Aliases fixes: ls alias improvements and frontend-dependent fixes.

Isolated some aliases to the classes that can only run in certain
frontends, so we don't try to call 'clear' on the Qt terminal (which
doeesn't work).

IPython/core/alias.py

@@ -1,258 +1,264 b''
 #!/usr/bin/env python
 # encoding: utf-8
 """
 System command aliases.
 
 Authors:
 
 * Fernando Perez
 * Brian Granger
 """
 
 #-----------------------------------------------------------------------------
-#  Copyright (C) 2008-2009  The IPython Development Team
+#  Copyright (C) 2008-2010  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.
+#  Distributed under the terms of the BSD License.
+#
+#  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import __builtin__
 import keyword
 import os
 import re
 import sys
 
 from IPython.config.configurable import Configurable
 from IPython.core.splitinput import split_user_input
 
 from IPython.utils.traitlets import List, Instance
 from IPython.utils.autoattr import auto_attr
 from IPython.utils.warn import warn, error
 
 #-----------------------------------------------------------------------------
 # Utilities
 #-----------------------------------------------------------------------------
 
 # This is used as the pattern for calls to split_user_input.
 shell_line_split = re.compile(r'^(\s*)(\S*\s*)(.*$)')
 
 def default_aliases():
-    # Make some aliases automatically
-    # Prepare list of shell aliases to auto-define
+    """Return list of shell aliases to auto-define.
+    """
+    # Note: the aliases defined here should be safe to use on a kernel
+    # regardless of what frontend it is attached to.  Frontends that use a
+    # kernel in-process can define additional aliases that will only work in
+    # their case.  For example, things like 'less' or 'clear' that manipulate
+    # the terminal should NOT be declared here, as they will only work if the
+    # kernel is running inside a true terminal, and not over the network.
+    
     if os.name == 'posix':
-        default_aliases = ('mkdir mkdir', 'rmdir rmdir',
-                      'mv mv -i','rm rm -i','cp cp -i',
-                      'cat cat','less less','clear clear',
-                      # a better ls
-                      'ls ls -F',
+        default_aliases = [('mkdir', 'mkdir'), ('rmdir', 'rmdir'),
+                           ('mv', 'mv -i'), ('rm', 'rm -i'), ('cp', 'cp -i'),
+                           ('cat', 'cat'),
+                           ]
+        # Useful set of ls aliases.  The GNU and BSD options are a little
+        # different, so we make aliases that provide as similar as possible
+        # behavior in ipython, by passing the right flags for each platform
+        if sys.platform.startswith('linux'):
+            ls_aliases = [('ls', 'ls -F --color'),
                       # long ls
-                      'll ls -lF')
-        # Extra ls aliases with color, which need special treatment on BSD
-        # variants
-        ls_extra = ( # color ls
-                     'lc ls -F -o --color',
+                          ('ll', 'ls -F -o --color'),
                      # ls normal files only
-                     'lf ls -F -o --color %l | grep ^-',
+                          ('lf', 'ls -F -o --color %l | grep ^-'),
                      # ls symbolic links
-                     'lk ls -F -o --color %l | grep ^l',
+                          ('lk', 'ls -F -o --color %l | grep ^l'),
                      # directories or links to directories,
-                     'ldir ls -F -o --color %l | grep /$',
+                          ('ldir', 'ls -F -o --color %l | grep /$'),
                      # things which are executable
-                     'lx ls -F -o --color %l | grep ^-..x',
-                     )
-        # The BSDs don't ship GNU ls, so they don't understand the
-        # --color switch out of the box
-        if 'bsd' in sys.platform:
-            ls_extra = ( # ls normal files only
-                         'lf ls -lF | grep ^-',
+                          ('lx', 'ls -F -o --color %l | grep ^-..x'),
+                          ]
+        else:
+            # BSD, OSX, etc.
+            ls_aliases = [('ls', 'ls -F'),
+                          # long ls
+                          ('ll', 'ls -F -l'),
+                          # ls normal files only
+                          ('lf', 'ls -F -l %l | grep ^-'),
                          # ls symbolic links
-                         'lk ls -lF | grep ^l',
+                          ('lk', 'ls -F -l %l | grep ^l'),
                          # directories or links to directories,
-                         'ldir ls -lF | grep /$',
+                          ('ldir', 'ls -F -l %l | grep /$'),
                          # things which are executable
-                         'lx ls -lF | grep ^-..x',
-                         )
-        default_aliases = default_aliases + ls_extra
+                          ('lx', 'ls -F -l %l | grep ^-..x'),
+                          ]
+        default_aliases = default_aliases + ls_aliases
     elif os.name in ['nt','dos']:
-        default_aliases = ('ls dir /on',
-                      'ddir dir /ad /on', 'ldir dir /ad /on',
-                      'mkdir mkdir','rmdir rmdir','echo echo',
-                      'ren ren','cls cls','copy copy')
+        default_aliases = [('ls', 'dir /on'),
+                           ('ddir', 'dir /ad /on'), ('ldir', 'dir /ad /on'),
+                           ('mkdir', 'mkdir'), ('rmdir', 'rmdir'),
+                           ('echo', 'echo'), ('ren', 'ren'), ('copy', 'copy'),
+                           ]
     else:
-        default_aliases = ()
-    return [s.split(None,1) for s in default_aliases]
+        default_aliases = []
+        
+    return default_aliases
 
 
 class AliasError(Exception):
     pass
 
 
 class InvalidAliasError(AliasError):
     pass
 
-
 #-----------------------------------------------------------------------------
 # Main AliasManager class
 #-----------------------------------------------------------------------------
 
-
 class AliasManager(Configurable):
 
     default_aliases = List(default_aliases(), config=True)
     user_aliases = List(default_value=[], config=True)
     shell = Instance('IPython.core.interactiveshell.InteractiveShellABC')
 
     def __init__(self, shell=None, config=None):
         super(AliasManager, self).__init__(shell=shell, config=config)
         self.alias_table = {}
         self.exclude_aliases()
         self.init_aliases()
 
     def __contains__(self, name):
-        if name in self.alias_table:
-            return True
-        else:
-            return False
+        return name in self.alias_table
 
     @property
     def aliases(self):
         return [(item[0], item[1][1]) for item in self.alias_table.iteritems()]
 
     def exclude_aliases(self):
         # set of things NOT to alias (keywords, builtins and some magics)
         no_alias = set(['cd','popd','pushd','dhist','alias','unalias'])
         no_alias.update(set(keyword.kwlist))
         no_alias.update(set(__builtin__.__dict__.keys()))
         self.no_alias = no_alias
 
     def init_aliases(self):
         # Load default aliases
         for name, cmd in self.default_aliases:
             self.soft_define_alias(name, cmd)
 
         # Load user aliases
         for name, cmd in self.user_aliases:
             self.soft_define_alias(name, cmd)
 
     def clear_aliases(self):
         self.alias_table.clear()
 
     def soft_define_alias(self, name, cmd):
         """Define an alias, but don't raise on an AliasError."""
         try:
             self.define_alias(name, cmd)
         except AliasError, e:
             error("Invalid alias: %s" % e)
 
     def define_alias(self, name, cmd):
         """Define a new alias after validating it.
 
         This will raise an :exc:`AliasError` if there are validation
         problems.
         """
         nargs = self.validate_alias(name, cmd)
         self.alias_table[name] = (nargs, cmd)
 
     def undefine_alias(self, name):
         if self.alias_table.has_key(name):
             del self.alias_table[name]
 
     def validate_alias(self, name, cmd):
         """Validate an alias and return the its number of arguments."""
         if name in self.no_alias:
             raise InvalidAliasError("The name %s can't be aliased "
                                     "because it is a keyword or builtin." % name)
         if not (isinstance(cmd, basestring)):
             raise InvalidAliasError("An alias command must be a string, "
                                     "got: %r" % name)
         nargs = cmd.count('%s')
         if nargs>0 and cmd.find('%l')>=0:
             raise InvalidAliasError('The %s and %l specifiers are mutually '
                                     'exclusive in alias definitions.')
         return nargs
 
     def call_alias(self, alias, rest=''):
         """Call an alias given its name and the rest of the line."""
         cmd = self.transform_alias(alias, rest)
         try:
             self.shell.system(cmd)
         except:
             self.shell.showtraceback()
 
     def transform_alias(self, alias,rest=''):
         """Transform alias to system command string."""
         nargs, cmd = self.alias_table[alias]
 
         if ' ' in cmd and os.path.isfile(cmd):
             cmd = '"%s"' % cmd
 
         # Expand the %l special to be the user's input line
         if cmd.find('%l') >= 0:
             cmd = cmd.replace('%l', rest)
             rest = ''
         if nargs==0:
             # Simple, argument-less aliases
             cmd = '%s %s' % (cmd, rest)
         else:
             # Handle aliases with positional arguments
             args = rest.split(None, nargs)
             if len(args) < nargs:
                 raise AliasError('Alias <%s> requires %s arguments, %s given.' %
                       (alias, nargs, len(args)))
             cmd = '%s %s' % (cmd % tuple(args[:nargs]),' '.join(args[nargs:]))
         return cmd
 
     def expand_alias(self, line):
         """ Expand an alias in the command line 
         
         Returns the provided command line, possibly with the first word 
         (command) translated according to alias expansion rules.
         
         [ipython]|16> _ip.expand_aliases("np myfile.txt")
                  <16> 'q:/opt/np/notepad++.exe myfile.txt'
         """
         
         pre,fn,rest = split_user_input(line)
         res = pre + self.expand_aliases(fn, rest)
         return res
 
     def expand_aliases(self, fn, rest):
         """Expand multiple levels of aliases:
         
         if:
         
         alias foo bar /tmp
         alias baz foo
         
         then:
         
         baz huhhahhei -> bar /tmp huhhahhei
-        
         """
         line = fn + " " + rest
         
         done = set()
         while 1:
             pre,fn,rest = split_user_input(line, shell_line_split)
             if fn in self.alias_table:
                 if fn in done:
                     warn("Cyclic alias definition, repeated '%s'" % fn)
                     return ""
                 done.add(fn)
 
                 l2 = self.transform_alias(fn, rest)
                 if l2 == line:
                     break
                 # ls -> ls -F should not recurse forever
                 if l2.split(None,1)[0] == line.split(None,1)[0]:
                     line = l2
                     break
                 line=l2
             else:
                 break
                 
         return line

IPython/frontend/terminal/interactiveshell.py

@@ -1,630 +1,652 b''
 # -*- coding: utf-8 -*-
 """Subclass of InteractiveShell for terminal based frontends."""
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2001 Janko Hauser <[e-mail]>
 #  Copyright (C) 2001-2007 Fernando Perez. <[e-mail]>
 #  Copyright (C) 2008-2010  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import __builtin__
 import bdb
 from contextlib import nested
 import os
 import re
 import sys
 
 from IPython.core.error import TryNext
 from IPython.core.usage import interactive_usage, default_banner
 from IPython.core.inputlist import InputList
 from IPython.core.interactiveshell import InteractiveShell, InteractiveShellABC
 from IPython.lib.inputhook import enable_gui
 from IPython.lib.pylabtools import pylab_activate
 from IPython.utils.terminal import toggle_set_term_title, set_term_title
 from IPython.utils.process import abbrev_cwd
 from IPython.utils.warn import warn
 from IPython.utils.text import num_ini_spaces
 from IPython.utils.traitlets import Int, Str, CBool
 
 
 #-----------------------------------------------------------------------------
 # Utilities
 #-----------------------------------------------------------------------------
 
 
 def get_default_editor():
     try:
         ed = os.environ['EDITOR']
     except KeyError:
         if os.name == 'posix':
             ed = 'vi'  # the only one guaranteed to be there!
         else:
             ed = 'notepad' # same in Windows!
     return ed
 
 
 # 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
 
 
 #-----------------------------------------------------------------------------
 # Main class
 #-----------------------------------------------------------------------------
 
 
 class TerminalInteractiveShell(InteractiveShell):
 
     autoedit_syntax = CBool(False, config=True)
     banner = Str('')
     banner1 = Str(default_banner, config=True)
     banner2 = Str('', config=True)
     confirm_exit = CBool(True, config=True)
     # This display_banner only controls whether or not self.show_banner()
     # is called when mainloop/interact are called.  The default is False
     # because for the terminal based application, the banner behavior
     # is controlled by Global.display_banner, which IPythonApp looks at
     # to determine if *it* should call show_banner() by hand or not.
     display_banner = CBool(False) # This isn't configurable!
     embedded = CBool(False)
     embedded_active = CBool(False)
     editor = Str(get_default_editor(), config=True)
     pager = Str('less', config=True)
 
     screen_length = Int(0, config=True)
     term_title = CBool(False, config=True)
 
     def __init__(self, config=None, ipython_dir=None, user_ns=None,
                  user_global_ns=None, custom_exceptions=((),None),
                  usage=None, banner1=None, banner2=None,
                  display_banner=None):
 
         super(TerminalInteractiveShell, self).__init__(
             config=config, ipython_dir=ipython_dir, user_ns=user_ns,
             user_global_ns=user_global_ns, custom_exceptions=custom_exceptions
         )
         self.init_term_title()
         self.init_usage(usage)
         self.init_banner(banner1, banner2, display_banner)
 
     #-------------------------------------------------------------------------
     # Things related to the terminal
     #-------------------------------------------------------------------------
 
     @property
     def usable_screen_length(self):
         if self.screen_length == 0:
             return 0
         else:
             num_lines_bot = self.separate_in.count('\n')+1
             return self.screen_length - num_lines_bot
 
     def init_term_title(self):
         # Enable or disable the terminal title.
         if self.term_title:
             toggle_set_term_title(True)
             set_term_title('IPython: ' + abbrev_cwd())
         else:
             toggle_set_term_title(False)
 
     #-------------------------------------------------------------------------
+    # Things related to aliases
+    #-------------------------------------------------------------------------
+
+    def init_alias(self):
+        # The parent class defines aliases that can be safely used with any
+        # frontend.
+        super(TerminalInteractiveShell, self).init_alias()
+
+        # Now define aliases that only make sense on the terminal, because they
+        # need direct access to the console in a way that we can't emulate in
+        # GUI or web frontend
+        if os.name == 'posix':
+            aliases = [('clear', 'clear'), ('more', 'more'), ('less', 'less'),
+                       ('man', 'man')]
+        elif os.name == 'nt':
+            aliases = [('cls', 'cls')]
+
+
+        for name, cmd in aliases:
+            self.alias_manager.define_alias(name, cmd)
+
+    #-------------------------------------------------------------------------
     # Things related to the banner and usage
     #-------------------------------------------------------------------------
 
     def _banner1_changed(self):
         self.compute_banner()
 
     def _banner2_changed(self):
         self.compute_banner()
 
     def _term_title_changed(self, name, new_value):
         self.init_term_title()
 
     def init_banner(self, banner1, banner2, display_banner):
         if banner1 is not None:
             self.banner1 = banner1
         if banner2 is not None:
             self.banner2 = banner2
         if display_banner is not None:
             self.display_banner = display_banner
         self.compute_banner()
 
     def show_banner(self, banner=None):
         if banner is None:
             banner = self.banner
         self.write(banner)
 
     def compute_banner(self):
         self.banner = self.banner1 + '\n'
         if self.profile:
             self.banner += '\nIPython profile: %s\n' % self.profile
         if self.banner2:
             self.banner += '\n' + self.banner2 + '\n'
 
     def init_usage(self, usage=None):
         if usage is None:
             self.usage = interactive_usage
         else:
             self.usage = usage
 
     #-------------------------------------------------------------------------
     # Mainloop and code execution logic
     #-------------------------------------------------------------------------
 
     def mainloop(self, display_banner=None):
         """Start the mainloop.
 
         If an optional banner argument is given, it will override the
         internally created default banner.
         """
         
         with nested(self.builtin_trap, self.display_trap):
 
             # if you run stuff with -c <cmd>, raw hist is not updated
             # ensure that it's in sync
             if len(self.input_hist) != len (self.input_hist_raw):
                 self.input_hist_raw = InputList(self.input_hist)
 
             while 1:
                 try:
                     self.interact(display_banner=display_banner)
                     #self.interact_with_readline()                
                     # XXX for testing of a readline-decoupled repl loop, call
                     # interact_with_readline above
                     break
                 except KeyboardInterrupt:
                     # this should not be necessary, but KeyboardInterrupt
                     # handling seems rather unpredictable...
                     self.write("\nKeyboardInterrupt in interact()\n")
 
     def interact(self, display_banner=None):
         """Closely emulate the interactive Python console."""
 
         # batch run -> do not interact        
         if self.exit_now:
             return
 
         if display_banner is None:
             display_banner = self.display_banner
         if display_banner:
             self.show_banner()
 
         more = 0
         
         # Mark activity in the builtins
         __builtin__.__dict__['__IPYTHON__active'] += 1
         
         if self.has_readline:
             self.readline_startup_hook(self.pre_readline)
         # exit_now is set by a call to %Exit or %Quit, through the
         # ask_exit callback.
         
         while not self.exit_now:
             self.hooks.pre_prompt_hook()
             if more:
                 try:
                     prompt = self.hooks.generate_prompt(True)
                 except:
                     self.showtraceback()
                 if self.autoindent:
                     self.rl_do_indent = True
                     
             else:
                 try:
                     prompt = self.hooks.generate_prompt(False)
                 except:
                     self.showtraceback()
             try:
                 line = self.raw_input(prompt, more)
                 if self.exit_now:
                     # quick exit on sys.std[in|out] close
                     break
                 if self.autoindent:
                     self.rl_do_indent = False
                     
             except KeyboardInterrupt:
                 #double-guard against keyboardinterrupts during kbdint handling
                 try:
                     self.write('\nKeyboardInterrupt\n')
                     self.resetbuffer()
                     # keep cache in sync with the prompt counter:
                     self.displayhook.prompt_count -= 1
     
                     if self.autoindent:
                         self.indent_current_nsp = 0
                     more = 0
                 except KeyboardInterrupt:
                     pass
             except EOFError:
                 if self.autoindent:
                     self.rl_do_indent = False
                     if self.has_readline:
                         self.readline_startup_hook(None)
                 self.write('\n')
                 self.exit()
             except bdb.BdbQuit:
                 warn('The Python debugger has exited with a BdbQuit exception.\n'
                      'Because of how pdb handles the stack, it is impossible\n'
                      'for IPython to properly format this particular exception.\n'
                      'IPython will resume normal operation.')
             except:
                 # exceptions here are VERY RARE, but they can be triggered
                 # asynchronously by signal handlers, for example.
                 self.showtraceback()
             else:
                 more = self.push_line(line)
                 if (self.SyntaxTB.last_syntax_error and
                     self.autoedit_syntax):
                     self.edit_syntax_error()
 
         # We are off again...
         __builtin__.__dict__['__IPYTHON__active'] -= 1
 
         # Turn off the exit flag, so the mainloop can be restarted if desired
         self.exit_now = False
 
     def raw_input(self,prompt='',continue_prompt=False):
         """Write a prompt and read a line.
 
         The returned line does not include the trailing newline.
         When the user enters the EOF key sequence, EOFError is raised.
 
         Optional inputs:
 
           - prompt(''): a string to be printed to prompt the user.
 
           - continue_prompt(False): whether this line is the first one or a
           continuation in a sequence of inputs.
         """
         # growl.notify("raw_input: ", "prompt = %r\ncontinue_prompt = %s" % (prompt, continue_prompt))
 
         # Code run by the user may have modified the readline completer state.
         # We must ensure that our completer is back in place.
 
         if self.has_readline:
             self.set_readline_completer()
         
         try:
             line = raw_input_original(prompt).decode(self.stdin_encoding)
         except ValueError:
             warn("\n********\nYou or a %run:ed script called sys.stdin.close()"
                  " or sys.stdout.close()!\nExiting IPython!")
             self.ask_exit()
             return ""
 
         # Try to be reasonably smart about not re-indenting pasted input more
         # than necessary.  We do this by trimming out the auto-indent initial
         # spaces, if the user's actual input started itself with whitespace.
         #debugx('self.buffer[-1]')
 
         if self.autoindent:
             if num_ini_spaces(line) > self.indent_current_nsp:
                 line = line[self.indent_current_nsp:]
                 self.indent_current_nsp = 0
             
         # store the unfiltered input before the user has any chance to modify
         # it.
         if line.strip():
             if continue_prompt:
                 self.input_hist_raw[-1] += '%s\n' % line
                 if self.has_readline and self.readline_use:
                     try:
                         histlen = self.readline.get_current_history_length()
                         if histlen > 1:
                             newhist = self.input_hist_raw[-1].rstrip()
                             self.readline.remove_history_item(histlen-1)
                             self.readline.replace_history_item(histlen-2,
                                             newhist.encode(self.stdin_encoding))
                     except AttributeError:
                         pass # re{move,place}_history_item are new in 2.4.                
             else:
                 self.input_hist_raw.append('%s\n' % line)                
             # only entries starting at first column go to shadow history
             if line.lstrip() == line:
                 self.shadowhist.add(line.strip())
         elif not continue_prompt:
             self.input_hist_raw.append('\n')
         try:
             lineout = self.prefilter_manager.prefilter_lines(line,continue_prompt)
         except:
             # blanket except, in case a user-defined prefilter crashes, so it
             # can't take all of ipython with it.
             self.showtraceback()
             return ''
         else:
             return lineout
 
     # TODO: The following three methods are an early attempt to refactor
     # the main code execution logic. We don't use them, but they may be
     # helpful when we refactor the code execution logic further.
     # def interact_prompt(self):
     #     """ Print the prompt (in read-eval-print loop) 
     # 
     #     Provided for those who want to implement their own read-eval-print loop (e.g. GUIs), not 
     #     used in standard IPython flow.
     #     """
     #     if self.more:
     #         try:
     #             prompt = self.hooks.generate_prompt(True)
     #         except:
     #             self.showtraceback()
     #         if self.autoindent:
     #             self.rl_do_indent = True
     # 
     #     else:
     #         try:
     #             prompt = self.hooks.generate_prompt(False)
     #         except:
     #             self.showtraceback()
     #     self.write(prompt)
     # 
     # def interact_handle_input(self,line):
     #     """ Handle the input line (in read-eval-print loop)
     #     
     #     Provided for those who want to implement their own read-eval-print loop (e.g. GUIs), not 
     #     used in standard IPython flow.        
     #     """
     #     if line.lstrip() == line:
     #         self.shadowhist.add(line.strip())
     #     lineout = self.prefilter_manager.prefilter_lines(line,self.more)
     # 
     #     if line.strip():
     #         if self.more:
     #             self.input_hist_raw[-1] += '%s\n' % line
     #         else:
     #             self.input_hist_raw.append('%s\n' % line)                
     # 
     #     
     #     self.more = self.push_line(lineout)
     #     if (self.SyntaxTB.last_syntax_error and
     #         self.autoedit_syntax):
     #         self.edit_syntax_error()
     # 
     # def interact_with_readline(self):
     #     """ Demo of using interact_handle_input, interact_prompt
     #     
     #     This is the main read-eval-print loop. If you need to implement your own (e.g. for GUI),
     #     it should work like this.
     #     """ 
     #     self.readline_startup_hook(self.pre_readline)
     #     while not self.exit_now:
     #         self.interact_prompt()
     #         if self.more:
     #             self.rl_do_indent = True
     #         else:
     #             self.rl_do_indent = False
     #         line = raw_input_original().decode(self.stdin_encoding)
     #         self.interact_handle_input(line)
 
     #-------------------------------------------------------------------------
     # Methods to support auto-editing of SyntaxErrors.
     #-------------------------------------------------------------------------
 
     def edit_syntax_error(self):
         """The bottom half of the syntax error handler called in the main loop.
 
         Loop until syntax error is fixed or user cancels.
         """
 
         while self.SyntaxTB.last_syntax_error:
             # copy and clear last_syntax_error
             err = self.SyntaxTB.clear_err_state()
             if not self._should_recompile(err):
                 return
             try:
                 # may set last_syntax_error again if a SyntaxError is raised
                 self.safe_execfile(err.filename,self.user_ns)
             except:
                 self.showtraceback()
             else:
                 try:
                     f = file(err.filename)
                     try:
                         # This should be inside a display_trap block and I 
                         # think it is.
                         sys.displayhook(f.read())
                     finally:
                         f.close()
                 except:
                     self.showtraceback()
 
     def _should_recompile(self,e):
         """Utility routine for edit_syntax_error"""
 
         if e.filename in ('<ipython console>','<input>','<string>',
                           '<console>','<BackgroundJob compilation>',
                           None):
                               
             return False
         try:
             if (self.autoedit_syntax and 
                 not self.ask_yes_no('Return to editor to correct syntax error? '
                               '[Y/n] ','y')):
                 return False
         except EOFError:
             return False
 
         def int0(x):
             try:
                 return int(x)
             except TypeError:
                 return 0
         # always pass integer line and offset values to editor hook
         try:
             self.hooks.fix_error_editor(e.filename,
                 int0(e.lineno),int0(e.offset),e.msg)
         except TryNext:
             warn('Could not open editor')
             return False
         return True
 
     #-------------------------------------------------------------------------
     # Things related to GUI support and pylab
     #-------------------------------------------------------------------------
 
     def enable_pylab(self, gui=None):
         """Activate pylab support at runtime.
 
         This turns on support for matplotlib, preloads into the interactive
         namespace all of numpy and pylab, and configures IPython to correcdtly
         interact with the GUI event loop.  The GUI backend to be used can be
         optionally selected with the optional :param:`gui` argument.
 
         Parameters
         ----------
         gui : optional, string
 
           If given, dictates the choice of matplotlib GUI backend to use
           (should be one of IPython's supported backends, 'tk', 'qt', 'wx' or
           'gtk'), otherwise we use the default chosen by matplotlib (as
           dictated by the matplotlib build-time options plus the user's
           matplotlibrc configuration file).
         """
         # We want to prevent the loading of pylab to pollute the user's
         # namespace as shown by the %who* magics, so we execute the activation
         # code in an empty namespace, and we update *both* user_ns and
         # user_ns_hidden with this information.
         ns = {}
         gui = pylab_activate(ns, gui)
         self.user_ns.update(ns)
         self.user_ns_hidden.update(ns)
         # Now we must activate the gui pylab wants to use, and fix %run to take
         # plot updates into account
         enable_gui(gui)
         self.magic_run = self._pylab_magic_run
 
     #-------------------------------------------------------------------------
     # Things related to exiting
     #-------------------------------------------------------------------------
 
     def ask_exit(self):
         """ Ask the shell to exit. Can be overiden and used as a callback. """
         self.exit_now = True
 
     def exit(self):
         """Handle interactive exit.
 
         This method calls the ask_exit callback."""
         if self.confirm_exit:
             if self.ask_yes_no('Do you really want to exit ([y]/n)?','y'):
                 self.ask_exit()
         else:
             self.ask_exit()
             
     #------------------------------------------------------------------------
     # Magic overrides
     #------------------------------------------------------------------------
     # Once the base class stops inheriting from magic, this code needs to be
     # moved into a separate machinery as well.  For now, at least isolate here
     # the magics which this class needs to implement differently from the base
     # class, or that are unique to it.
 
     def magic_autoindent(self, parameter_s = ''):
         """Toggle autoindent on/off (if available)."""
 
         self.shell.set_autoindent()
         print "Automatic indentation is:",['OFF','ON'][self.shell.autoindent]
 
     def magic_cpaste(self, parameter_s=''):
         """Paste & execute a pre-formatted code block from clipboard.
         
         You must terminate the block with '--' (two minus-signs) alone on the
         line. You can also provide your own sentinel with '%paste -s %%' ('%%' 
         is the new sentinel for this operation)
         
         The block is dedented prior to execution to enable execution of method
         definitions. '>' and '+' characters at the beginning of a line are
         ignored, to allow pasting directly from e-mails, diff files and
         doctests (the '...' continuation prompt is also stripped).  The
         executed block is also assigned to variable named 'pasted_block' for
         later editing with '%edit pasted_block'.
         
         You can also pass a variable name as an argument, e.g. '%cpaste foo'.
         This assigns the pasted block to variable 'foo' as string, without 
         dedenting or executing it (preceding >>> and + is still stripped)
         
         '%cpaste -r' re-executes the block previously entered by cpaste.
         
         Do not be alarmed by garbled output on Windows (it's a readline bug). 
         Just press enter and type -- (and press enter again) and the block 
         will be what was just pasted.
         
         IPython statements (magics, shell escapes) are not supported (yet).
 
         See also
         --------
         paste: automatically pull code from clipboard.
         """
         
         opts,args = self.parse_options(parameter_s,'rs:',mode='string')
         par = args.strip()
         if opts.has_key('r'):
             self._rerun_pasted()
             return
         
         sentinel = opts.get('s','--')
 
         block = self._strip_pasted_lines_for_code(
             self._get_pasted_lines(sentinel))
 
         self._execute_block(block, par)
 
     def magic_paste(self, parameter_s=''):
         """Paste & execute a pre-formatted code block from clipboard.
         
         The text is pulled directly from the clipboard without user
         intervention and printed back on the screen before execution (unless
         the -q flag is given to force quiet mode).
 
         The block is dedented prior to execution to enable execution of method
         definitions. '>' and '+' characters at the beginning of a line are
         ignored, to allow pasting directly from e-mails, diff files and
         doctests (the '...' continuation prompt is also stripped).  The
         executed block is also assigned to variable named 'pasted_block' for
         later editing with '%edit pasted_block'.
         
         You can also pass a variable name as an argument, e.g. '%paste foo'.
         This assigns the pasted block to variable 'foo' as string, without 
         dedenting or executing it (preceding >>> and + is still stripped)
 
         Options
         -------
         
           -r: re-executes the block previously entered by cpaste.
 
           -q: quiet mode: do not echo the pasted text back to the terminal.
         
         IPython statements (magics, shell escapes) are not supported (yet).
 
         See also
         --------
         cpaste: manually paste code into terminal until you mark its end.
         """
         opts,args = self.parse_options(parameter_s,'rq',mode='string')
         par = args.strip()
         if opts.has_key('r'):
             self._rerun_pasted()
             return
 
         text = self.shell.hooks.clipboard_get()
         block = self._strip_pasted_lines_for_code(text.splitlines())
 
         # By default, echo back to terminal unless quiet mode is requested
         if not opts.has_key('q'):
             write = self.shell.write
             write(self.shell.pycolorize(block))
             if not block.endswith('\n'):
                 write('\n')
             write("## -- End pasted text --\n")
             
         self._execute_block(block, par)
 
 
 InteractiveShellABC.register(TerminalInteractiveShell)