move InteractiveShellApp before TerminalIPythonApp in TerminalApp class list

This is useful because InteractiveShellApp is a parent that affects
all IPython apps, so it makes sense to come first.

The change affects auto generated ipython_config.py and the output
of `ipython --help-all`.

Also prevents duplicate entries for `self.__class__`

closes gh-658

IPython/config/application.py

@@ -1,421 +1,422
 # encoding: utf-8
 """
 A base class for a configurable application.
 
 Authors:
 
 * Brian Granger
 * Min RK
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import logging
 import os
 import re
 import sys
 from copy import deepcopy
 
 from IPython.config.configurable import SingletonConfigurable
 from IPython.config.loader import (
     KeyValueConfigLoader, PyFileConfigLoader, Config, ArgumentError
 )
 
 from IPython.utils.traitlets import (
     Unicode, List, Int, Enum, Dict, Instance, TraitError
 )
 from IPython.utils.importstring import import_item
 from IPython.utils.text import indent, wrap_paragraphs, dedent
 
 #-----------------------------------------------------------------------------
 # function for re-wrapping a helpstring
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Descriptions for the various sections
 #-----------------------------------------------------------------------------
 
 # merge flags&aliases into options
 option_description = """
 IPython command-line arguments are passed as '--<flag>', or '--<name>=<value>'.
 
 Arguments that take values are actually convenience aliases to full
 Configurables, whose aliases are listed on the help line. For more information
 on full configurables, see '--help-all'.
 """.strip() # trim newlines of front and back
 
 keyvalue_description = """
 Parameters are set from command-line arguments of the form:
 `--Class.trait=value`.
 This line is evaluated in Python, so simple expressions are allowed, e.g.::
 `--C.a='range(3)'` For setting C.a=[0,1,2].
 """.strip() # trim newlines of front and back
 
 subcommand_description = """
 Subcommands are launched as `{app} cmd [args]`. For information on using
 subcommand 'cmd', do: `{app} cmd -h`.
 """.strip().format(app=os.path.basename(sys.argv[0]))
 # get running program name
 
 #-----------------------------------------------------------------------------
 # Application class
 #-----------------------------------------------------------------------------
 
 
 class ApplicationError(Exception):
     pass
 
 
 class Application(SingletonConfigurable):
     """A singleton application with full configuration support."""
 
     # The name of the application, will usually match the name of the command
     # line application
     name = Unicode(u'application')
 
     # The description of the application that is printed at the beginning
     # of the help.
     description = Unicode(u'This is an application.')
     # default section descriptions
     option_description = Unicode(option_description)
     keyvalue_description = Unicode(keyvalue_description)
     subcommand_description = Unicode(subcommand_description)
 
     # The usage and example string that goes at the end of the help string.
     examples = Unicode()
 
     # A sequence of Configurable subclasses whose config=True attributes will
     # be exposed at the command line.
     classes = List([])
 
     # The version string of this application.
     version = Unicode(u'0.0')
 
     # The log level for the application
     log_level = Enum((0,10,20,30,40,50,'DEBUG','INFO','WARN','ERROR','CRITICAL'),
                     default_value=logging.WARN,
                     config=True,
                     help="Set the log level by value or name.")
     def _log_level_changed(self, name, old, new):
         """Adjust the log level when log_level is set."""
         if isinstance(new, basestring):
             new = getattr(logging, new)
             self.log_level = new
         self.log.setLevel(new)
     
     # the alias map for configurables
     aliases = Dict({'log-level' : 'Application.log_level'})
     
     # flags for loading Configurables or store_const style flags
     # flags are loaded from this dict by '--key' flags
     # this must be a dict of two-tuples, the first element being the Config/dict
     # and the second being the help string for the flag
     flags = Dict()
     def _flags_changed(self, name, old, new):
         """ensure flags dict is valid"""
         for key,value in new.iteritems():
             assert len(value) == 2, "Bad flag: %r:%s"%(key,value)
             assert isinstance(value[0], (dict, Config)), "Bad flag: %r:%s"%(key,value)
             assert isinstance(value[1], basestring), "Bad flag: %r:%s"%(key,value)
         
     
     # subcommands for launching other applications
     # if this is not empty, this will be a parent Application
     # this must be a dict of two-tuples, 
     # the first element being the application class/import string
     # and the second being the help string for the subcommand
     subcommands = Dict()
     # parse_command_line will initialize a subapp, if requested
     subapp = Instance('IPython.config.application.Application', allow_none=True)
     
     # extra command-line arguments that don't set config values
     extra_args = List(Unicode)
     
 
     def __init__(self, **kwargs):
         SingletonConfigurable.__init__(self, **kwargs)
-        # Add my class to self.classes so my attributes appear in command line
-        # options.
+        # Ensure my class is in self.classes, so my attributes appear in command line
+        # options and config files.
+        if self.__class__ not in self.classes:
         self.classes.insert(0, self.__class__)
         
         self.init_logging()
 
     def _config_changed(self, name, old, new):
         SingletonConfigurable._config_changed(self, name, old, new)
         self.log.debug('Config changed:')
         self.log.debug(repr(new))
 
     def init_logging(self):
         """Start logging for this application.
 
         The default is to log to stdout using a StreaHandler. The log level
         starts at loggin.WARN, but this can be adjusted by setting the 
         ``log_level`` attribute.
         """
         self.log = logging.getLogger(self.__class__.__name__)
         self.log.setLevel(self.log_level)
         if sys.executable.endswith('pythonw.exe'):
             # this should really go to a file, but file-logging is only
             # hooked up in parallel applications
             self._log_handler = logging.StreamHandler(open(os.devnull, 'w'))
         else:
             self._log_handler = logging.StreamHandler()
         self._log_formatter = logging.Formatter("[%(name)s] %(message)s")
         self._log_handler.setFormatter(self._log_formatter)
         self.log.addHandler(self._log_handler)
 
     def initialize(self, argv=None):
         """Do the basic steps to configure me.
         
         Override in subclasses.
         """
         self.parse_command_line(argv)
         
     
     def start(self):
         """Start the app mainloop.
         
         Override in subclasses.
         """
         if self.subapp is not None:
             return self.subapp.start()
     
     def print_alias_help(self):
         """Print the alias part of the help."""
         if not self.aliases:
             return
         
         lines = []
         classdict = {}
         for cls in self.classes:
             # include all parents (up to, but excluding Configurable) in available names
             for c in cls.mro()[:-3]:
                 classdict[c.__name__] = c
         
         for alias, longname in self.aliases.iteritems():
             classname, traitname = longname.split('.',1)
             cls = classdict[classname]
             
             trait = cls.class_traits(config=True)[traitname]
             help = cls.class_get_trait_help(trait).splitlines()
             # reformat first line
             help[0] = help[0].replace(longname, alias) + ' (%s)'%longname
             lines.extend(help)
         # lines.append('')
         print os.linesep.join(lines)
     
     def print_flag_help(self):
         """Print the flag part of the help."""
         if not self.flags:
             return
         
         lines = []
         for m, (cfg,help) in self.flags.iteritems():
             lines.append('--'+m)
             lines.append(indent(dedent(help.strip())))
         # lines.append('')
         print os.linesep.join(lines)
     
     def print_options(self):
         if not self.flags and not self.aliases:
             return
         lines = ['Options']
         lines.append('-'*len(lines[0]))
         lines.append('')
         for p in wrap_paragraphs(self.option_description):
             lines.append(p)
             lines.append('')
         print os.linesep.join(lines)
         self.print_flag_help()
         self.print_alias_help()
         print
     
     def print_subcommands(self):
         """Print the subcommand part of the help."""
         if not self.subcommands:
             return
         
         lines = ["Subcommands"]
         lines.append('-'*len(lines[0]))
         lines.append('')
         for p in wrap_paragraphs(self.subcommand_description):
             lines.append(p)
             lines.append('')
         for subc, (cls, help) in self.subcommands.iteritems():
             lines.append(subc)
             if help:
                 lines.append(indent(dedent(help.strip())))
         lines.append('')
         print os.linesep.join(lines)
     
     def print_help(self, classes=False):
         """Print the help for each Configurable class in self.classes.
         
         If classes=False (the default), only flags and aliases are printed.
         """
         self.print_subcommands()
         self.print_options()
         
         if classes:
             if self.classes:
                 print "Class parameters"
                 print "----------------"
                 print
                 for p in wrap_paragraphs(self.keyvalue_description):
                     print p
                     print
         
             for cls in self.classes:
                 cls.class_print_help()
                 print
         else:
             print "To see all available configurables, use `--help-all`"
             print
 
     def print_description(self):
         """Print the application description."""
         for p in wrap_paragraphs(self.description):
             print p
             print
 
     def print_examples(self):
         """Print usage and examples.
 
         This usage string goes at the end of the command line help string
         and should contain examples of the application's usage.
         """
         if self.examples:
             print "Examples"
             print "--------"
             print
             print indent(dedent(self.examples.strip()))
             print
 
     def print_version(self):
         """Print the version string."""
         print self.version
 
     def update_config(self, config):
         """Fire the traits events when the config is updated."""
         # Save a copy of the current config.
         newconfig = deepcopy(self.config)
         # Merge the new config into the current one.
         newconfig._merge(config)
         # Save the combined config as self.config, which triggers the traits
         # events.
         self.config = newconfig
     
     def initialize_subcommand(self, subc, argv=None):
         """Initialize a subcommand with argv."""
         subapp,help = self.subcommands.get(subc)
         
         if isinstance(subapp, basestring):
             subapp = import_item(subapp)
         
         # clear existing instances
         self.__class__.clear_instance()
         # instantiate
         self.subapp = subapp.instance()
         # and initialize subapp
         self.subapp.initialize(argv)
         
     def parse_command_line(self, argv=None):
         """Parse the command line arguments."""
         argv = sys.argv[1:] if argv is None else argv
 
         if self.subcommands and len(argv) > 0:
             # we have subcommands, and one may have been specified
             subc, subargv = argv[0], argv[1:]
             if re.match(r'^\w(\-?\w)*$', subc) and subc in self.subcommands:
                 # it's a subcommand, and *not* a flag or class parameter
                 return self.initialize_subcommand(subc, subargv)
             
         if '-h' in argv or '--help' in argv or '--help-all' in argv:
             self.print_description()
             self.print_help('--help-all' in argv)
             self.print_examples()
             self.exit(0)
 
         if '--version' in argv:
             self.print_version()
             self.exit(0)
         
         loader = KeyValueConfigLoader(argv=argv, aliases=self.aliases,
                                         flags=self.flags)
         try:
             config = loader.load_config()
             self.update_config(config)
         except (TraitError, ArgumentError) as e:
             self.print_description()
             self.print_help()
             self.print_examples()
             self.log.fatal(str(e))
             self.exit(1)
         # store unparsed args in extra_args
         self.extra_args = loader.extra_args
 
     def load_config_file(self, filename, path=None):
         """Load a .py based config file by filename and path."""
         loader = PyFileConfigLoader(filename, path=path)
         config = loader.load_config()
         self.update_config(config)
     
     def generate_config_file(self):
         """generate default config file from Configurables"""
         lines = ["# Configuration file for %s."%self.name]
         lines.append('')
         lines.append('c = get_config()')
         lines.append('')
         for cls in self.classes:
             lines.append(cls.class_config_section())
         return '\n'.join(lines)
 
     def exit(self, exit_status=0):
         self.log.debug("Exiting application: %s" % self.name)
         sys.exit(exit_status)
 
 #-----------------------------------------------------------------------------
 # utility functions, for convenience
 #-----------------------------------------------------------------------------
 
 def boolean_flag(name, configurable, set_help='', unset_help=''):
     """Helper for building basic --trait, --no-trait flags.
     
     Parameters
     ----------
     
     name : str
         The name of the flag.
     configurable : str
         The 'Class.trait' string of the trait to be set/unset with the flag
     set_help : unicode
         help string for --name flag
     unset_help : unicode
         help string for --no-name flag
     
     Returns
     -------
     
     cfg : dict
         A dict with two keys: 'name', and 'no-name', for setting and unsetting
         the trait, respectively.
     """
     # default helpstrings
     set_help = set_help or "set %s=True"%configurable
     unset_help = unset_help or "set %s=False"%configurable
     
     cls,trait = configurable.split('.')
     
     setter = {cls : {trait : True}}
     unsetter = {cls : {trait : False}}
     return {name : (setter, set_help), 'no-'+name : (unsetter, unset_help)}
 

IPython/frontend/terminal/ipapp.py

@@ -1,374 +1,383
 #!/usr/bin/env python
 # encoding: utf-8
 """
 The :class:`~IPython.core.application.Application` object for the command
 line :command:`ipython` program.
 
 Authors
 -------
 
 * Brian Granger
 * Fernando Perez
 * Min Ragan-Kelley
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2010  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from __future__ import absolute_import
 
 import logging
 import os
 import sys
 
 from IPython.config.loader import (
     Config, PyFileConfigLoader
 )
 from IPython.config.application import boolean_flag
 from IPython.core import release
 from IPython.core import usage
 from IPython.core.crashhandler import CrashHandler
 from IPython.core.formatters import PlainTextFormatter
 from IPython.core.application import (
     ProfileDir, BaseIPythonApplication, base_flags, base_aliases
 )
 from IPython.core.shellapp import (
     InteractiveShellApp, shell_flags, shell_aliases
 )
 from IPython.frontend.terminal.interactiveshell import TerminalInteractiveShell
 from IPython.lib import inputhook
 from IPython.utils import warn
 from IPython.utils.path import get_ipython_dir, check_for_old_config
 from IPython.utils.traitlets import (
-    Bool, Dict, CaselessStrEnum
+    Bool, List, Dict, CaselessStrEnum
 )
 
 #-----------------------------------------------------------------------------
 # Globals, utilities and helpers
 #-----------------------------------------------------------------------------
 
 #: The default config file name for this application.
 default_config_file_name = u'ipython_config.py'
 
 _examples = """
 ipython --pylab            # start in pylab mode
 ipython --pylab=qt         # start in pylab mode with the qt4 backend
 ipython --log-level=DEBUG  # set logging to DEBUG
 ipython --profile=foo      # start with profile foo
 
 ipython qtconsole          # start the qtconsole GUI application
 ipython qtconsole -h       # show the help string for the qtconsole subcmd
 
 ipython profile create foo # create profile foo w/ default config files
 ipython profile -h         # show the help string for the profile subcmd
 """
 
 #-----------------------------------------------------------------------------
 # Crash handler for this application
 #-----------------------------------------------------------------------------
 
 class IPAppCrashHandler(CrashHandler):
     """sys.excepthook for IPython itself, leaves a detailed report on disk."""
 
     def __init__(self, app):
         contact_name = release.authors['Fernando'][0]
         contact_email = release.authors['Fernando'][1]
         bug_tracker = 'http://github.com/ipython/ipython/issues'
         super(IPAppCrashHandler,self).__init__(
             app, contact_name, contact_email, bug_tracker
         )
 
     def make_report(self,traceback):
         """Return a string containing a crash report."""
 
         sec_sep = self.section_sep
         # Start with parent report
         report = [super(IPAppCrashHandler, self).make_report(traceback)]
         # Add interactive-specific info we may have
         rpt_add = report.append
         try:
             rpt_add(sec_sep+"History of session input:")
             for line in self.app.shell.user_ns['_ih']:
                 rpt_add(line)
             rpt_add('\n*** Last line of input (may not be in above history):\n')
             rpt_add(self.app.shell._last_input_line+'\n')
         except:
             pass
 
         return ''.join(report)
 
 #-----------------------------------------------------------------------------
 # Aliases and Flags
 #-----------------------------------------------------------------------------
 flags = dict(base_flags)
 flags.update(shell_flags)
 addflag = lambda *args: flags.update(boolean_flag(*args))
 addflag('autoedit-syntax', 'TerminalInteractiveShell.autoedit_syntax',
         'Turn on auto editing of files with syntax errors.',
         'Turn off auto editing of files with syntax errors.'
 )
 addflag('banner', 'TerminalIPythonApp.display_banner',
         "Display a banner upon starting IPython.",
         "Don't display a banner upon starting IPython."
 )
 addflag('confirm-exit', 'TerminalInteractiveShell.confirm_exit',
     """Set to confirm when you try to exit IPython with an EOF (Control-D
     in Unix, Control-Z/Enter in Windows). By typing 'exit' or 'quit',
     you can force a direct exit without any confirmation.""",
     "Don't prompt the user when exiting."
 )
 addflag('term-title', 'TerminalInteractiveShell.term_title',
     "Enable auto setting the terminal title.",
     "Disable auto setting the terminal title."
 )
 classic_config = Config()
 classic_config.InteractiveShell.cache_size = 0
 classic_config.PlainTextFormatter.pprint = False
 classic_config.InteractiveShell.prompt_in1 = '>>> '
 classic_config.InteractiveShell.prompt_in2 = '... '
 classic_config.InteractiveShell.prompt_out = ''
 classic_config.InteractiveShell.separate_in = ''
 classic_config.InteractiveShell.separate_out = ''
 classic_config.InteractiveShell.separate_out2 = ''
 classic_config.InteractiveShell.colors = 'NoColor'
 classic_config.InteractiveShell.xmode = 'Plain'
 
 flags['classic']=(
     classic_config,
     "Gives IPython a similar feel to the classic Python prompt."
 )
 # # log doesn't make so much sense this way anymore
 # paa('--log','-l',
 #     action='store_true', dest='InteractiveShell.logstart',
 #     help="Start logging to the default log file (./ipython_log.py).")
 #
 # # quick is harder to implement
 flags['quick']=(
     {'TerminalIPythonApp' : {'quick' : True}},
     "Enable quick startup with no config files."
 )
 
 flags['i'] = (
     {'TerminalIPythonApp' : {'force_interact' : True}},
     """If running code from the command line, become interactive afterwards.
     Note: can also be given simply as '-i.'"""
 )
 flags['pylab'] = (
     {'TerminalIPythonApp' : {'pylab' : 'auto'}},
     """Pre-load matplotlib and numpy for interactive use with
     the default matplotlib backend."""
 )
 
 aliases = dict(base_aliases)
 aliases.update(shell_aliases)
 
 # it's possible we don't want short aliases for *all* of these:
 aliases.update(dict(
     gui='TerminalIPythonApp.gui',
     pylab='TerminalIPythonApp.pylab',
 ))
 
 #-----------------------------------------------------------------------------
 # Main classes and functions
 #-----------------------------------------------------------------------------
 
 class TerminalIPythonApp(BaseIPythonApplication, InteractiveShellApp):
     name = u'ipython'
     description = usage.cl_usage
     default_config_file_name = default_config_file_name
     crash_handler_class = IPAppCrashHandler
     examples = _examples
 
     flags = Dict(flags)
     aliases = Dict(aliases)
-    classes = [InteractiveShellApp, TerminalInteractiveShell, ProfileDir,
-               PlainTextFormatter]
+    classes = List()
+    def _classes_default(self):
+        """This has to be in a method, for TerminalIPythonApp to be available."""
+        return [
+            InteractiveShellApp, # ShellApp comes before TerminalApp, because
+            self.__class__,      # it will also affect subclasses (e.g. QtConsole)
+            TerminalInteractiveShell,
+            ProfileDir,
+            PlainTextFormatter,
+        ]
+    
     subcommands = Dict(dict(
         qtconsole=('IPython.frontend.qt.console.qtconsoleapp.IPythonQtConsoleApp',
             """Launch the IPython Qt Console."""
         ),
         profile = ("IPython.core.profileapp.ProfileApp",
             "Create and manage IPython profiles.")
     ))
     
     # *do* autocreate requested profile, but don't create the config file.
     auto_create=Bool(True)
     # configurables
     ignore_old_config=Bool(False, config=True,
         help="Suppress warning messages about legacy config files"
     )
     quick = Bool(False, config=True,
         help="""Start IPython quickly by skipping the loading of config files."""
     )
     def _quick_changed(self, name, old, new):
         if new:
             self.load_config_file = lambda *a, **kw: None
             self.ignore_old_config=True
 
     gui = CaselessStrEnum(('qt','wx','gtk'), config=True,
         help="Enable GUI event loop integration ('qt', 'wx', 'gtk')."
     )
     pylab = CaselessStrEnum(['tk', 'qt', 'wx', 'gtk', 'osx', 'auto'],
         config=True,
         help="""Pre-load matplotlib and numpy for interactive use,
         selecting a particular matplotlib backend and loop integration.
         """
     )
     display_banner = Bool(True, config=True,
         help="Whether to display a banner upon starting IPython."
     )
 
     # if there is code of files to run from the cmd line, don't interact
     # unless the --i flag (App.force_interact) is true.
     force_interact = Bool(False, config=True,
         help="""If a command or file is given via the command-line,
         e.g. 'ipython foo.py"""
     )
     def _force_interact_changed(self, name, old, new):
         if new:
             self.interact = True
     
     def _file_to_run_changed(self, name, old, new):
         if new and not self.force_interact:
                 self.interact = False
     _code_to_run_changed = _file_to_run_changed
 
     # internal, not-configurable
     interact=Bool(True)
 
 
     def parse_command_line(self, argv=None):
         """override to allow old '-pylab' flag with deprecation warning"""
 
         argv = sys.argv[1:] if argv is None else argv
 
         if '-pylab' in argv:
             # deprecated `-pylab` given,
             # warn and transform into current syntax
             argv = argv[:] # copy, don't clobber
             idx = argv.index('-pylab')
             warn.warn("`-pylab` flag has been deprecated.\n"
             "    Use `--pylab` instead, or `--pylab=foo` to specify a backend.")
             sub = '--pylab'
             if len(argv) > idx+1:
                 # check for gui arg, as in '-pylab qt'
                 gui = argv[idx+1]
                 if gui in ('wx', 'qt', 'qt4', 'gtk', 'auto'):
                     sub = '--pylab='+gui
                     argv.pop(idx+1)
             argv[idx] = sub
         
         return super(TerminalIPythonApp, self).parse_command_line(argv)
 
     def initialize(self, argv=None):
         """Do actions after construct, but before starting the app."""
         super(TerminalIPythonApp, self).initialize(argv)
         if self.subapp is not None:
             # don't bother initializing further, starting subapp
             return
         if not self.ignore_old_config:
             check_for_old_config(self.ipython_dir)
         # print self.extra_args
         if self.extra_args:
             self.file_to_run = self.extra_args[0]
         # create the shell
         self.init_shell()
         # and draw the banner
         self.init_banner()
         # Now a variety of things that happen after the banner is printed.
         self.init_gui_pylab()
         self.init_extensions()
         self.init_code()
 
     def init_shell(self):
         """initialize the InteractiveShell instance"""
         # I am a little hesitant to put these into InteractiveShell itself.
         # But that might be the place for them
         sys.path.insert(0, '')
 
         # Create an InteractiveShell instance.
         # shell.display_banner should always be False for the terminal 
         # based app, because we call shell.show_banner() by hand below
         # so the banner shows *before* all extension loading stuff.
         self.shell = TerminalInteractiveShell.instance(config=self.config,
                         display_banner=False, profile_dir=self.profile_dir,
                         ipython_dir=self.ipython_dir)
 
     def init_banner(self):
         """optionally display the banner"""
         if self.display_banner and self.interact:
             self.shell.show_banner()
         # Make sure there is a space below the banner.
         if self.log_level <= logging.INFO: print
 
 
     def init_gui_pylab(self):
         """Enable GUI event loop integration, taking pylab into account."""
         gui = self.gui
 
         # Using `pylab` will also require gui activation, though which toolkit
         # to use may be chosen automatically based on mpl configuration.
         if self.pylab:
             activate = self.shell.enable_pylab
             if self.pylab == 'auto':
                 gui = None
             else:
                 gui = self.pylab
         else:
             # Enable only GUI integration, no pylab
             activate = inputhook.enable_gui
 
         if gui or self.pylab:
             try:
                 self.log.info("Enabling GUI event loop integration, "
                               "toolkit=%s, pylab=%s" % (gui, self.pylab) )
                 activate(gui)
             except:
                 self.log.warn("Error in enabling GUI event loop integration:")
                 self.shell.showtraceback()
 
     def start(self):
         if self.subapp is not None:
             return self.subapp.start()
         # perform any prexec steps:
         if self.interact:
             self.log.debug("Starting IPython's mainloop...")
             self.shell.mainloop()
         else:
             self.log.debug("IPython not interactive...")
 
 
 def load_default_config(ipython_dir=None):
     """Load the default config file from the default ipython_dir.
 
     This is useful for embedded shells.
     """
     if ipython_dir is None:
         ipython_dir = get_ipython_dir()
     profile_dir = os.path.join(ipython_dir, 'profile_default')
     cl = PyFileConfigLoader(default_config_file_name, profile_dir)
     try:
         config = cl.load_config()
     except IOError:
         # no config found
         config = Config()
     return config
 
 
 def launch_new_instance():
     """Create and run a full blown IPython instance"""
     app = TerminalIPythonApp.instance()
     app.initialize()
     app.start()
 
 
 if __name__ == '__main__':
     launch_new_instance()