docs: embed: add parameters to docstring

The docstring of IPython.terminal.embed.embed() does not document its
arguments. Add a "Parameters" section, and document each argument
appropriately:

- for 'header', rephrase the corresponding description from the
docstring of InteractiveShellEmbed.__call__, to which this argument is
passed (__call__ itself is missing from the generated API documentation
since sphinx.ext.autodoc does not document special members by default).
- for 'compile_flags', refer to the documentation of
InteractiveShellEmbed.mainloop, to which this argument is passed.
- for 'kwargs', refer to the constructor of InteractiveShellEmbed, and
fold in the sentence mentioning the 'config' argument.

IPython/terminal/embed.py

@@ -1,410 +1,420 b''
 # encoding: utf-8
 """
 An embedded IPython shell.
 """
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 
 import sys
 import warnings
 
 from IPython.core import ultratb, compilerop
 from IPython.core import magic_arguments
 from IPython.core.magic import Magics, magics_class, line_magic
 from IPython.core.interactiveshell import DummyMod, InteractiveShell
 from IPython.terminal.interactiveshell import TerminalInteractiveShell
 from IPython.terminal.ipapp import load_default_config
 
 from traitlets import Bool, CBool, Unicode
 from IPython.utils.io import ask_yes_no
 
 from typing import Set
 
 class KillEmbedded(Exception):pass
 
 # kept for backward compatibility as IPython 6 was released with
 # the typo. See https://github.com/ipython/ipython/pull/10706
 KillEmbeded = KillEmbedded
 
 # This is an additional magic that is exposed in embedded shells.
 @magics_class
 class EmbeddedMagics(Magics):
 
     @line_magic
     @magic_arguments.magic_arguments()
     @magic_arguments.argument('-i', '--instance', action='store_true',
                               help='Kill instance instead of call location')
     @magic_arguments.argument('-x', '--exit', action='store_true',
                               help='Also exit the current session')
     @magic_arguments.argument('-y', '--yes', action='store_true',
                               help='Do not ask confirmation')
     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 for the given call
         location. 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 Instance Option:
 
             If for some reasons you need to kill the location where the instance
             is created and not called, for example if you create a single
             instance in one place and debug in many locations, you can use the
             ``--instance`` option to kill this specific instance. Like for the
             ``call location`` killing an "instance" should work even if it is
             recreated within a loop.
 
         .. note::
 
             This was the default behavior before IPython 5.2
 
         """
 
         args = magic_arguments.parse_argstring(self.kill_embedded, parameter_s)
         print(args)
         if args.instance:
             # let no ask
             if not args.yes:
                 kill = ask_yes_no(
                     "Are you sure you want to kill this embedded instance? [y/N] ", 'n')
             else:
                 kill = True
             if kill:
                 self.shell._disable_init_location()
                 print("This embedded IPython instance will not reactivate anymore "
                       "once you exit.")
         else:
             if not args.yes:
                 kill = ask_yes_no(
                     "Are you sure you want to kill this embedded call_location? [y/N] ", 'n')
             else:
                 kill = True
             if kill:
                 self.shell.embedded_active = False
                 print("This embedded IPython  call location will not reactivate anymore "
                       "once you exit.")
 
         if args.exit:
             # Ask-exit does not really ask, it just set internals flags to exit
             # on next loop.
             self.shell.ask_exit()
 
 
     @line_magic
     def exit_raise(self, parameter_s=''):
         """%exit_raise Make the current embedded kernel exit and raise and exception.
 
         This function sets an internal flag so that an embedded IPython will
         raise a `IPython.terminal.embed.KillEmbedded` Exception on exit, and then exit the current I. This is
         useful to permanently exit a loop that create IPython embed instance.
         """
 
         self.shell.should_raise = True
         self.shell.ask_exit()
 
 
 class _Sentinel:
     def __init__(self, repr):
         assert isinstance(repr, str)
         self.repr = repr
 
     def __repr__(self):
         return repr
 
 
 class InteractiveShellEmbed(TerminalInteractiveShell):
 
     dummy_mode = Bool(False)
     exit_msg = Unicode('')
     embedded = CBool(True)
     should_raise = CBool(False)
     # Like the base class display_banner is not configurable, but here it
     # is True by default.
     display_banner = CBool(True)
     exit_msg = Unicode()
 
     # When embedding, by default we don't change the terminal title
     term_title = Bool(False,
         help="Automatically set the terminal title"
     ).tag(config=True)
 
     _inactive_locations: Set[str] = set()
 
     def _disable_init_location(self):
         """Disable the current Instance creation location"""
         InteractiveShellEmbed._inactive_locations.add(self._init_location_id)
 
     @property
     def embedded_active(self):
         return (self._call_location_id not in InteractiveShellEmbed._inactive_locations)\
             and (self._init_location_id not in InteractiveShellEmbed._inactive_locations)
 
     @embedded_active.setter
     def embedded_active(self, value):
         if value:
             InteractiveShellEmbed._inactive_locations.discard(
                 self._call_location_id)
             InteractiveShellEmbed._inactive_locations.discard(
                 self._init_location_id)
         else:
             InteractiveShellEmbed._inactive_locations.add(
                 self._call_location_id)
 
     def __init__(self, **kw):
         assert (
             "user_global_ns" not in kw
         ), "Key word argument `user_global_ns` has been replaced by `user_module` since IPython 4.0."
 
         clid = kw.pop('_init_location_id', None)
         if not clid:
             frame = sys._getframe(1)
             clid = '%s:%s' % (frame.f_code.co_filename, frame.f_lineno)
         self._init_location_id = clid
 
         super(InteractiveShellEmbed,self).__init__(**kw)
 
         # 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):
         """
         Explicitly overwrite :mod:`IPython.core.interactiveshell` to do nothing.
         """
         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,
         compile_flags=None,
         **kw
     ):
         """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).
         """
 
         # we are called, set the underlying interactiveshell not to exit.
         self.keep_running = True
 
         # If the user has turned it off, go away
         clid = kw.pop('_call_location_id', None)
         if not clid:
             frame = sys._getframe(1)
             clid = '%s:%s' % (frame.f_code.co_filename, frame.f_lineno)
         self._call_location_id = clid
 
         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
 
         # self.banner is auto computed
         if header:
             self.old_banner2 = self.banner2
             self.banner2 = self.banner2 + '\n' + header + '\n'
         else:
             self.old_banner2 = ''
 
         if self.display_banner:
             self.show_banner()
 
         # 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, compile_flags=compile_flags
         )
 
         self.banner2 = self.old_banner2
 
         if self.exit_msg is not None:
             print(self.exit_msg)
 
         if self.should_raise:
             raise KillEmbedded('Embedded IPython raising error, as user requested.')
 
     def mainloop(
         self,
         local_ns=None,
         module=None,
         stack_depth=0,
         compile_flags=None,
     ):
         """Embeds IPython into a running python program.
 
         Parameters
         ----------
         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 : int
             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 :func:`compile` function.
             If given as None, they are automatically taken from the scope where
             the shell was called.
 
         """
         
         # 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
                 try:
                     module = sys.modules[global_ns['__name__']]
                 except KeyError:
                     warnings.warn("Failed to get module %s" % \
                         global_ns.get('__name__', 'unknown module')
                     )
                     module = DummyMod()
                     module.__dict__ = global_ns
             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:
             reentrant_local_ns = {k: v for (k, v) in local_ns.items() if k not in self.user_ns_hidden.keys()}
             self.user_ns = reentrant_local_ns
             self.init_user_ns()
 
         # Compiler flags
         if compile_flags is not None:
             self.compile.flags = compile_flags
 
         # 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 self.builtin_trap, self.display_trap:
             self.interact()
         
         # now, purge out the local namespace of IPython's hidden variables.
         if local_ns is not None:
             local_ns.update({k: v for (k, v) in self.user_ns.items() if k not in self.user_ns_hidden.keys()})
 
         
         # 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(*, header="", compile_flags=None, **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(header='First time')
         c = 30
         d = 40
         embed()
 
+    Parameters
+    ----------
+
+    header : str
+        Optional header string to print at startup.
+    compile_flags
+        Passed to the `compile_flags` parameter of :py:meth:`InteractiveShellEmbed.mainloop()`,
+        which is called when the :class:`InteractiveShellEmbed` instance is called.
+    **kwargs : various, optional
+        Any other kwargs will be passed to the :class:`InteractiveShellEmbed` constructor.
     Full customization can be done by passing a traitlets :class:`Config` in as the
     `config` argument (see :ref:`configure_start_ipython`).
     """
     config = kwargs.get('config')
     if config is None:
         config = load_default_config()
         config.InteractiveShellEmbed = config.TerminalInteractiveShell
         kwargs['config'] = config
     using = kwargs.get('using', 'sync')
     if using :
         kwargs['config'].update({'TerminalInteractiveShell':{'loop_runner':using, 'colors':'NoColor', 'autoawait': using!='sync'}})
     #save ps1/ps2 if defined
     ps1 = None
     ps2 = None
     try:
         ps1 = sys.ps1
         ps2 = sys.ps2
     except AttributeError:
         pass
     #save previous instance
     saved_shell_instance = InteractiveShell._instance
     if saved_shell_instance is not None:
         cls = type(saved_shell_instance)
         cls.clear_instance()
     frame = sys._getframe(1)
     shell = InteractiveShellEmbed.instance(_init_location_id='%s:%s' % (
         frame.f_code.co_filename, frame.f_lineno), **kwargs)
     shell(header=header, stack_depth=2, compile_flags=compile_flags,
         _call_location_id='%s:%s' % (frame.f_code.co_filename, frame.f_lineno))
     InteractiveShellEmbed.clear_instance()
     #restore previous instance
     if saved_shell_instance is not None:
         cls = type(saved_shell_instance)
         cls.clear_instance()
         for subclass in cls._walk_mro():
             subclass._instance = saved_shell_instance
     if ps1 is not None:
         sys.ps1 = ps1
         sys.ps2 = ps2