Better error messages for common magic commands.

Print a helpful message when the user calls a magic command with a missing
argument, rather than a long traceback.

IPython/core/magics/code.py

@@ -1,526 +1,531 b''
 """Implementation of code management magic functions.
 """
 #-----------------------------------------------------------------------------
 #  Copyright (c) 2012 The IPython Development Team.
 #
 #  Distributed under the terms of the Modified BSD License.
 #
 #  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # Stdlib
 import inspect
 import io
 import json
 import os
 import sys
 from urllib2 import urlopen
 
 # Our own packages
-from IPython.core.error import TryNext, StdinNotImplementedError
+from IPython.core.error import TryNext, StdinNotImplementedError, UsageError
 from IPython.core.macro import Macro
 from IPython.core.magic import Magics, magics_class, line_magic
 from IPython.core.oinspect import find_file, find_source_lines
 from IPython.testing.skipdoctest import skip_doctest
 from IPython.utils import openpy
 from IPython.utils import py3compat
 from IPython.utils.io import file_read
 from IPython.utils.path import get_py_filename, unquote_filename
 from IPython.utils.warn import warn
 
 #-----------------------------------------------------------------------------
 # Magic implementation classes
 #-----------------------------------------------------------------------------
 
 # Used for exception handling in magic_edit
 class MacroToEdit(ValueError): pass
 
 
 @magics_class
 class CodeMagics(Magics):
     """Magics related to code management (loading, saving, editing, ...)."""
 
     @line_magic
     def save(self, parameter_s=''):
         """Save a set of lines or a macro to a given filename.
 
         Usage:\\
           %save [options] filename n1-n2 n3-n4 ... n5 .. n6 ...
 
         Options:
 
           -r: use 'raw' input.  By default, the 'processed' history is used,
           so that magics are loaded in their transformed version to valid
           Python.  If this option is given, the raw input as typed as the
           command line is used instead.
           
           -f: force overwrite.  If file exists, %save will prompt for overwrite
           unless -f is given.
 
           -a: append to the file instead of overwriting it.
 
         This function uses the same syntax as %history for input ranges,
         then saves the lines to the filename you specify.
 
         It adds a '.py' extension to the file if you don't do so yourself, and
         it asks for confirmation before overwriting existing files.
 
         If `-r` option is used, the default extension is `.ipy`.
         """
 
         opts,args = self.parse_options(parameter_s,'fra',mode='list')
+        if not args:
+            raise UsageError('Missing filename.')
         raw = 'r' in opts
         force = 'f' in opts
         append = 'a' in opts
         mode = 'a' if append else 'w'
         ext = u'.ipy' if raw else u'.py'
         fname, codefrom = unquote_filename(args[0]), " ".join(args[1:])
         if not fname.endswith((u'.py',u'.ipy')):
             fname += ext
         file_exists = os.path.isfile(fname)
         if file_exists and not force and not append:
             try:
                 overwrite = self.shell.ask_yes_no('File `%s` exists. Overwrite (y/[N])? ' % fname, default='n')
             except StdinNotImplementedError:
                 print "File `%s` exists. Use `%%save -f %s` to force overwrite" % (fname, parameter_s)
                 return
             if not overwrite :
                 print 'Operation cancelled.'
                 return
         try:
             cmds = self.shell.find_user_code(codefrom,raw)
         except (TypeError, ValueError) as e:
             print e.args[0]
             return
         out = py3compat.cast_unicode(cmds)
         with io.open(fname, mode, encoding="utf-8") as f:
             if not file_exists or not append:
                 f.write(u"# coding: utf-8\n")
             f.write(out)
             # make sure we end on a newline
             if not out.endswith(u'\n'):
                 f.write(u'\n')
         print 'The following commands were written to file `%s`:' % fname
         print cmds
 
     @line_magic
     def pastebin(self, parameter_s=''):
         """Upload code to Github's Gist paste bin, returning the URL.
 
         Usage:\\
           %pastebin [-d "Custom description"] 1-7
 
         The argument can be an input history range, a filename, or the name of a
         string or macro.
 
         Options:
 
           -d: Pass a custom description for the gist. The default will say
               "Pasted from IPython".
         """
         opts, args = self.parse_options(parameter_s, 'd:')
 
         try:
             code = self.shell.find_user_code(args)
         except (ValueError, TypeError) as e:
             print e.args[0]
             return
 
         post_data = json.dumps({
           "description": opts.get('d', "Pasted from IPython"),
           "public": True,
           "files": {
             "file1.py": {
               "content": code
             }
           }
         }).encode('utf-8')
 
         response = urlopen("https://api.github.com/gists", post_data)
         response_data = json.loads(response.read().decode('utf-8'))
         return response_data['html_url']
 
     @line_magic
     def loadpy(self, arg_s):
         """Alias of `%load`
 
         `%loadpy` has gained some flexibility and droped the requirement of a `.py`
         extension. So it has been renamed simply into %load. You can look at
         `%load`'s docstring for more info.
         """
         self.load(arg_s)
 
     @line_magic
     def load(self, arg_s):
         """Load code into the current frontend.
 
         Usage:\\
           %load [options] source
 
           where source can be a filename, URL, input history range or macro
 
         Options:
         --------
           -y : Don't ask confirmation for loading source above 200 000 characters.
 
         This magic command can either take a local filename, a URL, an history
         range (see %history) or a macro as argument, it will prompt for
         confirmation before loading source with more than 200 000 characters, unless
         -y flag is passed or if the frontend does not support raw_input::
 
         %load myscript.py
         %load 7-27
         %load myMacro
         %load http://www.example.com/myscript.py
         """
         opts,args = self.parse_options(arg_s,'y')
+        if not args:
+            raise UsageError('Missing filename, URL, input history range, '
+                             'or macro.')
 
         contents = self.shell.find_user_code(args)
         l = len(contents)
 
         # 200 000 is ~ 2500 full 80 caracter lines
         # so in average, more than 5000 lines
         if l > 200000 and 'y' not in opts:
             try:
                 ans = self.shell.ask_yes_no(("The text you're trying to load seems pretty big"\
                 " (%d characters). Continue (y/[N]) ?" % l), default='n' )
             except StdinNotImplementedError:
                 #asume yes if raw input not implemented
                 ans = True
 
             if ans is False :
                 print 'Operation cancelled.'
                 return
 
         self.shell.set_next_input(contents)
 
     @staticmethod
     def _find_edit_target(shell, args, opts, last_call):
         """Utility method used by magic_edit to find what to edit."""
 
         def make_filename(arg):
             "Make a filename from the given args"
             arg = unquote_filename(arg)
             try:
                 filename = get_py_filename(arg)
             except IOError:
                 # If it ends with .py but doesn't already exist, assume we want
                 # a new file.
                 if arg.endswith('.py'):
                     filename = arg
                 else:
                     filename = None
             return filename
 
         # Set a few locals from the options for convenience:
         opts_prev = 'p' in opts
         opts_raw = 'r' in opts
 
         # custom exceptions
         class DataIsObject(Exception): pass
 
         # Default line number value
         lineno = opts.get('n',None)
 
         if opts_prev:
             args = '_%s' % last_call[0]
             if args not in shell.user_ns:
                 args = last_call[1]
 
         # use last_call to remember the state of the previous call, but don't
         # let it be clobbered by successive '-p' calls.
         try:
             last_call[0] = shell.displayhook.prompt_count
             if not opts_prev:
                 last_call[1] = args
         except:
             pass
 
         # by default this is done with temp files, except when the given
         # arg is a filename
         use_temp = True
 
         data = ''
 
         # First, see if the arguments should be a filename.
         filename = make_filename(args)
         if filename:
             use_temp = False
         elif args:
             # Mode where user specifies ranges of lines, like in %macro.
             data = shell.extract_input_lines(args, opts_raw)
             if not data:
                 try:
                     # Load the parameter given as a variable. If not a string,
                     # process it as an object instead (below)
 
                     #print '*** args',args,'type',type(args)  # dbg
                     data = eval(args, shell.user_ns)
                     if not isinstance(data, basestring):
                         raise DataIsObject
 
                 except (NameError,SyntaxError):
                     # given argument is not a variable, try as a filename
                     filename = make_filename(args)
                     if filename is None:
                         warn("Argument given (%s) can't be found as a variable "
                              "or as a filename." % args)
                         return
                     use_temp = False
 
                 except DataIsObject:
                     # macros have a special edit function
                     if isinstance(data, Macro):
                         raise MacroToEdit(data)
 
                     # For objects, try to edit the file where they are defined
                     filename = find_file(data)
                     if filename:
                         if 'fakemodule' in filename.lower() and \
                             inspect.isclass(data):
                             # class created by %edit? Try to find source
                             # by looking for method definitions instead, the
                             # __module__ in those classes is FakeModule.
                             attrs = [getattr(data, aname) for aname in dir(data)]
                             for attr in attrs:
                                 if not inspect.ismethod(attr):
                                     continue
                                 filename = find_file(attr)
                                 if filename and \
                                   'fakemodule' not in filename.lower():
                                     # change the attribute to be the edit
                                     # target instead
                                     data = attr
                                     break
 
                         datafile = 1
                     if filename is None:
                         filename = make_filename(args)
                         datafile = 1
                         warn('Could not find file where `%s` is defined.\n'
                              'Opening a file named `%s`' % (args, filename))
                     # Now, make sure we can actually read the source (if it was
                     # in a temp file it's gone by now).
                     if datafile:
                         if lineno is None:
                             lineno = find_source_lines(data)
                         if lineno is None:
                             filename = make_filename(args)
                             if filename is None:
                                 warn('The file `%s` where `%s` was defined '
                                      'cannot be read.' % (filename, data))
                                 return
                     use_temp = False
 
         if use_temp:
             filename = shell.mktempfile(data)
             print 'IPython will make a temporary file named:',filename
 
         return filename, lineno, use_temp
 
     def _edit_macro(self,mname,macro):
         """open an editor with the macro data in a file"""
         filename = self.shell.mktempfile(macro.value)
         self.shell.hooks.editor(filename)
 
         # and make a new macro object, to replace the old one
         mfile = open(filename)
         mvalue = mfile.read()
         mfile.close()
         self.shell.user_ns[mname] = Macro(mvalue)
 
     @skip_doctest
     @line_magic
     def edit(self, parameter_s='',last_call=['','']):
         """Bring up an editor and execute the resulting code.
 
         Usage:
           %edit [options] [args]
 
         %edit runs IPython's editor hook. The default version of this hook is
         set to call the editor specified by your $EDITOR environment variable.
         If this isn't found, it will default to vi under Linux/Unix and to
         notepad under Windows. See the end of this docstring for how to change
         the editor hook.
 
         You can also set the value of this editor via the
         ``TerminalInteractiveShell.editor`` option in your configuration file.
         This is useful if you wish to use a different editor from your typical
         default with IPython (and for Windows users who typically don't set
         environment variables).
 
         This command allows you to conveniently edit multi-line code right in
         your IPython session.
 
         If called without arguments, %edit opens up an empty editor with a
         temporary file and will execute the contents of this file when you
         close it (don't forget to save it!).
 
 
         Options:
 
         -n <number>: open the editor at a specified line number.  By default,
         the IPython editor hook uses the unix syntax 'editor +N filename', but
         you can configure this by providing your own modified hook if your
         favorite editor supports line-number specifications with a different
         syntax.
 
         -p: this will call the editor with the same data as the previous time
         it was used, regardless of how long ago (in your current session) it
         was.
 
         -r: use 'raw' input.  This option only applies to input taken from the
         user's history.  By default, the 'processed' history is used, so that
         magics are loaded in their transformed version to valid Python.  If
         this option is given, the raw input as typed as the command line is
         used instead.  When you exit the editor, it will be executed by
         IPython's own processor.
 
         -x: do not execute the edited code immediately upon exit. This is
         mainly useful if you are editing programs which need to be called with
         command line arguments, which you can then do using %run.
 
 
         Arguments:
 
         If arguments are given, the following possibilities exist:
 
         - If the argument is a filename, IPython will load that into the
           editor. It will execute its contents with execfile() when you exit,
           loading any code in the file into your interactive namespace.
 
         - The arguments are ranges of input history,  e.g. "7 ~1/4-6".
           The syntax is the same as in the %history magic.
 
         - If the argument is a string variable, its contents are loaded
           into the editor. You can thus edit any string which contains
           python code (including the result of previous edits).
 
         - If the argument is the name of an object (other than a string),
           IPython will try to locate the file where it was defined and open the
           editor at the point where it is defined. You can use `%edit function`
           to load an editor exactly at the point where 'function' is defined,
           edit it and have the file be executed automatically.
 
         - If the object is a macro (see %macro for details), this opens up your
           specified editor with a temporary file containing the macro's data.
           Upon exit, the macro is reloaded with the contents of the file.
 
         Note: opening at an exact line is only supported under Unix, and some
         editors (like kedit and gedit up to Gnome 2.8) do not understand the
         '+NUMBER' parameter necessary for this feature. Good editors like
         (X)Emacs, vi, jed, pico and joe all do.
 
         After executing your code, %edit will return as output the code you
         typed in the editor (except when it was an existing file). This way
         you can reload the code in further invocations of %edit as a variable,
         via _<NUMBER> or Out[<NUMBER>], where <NUMBER> is the prompt number of
         the output.
 
         Note that %edit is also available through the alias %ed.
 
         This is an example of creating a simple function inside the editor and
         then modifying it. First, start up the editor::
 
           In [1]: edit
           Editing... done. Executing edited code...
           Out[1]: 'def foo():\\n    print "foo() was defined in an editing
           session"\\n'
 
         We can then call the function foo()::
 
           In [2]: foo()
           foo() was defined in an editing session
 
         Now we edit foo.  IPython automatically loads the editor with the
         (temporary) file where foo() was previously defined::
 
           In [3]: edit foo
           Editing... done. Executing edited code...
 
         And if we call foo() again we get the modified version::
 
           In [4]: foo()
           foo() has now been changed!
 
         Here is an example of how to edit a code snippet successive
         times. First we call the editor::
 
           In [5]: edit
           Editing... done. Executing edited code...
           hello
           Out[5]: "print 'hello'\\n"
 
         Now we call it again with the previous output (stored in _)::
 
           In [6]: edit _
           Editing... done. Executing edited code...
           hello world
           Out[6]: "print 'hello world'\\n"
 
         Now we call it with the output #8 (stored in _8, also as Out[8])::
 
           In [7]: edit _8
           Editing... done. Executing edited code...
           hello again
           Out[7]: "print 'hello again'\\n"
 
 
         Changing the default editor hook:
 
         If you wish to write your own editor hook, you can put it in a
         configuration file which you load at startup time.  The default hook
         is defined in the IPython.core.hooks module, and you can use that as a
         starting example for further modifications.  That file also has
         general instructions on how to set a new hook for use once you've
         defined it."""
         opts,args = self.parse_options(parameter_s,'prxn:')
 
         try:
             filename, lineno, is_temp = self._find_edit_target(self.shell, 
                                                        args, opts, last_call)
         except MacroToEdit as e:
             self._edit_macro(args, e.args[0])
             return
 
         # do actual editing here
         print 'Editing...',
         sys.stdout.flush()
         try:
             # Quote filenames that may have spaces in them
             if ' ' in filename:
                 filename = "'%s'" % filename
             self.shell.hooks.editor(filename,lineno)
         except TryNext:
             warn('Could not open editor')
             return
 
         # XXX TODO: should this be generalized for all string vars?
         # For now, this is special-cased to blocks created by cpaste
         if args.strip() == 'pasted_block':
             self.shell.user_ns['pasted_block'] = file_read(filename)
 
         if 'x' in opts:  # -x prevents actual execution
             print
         else:
             print 'done. Executing edited code...'
             if 'r' in opts:    # Untranslated IPython code
                 self.shell.run_cell(file_read(filename),
                                                     store_history=False)
             else:
                 self.shell.safe_execfile(filename, self.shell.user_ns,
                                          self.shell.user_ns)
 
         if is_temp:
             try:
                 return open(filename).read()
             except IOError as msg:
                 if msg.filename == filename:
                     warn('File not found. Did you forget to save?')
                     return
                 else:
                     self.shell.showtraceback()

IPython/core/magics/extension.py

@@ -1,69 +1,76 b''
 """Implementation of magic functions for the extension machinery.
 """
 #-----------------------------------------------------------------------------
 #  Copyright (c) 2012 The IPython Development Team.
 #
 #  Distributed under the terms of the Modified BSD License.
 #
 #  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # Stdlib
 import os
 
 # Our own packages
+from IPython.core.error import UsageError
 from IPython.core.magic import Magics, magics_class, line_magic
 
 #-----------------------------------------------------------------------------
 # Magic implementation classes
 #-----------------------------------------------------------------------------
 
 @magics_class
 class ExtensionMagics(Magics):
     """Magics to manage the IPython extensions system."""
 
     @line_magic
     def install_ext(self, parameter_s=''):
         """Download and install an extension from a URL, e.g.::
 
             %install_ext https://bitbucket.org/birkenfeld/ipython-physics/raw/d1310a2ab15d/physics.py
 
         The URL should point to an importable Python module - either a .py file
         or a .zip file.
 
         Parameters:
 
           -n filename : Specify a name for the file, rather than taking it from
                         the URL.
         """
         opts, args = self.parse_options(parameter_s, 'n:')
         try:
             filename = self.shell.extension_manager.install_extension(args,
                                                                  opts.get('n'))
         except ValueError as e:
             print e
             return
 
         filename = os.path.basename(filename)
         print "Installed %s. To use it, type:" % filename
         print "  %%load_ext %s" % os.path.splitext(filename)[0]
 
 
     @line_magic
     def load_ext(self, module_str):
         """Load an IPython extension by its module name."""
+        if not module_str:
+            raise UsageError('Missing module name.')
         return self.shell.extension_manager.load_extension(module_str)
 
     @line_magic
     def unload_ext(self, module_str):
         """Unload an IPython extension by its module name."""
+        if not module_str:
+            raise UsageError('Missing module name.')
         self.shell.extension_manager.unload_extension(module_str)
 
     @line_magic
     def reload_ext(self, module_str):
         """Reload an IPython extension by its module name."""
+        if not module_str:
+            raise UsageError('Missing module name.')
         self.shell.extension_manager.reload_extension(module_str)

IPython/core/magics/namespace.py

@@ -1,700 +1,702 b''
 """Implementation of namespace-related magic functions.
 """
 #-----------------------------------------------------------------------------
 #  Copyright (c) 2012 The IPython Development Team.
 #
 #  Distributed under the terms of the Modified BSD License.
 #
 #  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # Stdlib
 import gc
 import re
 import sys
 
 # Our own packages
 from IPython.core import page
-from IPython.core.error import StdinNotImplementedError
+from IPython.core.error import StdinNotImplementedError, UsageError
 from IPython.core.magic import Magics, magics_class, line_magic
 from IPython.testing.skipdoctest import skip_doctest
 from IPython.utils.encoding import DEFAULT_ENCODING
 from IPython.utils.path import get_py_filename
 
 #-----------------------------------------------------------------------------
 # Magic implementation classes
 #-----------------------------------------------------------------------------
 
 @magics_class
 class NamespaceMagics(Magics):
     """Magics to manage various aspects of the user's namespace.
 
     These include listing variables, introspecting into them, etc.
     """
 
     @line_magic
     def pinfo(self, parameter_s='', namespaces=None):
         """Provide detailed information about an object.
 
         '%pinfo object' is just a synonym for object? or ?object."""
 
         #print 'pinfo par: <%s>' % parameter_s  # dbg
         # detail_level: 0 -> obj? , 1 -> obj??
         detail_level = 0
         # We need to detect if we got called as 'pinfo pinfo foo', which can
         # happen if the user types 'pinfo foo?' at the cmd line.
         pinfo,qmark1,oname,qmark2 = \
                re.match('(pinfo )?(\?*)(.*?)(\??$)',parameter_s).groups()
         if pinfo or qmark1 or qmark2:
             detail_level = 1
         if "*" in oname:
             self.psearch(oname)
         else:
             self.shell._inspect('pinfo', oname, detail_level=detail_level,
                                 namespaces=namespaces)
 
     @line_magic
     def pinfo2(self, parameter_s='', namespaces=None):
         """Provide extra detailed information about an object.
 
         '%pinfo2 object' is just a synonym for object?? or ??object."""
         self.shell._inspect('pinfo', parameter_s, detail_level=1,
                             namespaces=namespaces)
 
     @skip_doctest
     @line_magic
     def pdef(self, parameter_s='', namespaces=None):
         """Print the definition header for any callable object.
 
         If the object is a class, print the constructor information.
 
         Examples
         --------
         ::
 
           In [3]: %pdef urllib.urlopen
           urllib.urlopen(url, data=None, proxies=None)
         """
         self.shell._inspect('pdef',parameter_s, namespaces)
 
     @line_magic
     def pdoc(self, parameter_s='', namespaces=None):
         """Print the docstring for an object.
 
         If the given object is a class, it will print both the class and the
         constructor docstrings."""
         self.shell._inspect('pdoc',parameter_s, namespaces)
 
     @line_magic
     def psource(self, parameter_s='', namespaces=None):
         """Print (or run through pager) the source code for an object."""
+        if not parameter_s:
+            raise UsageError('Missing object name.')
         self.shell._inspect('psource',parameter_s, namespaces)
 
     @line_magic
     def pfile(self, parameter_s=''):
         """Print (or run through pager) the file where an object is defined.
 
         The file opens at the line where the object definition begins. IPython
         will honor the environment variable PAGER if set, and otherwise will
         do its best to print the file in a convenient form.
 
         If the given argument is not an object currently defined, IPython will
         try to interpret it as a filename (automatically adding a .py extension
         if needed). You can thus use %pfile as a syntax highlighting code
         viewer."""
 
         # first interpret argument as an object name
         out = self.shell._inspect('pfile',parameter_s)
         # if not, try the input as a filename
         if out == 'not found':
             try:
                 filename = get_py_filename(parameter_s)
             except IOError as msg:
                 print msg
                 return
             page.page(self.shell.inspector.format(open(filename).read()))
 
     @line_magic
     def psearch(self, parameter_s=''):
         """Search for object in namespaces by wildcard.
 
         %psearch [options] PATTERN [OBJECT TYPE]
 
         Note: ? can be used as a synonym for %psearch, at the beginning or at
         the end: both a*? and ?a* are equivalent to '%psearch a*'.  Still, the
         rest of the command line must be unchanged (options come first), so
         for example the following forms are equivalent
 
         %psearch -i a* function
         -i a* function?
         ?-i a* function
 
         Arguments:
 
           PATTERN
 
           where PATTERN is a string containing * as a wildcard similar to its
           use in a shell.  The pattern is matched in all namespaces on the
           search path. By default objects starting with a single _ are not
           matched, many IPython generated objects have a single
           underscore. The default is case insensitive matching. Matching is
           also done on the attributes of objects and not only on the objects
           in a module.
 
           [OBJECT TYPE]
 
           Is the name of a python type from the types module. The name is
           given in lowercase without the ending type, ex. StringType is
           written string. By adding a type here only objects matching the
           given type are matched. Using all here makes the pattern match all
           types (this is the default).
 
         Options:
 
           -a: makes the pattern match even objects whose names start with a
           single underscore.  These names are normally omitted from the
           search.
 
           -i/-c: make the pattern case insensitive/sensitive.  If neither of
           these options are given, the default is read from your configuration
           file, with the option ``InteractiveShell.wildcards_case_sensitive``.
           If this option is not specified in your configuration file, IPython's
           internal default is to do a case sensitive search.
 
           -e/-s NAMESPACE: exclude/search a given namespace.  The pattern you
           specify can be searched in any of the following namespaces:
           'builtin', 'user', 'user_global','internal', 'alias', where
           'builtin' and 'user' are the search defaults.  Note that you should
           not use quotes when specifying namespaces.
 
           'Builtin' contains the python module builtin, 'user' contains all
           user data, 'alias' only contain the shell aliases and no python
           objects, 'internal' contains objects used by IPython.  The
           'user_global' namespace is only used by embedded IPython instances,
           and it contains module-level globals.  You can add namespaces to the
           search with -s or exclude them with -e (these options can be given
           more than once).
 
         Examples
         --------
         ::
 
           %psearch a*            -> objects beginning with an a
           %psearch -e builtin a* -> objects NOT in the builtin space starting in a
           %psearch a* function   -> all functions beginning with an a
           %psearch re.e*         -> objects beginning with an e in module re
           %psearch r*.e*         -> objects that start with e in modules starting in r
           %psearch r*.* string   -> all strings in modules beginning with r
 
         Case sensitive search::
 
           %psearch -c a*         list all object beginning with lower case a
 
         Show objects beginning with a single _::
 
           %psearch -a _*         list objects beginning with a single underscore
         """
         try:
             parameter_s.encode('ascii')
         except UnicodeEncodeError:
             print 'Python identifiers can only contain ascii characters.'
             return
 
         # default namespaces to be searched
         def_search = ['user_local', 'user_global', 'builtin']
 
         # Process options/args
         opts,args = self.parse_options(parameter_s,'cias:e:',list_all=True)
         opt = opts.get
         shell = self.shell
         psearch = shell.inspector.psearch
 
         # select case options
         if 'i' in opts:
             ignore_case = True
         elif 'c' in opts:
             ignore_case = False
         else:
             ignore_case = not shell.wildcards_case_sensitive
 
         # Build list of namespaces to search from user options
         def_search.extend(opt('s',[]))
         ns_exclude = ns_exclude=opt('e',[])
         ns_search = [nm for nm in def_search if nm not in ns_exclude]
 
         # Call the actual search
         try:
             psearch(args,shell.ns_table,ns_search,
                     show_all=opt('a'),ignore_case=ignore_case)
         except:
             shell.showtraceback()
 
     @skip_doctest
     @line_magic
     def who_ls(self, parameter_s=''):
         """Return a sorted list of all interactive variables.
 
         If arguments are given, only variables of types matching these
         arguments are returned.
 
         Examples
         --------
 
         Define two variables and list them with who_ls::
 
           In [1]: alpha = 123
 
           In [2]: beta = 'test'
 
           In [3]: %who_ls
           Out[3]: ['alpha', 'beta']
 
           In [4]: %who_ls int
           Out[4]: ['alpha']
 
           In [5]: %who_ls str
           Out[5]: ['beta']
         """
 
         user_ns = self.shell.user_ns
         user_ns_hidden = self.shell.user_ns_hidden
         out = [ i for i in user_ns
                 if not i.startswith('_') \
                 and not i in user_ns_hidden ]
 
         typelist = parameter_s.split()
         if typelist:
             typeset = set(typelist)
             out = [i for i in out if type(user_ns[i]).__name__ in typeset]
 
         out.sort()
         return out
 
     @skip_doctest
     @line_magic
     def who(self, parameter_s=''):
         """Print all interactive variables, with some minimal formatting.
 
         If any arguments are given, only variables whose type matches one of
         these are printed.  For example::
 
           %who function str
 
         will only list functions and strings, excluding all other types of
         variables.  To find the proper type names, simply use type(var) at a
         command line to see how python prints type names.  For example:
 
         ::
 
           In [1]: type('hello')\\
           Out[1]: <type 'str'>
 
         indicates that the type name for strings is 'str'.
 
         ``%who`` always excludes executed names loaded through your configuration
         file and things which are internal to IPython.
 
         This is deliberate, as typically you may load many modules and the
         purpose of %who is to show you only what you've manually defined.
 
         Examples
         --------
 
         Define two variables and list them with who::
 
           In [1]: alpha = 123
 
           In [2]: beta = 'test'
 
           In [3]: %who
           alpha   beta
 
           In [4]: %who int
           alpha
 
           In [5]: %who str
           beta
         """
 
         varlist = self.who_ls(parameter_s)
         if not varlist:
             if parameter_s:
                 print 'No variables match your requested type.'
             else:
                 print 'Interactive namespace is empty.'
             return
 
         # if we have variables, move on...
         count = 0
         for i in varlist:
             print i+'\t',
             count += 1
             if count > 8:
                 count = 0
                 print
         print
 
     @skip_doctest
     @line_magic
     def whos(self, parameter_s=''):
         """Like %who, but gives some extra information about each variable.
 
         The same type filtering of %who can be applied here.
 
         For all variables, the type is printed. Additionally it prints:
 
           - For {},[],(): their length.
 
           - For numpy arrays, a summary with shape, number of
           elements, typecode and size in memory.
 
           - Everything else: a string representation, snipping their middle if
           too long.
 
         Examples
         --------
 
         Define two variables and list them with whos::
 
           In [1]: alpha = 123
 
           In [2]: beta = 'test'
 
           In [3]: %whos
           Variable   Type        Data/Info
           --------------------------------
           alpha      int         123
           beta       str         test
         """
 
         varnames = self.who_ls(parameter_s)
         if not varnames:
             if parameter_s:
                 print 'No variables match your requested type.'
             else:
                 print 'Interactive namespace is empty.'
             return
 
         # if we have variables, move on...
 
         # for these types, show len() instead of data:
         seq_types = ['dict', 'list', 'tuple']
 
         # for numpy arrays, display summary info
         ndarray_type = None
         if 'numpy' in sys.modules:
             try:
                 from numpy import ndarray
             except ImportError:
                 pass
             else:
                 ndarray_type = ndarray.__name__
 
         # Find all variable names and types so we can figure out column sizes
         def get_vars(i):
             return self.shell.user_ns[i]
 
         # some types are well known and can be shorter
         abbrevs = {'IPython.core.macro.Macro' : 'Macro'}
         def type_name(v):
             tn = type(v).__name__
             return abbrevs.get(tn,tn)
 
         varlist = map(get_vars,varnames)
 
         typelist = []
         for vv in varlist:
             tt = type_name(vv)
 
             if tt=='instance':
                 typelist.append( abbrevs.get(str(vv.__class__),
                                              str(vv.__class__)))
             else:
                 typelist.append(tt)
 
         # column labels and # of spaces as separator
         varlabel = 'Variable'
         typelabel = 'Type'
         datalabel = 'Data/Info'
         colsep = 3
         # variable format strings
         vformat    = "{0:<{varwidth}}{1:<{typewidth}}"
         aformat    = "%s: %s elems, type `%s`, %s bytes"
         # find the size of the columns to format the output nicely
         varwidth = max(max(map(len,varnames)), len(varlabel)) + colsep
         typewidth = max(max(map(len,typelist)), len(typelabel)) + colsep
         # table header
         print varlabel.ljust(varwidth) + typelabel.ljust(typewidth) + \
               ' '+datalabel+'\n' + '-'*(varwidth+typewidth+len(datalabel)+1)
         # and the table itself
         kb = 1024
         Mb = 1048576  # kb**2
         for vname,var,vtype in zip(varnames,varlist,typelist):
             print vformat.format(vname, vtype, varwidth=varwidth, typewidth=typewidth),
             if vtype in seq_types:
                 print "n="+str(len(var))
             elif vtype == ndarray_type:
                 vshape = str(var.shape).replace(',','').replace(' ','x')[1:-1]
                 if vtype==ndarray_type:
                     # numpy
                     vsize  = var.size
                     vbytes = vsize*var.itemsize
                     vdtype = var.dtype
 
                 if vbytes < 100000:
                     print aformat % (vshape, vsize, vdtype, vbytes)
                 else:
                     print aformat % (vshape, vsize, vdtype, vbytes),
                     if vbytes < Mb:
                         print '(%s kb)' % (vbytes/kb,)
                     else:
                         print '(%s Mb)' % (vbytes/Mb,)
             else:
                 try:
                     vstr = str(var)
                 except UnicodeEncodeError:
                     vstr = unicode(var).encode(DEFAULT_ENCODING,
                                                'backslashreplace')
                 except:
                     vstr = "<object with id %d (str() failed)>" % id(var)
                 vstr = vstr.replace('\n', '\\n')
                 if len(vstr) < 50:
                     print vstr
                 else:
                     print vstr[:25] + "<...>" + vstr[-25:]
 
     @line_magic
     def reset(self, parameter_s=''):
         """Resets the namespace by removing all names defined by the user, if
         called without arguments, or by removing some types of objects, such
         as everything currently in IPython's In[] and Out[] containers (see
         the parameters for details).
 
         Parameters
         ----------
         -f : force reset without asking for confirmation.
 
         -s : 'Soft' reset: Only clears your namespace, leaving history intact.
             References to objects may be kept. By default (without this option),
             we do a 'hard' reset, giving you a new session and removing all
             references to objects from the current session.
 
         in : reset input history
 
         out : reset output history
 
         dhist : reset directory history
 
         array : reset only variables that are NumPy arrays
 
         See Also
         --------
         magic_reset_selective : invoked as ``%reset_selective``
 
         Examples
         --------
         ::
 
           In [6]: a = 1
 
           In [7]: a
           Out[7]: 1
 
           In [8]: 'a' in _ip.user_ns
           Out[8]: True
 
           In [9]: %reset -f
 
           In [1]: 'a' in _ip.user_ns
           Out[1]: False
 
           In [2]: %reset -f in
           Flushing input history
 
           In [3]: %reset -f dhist in
           Flushing directory history
           Flushing input history
 
         Notes
         -----
         Calling this magic from clients that do not implement standard input,
         such as the ipython notebook interface, will reset the namespace
         without confirmation.
         """
         opts, args = self.parse_options(parameter_s,'sf', mode='list')
         if 'f' in opts:
             ans = True
         else:
             try:
                 ans = self.shell.ask_yes_no(
                 "Once deleted, variables cannot be recovered. Proceed (y/[n])?",
                 default='n')
             except StdinNotImplementedError:
                 ans = True
         if not ans:
             print 'Nothing done.'
             return
 
         if 's' in opts:                     # Soft reset
             user_ns = self.shell.user_ns
             for i in self.who_ls():
                 del(user_ns[i])
         elif len(args) == 0:                # Hard reset
             self.shell.reset(new_session = False)
 
         # reset in/out/dhist/array: previously extensinions/clearcmd.py
         ip = self.shell
         user_ns = self.shell.user_ns  # local lookup, heavily used
 
         for target in args:
             target = target.lower() # make matches case insensitive
             if target == 'out':
                 print "Flushing output cache (%d entries)" % len(user_ns['_oh'])
                 self.shell.displayhook.flush()
 
             elif target == 'in':
                 print "Flushing input history"
                 pc = self.shell.displayhook.prompt_count + 1
                 for n in range(1, pc):
                     key = '_i'+repr(n)
                     user_ns.pop(key,None)
                 user_ns.update(dict(_i=u'',_ii=u'',_iii=u''))
                 hm = ip.history_manager
                 # don't delete these, as %save and %macro depending on the
                 # length of these lists to be preserved
                 hm.input_hist_parsed[:] = [''] * pc
                 hm.input_hist_raw[:] = [''] * pc
                 # hm has internal machinery for _i,_ii,_iii, clear it out
                 hm._i = hm._ii = hm._iii = hm._i00 =  u''
 
             elif target == 'array':
                 # Support cleaning up numpy arrays
                 try:
                     from numpy import ndarray
                     # This must be done with items and not iteritems because
                     # we're going to modify the dict in-place.
                     for x,val in user_ns.items():
                         if isinstance(val,ndarray):
                             del user_ns[x]
                 except ImportError:
                     print "reset array only works if Numpy is available."
 
             elif target == 'dhist':
                 print "Flushing directory history"
                 del user_ns['_dh'][:]
 
             else:
                 print "Don't know how to reset ",
                 print target + ", please run `%reset?` for details"
 
         gc.collect()
 
     @line_magic
     def reset_selective(self, parameter_s=''):
         """Resets the namespace by removing names defined by the user.
 
         Input/Output history are left around in case you need them.
 
         %reset_selective [-f] regex
 
         No action is taken if regex is not included
 
         Options
           -f : force reset without asking for confirmation.
 
         See Also
         --------
         magic_reset : invoked as ``%reset``
 
         Examples
         --------
 
         We first fully reset the namespace so your output looks identical to
         this example for pedagogical reasons; in practice you do not need a
         full reset::
 
           In [1]: %reset -f
 
         Now, with a clean namespace we can make a few variables and use
         ``%reset_selective`` to only delete names that match our regexp::
 
           In [2]: a=1; b=2; c=3; b1m=4; b2m=5; b3m=6; b4m=7; b2s=8
 
           In [3]: who_ls
           Out[3]: ['a', 'b', 'b1m', 'b2m', 'b2s', 'b3m', 'b4m', 'c']
 
           In [4]: %reset_selective -f b[2-3]m
 
           In [5]: who_ls
           Out[5]: ['a', 'b', 'b1m', 'b2s', 'b4m', 'c']
 
           In [6]: %reset_selective -f d
 
           In [7]: who_ls
           Out[7]: ['a', 'b', 'b1m', 'b2s', 'b4m', 'c']
 
           In [8]: %reset_selective -f c
 
           In [9]: who_ls
           Out[9]: ['a', 'b', 'b1m', 'b2s', 'b4m']
 
           In [10]: %reset_selective -f b
 
           In [11]: who_ls
           Out[11]: ['a']
 
         Notes
         -----
         Calling this magic from clients that do not implement standard input,
         such as the ipython notebook interface, will reset the namespace
         without confirmation.
         """
 
         opts, regex = self.parse_options(parameter_s,'f')
 
         if 'f' in opts:
             ans = True
         else:
             try:
                 ans = self.shell.ask_yes_no(
                 "Once deleted, variables cannot be recovered. Proceed (y/[n])? ",
                 default='n')
             except StdinNotImplementedError:
                 ans = True
         if not ans:
             print 'Nothing done.'
             return
         user_ns = self.shell.user_ns
         if not regex:
             print 'No regex pattern specified. Nothing done.'
             return
         else:
             try:
                 m = re.compile(regex)
             except TypeError:
                 raise TypeError('regex must be a string or compiled pattern')
             for i in self.who_ls():
                 if m.search(i):
                     del(user_ns[i])
 
     @line_magic
     def xdel(self, parameter_s=''):
         """Delete a variable, trying to clear it from anywhere that
         IPython's machinery has references to it. By default, this uses
         the identity of the named object in the user namespace to remove
         references held under other names. The object is also removed
         from the output history.
 
         Options
           -n : Delete the specified name from all namespaces, without
           checking their identity.
         """
         opts, varname = self.parse_options(parameter_s,'n')
         try:
             self.shell.del_var(varname, ('n' in opts))
         except (NameError, ValueError) as e:
             print type(e).__name__ +": "+ str(e)

IPython/core/magics/osm.py

@@ -1,721 +1,724 b''
 """Implementation of magic functions for interaction with the OS.
 
 Note: this module is named 'osm' instead of 'os' to avoid a collision with the
 builtin.
 """
 #-----------------------------------------------------------------------------
 #  Copyright (c) 2012 The IPython Development Team.
 #
 #  Distributed under the terms of the Modified BSD License.
 #
 #  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # Stdlib
 import io
 import os
 import re
 import sys
 from pprint import pformat
 
 # Our own packages
 from IPython.core import magic_arguments
 from IPython.core import oinspect
 from IPython.core import page
 from IPython.core.error import UsageError, StdinNotImplementedError
 from IPython.core.magic import  (
     Magics, compress_dhist, magics_class, line_magic, cell_magic, line_cell_magic
 )
 from IPython.testing.skipdoctest import skip_doctest
 from IPython.utils.io import file_read, nlprint
 from IPython.utils.path import get_py_filename, unquote_filename
 from IPython.utils.process import abbrev_cwd
 from IPython.utils.terminal import set_term_title
 #-----------------------------------------------------------------------------
 # Magic implementation classes
 #-----------------------------------------------------------------------------
 @magics_class
 class OSMagics(Magics):
     """Magics to interact with the underlying OS (shell-type functionality).
     """
 
     @skip_doctest
     @line_magic
     def alias(self, parameter_s=''):
         """Define an alias for a system command.
 
         '%alias alias_name cmd' defines 'alias_name' as an alias for 'cmd'
 
         Then, typing 'alias_name params' will execute the system command 'cmd
         params' (from your underlying operating system).
 
         Aliases have lower precedence than magic functions and Python normal
         variables, so if 'foo' is both a Python variable and an alias, the
         alias can not be executed until 'del foo' removes the Python variable.
 
         You can use the %l specifier in an alias definition to represent the
         whole line when the alias is called.  For example::
 
           In [2]: alias bracket echo "Input in brackets: <%l>"
           In [3]: bracket hello world
           Input in brackets: <hello world>
 
         You can also define aliases with parameters using %s specifiers (one
         per parameter)::
 
           In [1]: alias parts echo first %s second %s
           In [2]: %parts A B
           first A second B
           In [3]: %parts A
           Incorrect number of arguments: 2 expected.
           parts is an alias to: 'echo first %s second %s'
 
         Note that %l and %s are mutually exclusive.  You can only use one or
         the other in your aliases.
 
         Aliases expand Python variables just like system calls using ! or !!
         do: all expressions prefixed with '$' get expanded.  For details of
         the semantic rules, see PEP-215:
         http://www.python.org/peps/pep-0215.html.  This is the library used by
         IPython for variable expansion.  If you want to access a true shell
         variable, an extra $ is necessary to prevent its expansion by
         IPython::
 
           In [6]: alias show echo
           In [7]: PATH='A Python string'
           In [8]: show $PATH
           A Python string
           In [9]: show $$PATH
           /usr/local/lf9560/bin:/usr/local/intel/compiler70/ia32/bin:...
 
         You can use the alias facility to acess all of $PATH.  See the %rehash
         and %rehashx functions, which automatically create aliases for the
         contents of your $PATH.
 
         If called with no parameters, %alias prints the current alias table."""
 
         par = parameter_s.strip()
         if not par:
             aliases = sorted(self.shell.alias_manager.aliases)
             # stored = self.shell.db.get('stored_aliases', {} )
             # for k, v in stored:
             #     atab.append(k, v[0])
 
             print "Total number of aliases:", len(aliases)
             sys.stdout.flush()
             return aliases
 
         # Now try to define a new one
         try:
             alias,cmd = par.split(None, 1)
         except:
             print oinspect.getdoc(self.alias)
         else:
             self.shell.alias_manager.soft_define_alias(alias, cmd)
     # end magic_alias
 
     @line_magic
     def unalias(self, parameter_s=''):
         """Remove an alias"""
 
         aname = parameter_s.strip()
         self.shell.alias_manager.undefine_alias(aname)
         stored = self.shell.db.get('stored_aliases', {} )
         if aname in stored:
             print "Removing %stored alias",aname
             del stored[aname]
             self.shell.db['stored_aliases'] = stored
 
     @line_magic
     def rehashx(self, parameter_s=''):
         """Update the alias table with all executable files in $PATH.
 
         This version explicitly checks that every entry in $PATH is a file
         with execute access (os.X_OK), so it is much slower than %rehash.
 
         Under Windows, it checks executability as a match against a
         '|'-separated string of extensions, stored in the IPython config
         variable win_exec_ext.  This defaults to 'exe|com|bat'.
 
         This function also resets the root module cache of module completer,
         used on slow filesystems.
         """
         from IPython.core.alias import InvalidAliasError
 
         # for the benefit of module completer in ipy_completers.py
         del self.shell.db['rootmodules']
 
         path = [os.path.abspath(os.path.expanduser(p)) for p in
             os.environ.get('PATH','').split(os.pathsep)]
         path = filter(os.path.isdir,path)
 
         syscmdlist = []
         # Now define isexec in a cross platform manner.
         if os.name == 'posix':
             isexec = lambda fname:os.path.isfile(fname) and \
                      os.access(fname,os.X_OK)
         else:
             try:
                 winext = os.environ['pathext'].replace(';','|').replace('.','')
             except KeyError:
                 winext = 'exe|com|bat|py'
             if 'py' not in winext:
                 winext += '|py'
             execre = re.compile(r'(.*)\.(%s)$' % winext,re.IGNORECASE)
             isexec = lambda fname:os.path.isfile(fname) and execre.match(fname)
         savedir = os.getcwdu()
 
         # Now walk the paths looking for executables to alias.
         try:
             # write the whole loop for posix/Windows so we don't have an if in
             # the innermost part
             if os.name == 'posix':
                 for pdir in path:
                     os.chdir(pdir)
                     for ff in os.listdir(pdir):
                         if isexec(ff):
                             try:
                                 # Removes dots from the name since ipython
                                 # will assume names with dots to be python.
                                 self.shell.alias_manager.define_alias(
                                     ff.replace('.',''), ff)
                             except InvalidAliasError:
                                 pass
                             else:
                                 syscmdlist.append(ff)
             else:
                 no_alias = self.shell.alias_manager.no_alias
                 for pdir in path:
                     os.chdir(pdir)
                     for ff in os.listdir(pdir):
                         base, ext = os.path.splitext(ff)
                         if isexec(ff) and base.lower() not in no_alias:
                             if ext.lower() == '.exe':
                                 ff = base
                                 try:
                                     # Removes dots from the name since ipython
                                     # will assume names with dots to be python.
                                     self.shell.alias_manager.define_alias(
                                         base.lower().replace('.',''), ff)
                                 except InvalidAliasError:
                                     pass
                                 syscmdlist.append(ff)
             self.shell.db['syscmdlist'] = syscmdlist
         finally:
             os.chdir(savedir)
 
     @skip_doctest
     @line_magic
     def pwd(self, parameter_s=''):
         """Return the current working directory path.
 
         Examples
         --------
         ::
 
           In [9]: pwd
           Out[9]: '/home/tsuser/sprint/ipython'
         """
         return os.getcwdu()
 
     @skip_doctest
     @line_magic
     def cd(self, parameter_s=''):
         """Change the current working directory.
 
         This command automatically maintains an internal list of directories
         you visit during your IPython session, in the variable _dh. The
         command %dhist shows this history nicely formatted. You can also
         do 'cd -<tab>' to see directory history conveniently.
 
         Usage:
 
           cd 'dir': changes to directory 'dir'.
 
           cd -: changes to the last visited directory.
 
           cd -<n>: changes to the n-th directory in the directory history.
 
           cd --foo: change to directory that matches 'foo' in history
 
           cd -b <bookmark_name>: jump to a bookmark set by %bookmark
              (note: cd <bookmark_name> is enough if there is no
               directory <bookmark_name>, but a bookmark with the name exists.)
               'cd -b <tab>' allows you to tab-complete bookmark names.
 
         Options:
 
         -q: quiet.  Do not print the working directory after the cd command is
         executed.  By default IPython's cd command does print this directory,
         since the default prompts do not display path information.
 
         Note that !cd doesn't work for this purpose because the shell where
         !command runs is immediately discarded after executing 'command'.
 
         Examples
         --------
         ::
 
           In [10]: cd parent/child
           /home/tsuser/parent/child
         """
 
         oldcwd = os.getcwdu()
         numcd = re.match(r'(-)(\d+)$',parameter_s)
         # jump in directory history by number
         if numcd:
             nn = int(numcd.group(2))
             try:
                 ps = self.shell.user_ns['_dh'][nn]
             except IndexError:
                 print 'The requested directory does not exist in history.'
                 return
             else:
                 opts = {}
         elif parameter_s.startswith('--'):
             ps = None
             fallback = None
             pat = parameter_s[2:]
             dh = self.shell.user_ns['_dh']
             # first search only by basename (last component)
             for ent in reversed(dh):
                 if pat in os.path.basename(ent) and os.path.isdir(ent):
                     ps = ent
                     break
 
                 if fallback is None and pat in ent and os.path.isdir(ent):
                     fallback = ent
 
             # if we have no last part match, pick the first full path match
             if ps is None:
                 ps = fallback
 
             if ps is None:
                 print "No matching entry in directory history"
                 return
             else:
                 opts = {}
 
 
         else:
             #turn all non-space-escaping backslashes to slashes,
             # for c:\windows\directory\names\
             parameter_s = re.sub(r'\\(?! )','/', parameter_s)
             opts,ps = self.parse_options(parameter_s,'qb',mode='string')
         # jump to previous
         if ps == '-':
             try:
                 ps = self.shell.user_ns['_dh'][-2]
             except IndexError:
                 raise UsageError('%cd -: No previous directory to change to.')
         # jump to bookmark if needed
         else:
             if not os.path.isdir(ps) or 'b' in opts:
                 bkms = self.shell.db.get('bookmarks', {})
 
                 if ps in bkms:
                     target = bkms[ps]
                     print '(bookmark:%s) -> %s' % (ps, target)
                     ps = target
                 else:
                     if 'b' in opts:
                         raise UsageError("Bookmark '%s' not found.  "
                               "Use '%%bookmark -l' to see your bookmarks." % ps)
 
         # strip extra quotes on Windows, because os.chdir doesn't like them
         ps = unquote_filename(ps)
         # at this point ps should point to the target dir
         if ps:
             try:
                 os.chdir(os.path.expanduser(ps))
                 if hasattr(self.shell, 'term_title') and self.shell.term_title:
                     set_term_title('IPython: ' + abbrev_cwd())
             except OSError:
                 print sys.exc_info()[1]
             else:
                 cwd = os.getcwdu()
                 dhist = self.shell.user_ns['_dh']
                 if oldcwd != cwd:
                     dhist.append(cwd)
                     self.shell.db['dhist'] = compress_dhist(dhist)[-100:]
 
         else:
             os.chdir(self.shell.home_dir)
             if hasattr(self.shell, 'term_title') and self.shell.term_title:
                 set_term_title('IPython: ' + '~')
             cwd = os.getcwdu()
             dhist = self.shell.user_ns['_dh']
 
             if oldcwd != cwd:
                 dhist.append(cwd)
                 self.shell.db['dhist'] = compress_dhist(dhist)[-100:]
         if not 'q' in opts and self.shell.user_ns['_dh']:
             print self.shell.user_ns['_dh'][-1]
 
 
     @line_magic
     def env(self, parameter_s=''):
         """List environment variables."""
 
         return dict(os.environ)
 
     @line_magic
     def pushd(self, parameter_s=''):
         """Place the current dir on stack and change directory.
 
         Usage:\\
           %pushd ['dirname']
         """
 
         dir_s = self.shell.dir_stack
         tgt = os.path.expanduser(unquote_filename(parameter_s))
         cwd = os.getcwdu().replace(self.shell.home_dir,'~')
         if tgt:
             self.cd(parameter_s)
         dir_s.insert(0,cwd)
         return self.shell.magic('dirs')
 
     @line_magic
     def popd(self, parameter_s=''):
         """Change to directory popped off the top of the stack.
         """
         if not self.shell.dir_stack:
             raise UsageError("%popd on empty stack")
         top = self.shell.dir_stack.pop(0)
         self.cd(top)
         print "popd ->",top
 
     @line_magic
     def dirs(self, parameter_s=''):
         """Return the current directory stack."""
 
         return self.shell.dir_stack
 
     @line_magic
     def dhist(self, parameter_s=''):
         """Print your history of visited directories.
 
         %dhist       -> print full history\\
         %dhist n     -> print last n entries only\\
         %dhist n1 n2 -> print entries between n1 and n2 (n1 not included)\\
 
         This history is automatically maintained by the %cd command, and
         always available as the global list variable _dh. You can use %cd -<n>
         to go to directory number <n>.
 
         Note that most of time, you should view directory history by entering
         cd -<TAB>.
 
         """
 
         dh = self.shell.user_ns['_dh']
         if parameter_s:
             try:
                 args = map(int,parameter_s.split())
             except:
                 self.arg_err(self.dhist)
                 return
             if len(args) == 1:
                 ini,fin = max(len(dh)-(args[0]),0),len(dh)
             elif len(args) == 2:
                 ini,fin = args
             else:
                 self.arg_err(self.dhist)
                 return
         else:
             ini,fin = 0,len(dh)
         nlprint(dh,
                 header = 'Directory history (kept in _dh)',
                 start=ini,stop=fin)
 
     @skip_doctest
     @line_magic
     def sc(self, parameter_s=''):
         """Shell capture - run shell command and capture output (DEPRECATED use !).
 
         DEPRECATED. Suboptimal, retained for backwards compatibility.
 
         You should use the form 'var = !command' instead. Example:
 
          "%sc -l myfiles = ls ~" should now be written as
 
          "myfiles = !ls ~"
 
         myfiles.s, myfiles.l and myfiles.n still apply as documented
         below.
 
         --
         %sc [options] varname=command
 
         IPython will run the given command using commands.getoutput(), and
         will then update the user's interactive namespace with a variable
         called varname, containing the value of the call.  Your command can
         contain shell wildcards, pipes, etc.
 
         The '=' sign in the syntax is mandatory, and the variable name you
         supply must follow Python's standard conventions for valid names.
 
         (A special format without variable name exists for internal use)
 
         Options:
 
           -l: list output.  Split the output on newlines into a list before
           assigning it to the given variable.  By default the output is stored
           as a single string.
 
           -v: verbose.  Print the contents of the variable.
 
         In most cases you should not need to split as a list, because the
         returned value is a special type of string which can automatically
         provide its contents either as a list (split on newlines) or as a
         space-separated string.  These are convenient, respectively, either
         for sequential processing or to be passed to a shell command.
 
         For example::
 
             # Capture into variable a
             In [1]: sc a=ls *py
 
             # a is a string with embedded newlines
             In [2]: a
             Out[2]: 'setup.py\\nwin32_manual_post_install.py'
 
             # which can be seen as a list:
             In [3]: a.l
             Out[3]: ['setup.py', 'win32_manual_post_install.py']
 
             # or as a whitespace-separated string:
             In [4]: a.s
             Out[4]: 'setup.py win32_manual_post_install.py'
 
             # a.s is useful to pass as a single command line:
             In [5]: !wc -l $a.s
               146 setup.py
               130 win32_manual_post_install.py
               276 total
 
             # while the list form is useful to loop over:
             In [6]: for f in a.l:
               ...:      !wc -l $f
               ...:
             146 setup.py
             130 win32_manual_post_install.py
 
         Similarly, the lists returned by the -l option are also special, in
         the sense that you can equally invoke the .s attribute on them to
         automatically get a whitespace-separated string from their contents::
 
             In [7]: sc -l b=ls *py
 
             In [8]: b
             Out[8]: ['setup.py', 'win32_manual_post_install.py']
 
             In [9]: b.s
             Out[9]: 'setup.py win32_manual_post_install.py'
 
         In summary, both the lists and strings used for output capture have
         the following special attributes::
 
             .l (or .list) : value as list.
             .n (or .nlstr): value as newline-separated string.
             .s (or .spstr): value as space-separated string.
         """
 
         opts,args = self.parse_options(parameter_s, 'lv')
         # Try to get a variable name and command to run
         try:
             # the variable name must be obtained from the parse_options
             # output, which uses shlex.split to strip options out.
             var,_ = args.split('=', 1)
             var = var.strip()
             # But the command has to be extracted from the original input
             # parameter_s, not on what parse_options returns, to avoid the
             # quote stripping which shlex.split performs on it.
             _,cmd = parameter_s.split('=', 1)
         except ValueError:
             var,cmd = '',''
         # If all looks ok, proceed
         split = 'l' in opts
         out = self.shell.getoutput(cmd, split=split)
         if 'v' in opts:
             print '%s ==\n%s' % (var, pformat(out))
         if var:
             self.shell.user_ns.update({var:out})
         else:
             return out
 
     @line_cell_magic
     def sx(self, line='', cell=None):
         """Shell execute - run shell command and capture output (!! is short-hand).
 
         %sx command
 
         IPython will run the given command using commands.getoutput(), and
         return the result formatted as a list (split on '\\n').  Since the
         output is _returned_, it will be stored in ipython's regular output
         cache Out[N] and in the '_N' automatic variables.
 
         Notes:
 
         1) If an input line begins with '!!', then %sx is automatically
         invoked.  That is, while::
 
           !ls
 
         causes ipython to simply issue system('ls'), typing::
 
           !!ls
 
         is a shorthand equivalent to::
 
           %sx ls
 
         2) %sx differs from %sc in that %sx automatically splits into a list,
         like '%sc -l'.  The reason for this is to make it as easy as possible
         to process line-oriented shell output via further python commands.
         %sc is meant to provide much finer control, but requires more
         typing.
 
         3) Just like %sc -l, this is a list with special attributes:
         ::
 
           .l (or .list) : value as list.
           .n (or .nlstr): value as newline-separated string.
           .s (or .spstr): value as whitespace-separated string.
 
         This is very useful when trying to use such lists as arguments to
         system commands."""
         
         if cell is None:
             # line magic
             return self.shell.getoutput(line)
         else:
             opts,args = self.parse_options(line, '', 'out=')
             output = self.shell.getoutput(cell)
             out_name = opts.get('out', opts.get('o'))
             if out_name:
                 self.shell.user_ns[out_name] = output
             else:
                 return output
 
     system = line_cell_magic('system')(sx)
     bang = cell_magic('!')(sx)
 
     @line_magic
     def bookmark(self, parameter_s=''):
         """Manage IPython's bookmark system.
 
         %bookmark <name>       - set bookmark to current dir
         %bookmark <name> <dir> - set bookmark to <dir>
         %bookmark -l           - list all bookmarks
         %bookmark -d <name>    - remove bookmark
         %bookmark -r           - remove all bookmarks
 
         You can later on access a bookmarked folder with::
 
           %cd -b <name>
 
         or simply '%cd <name>' if there is no directory called <name> AND
         there is such a bookmark defined.
 
         Your bookmarks persist through IPython sessions, but they are
         associated with each profile."""
 
         opts,args = self.parse_options(parameter_s,'drl',mode='list')
         if len(args) > 2:
             raise UsageError("%bookmark: too many arguments")
 
         bkms = self.shell.db.get('bookmarks',{})
 
         if 'd' in opts:
             try:
                 todel = args[0]
             except IndexError:
                 raise UsageError(
                     "%bookmark -d: must provide a bookmark to delete")
             else:
                 try:
                     del bkms[todel]
                 except KeyError:
                     raise UsageError(
                         "%%bookmark -d: Can't delete bookmark '%s'" % todel)
 
         elif 'r' in opts:
             bkms = {}
         elif 'l' in opts:
             bks = bkms.keys()
             bks.sort()
             if bks:
                 size = max(map(len, bks))
             else:
                 size = 0
             fmt = '%-'+str(size)+'s -> %s'
             print 'Current bookmarks:'
             for bk in bks:
                 print fmt % (bk, bkms[bk])
         else:
             if not args:
                 raise UsageError("%bookmark: You must specify the bookmark name")
             elif len(args)==1:
                 bkms[args[0]] = os.getcwdu()
             elif len(args)==2:
                 bkms[args[0]] = args[1]
         self.shell.db['bookmarks'] = bkms
 
     @line_magic
     def pycat(self, parameter_s=''):
         """Show a syntax-highlighted file through a pager.
 
         This magic is similar to the cat utility, but it will assume the file
         to be Python source and will show it with syntax highlighting.
 
         This magic command can either take a local filename, an url,
         an history range (see %history) or a macro as argument ::
 
         %pycat myscript.py
         %pycat 7-27
         %pycat myMacro
         %pycat http://www.example.com/myscript.py
         """
+        if not parameter_s:
+            raise UsageError('Missing filename, URL, input history range, '
+                             'or macro.')
 
         try :
             cont = self.shell.find_user_code(parameter_s)
         except (ValueError, IOError):
             print "Error: no such file, variable, URL, history range or macro"
             return
 
         page.page(self.shell.pycolorize(cont))
 
     @magic_arguments.magic_arguments()
     @magic_arguments.argument(
         '-a', '--amend', action='store_true', default=False,
         help='Open file for amending if it exists'
     )
     @magic_arguments.argument(
         'filename', type=unicode,
         help='file to write'
     )
     @cell_magic
     def file(self, line, cell):
         """Write the contents of the cell to a file.
         
         For frontends that do not support stdin (Notebook), -f is implied.
         """
         args = magic_arguments.parse_argstring(self.file, line)
         filename = unquote_filename(args.filename)
         
         if os.path.exists(filename):
             if args.amend:
                 print "Amending to %s" % filename
             else:
                 print "Overwriting %s" % filename
         else:
             print "Writing %s" % filename
         
         mode = 'a' if args.amend else 'w'
         with io.open(filename, mode, encoding='utf-8') as f:
             f.write(cell)

IPython/zmq/zmqshell.py

@@ -1,584 +1,588 b''
 """A ZMQ-based subclass of InteractiveShell.
 
 This code is meant to ease the refactoring of the base InteractiveShell into
 something with a cleaner architecture for 2-process use, without actually
 breaking InteractiveShell itself.  So we're doing something a bit ugly, where
 we subclass and override what we want to fix.  Once this is working well, we
 can go back to the base class and refactor the code for a cleaner inheritance
 implementation that doesn't rely on so much monkeypatching.
 
 But this lets us maintain a fully working IPython as we develop the new
 machinery.  This should thus be thought of as scaffolding.
 """
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from __future__ import print_function
 
 # Stdlib
 import os
 import sys
 import time
 
 # System library imports
 from zmq.eventloop import ioloop
 
 # Our own
 from IPython.core.interactiveshell import (
     InteractiveShell, InteractiveShellABC
 )
 from IPython.core import page
 from IPython.core.autocall import ZMQExitAutocall
 from IPython.core.displaypub import DisplayPublisher
+from IPython.core.error import UsageError
 from IPython.core.magics import MacroToEdit, CodeMagics
 from IPython.core.magic import magics_class, line_magic, Magics
 from IPython.core.payloadpage import install_payload_page
 from IPython.lib.kernel import (
     get_connection_file, get_connection_info, connect_qtconsole
 )
 from IPython.testing.skipdoctest import skip_doctest
 from IPython.utils import io
 from IPython.utils.jsonutil import json_clean, encode_images
 from IPython.utils.process import arg_split
 from IPython.utils import py3compat
 from IPython.utils.traitlets import Instance, Type, Dict, CBool, CBytes
 from IPython.utils.warn import warn, error
 from IPython.zmq.displayhook import ZMQShellDisplayHook
 from IPython.zmq.datapub import ZMQDataPublisher
 from IPython.zmq.session import extract_header
 from session import Session
 
 #-----------------------------------------------------------------------------
 # Functions and classes
 #-----------------------------------------------------------------------------
 
 class ZMQDisplayPublisher(DisplayPublisher):
     """A display publisher that publishes data using a ZeroMQ PUB socket."""
 
     session = Instance(Session)
     pub_socket = Instance('zmq.Socket')
     parent_header = Dict({})
     topic = CBytes(b'displaypub')
 
     def set_parent(self, parent):
         """Set the parent for outbound messages."""
         self.parent_header = extract_header(parent)
     
     def _flush_streams(self):
         """flush IO Streams prior to display"""
         sys.stdout.flush()
         sys.stderr.flush()
 
     def publish(self, source, data, metadata=None):
         self._flush_streams()
         if metadata is None:
             metadata = {}
         self._validate_data(source, data, metadata)
         content = {}
         content['source'] = source
         content['data'] = encode_images(data)
         content['metadata'] = metadata
         self.session.send(
             self.pub_socket, u'display_data', json_clean(content),
             parent=self.parent_header, ident=self.topic,
         )
 
     def clear_output(self, stdout=True, stderr=True, other=True):
         content = dict(stdout=stdout, stderr=stderr, other=other)
         
         if stdout:
             print('\r', file=sys.stdout, end='')
         if stderr:
             print('\r', file=sys.stderr, end='')
         
         self._flush_streams()
         
         self.session.send(
             self.pub_socket, u'clear_output', content,
             parent=self.parent_header, ident=self.topic,
         )
 
 @magics_class
 class KernelMagics(Magics):
     #------------------------------------------------------------------------
     # 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.
 
     @line_magic
     def doctest_mode(self, parameter_s=''):
         """Toggle doctest mode on and off.
 
         This mode is intended to make IPython behave as much as possible like a
         plain Python shell, from the perspective of how its prompts, exceptions
         and output look.  This makes it easy to copy and paste parts of a
         session into doctests.  It does so by:
 
         - Changing the prompts to the classic ``>>>`` ones.
         - Changing the exception reporting mode to 'Plain'.
         - Disabling pretty-printing of output.
 
         Note that IPython also supports the pasting of code snippets that have
         leading '>>>' and '...' prompts in them.  This means that you can paste
         doctests from files or docstrings (even if they have leading
         whitespace), and the code will execute correctly.  You can then use
         '%history -t' to see the translated history; this will give you the
         input after removal of all the leading prompts and whitespace, which
         can be pasted back into an editor.
 
         With these features, you can switch into this mode easily whenever you
         need to do testing and changes to doctests, without having to leave
         your existing IPython session.
         """
 
         from IPython.utils.ipstruct import Struct
 
         # Shorthands
         shell = self.shell
         disp_formatter = self.shell.display_formatter
         ptformatter = disp_formatter.formatters['text/plain']
         # dstore is a data store kept in the instance metadata bag to track any
         # changes we make, so we can undo them later.
         dstore = shell.meta.setdefault('doctest_mode', Struct())
         save_dstore = dstore.setdefault
 
         # save a few values we'll need to recover later
         mode = save_dstore('mode', False)
         save_dstore('rc_pprint', ptformatter.pprint)
         save_dstore('rc_plain_text_only',disp_formatter.plain_text_only)
         save_dstore('xmode', shell.InteractiveTB.mode)
 
         if mode == False:
             # turn on
             ptformatter.pprint = False
             disp_formatter.plain_text_only = True
             shell.magic('xmode Plain')
         else:
             # turn off
             ptformatter.pprint = dstore.rc_pprint
             disp_formatter.plain_text_only = dstore.rc_plain_text_only
             shell.magic("xmode " + dstore.xmode)
 
         # Store new mode and inform on console
         dstore.mode = bool(1-int(mode))
         mode_label = ['OFF','ON'][dstore.mode]
         print('Doctest mode is:', mode_label)
 
         # Send the payload back so that clients can modify their prompt display
         payload = dict(
             source='IPython.zmq.zmqshell.ZMQInteractiveShell.doctest_mode',
             mode=dstore.mode)
         shell.payload_manager.write_payload(payload)
         
     
     _find_edit_target = CodeMagics._find_edit_target
 
     @skip_doctest
     @line_magic
     def edit(self, parameter_s='', last_call=['','']):
         """Bring up an editor and execute the resulting code.
 
         Usage:
           %edit [options] [args]
 
         %edit runs an external text editor. You will need to set the command for
         this editor via the ``TerminalInteractiveShell.editor`` option in your
         configuration file before it will work.
 
         This command allows you to conveniently edit multi-line code right in
         your IPython session.
 
         If called without arguments, %edit opens up an empty editor with a
         temporary file and will execute the contents of this file when you
         close it (don't forget to save it!).
 
 
         Options:
 
         -n <number>: open the editor at a specified line number.  By default,
         the IPython editor hook uses the unix syntax 'editor +N filename', but
         you can configure this by providing your own modified hook if your
         favorite editor supports line-number specifications with a different
         syntax.
 
         -p: this will call the editor with the same data as the previous time
         it was used, regardless of how long ago (in your current session) it
         was.
 
         -r: use 'raw' input.  This option only applies to input taken from the
         user's history.  By default, the 'processed' history is used, so that
         magics are loaded in their transformed version to valid Python.  If
         this option is given, the raw input as typed as the command line is
         used instead.  When you exit the editor, it will be executed by
         IPython's own processor.
 
         -x: do not execute the edited code immediately upon exit. This is
         mainly useful if you are editing programs which need to be called with
         command line arguments, which you can then do using %run.
 
 
         Arguments:
 
         If arguments are given, the following possibilites exist:
 
         - The arguments are numbers or pairs of colon-separated numbers (like
         1 4:8 9). These are interpreted as lines of previous input to be
         loaded into the editor. The syntax is the same of the %macro command.
 
         - If the argument doesn't start with a number, it is evaluated as a
         variable and its contents loaded into the editor. You can thus edit
         any string which contains python code (including the result of
         previous edits).
 
         - If the argument is the name of an object (other than a string),
         IPython will try to locate the file where it was defined and open the
         editor at the point where it is defined. You can use `%edit function`
         to load an editor exactly at the point where 'function' is defined,
         edit it and have the file be executed automatically.
 
         If the object is a macro (see %macro for details), this opens up your
         specified editor with a temporary file containing the macro's data.
         Upon exit, the macro is reloaded with the contents of the file.
 
         Note: opening at an exact line is only supported under Unix, and some
         editors (like kedit and gedit up to Gnome 2.8) do not understand the
         '+NUMBER' parameter necessary for this feature. Good editors like
         (X)Emacs, vi, jed, pico and joe all do.
 
         - If the argument is not found as a variable, IPython will look for a
         file with that name (adding .py if necessary) and load it into the
         editor. It will execute its contents with execfile() when you exit,
         loading any code in the file into your interactive namespace.
 
         After executing your code, %edit will return as output the code you
         typed in the editor (except when it was an existing file). This way
         you can reload the code in further invocations of %edit as a variable,
         via _<NUMBER> or Out[<NUMBER>], where <NUMBER> is the prompt number of
         the output.
 
         Note that %edit is also available through the alias %ed.
 
         This is an example of creating a simple function inside the editor and
         then modifying it. First, start up the editor:
 
         In [1]: ed
         Editing... done. Executing edited code...
         Out[1]: 'def foo():n    print "foo() was defined in an editing session"n'
 
         We can then call the function foo():
 
         In [2]: foo()
         foo() was defined in an editing session
 
         Now we edit foo.  IPython automatically loads the editor with the
         (temporary) file where foo() was previously defined:
 
         In [3]: ed foo
         Editing... done. Executing edited code...
 
         And if we call foo() again we get the modified version:
 
         In [4]: foo()
         foo() has now been changed!
 
         Here is an example of how to edit a code snippet successive
         times. First we call the editor:
 
         In [5]: ed
         Editing... done. Executing edited code...
         hello
         Out[5]: "print 'hello'n"
 
         Now we call it again with the previous output (stored in _):
 
         In [6]: ed _
         Editing... done. Executing edited code...
         hello world
         Out[6]: "print 'hello world'n"
 
         Now we call it with the output #8 (stored in _8, also as Out[8]):
 
         In [7]: ed _8
         Editing... done. Executing edited code...
         hello again
         Out[7]: "print 'hello again'n"
         """
 
         opts,args = self.parse_options(parameter_s,'prn:')
 
         try:
             filename, lineno, _ = CodeMagics._find_edit_target(self.shell, args, opts, last_call)
         except MacroToEdit as e:
             # TODO: Implement macro editing over 2 processes.
             print("Macro editing not yet implemented in 2-process model.")
             return
 
         # Make sure we send to the client an absolute path, in case the working
         # directory of client and kernel don't match
         filename = os.path.abspath(filename)
 
         payload = {
             'source' : 'IPython.zmq.zmqshell.ZMQInteractiveShell.edit_magic',
             'filename' : filename,
             'line_number' : lineno
         }
         self.shell.payload_manager.write_payload(payload)
 
     # A few magics that are adapted to the specifics of using pexpect and a
     # remote terminal
 
     @line_magic
     def clear(self, arg_s):
         """Clear the terminal."""
         if os.name == 'posix':
             self.shell.system("clear")
         else:
             self.shell.system("cls")
 
     if os.name == 'nt':
         # This is the usual name in windows
         cls = line_magic('cls')(clear)
 
     # Terminal pagers won't work over pexpect, but we do have our own pager
 
     @line_magic
     def less(self, arg_s):
         """Show a file through the pager.
 
         Files ending in .py are syntax-highlighted."""
+        if not arg_s:
+            raise UsageError('Missing filename.')
+
         cont = open(arg_s).read()
         if arg_s.endswith('.py'):
             cont = self.shell.pycolorize(cont)
         page.page(cont)
 
     more = line_magic('more')(less)
 
     # Man calls a pager, so we also need to redefine it
     if os.name == 'posix':
         @line_magic
         def man(self, arg_s):
             """Find the man page for the given command and display in pager."""
             page.page(self.shell.getoutput('man %s | col -b' % arg_s,
                                            split=False))
 
     @line_magic
     def connect_info(self, arg_s):
         """Print information for connecting other clients to this kernel
         
         It will print the contents of this session's connection file, as well as
         shortcuts for local clients.
         
         In the simplest case, when called from the most recently launched kernel,
         secondary clients can be connected, simply with:
         
         $> ipython <app> --existing
         
         """
         
         from IPython.core.application import BaseIPythonApplication as BaseIPApp
         
         if BaseIPApp.initialized():
             app = BaseIPApp.instance()
             security_dir = app.profile_dir.security_dir
             profile = app.profile
         else:
             profile = 'default'
             security_dir = ''
         
         try:
             connection_file = get_connection_file()
             info = get_connection_info(unpack=False)
         except Exception as e:
             error("Could not get connection info: %r" % e)
             return
         
         # add profile flag for non-default profile
         profile_flag = "--profile %s" % profile if profile != 'default' else ""
         
         # if it's in the security dir, truncate to basename
         if security_dir == os.path.dirname(connection_file):
             connection_file = os.path.basename(connection_file)
         
         
         print (info + '\n')
         print ("Paste the above JSON into a file, and connect with:\n"
             "    $> ipython <app> --existing <file>\n"
             "or, if you are local, you can connect with just:\n"
             "    $> ipython <app> --existing {0} {1}\n"
             "or even just:\n"
             "    $> ipython <app> --existing {1}\n"
             "if this is the most recent IPython session you have started.".format(
             connection_file, profile_flag
             )
         )
 
     @line_magic
     def qtconsole(self, arg_s):
         """Open a qtconsole connected to this kernel.
         
         Useful for connecting a qtconsole to running notebooks, for better
         debugging.
         """
         
         # %qtconsole should imply bind_kernel for engines:
         try:
             from IPython.parallel import bind_kernel
         except ImportError:
             # technically possible, because parallel has higher pyzmq min-version
             pass
         else:
             bind_kernel()
         
         try:
             p = connect_qtconsole(argv=arg_split(arg_s, os.name=='posix'))
         except Exception as e:
             error("Could not start qtconsole: %r" % e)
             return
 
 def safe_unicode(e):
     """unicode(e) with various fallbacks. Used for exceptions, which may not be
     safe to call unicode() on.
     """
     try:
         return unicode(e)
     except UnicodeError:
         pass
 
     try:
         return py3compat.str_to_unicode(str(e))
     except UnicodeError:
         pass
 
     try:
         return py3compat.str_to_unicode(repr(e))
     except UnicodeError:
         pass
 
     return u'Unrecoverably corrupt evalue'
 
 
 class ZMQInteractiveShell(InteractiveShell):
     """A subclass of InteractiveShell for ZMQ."""
 
     displayhook_class = Type(ZMQShellDisplayHook)
     display_pub_class = Type(ZMQDisplayPublisher)
     data_pub_class = Type(ZMQDataPublisher)
 
     # Override the traitlet in the parent class, because there's no point using
     # readline for the kernel. Can be removed when the readline code is moved
     # to the terminal frontend.
     colors_force = CBool(True)
     readline_use = CBool(False)
     # autoindent has no meaning in a zmqshell, and attempting to enable it
     # will print a warning in the absence of readline.
     autoindent = CBool(False)
 
     exiter = Instance(ZMQExitAutocall)
     def _exiter_default(self):
         return ZMQExitAutocall(self)
     
     def _exit_now_changed(self, name, old, new):
         """stop eventloop when exit_now fires"""
         if new:
             loop = ioloop.IOLoop.instance()
             loop.add_timeout(time.time()+0.1, loop.stop)
 
     keepkernel_on_exit = None
 
     # Over ZeroMQ, GUI control isn't done with PyOS_InputHook as there is no
     # interactive input being read; we provide event loop support in ipkernel
     from .eventloops import enable_gui
     enable_gui = staticmethod(enable_gui)
 
     def init_environment(self):
         """Configure the user's environment.
 
         """
         env = os.environ
         # These two ensure 'ls' produces nice coloring on BSD-derived systems
         env['TERM'] = 'xterm-color'
         env['CLICOLOR'] = '1'
         # Since normal pagers don't work at all (over pexpect we don't have
         # single-key control of the subprocess), try to disable paging in
         # subprocesses as much as possible.
         env['PAGER'] = 'cat'
         env['GIT_PAGER'] = 'cat'
         
         # And install the payload version of page.
         install_payload_page()
 
     def auto_rewrite_input(self, cmd):
         """Called to show the auto-rewritten input for autocall and friends.
 
         FIXME: this payload is currently not correctly processed by the
         frontend.
         """
         new = self.prompt_manager.render('rewrite') + cmd
         payload = dict(
             source='IPython.zmq.zmqshell.ZMQInteractiveShell.auto_rewrite_input',
             transformed_input=new,
             )
         self.payload_manager.write_payload(payload)
 
     def ask_exit(self):
         """Engage the exit actions."""
         self.exit_now = True
         payload = dict(
             source='IPython.zmq.zmqshell.ZMQInteractiveShell.ask_exit',
             exit=True,
             keepkernel=self.keepkernel_on_exit,
             )
         self.payload_manager.write_payload(payload)
 
     def _showtraceback(self, etype, evalue, stb):
 
         exc_content = {
             u'traceback' : stb,
             u'ename' : unicode(etype.__name__),
             u'evalue' : safe_unicode(evalue)
         }
 
         dh = self.displayhook
         # Send exception info over pub socket for other clients than the caller
         # to pick up
         topic = None
         if dh.topic:
             topic = dh.topic.replace(b'pyout', b'pyerr')
         
         exc_msg = dh.session.send(dh.pub_socket, u'pyerr', json_clean(exc_content), dh.parent_header, ident=topic)
 
         # FIXME - Hack: store exception info in shell object.  Right now, the
         # caller is reading this info after the fact, we need to fix this logic
         # to remove this hack.  Even uglier, we need to store the error status
         # here, because in the main loop, the logic that sets it is being
         # skipped because runlines swallows the exceptions.
         exc_content[u'status'] = u'error'
         self._reply_content = exc_content
         # /FIXME
 
         return exc_content
 
     def set_next_input(self, text):
         """Send the specified text to the frontend to be presented at the next
         input cell."""
         payload = dict(
             source='IPython.zmq.zmqshell.ZMQInteractiveShell.set_next_input',
             text=text
         )
         self.payload_manager.write_payload(payload)
     
     #-------------------------------------------------------------------------
     # Things related to magics
     #-------------------------------------------------------------------------
 
     def init_magics(self):
         super(ZMQInteractiveShell, self).init_magics()
         self.register_magics(KernelMagics)
         self.magics_manager.register_alias('ed', 'edit')
 
 
 
 InteractiveShellABC.register(ZMQInteractiveShell)