expand start_ipython / embed docstrings

clarify the difference between them.

IPython/__init__.py

@@ -1,106 +1,114 b''
 # encoding: utf-8
 """
 IPython: tools for interactive and parallel computing in Python.
 
 http://ipython.org
 """
 #-----------------------------------------------------------------------------
 #  Copyright (c) 2008-2011, IPython Development Team.
 #  Copyright (c) 2001-2007, Fernando Perez <[e-mail]>
 #  Copyright (c) 2001, Janko Hauser <[e-mail]>
 #  Copyright (c) 2001, Nathaniel Gray <[e-mail]>
 #
 #  Distributed under the terms of the Modified BSD License.
 #
 #  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from __future__ import absolute_import
 
 import os
 import sys
 
 #-----------------------------------------------------------------------------
 # Setup everything
 #-----------------------------------------------------------------------------
 
 # Don't forget to also update setup.py when this changes!
 if sys.version[0:3] < '2.6':
     raise ImportError('Python Version 2.6 or above is required for IPython.')
 
 # Make it easy to import extensions - they are always directly on pythonpath.
 # Therefore, non-IPython modules can be added to extensions directory.
 # This should probably be in ipapp.py.
 sys.path.append(os.path.join(os.path.dirname(__file__), "extensions"))
 
 #-----------------------------------------------------------------------------
 # Setup the top level names
 #-----------------------------------------------------------------------------
 
 from .config.loader import Config
 from .core.getipython import get_ipython
 from .core import release
 from .core.application import Application
 from .terminal.embed import embed
 
 from .core.error import TryNext
 from .core.interactiveshell import InteractiveShell
 from .testing import test
 from .utils.sysinfo import sys_info
 from .utils.frame import extract_module_locals
 
 # Release data
 __author__ = '%s <%s>' % (release.author, release.author_email)
 __license__  = release.license
 __version__  = release.version
 version_info = release.version_info
 
 def embed_kernel(module=None, local_ns=None, **kwargs):
     """Embed and start an IPython kernel in a given scope.
     
     Parameters
     ----------
     module : ModuleType, optional
         The module to load into IPython globals (default: caller)
     local_ns : dict, optional
         The namespace to load into IPython user namespace (default: caller)
     
     kwargs : various, optional
         Further keyword args are relayed to the IPKernelApp constructor,
         allowing configuration of the Kernel.  Will only have an effect
         on the first embed_kernel call for a given process.
     
     """
     
     (caller_module, caller_locals) = extract_module_locals(1)
     if module is None:
         module = caller_module
     if local_ns is None:
         local_ns = caller_locals
     
     # Only import .zmq when we really need it
     from IPython.kernel.zmq.embed import embed_kernel as real_embed_kernel
     real_embed_kernel(module=module, local_ns=local_ns, **kwargs)
 
 def start_ipython(argv=None, **kwargs):
-    """launch a normal IPython instance (as opposed to embedded)
+    """Launch a normal IPython instance (as opposed to embedded)
     
-    This is a public API method, and will survive implementation changes.
+    `IPython.embed()` puts a shell in a particular calling scope,
+    such as a function or method for debugging purposes,
+    which is often not desirable.
+    
+    `start_ipython()` does full, regular IPython initialization,
+    including loading startup files, configuration, etc.
+    much of which is skipped by `embed()`.
     
+    This is a public API method, and will survive implementation changes.
     
     Parameters
     ----------
     
     argv : list or None, optional
         If unspecified or None, IPython will parse command-line options from sys.argv.
         To prevent any command-line parsing, pass an empty list: `argv=[]`.
-    
+    user_ns : dict, optional
+        specify this dictionary to initialize the IPython user namespace with particular values.
     kwargs : various, optional
         Any other kwargs will be passed to the Application constructor,
         such as `config`.
     """
     from IPython.terminal.ipapp import launch_new_instance
     return launch_new_instance(argv=argv, **kwargs)

IPython/terminal/embed.py

@@ -1,296 +1,301 b''
 # encoding: utf-8
 """
 An embedded IPython shell.
 
 Authors:
 
 * Brian Granger
 * Fernando Perez
 
 Notes
 -----
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from __future__ import with_statement
 
 import sys
 import warnings
 
 # We need to use nested to support python 2.6, once we move to >=2.7, we can
 # use the with keyword's new builtin support for nested managers
 try:
     from contextlib import nested
 except:
     from IPython.utils.nested_context import nested
 
 from IPython.core import ultratb, compilerop
 from IPython.core.magic import Magics, magics_class, line_magic
 from IPython.terminal.interactiveshell import TerminalInteractiveShell
 from IPython.terminal.ipapp import load_default_config
 
 from IPython.utils.traitlets import Bool, CBool, Unicode
 from IPython.utils.io import ask_yes_no
 
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 # This is an additional magic that is exposed in embedded shells.
 @magics_class
 class EmbeddedMagics(Magics):
 
     @line_magic
     def kill_embedded(self, parameter_s=''):
         """%kill_embedded : deactivate for good the current embedded IPython.
 
         This function (after asking for confirmation) sets an internal flag so
         that an embedded IPython will never activate again.  This is useful to
         permanently disable a shell that is being called inside a loop: once
         you've figured out what you needed from it, you may then kill it and
         the program will then continue to run without the interactive shell
         interfering again.
         """
 
         kill = ask_yes_no("Are you sure you want to kill this embedded instance "
                          "(y/n)? [y/N] ",'n')
         if kill:
             self.shell.embedded_active = False
             print ("This embedded IPython will not reactivate anymore "
                    "once you exit.")
 
 
 class InteractiveShellEmbed(TerminalInteractiveShell):
 
     dummy_mode = Bool(False)
     exit_msg = Unicode('')
     embedded = CBool(True)
     embedded_active = CBool(True)
     # Like the base class display_banner is not configurable, but here it
     # is True by default.
     display_banner = CBool(True)
 
     def __init__(self, config=None, ipython_dir=None, user_ns=None,
                  user_module=None, custom_exceptions=((),None),
                  usage=None, banner1=None, banner2=None,
                  display_banner=None, exit_msg=u'', user_global_ns=None):
     
         if user_global_ns is not None:
             warnings.warn("user_global_ns has been replaced by user_module. The\
                            parameter will be ignored.", DeprecationWarning)
 
         super(InteractiveShellEmbed,self).__init__(
             config=config, ipython_dir=ipython_dir, user_ns=user_ns,
             user_module=user_module, custom_exceptions=custom_exceptions,
             usage=usage, banner1=banner1, banner2=banner2,
             display_banner=display_banner
         )
 
         self.exit_msg = exit_msg
 
         # don't use the ipython crash handler so that user exceptions aren't
         # trapped
         sys.excepthook = ultratb.FormattedTB(color_scheme=self.colors,
                                              mode=self.xmode,
                                              call_pdb=self.pdb)
 
     def init_sys_modules(self):
         pass
 
     def init_magics(self):
         super(InteractiveShellEmbed, self).init_magics()
         self.register_magics(EmbeddedMagics)
 
     def __call__(self, header='', local_ns=None, module=None, dummy=None,
                  stack_depth=1, global_ns=None, compile_flags=None):
         """Activate the interactive interpreter.
 
         __call__(self,header='',local_ns=None,module=None,dummy=None) -> Start
         the interpreter shell with the given local and global namespaces, and
         optionally print a header string at startup.
 
         The shell can be globally activated/deactivated using the
         dummy_mode attribute. This allows you to turn off a shell used
         for debugging globally.
 
         However, *each* time you call the shell you can override the current
         state of dummy_mode with the optional keyword parameter 'dummy'. For
         example, if you set dummy mode on with IPShell.dummy_mode = True, you
         can still have a specific call work by making it as IPShell(dummy=False).
         """
 
         # If the user has turned it off, go away
         if not self.embedded_active:
             return
 
         # Normal exits from interactive mode set this flag, so the shell can't
         # re-enter (it checks this variable at the start of interactive mode).
         self.exit_now = False
 
         # Allow the dummy parameter to override the global __dummy_mode
         if dummy or (dummy != 0 and self.dummy_mode):
             return
 
         if self.has_readline:
             self.set_readline_completer()
 
         # self.banner is auto computed
         if header:
             self.old_banner2 = self.banner2
             self.banner2 = self.banner2 + '\n' + header + '\n'
         else:
             self.old_banner2 = ''
 
         # Call the embedding code with a stack depth of 1 so it can skip over
         # our call and get the original caller's namespaces.
         self.mainloop(local_ns, module, stack_depth=stack_depth,
                       global_ns=global_ns, compile_flags=compile_flags)
 
         self.banner2 = self.old_banner2
 
         if self.exit_msg is not None:
             print self.exit_msg
 
     def mainloop(self, local_ns=None, module=None, stack_depth=0,
                  display_banner=None, global_ns=None, compile_flags=None):
         """Embeds IPython into a running python program.
 
         Input:
 
           - header: An optional header message can be specified.
 
           - local_ns, module: working local namespace (a dict) and module (a
           module or similar object). If given as None, they are automatically
           taken from the scope where the shell was called, so that
           program variables become visible.
 
           - stack_depth: specifies how many levels in the stack to go to
           looking for namespaces (when local_ns or module is None).  This
           allows an intermediate caller to make sure that this function gets
           the namespace from the intended level in the stack.  By default (0)
           it will get its locals and globals from the immediate caller.
 
           - compile_flags: A bit field identifying the __future__ features
           that are enabled, as passed to the builtin `compile` function. If
           given as None, they are automatically taken from the scope where the
           shell was called.
 
         Warning: it's possible to use this in a program which is being run by
         IPython itself (via %run), but some funny things will happen (a few
         globals get overwritten). In the future this will be cleaned up, as
         there is no fundamental reason why it can't work perfectly."""
         
         if (global_ns is not None) and (module is None):
             class DummyMod(object):
                 """A dummy module object for embedded IPython."""
                 pass
             warnings.warn("global_ns is deprecated, use module instead.", DeprecationWarning)
             module = DummyMod()
             module.__dict__ = global_ns
 
         # Get locals and globals from caller
         if ((local_ns is None or module is None or compile_flags is None)
             and self.default_user_namespaces):
             call_frame = sys._getframe(stack_depth).f_back
 
             if local_ns is None:
                 local_ns = call_frame.f_locals
             if module is None:
                 global_ns = call_frame.f_globals
                 module = sys.modules[global_ns['__name__']]
             if compile_flags is None:
                 compile_flags = (call_frame.f_code.co_flags &
                                  compilerop.PyCF_MASK)
         
         # Save original namespace and module so we can restore them after 
         # embedding; otherwise the shell doesn't shut down correctly.
         orig_user_module = self.user_module
         orig_user_ns = self.user_ns
         orig_compile_flags = self.compile.flags
         
         # Update namespaces and fire up interpreter
         
         # The global one is easy, we can just throw it in
         if module is not None:
             self.user_module = module
 
         # But the user/local one is tricky: ipython needs it to store internal
         # data, but we also need the locals. We'll throw our hidden variables
         # like _ih and get_ipython() into the local namespace, but delete them
         # later.
         if local_ns is not None:
             self.user_ns = local_ns
             self.init_user_ns()
 
         # Compiler flags
         if compile_flags is not None:
             self.compile.flags = compile_flags
 
         # Patch for global embedding to make sure that things don't overwrite
         # user globals accidentally. Thanks to Richard <[e-mail]>
         # FIXME. Test this a bit more carefully (the if.. is new)
         # N.B. This can't now ever be called. Not sure what it was for.
         # And now, since it wasn't called in the previous version, I'm
         # commenting out these lines so they can't be called with my new changes
         # --TK, 2011-12-10
         #if local_ns is None and module is None:
         #    self.user_global_ns.update(__main__.__dict__)
 
         # make sure the tab-completer has the correct frame information, so it
         # actually completes using the frame's locals/globals
         self.set_completer_frame()
 
         with nested(self.builtin_trap, self.display_trap):
             self.interact(display_banner=display_banner)
         
         # now, purge out the local namespace of IPython's hidden variables.
         if local_ns is not None:
             for name in self.user_ns_hidden:
                 local_ns.pop(name, None)
         
         # Restore original namespace so shell can shut down when we exit.
         self.user_module = orig_user_module
         self.user_ns = orig_user_ns
         self.compile.flags = orig_compile_flags
 
 
 def embed(**kwargs):
     """Call this to embed IPython at the current point in your program.
 
     The first invocation of this will create an :class:`InteractiveShellEmbed`
     instance and then call it.  Consecutive calls just call the already
     created instance.
 
+    If you don't want the kernel to initialize the namespace
+    from the scope of the surrounding function,
+    and/or you want to load full IPython configuration,
+    you probably want `IPython.start_ipython()` instead.
+
     Here is a simple example::
 
         from IPython import embed
         a = 10
         b = 20
         embed('First time')
         c = 30
         d = 40
         embed
 
     Full customization can be done by passing a :class:`Config` in as the
     config argument.
     """
     config = kwargs.get('config')
     header = kwargs.pop('header', u'')
     compile_flags = kwargs.pop('compile_flags', None)
     if config is None:
         config = load_default_config()
         config.InteractiveShellEmbed = config.TerminalInteractiveShell
         kwargs['config'] = config
     shell = InteractiveShellEmbed.instance(**kwargs)
     shell(header=header, stack_depth=2, compile_flags=compile_flags)