))
         else:
             handler(ident, msg)
             
         # Check whether we should exit, in case the incoming message set the
         # exit flag on
         if self.shell.exit_now:
             logger.debug('\nExiting IPython kernel...')
             # We do a normal, clean exit, which allows any actions registered
             # via atexit (such as history saving) to take place.
             sys.exit(0)
 
 
     def start(self):
         """ Start the kernel main loop.
         """
         while True:
             time.sleep(self._poll_interval)
             self.do_one_iteration()
 
     def record_ports(self, xrep_port, pub_port, req_port, hb_port):
         """Record the ports that this kernel is using.
 
         The creator of the Kernel instance must call this methods if they
         want the :meth:`connect_request` method to return the port numbers.
         """
         self._recorded_ports = {
             'xrep_port' : xrep_port,
             'pub_port' : pub_port,
             'req_port' : req_port,
             'hb_port' : hb_port
         }
 
     #---------------------------------------------------------------------------
     # Kernel request handlers
     #---------------------------------------------------------------------------
 
     def _publish_pyin(self, code, parent):
         """Publish the code request on the pyin stream."""
 
         pyin_msg = self.session.send(self.pub_socket, u'pyin',{u'code':code}, parent=parent)
 
     def execute_request(self, ident, parent):
         
         status_msg = self.session.send(self.pub_socket,
             u'status',
             {u'execution_state':u'busy'},
             parent=parent
         )
         
         try:
             content = parent[u'content']
             code = content[u'code']
             silent = content[u'silent'] 
         except:
             logger.error("Got bad msg: ")
             logger.error(str(Message(parent)))
             return
 
         shell = self.shell # we'll need this a lot here
 
         # Replace raw_input. Note that is not sufficient to replace 
         # raw_input in the user namespace.
         raw_input = lambda prompt='': self._raw_input(prompt, ident, parent)
         __builtin__.raw_input = raw_input
 
         # Set the parent message of the display hook and out streams.
         shell.displayhook.set_parent(parent)
         shell.display_pub.set_parent(parent)
         sys.stdout.set_parent(parent)
         sys.stderr.set_parent(parent)
 
         # Re-broadcast our input for the benefit of listening clients, and
         # start computing output
         if not silent:
             self._publish_pyin(code, parent)
 
         reply_content = {}
         try:
             if silent:
                 # run_code uses 'exec' mode, so no displayhook will fire, and it
                 # doesn't call logging or history manipulations.  Print
                 # statements in that code will obviously still execute.
                 shell.run_code(code)
             else:
                 # FIXME: the shell calls the exception handler itself.
                 shell._reply_content = None
                 shell.run_cell(code)
         except:
             status = u'error'
             # FIXME: this code right now isn't being used yet by default,
             # because the runlines() call above directly fires off exception
             # reporting.  This code, therefore, is only active in the scenario
             # where runlines itself has an unhandled exception.  We need to
             # uniformize this, for all exception construction to come from a
             # single location in the codbase.
             etype, evalue, tb = sys.exc_info()
             tb_list = traceback.format_exception(etype, evalue, tb)
             reply_content.update(shell._showtraceback(etype, evalue, tb_list))
         else:
             status = u'ok'
 
         reply_content[u'status'] = status
         
         # Return the execution counter so clients can display prompts
         reply_content['execution_count'] = shell.execution_count -1
 
         # FIXME - fish exception info out of shell, possibly left there by
         # runlines.  We'll need to clean up this logic later.
         if shell._reply_content is not None:
             reply_content.update(shell._reply_content)
 
         # At this point, we can tell whether the main code execution succeeded
         # or not.  If it did, we proceed to evaluate user_variables/expressions
         if reply_content['status'] == 'ok':
             reply_content[u'user_variables'] = \
                          shell.user_variables(content[u'user_variables'])
             reply_content[u'user_expressions'] = \
                          shell.user_expressions(content[u'user_expressions'])
         else:
             # If there was an error, don't even try to compute variables or
             # expressions
             reply_content[u'user_variables'] = {}
             reply_content[u'user_expressions'] = {}
 
         # Payloads should be retrieved regardless of outcome, so we can both
         # recover partial output (that could have been generated early in a
         # block, before an error) and clear the payload system always.
         reply_content[u'payload'] = shell.payload_manager.read_payload()
         # Be agressive about clearing the payload because we don't want
         # it to sit in memory until the next execute_request comes in.
         shell.payload_manager.clear_payload()
 
         # Flush output before sending the reply.
         sys.stdout.flush()
         sys.stderr.flush()
         # FIXME: on rare occasions, the flush doesn't seem to make it to the
         # clients... This seems to mitigate the problem, but we definitely need
         # to better understand what's going on.
         if self._execute_sleep:
             time.sleep(self._execute_sleep)
         
         # Send the reply.
         reply_msg = self.session.send(self.reply_socket, u'execute_reply',
                                       reply_content, parent, ident=ident)
         logger.debug(str(reply_msg))
 
         if reply_msg['content']['status'] == u'error':
             self._abort_queue()
 
         status_msg = self.session.send(self.pub_socket,
             u'status',
             {u'execution_state':u'idle'},
             parent=parent
         )
 
     def complete_request(self, ident, parent):
         txt, matches = self._complete(parent)
         matches = {'matches' : matches,
                    'matched_text' : txt,
                    'status' : 'ok'}
         completion_msg = self.session.send(self.reply_socket, 'complete_reply',
                                            matches, parent, ident)
         logger.debug(str(completion_msg))
 
     def object_info_request(self, ident, parent):
         object_info = self.shell.object_inspect(parent['content']['oname'])
         # Before we send this object over, we scrub it for JSON usage
         oinfo = json_clean(object_info)
         msg = self.session.send(self.reply_socket, 'object_info_reply',
                                 oinfo, parent, ident)
         logger.debug(msg)
 
     def history_tail_request(self, ident, parent):
         # We need to pull these out, as passing **kwargs doesn't work with
         # unicode keys before Python 2.6.5.
         n = parent['content']['n']
         raw = parent['content']['raw']
         output = parent['content']['output']
-        hist = self.shell.history_manager.get_hist_tail(n, raw=raw, output=output)
+        hist = self.shell.history_manager.get_tail(n, raw=raw, output=output)
         content = {'history' : list(hist)}
         msg = self.session.send(self.reply_socket, 'history_tail_reply',
                                 content, parent, ident)
         logger.debug(str(msg))
 
     def connect_request(self, ident, parent):
         if self._recorded_ports is not None:
             content = self._recorded_ports.copy()
         else:
             content = {}
         msg = self.session.send(self.reply_socket, 'connect_reply',
                                 content, parent, ident)
         logger.debug(msg)
 
     def shutdown_request(self, ident, parent):
         self.shell.exit_now = True
         self._shutdown_message = self.session.msg(u'shutdown_reply', parent['content'], parent)
         sys.exit(0)
 
     #---------------------------------------------------------------------------
     # Protected interface
     #---------------------------------------------------------------------------
 
     def _abort_queue(self):
         while True:
             ident,msg = self.session.recv(self.reply_socket, zmq.NOBLOCK)
             if msg is None:
                 break
             else:
                 assert ident is not None, \
                        "Unexpected missing message part."
 
             logger.debug("Aborting:\n"+str(Message(msg)))
             msg_type = msg['msg_type']
             reply_type = msg_type.split('_')[0] + '_reply'
             reply_msg = self.session.send(self.reply_socket, reply_type, 
                     {'status' : 'aborted'}, msg, ident=ident)
             logger.debug(reply_msg)
             # We need to wait a bit for requests to come in. This can probably
             # be set shorter for true asynchronous clients.
             time.sleep(0.1)
 
     def _raw_input(self, prompt, ident, parent):
         # Flush output before making the request.
         sys.stderr.flush()
         sys.stdout.flush()
 
         # Send the input request.
         content = dict(prompt=prompt)
         msg = self.session.send(self.req_socket, u'input_request', content, parent)
 
         # Await a response.
         ident, reply = self.session.recv(self.req_socket, 0)
         try:
             value = reply['content']['value']
         except:
             logger.error("Got bad raw_input reply: ")
             logger.error(str(Message(parent)))
             value = ''
         return value
     
     def _complete(self, msg):
         c = msg['content']
         try:
             cpos = int(c['cursor_pos'])
         except:
             # If we don't get something that we can convert to an integer, at
             # least attempt the completion guessing the cursor is at the end of
             # the text, if there's any, and otherwise of the line
             cpos = len(c['text'])
             if cpos==0:
                 cpos = len(c['line'])
         return self.shell.complete(c['text'], c['line'], cpos)
 
     def _object_info(self, context):
         symbol, leftover = self._symbol_from_context(context)
         if symbol is not None and not leftover:
             doc = getattr(symbol, '__doc__', '')
         else:
             doc = ''
         object_info = dict(docstring = doc)
         return object_info
 
     def _symbol_from_context(self, context):
         if not context:
             return None, context
 
         base_symbol_string = context[0]
         symbol = self.shell.user_ns.get(base_symbol_string, None)
         if symbol is None:
             symbol = __builtin__.__dict__.get(base_symbol_string, None)
         if symbol is None:
             return None, context
 
         context = context[1:]
         for i, name in enumerate(context):
             new_symbol = getattr(symbol, name, None)
             if new_symbol is None:
                 return symbol, context[i:]
             else:
                 symbol = new_symbol
 
         return symbol, []
 
     def _at_shutdown(self):
         """Actions taken at shutdown by the kernel, called by python's atexit.
         """
         # io.rprint("Kernel at_shutdown") # dbg
         if self._shutdown_message is not None:
             self.session.send(self.reply_socket, self._shutdown_message)
             self.session.send(self.pub_socket, self._shutdown_message)
             logger.debug(str(self._shutdown_message))
             # A very short sleep to give zmq time to flush its message buffers
             # before Python truly shuts down.
             time.sleep(0.01)
 
 
 class QtKernel(Kernel):
     """A Kernel subclass with Qt support."""
 
     def start(self):
         """Start a kernel with QtPy4 event loop integration."""
 
         from PyQt4 import QtCore
         from IPython.lib.guisupport import get_app_qt4, start_event_loop_qt4
 
         self.app = get_app_qt4([" "])
         self.app.setQuitOnLastWindowClosed(False)
         self.timer = QtCore.QTimer()
         self.timer.timeout.connect(self.do_one_iteration)
         # Units for the timer are in milliseconds
         self.timer.start(1000*self._poll_interval)
         start_event_loop_qt4(self.app)
 
 
 class WxKernel(Kernel):
     """A Kernel subclass with Wx support."""
 
     def start(self):
         """Start a kernel with wx event loop support."""
 
         import wx
         from IPython.lib.guisupport import start_event_loop_wx
 
         doi = self.do_one_iteration
          # Wx uses milliseconds
         poll_interval = int(1000*self._poll_interval)
 
         # We have to put the wx.Timer in a wx.Frame for it to fire properly.
         # We make the Frame hidden when we create it in the main app below.
         class TimerFrame(wx.Frame):
             def __init__(self, func):
                 wx.Frame.__init__(self, None, -1)
                 self.timer = wx.Timer(self)
                 # Units for the timer are in milliseconds
                 self.timer.Start(poll_interval)
                 self.Bind(wx.EVT_TIMER, self.on_timer)
                 self.func = func
 
             def on_timer(self, event):
                 self.func()
 
         # We need a custom wx.App to create our Frame subclass that has the
         # wx.Timer to drive the ZMQ event loop.
         class IPWxApp(wx.App):
             def OnInit(self):
                 self.frame = TimerFrame(doi)
                 self.frame.Show(False)
                 return True
 
         # The redirect=False here makes sure that wx doesn't replace
         # sys.stdout/stderr with its own classes.
         self.app = IPWxApp(redirect=False)
         start_event_loop_wx(self.app)
 
 
 class TkKernel(Kernel):
     """A Kernel subclass with Tk support."""
 
     def start(self):
         """Start a Tk enabled event loop."""
 
         import Tkinter
         doi = self.do_one_iteration
         # Tk uses milliseconds
         poll_interval = int(1000*self._poll_interval)
         # For Tkinter, we create a Tk object and call its withdraw method.
         class Timer(object):
             def __init__(self, func):
                 self.app = Tkinter.Tk()
                 self.app.withdraw()
                 self.func = func
                 
             def on_timer(self):
                 self.func()
                 self.app.after(poll_interval, self.on_timer)
                 
             def start(self):
                 self.on_timer()  # Call it once to get things going.
                 self.app.mainloop()
 
         self.timer = Timer(doi)
         self.timer.start()
 
 
 class GTKKernel(Kernel):
     """A Kernel subclass with GTK support."""
     
     def start(self):
         """Start the kernel, coordinating with the GTK event loop"""
         from .gui.gtkembed import GTKEmbed
         
         gtk_kernel = GTKEmbed(self)
         gtk_kernel.start()
 
 
 #-----------------------------------------------------------------------------
 # Kernel main and launch functions
 #-----------------------------------------------------------------------------
 
 def launch_kernel(ip=None, xrep_port=0, pub_port=0, req_port=0, hb_port=0,
                   independent=False, pylab=False, colors=None):
     """Launches a localhost kernel, binding to the specified ports.
 
     Parameters
     ----------
     ip  : str, optional
         The ip address the kernel will bind to.
     
     xrep_port : int, optional
         The port to use for XREP channel.
 
     pub_port : int, optional
         The port to use for the SUB channel.
 
     req_port : int, optional
         The port to use for the REQ (raw input) channel.
 
     hb_port : int, optional
         The port to use for the hearbeat REP channel.
 
     independent : bool, optional (default False) 
         If set, the kernel process is guaranteed to survive if this process
         dies. If not set, an effort is made to ensure that the kernel is killed
         when this process dies. Note that in this case it is still good practice
         to kill kernels manually before exiting.
 
     pylab : bool or string, optional (default False)
         If not False, the kernel will be launched with pylab enabled. If a
         string is passed, matplotlib will use the specified backend. Otherwise,
         matplotlib's default backend will be used.
 
     colors : None or string, optional (default None)
         If not None, specify the color scheme. One of (NoColor, LightBG, Linux)
 
     Returns
     -------
     A tuple of form:
         (kernel_process, xrep_port, pub_port, req_port)
     where kernel_process is a Popen object and the ports are integers.
     """
     extra_arguments = []
     if pylab:
         extra_arguments.append('--pylab')
         if isinstance(pylab, basestring):
             extra_arguments.append(pylab)
     if ip is not None:
         extra_arguments.append('--ip')
         if isinstance(ip, basestring):
             extra_arguments.append(ip)
     if colors is not None:
         extra_arguments.append('--colors')
         extra_arguments.append(colors)
     return base_launch_kernel('from IPython.zmq.ipkernel import main; main()',
                               xrep_port, pub_port, req_port, hb_port, 
                               independent, extra_arguments)
 
 
 def main():
     """ The IPython kernel main entry point.
     """
     parser = make_argument_parser()
     parser.add_argument('--pylab', type=str, metavar='GUI', nargs='?', 
                         const='auto', help = \
 "Pre-load matplotlib and numpy for interactive use. If GUI is not \
 given, the GUI backend is matplotlib's, otherwise use one of: \
 ['tk', 'gtk', 'qt', 'wx', 'inline'].")
     parser.add_argument('--colors',
         type=str, dest='colors',
         help="Set the color scheme (NoColor, Linux, and LightBG).",
         metavar='ZMQInteractiveShell.colors')
     namespace = parser.parse_args()
 
     kernel_class = Kernel
 
     kernel_classes = {
         'qt' : QtKernel,
         'qt4': QtKernel,
         'inline': Kernel,
         'wx' : WxKernel,
         'tk' : TkKernel,
         'gtk': GTKKernel,
     }
     if namespace.pylab:
         if namespace.pylab == 'auto':
             gui, backend = pylabtools.find_gui_and_backend()
         else:
             gui, backend = pylabtools.find_gui_and_backend(namespace.pylab)
         kernel_class = kernel_classes.get(gui)
         if kernel_class is None:
             raise ValueError('GUI is not supported: %r' % gui)
         pylabtools.activate_matplotlib(backend)
     if namespace.colors:
         ZMQInteractiveShell.colors=namespace.colors
 
     kernel = make_kernel(namespace, kernel_class, OutStream)
 
     if namespace.pylab:
         pylabtools.import_pylab(kernel.shell.user_ns, backend,
                                 shell=kernel.shell)
 
     start_kernel(namespace, kernel)
 
 
 if __name__ == '__main__':
     main()