Drop nested() function for context managers

IPython/terminal/console/interactiveshell.py

@@ -1,493 +1,488 b''
 # -*- coding: utf-8 -*-
 """terminal client to the IPython kernel
 
 """
 #-----------------------------------------------------------------------------
 # Copyright (C) 2013 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 print_function
 
 import bdb
 import signal
 import os
 import sys
 import time
 import subprocess
 from io import BytesIO
 import base64
 
 from Queue import Empty
 
-try:
-    from contextlib import nested
-except:
-    from IPython.utils.nested_context import nested
-
 from IPython.core import page
 from IPython.utils.warn import warn, error
 from IPython.utils import io
 from IPython.utils.traitlets import List, Enum, Any, Instance, Unicode, Float
 from IPython.utils.tempdir import NamedFileInTemporaryDirectory
 
 from IPython.terminal.interactiveshell import TerminalInteractiveShell
 from IPython.terminal.console.completer import ZMQCompleter
 
 
 class ZMQTerminalInteractiveShell(TerminalInteractiveShell):
     """A subclass of TerminalInteractiveShell that uses the 0MQ kernel"""
     _executing = False
     _execution_state = Unicode('')
     kernel_timeout = Float(60, config=True,
         help="""Timeout for giving up on a kernel (in seconds).
         
         On first connect and restart, the console tests whether the
         kernel is running and responsive by sending kernel_info_requests.
         This sets the timeout in seconds for how long the kernel can take
         before being presumed dead.
         """
     )
 
     image_handler = Enum(('PIL', 'stream', 'tempfile', 'callable'),
                          config=True, help=
         """
         Handler for image type output.  This is useful, for example,
         when connecting to the kernel in which pylab inline backend is
         activated.  There are four handlers defined.  'PIL': Use
         Python Imaging Library to popup image; 'stream': Use an
         external program to show the image.  Image will be fed into
         the STDIN of the program.  You will need to configure
         `stream_image_handler`; 'tempfile': Use an external program to
         show the image.  Image will be saved in a temporally file and
         the program is called with the temporally file.  You will need
         to configure `tempfile_image_handler`; 'callable': You can set
         any Python callable which is called with the image data.  You
         will need to configure `callable_image_handler`.
         """
     )
 
     stream_image_handler = List(config=True, help=
         """
         Command to invoke an image viewer program when you are using
         'stream' image handler.  This option is a list of string where
         the first element is the command itself and reminders are the
         options for the command.  Raw image data is given as STDIN to
         the program.
         """
     )
 
     tempfile_image_handler = List(config=True, help=
         """
         Command to invoke an image viewer program when you are using
         'tempfile' image handler.  This option is a list of string
         where the first element is the command itself and reminders
         are the options for the command.  You can use {file} and
         {format} in the string to represent the location of the
         generated image file and image format.
         """
     )
 
     callable_image_handler = Any(config=True, help=
         """
         Callable object called via 'callable' image handler with one
         argument, `data`, which is `msg["content"]["data"]` where
         `msg` is the message from iopub channel.  For exmaple, you can
         find base64 encoded PNG data as `data['image/png']`.
         """
     )
 
     mime_preference = List(
         default_value=['image/png', 'image/jpeg', 'image/svg+xml'],
         config=True, allow_none=False, help=
         """
         Preferred object representation MIME type in order.  First
         matched MIME type will be used.
         """
     )
 
     manager = Instance('IPython.kernel.KernelManager')
     client = Instance('IPython.kernel.KernelClient')
     def _client_changed(self, name, old, new):
         self.session_id = new.session.session
     session_id = Unicode()
 
     def init_completer(self):
         """Initialize the completion machinery.
 
         This creates completion machinery that can be used by client code,
         either interactively in-process (typically triggered by the readline
         library), programatically (such as in test suites) or out-of-prcess
         (typically over the network by remote frontends).
         """
         from IPython.core.completerlib import (module_completer,
                                                magic_run_completer, cd_completer)
         
         self.Completer = ZMQCompleter(self, self.client, config=self.config)
         
 
         self.set_hook('complete_command', module_completer, str_key = 'import')
         self.set_hook('complete_command', module_completer, str_key = 'from')
         self.set_hook('complete_command', magic_run_completer, str_key = '%run')
         self.set_hook('complete_command', cd_completer, str_key = '%cd')
 
         # Only configure readline if we truly are using readline.  IPython can
         # do tab-completion over the network, in GUIs, etc, where readline
         # itself may be absent
         if self.has_readline:
             self.set_readline_completer()
     
     def run_cell(self, cell, store_history=True):
         """Run a complete IPython cell.
         
         Parameters
         ----------
         cell : str
           The code (including IPython code such as %magic functions) to run.
         store_history : bool
           If True, the raw and translated cell will be stored in IPython's
           history. For user code calling back into IPython's machinery, this
           should be set to False.
         """
         if (not cell) or cell.isspace():
             return
 
         if cell.strip() == 'exit':
             # explicitly handle 'exit' command
             return self.ask_exit()
 
         # flush stale replies, which could have been ignored, due to missed heartbeats
         while self.client.shell_channel.msg_ready():
             self.client.shell_channel.get_msg()
         # shell_channel.execute takes 'hidden', which is the inverse of store_hist
         msg_id = self.client.shell_channel.execute(cell, not store_history)
         
         # first thing is wait for any side effects (output, stdin, etc.)
         self._executing = True
         self._execution_state = "busy"
         while self._execution_state != 'idle' and self.client.is_alive():
             try:
                 self.handle_stdin_request(msg_id, timeout=0.05)
             except Empty:
                 # display intermediate print statements, etc.
                 self.handle_iopub(msg_id)
                 pass
         
         # after all of that is done, wait for the execute reply
         while self.client.is_alive():
             try:
                 self.handle_execute_reply(msg_id, timeout=0.05)
             except Empty:
                 pass
             else:
                 break
         self._executing = False
 
     #-----------------
     # message handlers
     #-----------------
 
     def handle_execute_reply(self, msg_id, timeout=None):
         msg = self.client.shell_channel.get_msg(block=False, timeout=timeout)
         if msg["parent_header"].get("msg_id", None) == msg_id:
             
             self.handle_iopub(msg_id)
             
             content = msg["content"]
             status = content['status']
             
             if status == 'aborted':
                 self.write('Aborted\n')
                 return
             elif status == 'ok':
                 # print execution payloads as well:
                 for item in content["payload"]:
                     text = item.get('text', None)
                     if text:
                         page.page(text)
                
             elif status == 'error':
                 for frame in content["traceback"]:
                     print(frame, file=io.stderr)
             
             self.execution_count = int(content["execution_count"] + 1)
 
 
     def handle_iopub(self, msg_id):
         """ Method to process subscribe channel's messages
 
            This method consumes and processes messages on the IOPub channel,
            such as stdout, stderr, pyout and status.
            
            It only displays output that is caused by the given msg_id
         """
         while self.client.iopub_channel.msg_ready():
             sub_msg = self.client.iopub_channel.get_msg()
             msg_type = sub_msg['header']['msg_type']
             parent = sub_msg["parent_header"]
             if (not parent) or msg_id == parent['msg_id']:
                 if msg_type == 'status':
                     state = self._execution_state = sub_msg["content"]["execution_state"]
                     # idle messages mean an individual sequence is complete,
                     # so break out of consumption to allow other things to take over.
                     if state == 'idle':
                         break
 
                 elif msg_type == 'stream':
                     if sub_msg["content"]["name"] == "stdout":
                         print(sub_msg["content"]["data"], file=io.stdout, end="")
                         io.stdout.flush()
                     elif sub_msg["content"]["name"] == "stderr" :
                         print(sub_msg["content"]["data"], file=io.stderr, end="")
                         io.stderr.flush()
 
                 elif msg_type == 'pyout':
                     self.execution_count = int(sub_msg["content"]["execution_count"])
                     format_dict = sub_msg["content"]["data"]
                     self.handle_rich_data(format_dict)
                     # taken from DisplayHook.__call__:
                     hook = self.displayhook
                     hook.start_displayhook()
                     hook.write_output_prompt()
                     hook.write_format_data(format_dict)
                     hook.log_output(format_dict)
                     hook.finish_displayhook()
 
                 elif msg_type == 'display_data':
                     self.handle_rich_data(sub_msg["content"]["data"])
                     
 
     _imagemime = {
         'image/png': 'png',
         'image/jpeg': 'jpeg',
         'image/svg+xml': 'svg',
     }
 
     def handle_rich_data(self, data):
         for mime in self.mime_preference:
             if mime in data and mime in self._imagemime:
                 self.handle_image(data, mime)
                 return
 
     def handle_image(self, data, mime):
         handler = getattr(
             self, 'handle_image_{0}'.format(self.image_handler), None)
         if handler:
             handler(data, mime)
 
     def handle_image_PIL(self, data, mime):
         if mime not in ('image/png', 'image/jpeg'):
             return
         import PIL.Image
         raw = base64.decodestring(data[mime].encode('ascii'))
         img = PIL.Image.open(BytesIO(raw))
         img.show()
 
     def handle_image_stream(self, data, mime):
         raw = base64.decodestring(data[mime].encode('ascii'))
         imageformat = self._imagemime[mime]
         fmt = dict(format=imageformat)
         args = [s.format(**fmt) for s in self.stream_image_handler]
         with open(os.devnull, 'w') as devnull:
             proc = subprocess.Popen(
                 args, stdin=subprocess.PIPE,
                 stdout=devnull, stderr=devnull)
             proc.communicate(raw)
 
     def handle_image_tempfile(self, data, mime):
         raw = base64.decodestring(data[mime].encode('ascii'))
         imageformat = self._imagemime[mime]
         filename = 'tmp.{0}'.format(imageformat)
-        with nested(NamedFileInTemporaryDirectory(filename),
-                    open(os.devnull, 'w')) as (f, devnull):
+        with NamedFileInTemporaryDirectory(filename) as f, \
+                    open(os.devnull, 'w') as devnull:
             f.write(raw)
             f.flush()
             fmt = dict(file=f.name, format=imageformat)
             args = [s.format(**fmt) for s in self.tempfile_image_handler]
             subprocess.call(args, stdout=devnull, stderr=devnull)
 
     def handle_image_callable(self, data, mime):
         self.callable_image_handler(data)
 
     def handle_stdin_request(self, msg_id, timeout=0.1):
         """ Method to capture raw_input
         """
         msg_rep = self.client.stdin_channel.get_msg(timeout=timeout)
         # in case any iopub came while we were waiting:
         self.handle_iopub(msg_id)
         if msg_id == msg_rep["parent_header"].get("msg_id"):
             # wrap SIGINT handler
             real_handler = signal.getsignal(signal.SIGINT)
             def double_int(sig,frame):
                 # call real handler (forwards sigint to kernel),
                 # then raise local interrupt, stopping local raw_input
                 real_handler(sig,frame)
                 raise KeyboardInterrupt
             signal.signal(signal.SIGINT, double_int)
             
             try:
                 raw_data = raw_input(msg_rep["content"]["prompt"])
             except EOFError:
                 # turn EOFError into EOF character
                 raw_data = '\x04'
             except KeyboardInterrupt:
                 sys.stdout.write('\n')
                 return
             finally:
                 # restore SIGINT handler
                 signal.signal(signal.SIGINT, real_handler)
             
             # only send stdin reply if there *was not* another request
             # or execution finished while we were reading.
             if not (self.client.stdin_channel.msg_ready() or self.client.shell_channel.msg_ready()):
                 self.client.stdin_channel.input(raw_data)
 
     def mainloop(self, display_banner=False):
         while True:
             try:
                 self.interact(display_banner=display_banner)
                 #self.interact_with_readline()                
                 # XXX for testing of a readline-decoupled repl loop, call
                 # interact_with_readline above
                 break
             except KeyboardInterrupt:
                 # this should not be necessary, but KeyboardInterrupt
                 # handling seems rather unpredictable...
                 self.write("\nKeyboardInterrupt in interact()\n")
     
     def wait_for_kernel(self, timeout=None):
         """method to wait for a kernel to be ready"""
         tic = time.time()
         self.client.hb_channel.unpause()
         while True:
             msg_id = self.client.kernel_info()
             reply = None
             while True:
                 try:
                     reply = self.client.get_shell_msg(timeout=1)
                 except Empty:
                     break
                 else:
                     if reply['parent_header'].get('msg_id') == msg_id:
                         return True
             if timeout is not None \
                 and (time.time() - tic) > timeout \
                 and not self.client.hb_channel.is_beating():
                 # heart failed
                 return False
         return True
     
     def interact(self, display_banner=None):
         """Closely emulate the interactive Python console."""
 
         # batch run -> do not interact
         if self.exit_now:
             return
 
         if display_banner is None:
             display_banner = self.display_banner
         
         if isinstance(display_banner, basestring):
             self.show_banner(display_banner)
         elif display_banner:
             self.show_banner()
 
         more = False
         
         # run a non-empty no-op, so that we don't get a prompt until
         # we know the kernel is ready. This keeps the connection
         # message above the first prompt.
         if not self.wait_for_kernel(self.kernel_timeout):
             error("Kernel did not respond\n")
             return
         
         if self.has_readline:
             self.readline_startup_hook(self.pre_readline)
             hlen_b4_cell = self.readline.get_current_history_length()
         else:
             hlen_b4_cell = 0
         # exit_now is set by a call to %Exit or %Quit, through the
         # ask_exit callback.
 
         while not self.exit_now:
             if not self.client.is_alive():
                 # kernel died, prompt for action or exit
 
                 action = "restart" if self.manager else "wait for restart"
                 ans = self.ask_yes_no("kernel died, %s ([y]/n)?" % action, default='y')
                 if ans:
                     if self.manager:
                         self.manager.restart_kernel(True)
                     self.wait_for_kernel(self.kernel_timeout)
                 else:
                     self.exit_now = True
                 continue
             try:
                 # protect prompt block from KeyboardInterrupt
                 # when sitting on ctrl-C
                 self.hooks.pre_prompt_hook()
                 if more:
                     try:
                         prompt = self.prompt_manager.render('in2')
                     except Exception:
                         self.showtraceback()
                     if self.autoindent:
                         self.rl_do_indent = True
                     
                 else:
                     try:
                         prompt = self.separate_in + self.prompt_manager.render('in')
                     except Exception:
                         self.showtraceback()
                 
                 line = self.raw_input(prompt)
                 if self.exit_now:
                     # quick exit on sys.std[in|out] close
                     break
                 if self.autoindent:
                     self.rl_do_indent = False
                     
             except KeyboardInterrupt:
                 #double-guard against keyboardinterrupts during kbdint handling
                 try:
                     self.write('\nKeyboardInterrupt\n')
                     source_raw = self.input_splitter.source_raw_reset()[1]
                     hlen_b4_cell = self._replace_rlhist_multiline(source_raw, hlen_b4_cell)
                     more = False
                 except KeyboardInterrupt:
                     pass
             except EOFError:
                 if self.autoindent:
                     self.rl_do_indent = False
                     if self.has_readline:
                         self.readline_startup_hook(None)
                 self.write('\n')
                 self.exit()
             except bdb.BdbQuit:
                 warn('The Python debugger has exited with a BdbQuit exception.\n'
                      'Because of how pdb handles the stack, it is impossible\n'
                      'for IPython to properly format this particular exception.\n'
                      'IPython will resume normal operation.')
             except:
                 # exceptions here are VERY RARE, but they can be triggered
                 # asynchronously by signal handlers, for example.
                 self.showtraceback()
             else:
                 self.input_splitter.push(line)
                 more = self.input_splitter.push_accepts_more()
                 if (self.SyntaxTB.last_syntax_error and
                     self.autoedit_syntax):
                     self.edit_syntax_error()
                 if not more:
                     source_raw = self.input_splitter.source_raw_reset()[1]
                     hlen_b4_cell = self._replace_rlhist_multiline(source_raw, hlen_b4_cell)
                     self.run_cell(source_raw)
                 
 
         # Turn off the exit flag, so the mainloop can be restarted if desired
         self.exit_now = False

IPython/terminal/embed.py

@@ -1,301 +1,294 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):
+        with 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)

IPython/terminal/interactiveshell.py

@@ -1,697 +1,690 b''
 # -*- coding: utf-8 -*-
 """Subclass of InteractiveShell for terminal based frontends."""
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2001 Janko Hauser <[e-mail]>
 #  Copyright (C) 2001-2007 Fernando Perez. <[e-mail]>
 #  Copyright (C) 2008-2011  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 print_function
 
 import bdb
 import os
 import sys
 
-# 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.error import TryNext, UsageError
 from IPython.core.usage import interactive_usage, default_banner
 from IPython.core.inputsplitter import IPythonInputSplitter
 from IPython.core.interactiveshell import InteractiveShell, InteractiveShellABC
 from IPython.core.magic import Magics, magics_class, line_magic
 from IPython.testing.skipdoctest import skip_doctest
 from IPython.utils.encoding import get_stream_enc
 from IPython.utils import py3compat
 from IPython.utils.terminal import toggle_set_term_title, set_term_title
 from IPython.utils.process import abbrev_cwd
 from IPython.utils.warn import warn, error
 from IPython.utils.text import num_ini_spaces, SList, strip_email_quotes
 from IPython.utils.traitlets import Integer, CBool, Unicode
 
 #-----------------------------------------------------------------------------
 # Utilities
 #-----------------------------------------------------------------------------
 
 def get_default_editor():
     try:
         ed = os.environ['EDITOR']
     except KeyError:
         if os.name == 'posix':
             ed = 'vi'  # the only one guaranteed to be there!
         else:
             ed = 'notepad' # same in Windows!
     return ed
 
 
 def get_pasted_lines(sentinel, l_input=py3compat.input):
     """ Yield pasted lines until the user enters the given sentinel value.
     """
     print("Pasting code; enter '%s' alone on the line to stop or use Ctrl-D." \
           % sentinel)
     while True:
         try:
             l = l_input(':')
             if l == sentinel:
                 return
             else:
                 yield l
         except EOFError:
             print('<EOF>')
             return
 
 
 #------------------------------------------------------------------------
 # Terminal-specific magics
 #------------------------------------------------------------------------
 
 @magics_class
 class TerminalMagics(Magics):
     def __init__(self, shell):
         super(TerminalMagics, self).__init__(shell)
         self.input_splitter = IPythonInputSplitter()
         
     def store_or_execute(self, block, name):
         """ Execute a block, or store it in a variable, per the user's request.
         """
         if name:
             # If storing it for further editing
             self.shell.user_ns[name] = SList(block.splitlines())
             print("Block assigned to '%s'" % name)
         else:
             b = self.preclean_input(block)
             self.shell.user_ns['pasted_block'] = b
             self.shell.using_paste_magics = True
             try:
                 self.shell.run_cell(b)
             finally:
                 self.shell.using_paste_magics = False
     
     def preclean_input(self, block):
         lines = block.splitlines()
         while lines and not lines[0].strip():
             lines = lines[1:]
         return strip_email_quotes('\n'.join(lines))
 
     def rerun_pasted(self, name='pasted_block'):
         """ Rerun a previously pasted command.
         """
         b = self.shell.user_ns.get(name)
 
         # Sanity checks
         if b is None:
             raise UsageError('No previous pasted block available')
         if not isinstance(b, basestring):
             raise UsageError(
                 "Variable 'pasted_block' is not a string, can't execute")
 
         print("Re-executing '%s...' (%d chars)"% (b.split('\n',1)[0], len(b)))
         self.shell.run_cell(b)
 
     @line_magic
     def autoindent(self, parameter_s = ''):
         """Toggle autoindent on/off (if available)."""
 
         self.shell.set_autoindent()
         print("Automatic indentation is:",['OFF','ON'][self.shell.autoindent])
 
     @skip_doctest
     @line_magic
     def cpaste(self, parameter_s=''):
         """Paste & execute a pre-formatted code block from clipboard.
 
         You must terminate the block with '--' (two minus-signs) or Ctrl-D
         alone on the line. You can also provide your own sentinel with '%paste
         -s %%' ('%%' is the new sentinel for this operation)
 
         The block is dedented prior to execution to enable execution of method
         definitions. '>' and '+' characters at the beginning of a line are
         ignored, to allow pasting directly from e-mails, diff files and
         doctests (the '...' continuation prompt is also stripped).  The
         executed block is also assigned to variable named 'pasted_block' for
         later editing with '%edit pasted_block'.
 
         You can also pass a variable name as an argument, e.g. '%cpaste foo'.
         This assigns the pasted block to variable 'foo' as string, without
         dedenting or executing it (preceding >>> and + is still stripped)
 
         '%cpaste -r' re-executes the block previously entered by cpaste.
 
         Do not be alarmed by garbled output on Windows (it's a readline bug).
         Just press enter and type -- (and press enter again) and the block
         will be what was just pasted.
 
         IPython statements (magics, shell escapes) are not supported (yet).
 
         See also
         --------
         paste: automatically pull code from clipboard.
 
         Examples
         --------
         ::
 
           In [8]: %cpaste
           Pasting code; enter '--' alone on the line to stop.
           :>>> a = ["world!", "Hello"]
           :>>> print " ".join(sorted(a))
           :--
           Hello world!
         """
         opts, name = self.parse_options(parameter_s, 'rs:', mode='string')
         if 'r' in opts:
             self.rerun_pasted()
             return
 
         sentinel = opts.get('s', '--')
         block = '\n'.join(get_pasted_lines(sentinel))
         self.store_or_execute(block, name)
 
     @line_magic
     def paste(self, parameter_s=''):
         """Paste & execute a pre-formatted code block from clipboard.
 
         The text is pulled directly from the clipboard without user
         intervention and printed back on the screen before execution (unless
         the -q flag is given to force quiet mode).
 
         The block is dedented prior to execution to enable execution of method
         definitions. '>' and '+' characters at the beginning of a line are
         ignored, to allow pasting directly from e-mails, diff files and
         doctests (the '...' continuation prompt is also stripped).  The
         executed block is also assigned to variable named 'pasted_block' for
         later editing with '%edit pasted_block'.
 
         You can also pass a variable name as an argument, e.g. '%paste foo'.
         This assigns the pasted block to variable 'foo' as string, without
         executing it (preceding >>> and + is still stripped).
 
         Options
         -------
 
           -r: re-executes the block previously entered by cpaste.
 
           -q: quiet mode: do not echo the pasted text back to the terminal.
 
         IPython statements (magics, shell escapes) are not supported (yet).
 
         See also
         --------
         cpaste: manually paste code into terminal until you mark its end.
         """
         opts, name = self.parse_options(parameter_s, 'rq', mode='string')
         if 'r' in opts:
             self.rerun_pasted()
             return
         try:
             block = self.shell.hooks.clipboard_get()
         except TryNext as clipboard_exc:
             message = getattr(clipboard_exc, 'args')
             if message:
                 error(message[0])
             else:
                 error('Could not get text from the clipboard.')
             return
 
         # By default, echo back to terminal unless quiet mode is requested
         if 'q' not in opts:
             write = self.shell.write
             write(self.shell.pycolorize(block))
             if not block.endswith('\n'):
                 write('\n')
             write("## -- End pasted text --\n")
 
         self.store_or_execute(block, name)
 
     # Class-level: add a '%cls' magic only on Windows
     if sys.platform == 'win32':
         @line_magic
         def cls(self, s):
             """Clear screen.
             """
             os.system("cls")
 
 #-----------------------------------------------------------------------------
 # Main class
 #-----------------------------------------------------------------------------
 
 class TerminalInteractiveShell(InteractiveShell):
 
     autoedit_syntax = CBool(False, config=True,
         help="auto editing of files with syntax errors.")
     banner = Unicode('')
     banner1 = Unicode(default_banner, config=True,
         help="""The part of the banner to be printed before the profile"""
     )
     banner2 = Unicode('', config=True,
         help="""The part of the banner to be printed after the profile"""
     )
     confirm_exit = CBool(True, config=True,
         help="""
         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.""",
     )
     # This display_banner only controls whether or not self.show_banner()
     # is called when mainloop/interact are called.  The default is False
     # because for the terminal based application, the banner behavior
     # is controlled by Global.display_banner, which IPythonApp looks at
     # to determine if *it* should call show_banner() by hand or not.
     display_banner = CBool(False) # This isn't configurable!
     embedded = CBool(False)
     embedded_active = CBool(False)
     editor = Unicode(get_default_editor(), config=True,
         help="Set the editor used by IPython (default to $EDITOR/vi/notepad)."
     )
     pager = Unicode('less', config=True,
         help="The shell program to be used for paging.")
 
     screen_length = Integer(0, config=True,
         help=
         """Number of lines of your screen, used to control printing of very
         long strings.  Strings longer than this number of lines will be sent
         through a pager instead of directly printed.  The default value for
         this is 0, which means IPython will auto-detect your screen size every
         time it needs to print certain potentially long strings (this doesn't
         change the behavior of the 'print' keyword, it's only triggered
         internally). If for some reason this isn't working well (it needs
         curses support), specify it yourself. Otherwise don't change the
         default.""",
     )
     term_title = CBool(False, config=True,
         help="Enable auto setting the terminal title."
     )
     
     # This `using_paste_magics` is used to detect whether the code is being
     # executed via paste magics functions
     using_paste_magics = CBool(False)
 
     # In the terminal, GUI control is done via PyOS_InputHook
     @staticmethod
     def enable_gui(gui=None, app=None):
         """Switch amongst GUI input hooks by name.
         """
         # Deferred import
         from IPython.lib.inputhook import enable_gui as real_enable_gui
         try:
             return real_enable_gui(gui, app)
         except ValueError as e:
             raise UsageError("%s" % e)
     
     def __init__(self, config=None, ipython_dir=None, profile_dir=None,
                  user_ns=None, user_module=None, custom_exceptions=((),None),
                  usage=None, banner1=None, banner2=None, display_banner=None,
                  **kwargs):
 
         super(TerminalInteractiveShell, self).__init__(
             config=config, ipython_dir=ipython_dir, profile_dir=profile_dir, user_ns=user_ns,
             user_module=user_module, custom_exceptions=custom_exceptions,
             **kwargs
         )
         # use os.system instead of utils.process.system by default,
         # because piped system doesn't make sense in the Terminal:
         self.system = self.system_raw
 
         self.init_term_title()
         self.init_usage(usage)
         self.init_banner(banner1, banner2, display_banner)
 
     #-------------------------------------------------------------------------
     # Overrides of init stages
     #-------------------------------------------------------------------------
 
     def init_display_formatter(self):
         super(TerminalInteractiveShell, self).init_display_formatter()
         # terminal only supports plaintext
         self.display_formatter.active_types = ['text/plain']
 
     #-------------------------------------------------------------------------
     # Things related to the terminal
     #-------------------------------------------------------------------------
 
     @property
     def usable_screen_length(self):
         if self.screen_length == 0:
             return 0
         else:
             num_lines_bot = self.separate_in.count('\n')+1
             return self.screen_length - num_lines_bot
 
     def init_term_title(self):
         # Enable or disable the terminal title.
         if self.term_title:
             toggle_set_term_title(True)
             set_term_title('IPython: ' + abbrev_cwd())
         else:
             toggle_set_term_title(False)
 
     #-------------------------------------------------------------------------
     # Things related to aliases
     #-------------------------------------------------------------------------
 
     def init_alias(self):
         # The parent class defines aliases that can be safely used with any
         # frontend.
         super(TerminalInteractiveShell, self).init_alias()
 
         # Now define aliases that only make sense on the terminal, because they
         # need direct access to the console in a way that we can't emulate in
         # GUI or web frontend
         if os.name == 'posix':
             aliases = [('clear', 'clear'), ('more', 'more'), ('less', 'less'),
                        ('man', 'man')]
         elif os.name == 'nt':
             aliases = [('cls', 'cls')]
 
 
         for name, cmd in aliases:
             self.alias_manager.define_alias(name, cmd)
 
     #-------------------------------------------------------------------------
     # Things related to the banner and usage
     #-------------------------------------------------------------------------
 
     def _banner1_changed(self):
         self.compute_banner()
 
     def _banner2_changed(self):
         self.compute_banner()
 
     def _term_title_changed(self, name, new_value):
         self.init_term_title()
 
     def init_banner(self, banner1, banner2, display_banner):
         if banner1 is not None:
             self.banner1 = banner1
         if banner2 is not None:
             self.banner2 = banner2
         if display_banner is not None:
             self.display_banner = display_banner
         self.compute_banner()
 
     def show_banner(self, banner=None):
         if banner is None:
             banner = self.banner
         self.write(banner)
 
     def compute_banner(self):
         self.banner = self.banner1
         if self.profile and self.profile != 'default':
             self.banner += '\nIPython profile: %s\n' % self.profile
         if self.banner2:
             self.banner += '\n' + self.banner2
 
     def init_usage(self, usage=None):
         if usage is None:
             self.usage = interactive_usage
         else:
             self.usage = usage
 
     #-------------------------------------------------------------------------
     # Mainloop and code execution logic
     #-------------------------------------------------------------------------
 
     def mainloop(self, display_banner=None):
         """Start the mainloop.
 
         If an optional banner argument is given, it will override the
         internally created default banner.
         """
 
-        with nested(self.builtin_trap, self.display_trap):
+        with self.builtin_trap, self.display_trap:
 
             while 1:
                 try:
                     self.interact(display_banner=display_banner)
                     #self.interact_with_readline()
                     # XXX for testing of a readline-decoupled repl loop, call
                     # interact_with_readline above
                     break
                 except KeyboardInterrupt:
                     # this should not be necessary, but KeyboardInterrupt
                     # handling seems rather unpredictable...
                     self.write("\nKeyboardInterrupt in interact()\n")
 
     def _replace_rlhist_multiline(self, source_raw, hlen_before_cell):
         """Store multiple lines as a single entry in history"""
 
         # do nothing without readline or disabled multiline
         if not self.has_readline or not self.multiline_history:
             return hlen_before_cell
 
         # windows rl has no remove_history_item
         if not hasattr(self.readline, "remove_history_item"):
             return hlen_before_cell
 
         # skip empty cells
         if not source_raw.rstrip():
             return hlen_before_cell
 
         # nothing changed do nothing, e.g. when rl removes consecutive dups
         hlen = self.readline.get_current_history_length()
         if hlen == hlen_before_cell:
             return hlen_before_cell
 
         for i in range(hlen - hlen_before_cell):
             self.readline.remove_history_item(hlen - i - 1)
         stdin_encoding = get_stream_enc(sys.stdin, 'utf-8')
         self.readline.add_history(py3compat.unicode_to_str(source_raw.rstrip(),
                                     stdin_encoding))
         return self.readline.get_current_history_length()
 
     def interact(self, display_banner=None):
         """Closely emulate the interactive Python console."""
 
         # batch run -> do not interact
         if self.exit_now:
             return
 
         if display_banner is None:
             display_banner = self.display_banner
 
         if isinstance(display_banner, basestring):
             self.show_banner(display_banner)
         elif display_banner:
             self.show_banner()
 
         more = False
 
         if self.has_readline:
             self.readline_startup_hook(self.pre_readline)
             hlen_b4_cell = self.readline.get_current_history_length()
         else:
             hlen_b4_cell = 0
         # exit_now is set by a call to %Exit or %Quit, through the
         # ask_exit callback.
 
         while not self.exit_now:
             self.hooks.pre_prompt_hook()
             if more:
                 try:
                     prompt = self.prompt_manager.render('in2')
                 except:
                     self.showtraceback()
                 if self.autoindent:
                     self.rl_do_indent = True
 
             else:
                 try:
                     prompt = self.separate_in + self.prompt_manager.render('in')
                 except:
                     self.showtraceback()
             try:
                 line = self.raw_input(prompt)
                 if self.exit_now:
                     # quick exit on sys.std[in|out] close
                     break
                 if self.autoindent:
                     self.rl_do_indent = False
 
             except KeyboardInterrupt:
                 #double-guard against keyboardinterrupts during kbdint handling
                 try:
                     self.write('\nKeyboardInterrupt\n')
                     source_raw = self.input_splitter.source_raw_reset()[1]
                     hlen_b4_cell = \
                         self._replace_rlhist_multiline(source_raw, hlen_b4_cell)
                     more = False
                 except KeyboardInterrupt:
                     pass
             except EOFError:
                 if self.autoindent:
                     self.rl_do_indent = False
                     if self.has_readline:
                         self.readline_startup_hook(None)
                 self.write('\n')
                 self.exit()
             except bdb.BdbQuit:
                 warn('The Python debugger has exited with a BdbQuit exception.\n'
                      'Because of how pdb handles the stack, it is impossible\n'
                      'for IPython to properly format this particular exception.\n'
                      'IPython will resume normal operation.')
             except:
                 # exceptions here are VERY RARE, but they can be triggered
                 # asynchronously by signal handlers, for example.
                 self.showtraceback()
             else:
                 self.input_splitter.push(line)
                 more = self.input_splitter.push_accepts_more()
                 if (self.SyntaxTB.last_syntax_error and
                     self.autoedit_syntax):
                     self.edit_syntax_error()
                 if not more:
                     source_raw = self.input_splitter.source_raw_reset()[1]
                     self.run_cell(source_raw, store_history=True)
                     hlen_b4_cell = \
                         self._replace_rlhist_multiline(source_raw, hlen_b4_cell)
 
         # Turn off the exit flag, so the mainloop can be restarted if desired
         self.exit_now = False
 
     def raw_input(self, prompt=''):
         """Write a prompt and read a line.
 
         The returned line does not include the trailing newline.
         When the user enters the EOF key sequence, EOFError is raised.
 
         Optional inputs:
 
           - prompt(''): a string to be printed to prompt the user.
 
           - continue_prompt(False): whether this line is the first one or a
           continuation in a sequence of inputs.
         """
         # Code run by the user may have modified the readline completer state.
         # We must ensure that our completer is back in place.
 
         if self.has_readline:
             self.set_readline_completer()
         
         # raw_input expects str, but we pass it unicode sometimes
         prompt = py3compat.cast_bytes_py2(prompt)
 
         try:
             line = py3compat.str_to_unicode(self.raw_input_original(prompt))
         except ValueError:
             warn("\n********\nYou or a %run:ed script called sys.stdin.close()"
                  " or sys.stdout.close()!\nExiting IPython!\n")
             self.ask_exit()
             return ""
 
         # Try to be reasonably smart about not re-indenting pasted input more
         # than necessary.  We do this by trimming out the auto-indent initial
         # spaces, if the user's actual input started itself with whitespace.
         if self.autoindent:
             if num_ini_spaces(line) > self.indent_current_nsp:
                 line = line[self.indent_current_nsp:]
                 self.indent_current_nsp = 0
 
         return line
 
     #-------------------------------------------------------------------------
     # Methods to support auto-editing of SyntaxErrors.
     #-------------------------------------------------------------------------
 
     def edit_syntax_error(self):
         """The bottom half of the syntax error handler called in the main loop.
 
         Loop until syntax error is fixed or user cancels.
         """
 
         while self.SyntaxTB.last_syntax_error:
             # copy and clear last_syntax_error
             err = self.SyntaxTB.clear_err_state()
             if not self._should_recompile(err):
                 return
             try:
                 # may set last_syntax_error again if a SyntaxError is raised
                 self.safe_execfile(err.filename,self.user_ns)
             except:
                 self.showtraceback()
             else:
                 try:
                     f = open(err.filename)
                     try:
                         # This should be inside a display_trap block and I
                         # think it is.
                         sys.displayhook(f.read())
                     finally:
                         f.close()
                 except:
                     self.showtraceback()
 
     def _should_recompile(self,e):
         """Utility routine for edit_syntax_error"""
 
         if e.filename in ('<ipython console>','<input>','<string>',
                           '<console>','<BackgroundJob compilation>',
                           None):
 
             return False
         try:
             if (self.autoedit_syntax and
                 not self.ask_yes_no('Return to editor to correct syntax error? '
                               '[Y/n] ','y')):
                 return False
         except EOFError:
             return False
 
         def int0(x):
             try:
                 return int(x)
             except TypeError:
                 return 0
         # always pass integer line and offset values to editor hook
         try:
             self.hooks.fix_error_editor(e.filename,
                 int0(e.lineno),int0(e.offset),e.msg)
         except TryNext:
             warn('Could not open editor')
             return False
         return True
 
     #-------------------------------------------------------------------------
     # Things related to exiting
     #-------------------------------------------------------------------------
 
     def ask_exit(self):
         """ Ask the shell to exit. Can be overiden and used as a callback. """
         self.exit_now = True
 
     def exit(self):
         """Handle interactive exit.
 
         This method calls the ask_exit callback."""
         if self.confirm_exit:
             if self.ask_yes_no('Do you really want to exit ([y]/n)?','y'):
                 self.ask_exit()
         else:
             self.ask_exit()
 
     #-------------------------------------------------------------------------
     # Things related to magics
     #-------------------------------------------------------------------------
 
     def init_magics(self):
         super(TerminalInteractiveShell, self).init_magics()
         self.register_magics(TerminalMagics)
 
     def showindentationerror(self):
         super(TerminalInteractiveShell, self).showindentationerror()
         if not self.using_paste_magics:
             print("If you want to paste code into IPython, try the "
                 "%paste and %cpaste magic functions.")
 
 
 InteractiveShellABC.register(TerminalInteractiveShell)