Allow starting TerminalInteractiveShell more than once

1. always start with keep_running=True in `interact()`
2. don't close eventloop at end of mainloop (not sure this is the right thing to do)

IPython/terminal/interactiveshell.py

@@ -1,490 +1,488 b''
 """IPython terminal interface using prompt_toolkit"""
 from __future__ import print_function
 
 import os
 import sys
 import warnings
 from warnings import warn
 
 from IPython.core.interactiveshell import InteractiveShell, InteractiveShellABC
 from IPython.utils import io
 from IPython.utils.py3compat import PY3, cast_unicode_py2, input
 from IPython.utils.terminal import toggle_set_term_title, set_term_title
 from IPython.utils.process import abbrev_cwd
 from traitlets import Bool, Unicode, Dict, Integer, observe, Instance, Type, default, Enum
 
 from prompt_toolkit.enums import DEFAULT_BUFFER, EditingMode
 from prompt_toolkit.filters import (HasFocus, Condition, IsDone)
 from prompt_toolkit.history import InMemoryHistory
 from prompt_toolkit.shortcuts import create_prompt_application, create_eventloop, create_prompt_layout, create_output
 from prompt_toolkit.interface import CommandLineInterface
 from prompt_toolkit.key_binding.manager import KeyBindingManager
 from prompt_toolkit.layout.processors import ConditionalProcessor, HighlightMatchingBracketProcessor
 from prompt_toolkit.styles import PygmentsStyle, DynamicStyle
 
 from pygments.styles import get_style_by_name, get_all_styles
 from pygments.token import Token
 
 from .debugger import TerminalPdb, Pdb
 from .magics import TerminalMagics
 from .pt_inputhooks import get_inputhook_func
 from .prompts import Prompts, ClassicPrompts, RichPromptDisplayHook
 from .ptutils import IPythonPTCompleter, IPythonPTLexer
 from .shortcuts import register_ipython_shortcuts
 
 DISPLAY_BANNER_DEPRECATED = object()
 
 
 from pygments.style import Style
 
 class _NoStyle(Style): pass
 
 
 
 _style_overrides_light_bg = {
             Token.Prompt: '#0000ff',
             Token.PromptNum: '#0000ee bold',
             Token.OutPrompt: '#cc0000',
             Token.OutPromptNum: '#bb0000 bold',
 }
 
 _style_overrides_linux = {
             Token.Prompt: '#00cc00',
             Token.PromptNum: '#00bb00 bold',
             Token.OutPrompt: '#cc0000',
             Token.OutPromptNum: '#bb0000 bold',
 }
 
 
 
 def get_default_editor():
     try:
         ed = os.environ['EDITOR']
         if not PY3:
             ed = ed.decode()
         return ed
     except KeyError:
         pass
     except UnicodeError:
         warn("$EDITOR environment variable is not pure ASCII. Using platform "
              "default editor.")
 
     if os.name == 'posix':
         return 'vi'  # the only one guaranteed to be there!
     else:
         return 'notepad' # same in Windows!
 
 # conservatively check for tty
 # overridden streams can result in things like:
 # - sys.stdin = None
 # - no isatty method
 for _name in ('stdin', 'stdout', 'stderr'):
     _stream = getattr(sys, _name)
     if not _stream or not hasattr(_stream, 'isatty') or not _stream.isatty():
         _is_tty = False
         break
 else:
     _is_tty = True
 
 
 _use_simple_prompt = ('IPY_TEST_SIMPLE_PROMPT' in os.environ) or (not _is_tty)
 
 class TerminalInteractiveShell(InteractiveShell):
     space_for_menu = Integer(6, help='Number of line at the bottom of the screen '
                                                   'to reserve for the completion menu'
                             ).tag(config=True)
 
     def _space_for_menu_changed(self, old, new):
         self._update_layout()
 
     pt_cli = None
     debugger_history = None
     _pt_app = None
 
     simple_prompt = Bool(_use_simple_prompt,
         help="""Use `raw_input` for the REPL, without completion, multiline input, and prompt colors.
 
             Useful when controlling IPython as a subprocess, and piping STDIN/OUT/ERR. Known usage are:
             IPython own testing machinery, and emacs inferior-shell integration through elpy.
 
             This mode default to `True` if the `IPY_TEST_SIMPLE_PROMPT`
             environment variable is set, or the current terminal is not a tty.
 
             """
             ).tag(config=True)
 
     @property
     def debugger_cls(self):
         return Pdb if self.simple_prompt else TerminalPdb
 
     confirm_exit = Bool(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.""",
     ).tag(config=True)
 
     editing_mode = Unicode('emacs',
         help="Shortcut style to use at the prompt. 'vi' or 'emacs'.",
     ).tag(config=True)
 
     mouse_support = Bool(False,
         help="Enable mouse support in the prompt"
     ).tag(config=True)
 
     highlighting_style = Unicode('legacy',
             help="The name of a Pygments style to use for syntax highlighting: \n %s" % ', '.join(get_all_styles())
     ).tag(config=True)
 
     
     @observe('highlighting_style')
     @observe('colors')
     def _highlighting_style_changed(self, change):
         self.refresh_style()
 
     def refresh_style(self):
         self._style = self._make_style_from_name(self.highlighting_style)
 
 
     highlighting_style_overrides = Dict(
         help="Override highlighting format for specific tokens"
     ).tag(config=True)
 
     true_color = Bool(False,
         help=("Use 24bit colors instead of 256 colors in prompt highlighting. "
               "If your terminal supports true color, the following command "
               "should print 'TRUECOLOR' in orange: "
               "printf \"\\x1b[38;2;255;100;0mTRUECOLOR\\x1b[0m\\n\"")
     ).tag(config=True)
 
     editor = Unicode(get_default_editor(),
         help="Set the editor used by IPython (default to $EDITOR/vi/notepad)."
     ).tag(config=True)
 
     prompts_class = Type(Prompts, help='Class used to generate Prompt token for prompt_toolkit').tag(config=True)
 
     prompts = Instance(Prompts)
 
     @default('prompts')
     def _prompts_default(self):
         return self.prompts_class(self)
 
     @observe('prompts')
     def _(self, change):
         self._update_layout()
 
     @default('displayhook_class')
     def _displayhook_class_default(self):
         return RichPromptDisplayHook
 
     term_title = Bool(True,
         help="Automatically set the terminal title"
     ).tag(config=True)
 
     display_completions = Enum(('column', 'multicolumn','readlinelike'), 
         help= ( "Options for displaying tab completions, 'column', 'multicolumn', and "
                 "'readlinelike'. These options are for `prompt_toolkit`, see "
                 "`prompt_toolkit` documentation for more information."
                 ),
         default_value='multicolumn').tag(config=True)
 
     highlight_matching_brackets = Bool(True,
         help="Highlight matching brackets .",
     ).tag(config=True)
 
     @observe('term_title')
     def init_term_title(self, change=None):
         # 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)
 
     def init_display_formatter(self):
         super(TerminalInteractiveShell, self).init_display_formatter()
         # terminal only supports plain text
         self.display_formatter.active_types = ['text/plain']
 
     def init_prompt_toolkit_cli(self):
         if self.simple_prompt:
             # Fall back to plain non-interactive output for tests.
             # This is very limited, and only accepts a single line.
             def prompt():
                 return cast_unicode_py2(input('In [%d]: ' % self.execution_count))
             self.prompt_for_code = prompt
             return
 
         # Set up keyboard shortcuts
         kbmanager = KeyBindingManager.for_prompt()
         register_ipython_shortcuts(kbmanager.registry, self)
 
         # Pre-populate history from IPython's history database
         history = InMemoryHistory()
         last_cell = u""
         for __, ___, cell in self.history_manager.get_tail(self.history_load_length,
                                                         include_latest=True):
             # Ignore blank lines and consecutive duplicates
             cell = cell.rstrip()
             if cell and (cell != last_cell):
                 history.append(cell)
 
         self._style = self._make_style_from_name(self.highlighting_style)
         style = DynamicStyle(lambda: self._style)
 
         editing_mode = getattr(EditingMode, self.editing_mode.upper())
 
         self._pt_app = create_prompt_application(
                             editing_mode=editing_mode,
                             key_bindings_registry=kbmanager.registry,
                             history=history,
                             completer=IPythonPTCompleter(self.Completer),
                             enable_history_search=True,
                             style=style,
                             mouse_support=self.mouse_support,
                             **self._layout_options()
         )
         self._eventloop = create_eventloop(self.inputhook)
         self.pt_cli = CommandLineInterface(
             self._pt_app, eventloop=self._eventloop,
             output=create_output(true_color=self.true_color))
 
     def _make_style_from_name(self, name):
         """
         Small wrapper that make an IPython compatible style from a style name
 
         We need that to add style for prompt ... etc. 
         """
         style_overrides = {}
         if name == 'legacy':
             legacy = self.colors.lower()
             if legacy == 'linux':
                 style_cls = get_style_by_name('monokai')
                 style_overrides = _style_overrides_linux
             elif legacy == 'lightbg':
                 style_overrides = _style_overrides_light_bg
                 style_cls = get_style_by_name('pastie')
             elif legacy == 'neutral':
                 # The default theme needs to be visible on both a dark background
                 # and a light background, because we can't tell what the terminal
                 # looks like. These tweaks to the default theme help with that.
                 style_cls = get_style_by_name('default')
                 style_overrides.update({
                     Token.Number: '#007700',
                     Token.Operator: 'noinherit',
                     Token.String: '#BB6622',
                     Token.Name.Function: '#2080D0',
                     Token.Name.Class: 'bold #2080D0',
                     Token.Name.Namespace: 'bold #2080D0',
                     Token.Prompt: '#009900',
                     Token.PromptNum: '#00ff00 bold',
                     Token.OutPrompt: '#990000',
                     Token.OutPromptNum: '#ff0000 bold',
                 })
             elif legacy =='nocolor':
                 style_cls=_NoStyle
                 style_overrides = {}
             else :
                 raise ValueError('Got unknown colors: ', legacy)
         else :
             style_cls = get_style_by_name(name)
             style_overrides = {
                 Token.Prompt: '#009900',
                 Token.PromptNum: '#00ff00 bold',
                 Token.OutPrompt: '#990000',
                 Token.OutPromptNum: '#ff0000 bold',
             }
         style_overrides.update(self.highlighting_style_overrides)
         style = PygmentsStyle.from_defaults(pygments_style_cls=style_cls,
                                             style_dict=style_overrides)
 
         return style
 
     def _layout_options(self):
         """
         Return the current layout option for the current Terminal InteractiveShell
         """
         return {
                 'lexer':IPythonPTLexer(),
                 'reserve_space_for_menu':self.space_for_menu,
                 'get_prompt_tokens':self.prompts.in_prompt_tokens,
                 'get_continuation_tokens':self.prompts.continuation_prompt_tokens,
                 'multiline':True,
                 'display_completions_in_columns': (self.display_completions == 'multicolumn'),
 
                 # Highlight matching brackets, but only when this setting is
                 # enabled, and only when the DEFAULT_BUFFER has the focus.
                 'extra_input_processors': [ConditionalProcessor(
                         processor=HighlightMatchingBracketProcessor(chars='[](){}'),
                         filter=HasFocus(DEFAULT_BUFFER) & ~IsDone() &
                             Condition(lambda cli: self.highlight_matching_brackets))],
                 }
 
     def _update_layout(self):
         """
         Ask for a re computation of the application layout, if for example ,
         some configuration options have changed.
         """
         if self._pt_app:
             self._pt_app.layout = create_prompt_layout(**self._layout_options())
 
     def prompt_for_code(self):
         document = self.pt_cli.run(
             pre_run=self.pre_prompt, reset_current_buffer=True)
         return document.text
 
     def enable_win_unicode_console(self):
         import win_unicode_console
 
         if PY3:
             win_unicode_console.enable()
         else:
             # https://github.com/ipython/ipython/issues/9768
             from win_unicode_console.streams import (TextStreamWrapper,
                                  stdout_text_transcoded, stderr_text_transcoded)
 
             class LenientStrStreamWrapper(TextStreamWrapper):
                 def write(self, s):
                     if isinstance(s, bytes):
                         s = s.decode(self.encoding, 'replace')
 
                     self.base.write(s)
 
             stdout_text_str = LenientStrStreamWrapper(stdout_text_transcoded)
             stderr_text_str = LenientStrStreamWrapper(stderr_text_transcoded)
 
             win_unicode_console.enable(stdout=stdout_text_str,
                                        stderr=stderr_text_str)
 
     def init_io(self):
         if sys.platform not in {'win32', 'cli'}:
             return
 
         self.enable_win_unicode_console()
 
         import colorama
         colorama.init()
 
         # For some reason we make these wrappers around stdout/stderr.
         # For now, we need to reset them so all output gets coloured.
         # https://github.com/ipython/ipython/issues/8669
         # io.std* are deprecated, but don't show our own deprecation warnings
         # during initialization of the deprecated API.
         with warnings.catch_warnings():
             warnings.simplefilter('ignore', DeprecationWarning)
             io.stdout = io.IOStream(sys.stdout)
             io.stderr = io.IOStream(sys.stderr)
 
     def init_magics(self):
         super(TerminalInteractiveShell, self).init_magics()
         self.register_magics(TerminalMagics)
 
     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':
             for cmd in ['clear', 'more', 'less', 'man']:
                 self.alias_manager.soft_define_alias(cmd, cmd)
 
 
     def __init__(self, *args, **kwargs):
         super(TerminalInteractiveShell, self).__init__(*args, **kwargs)
         self.init_prompt_toolkit_cli()
         self.init_term_title()
         self.keep_running = True
 
         self.debugger_history = InMemoryHistory()
 
     def ask_exit(self):
         self.keep_running = False
 
     rl_next_input = None
 
     def pre_prompt(self):
         if self.rl_next_input:
             self.pt_cli.application.buffer.text = cast_unicode_py2(self.rl_next_input)
             self.rl_next_input = None
 
     def interact(self, display_banner=DISPLAY_BANNER_DEPRECATED):
 
         if display_banner is not DISPLAY_BANNER_DEPRECATED:
             warn('interact `display_banner` argument is deprecated since IPython 5.0. Call `show_banner()` if needed.', DeprecationWarning, stacklevel=2)
 
+        self.keep_running = True
         while self.keep_running:
             print(self.separate_in, end='')
 
             try:
                 code = self.prompt_for_code()
             except EOFError:
                 if (not self.confirm_exit) \
                         or self.ask_yes_no('Do you really want to exit ([y]/n)?','y','n'):
                     self.ask_exit()
 
             else:
                 if code:
                     self.run_cell(code, store_history=True)
 
     def mainloop(self, display_banner=DISPLAY_BANNER_DEPRECATED):
         # An extra layer of protection in case someone mashing Ctrl-C breaks
         # out of our internal code.
         if display_banner is not DISPLAY_BANNER_DEPRECATED:
             warn('mainloop `display_banner` argument is deprecated since IPython 5.0. Call `show_banner()` if needed.', DeprecationWarning, stacklevel=2)
         while True:
             try:
                 self.interact()
                 break
             except KeyboardInterrupt:
                 print("\nKeyboardInterrupt escaped interact()\n")
-        
-        if hasattr(self, '_eventloop'):
-            self._eventloop.close()
 
     _inputhook = None
     def inputhook(self, context):
         if self._inputhook is not None:
             self._inputhook(context)
 
     def enable_gui(self, gui=None):
         if gui:
             self._inputhook = get_inputhook_func(gui)
         else:
             self._inputhook = None
 
     # Run !system commands directly, not through pipes, so terminal programs
     # work correctly.
     system = InteractiveShell.system_raw
 
     def auto_rewrite_input(self, cmd):
         """Overridden from the parent class to use fancy rewriting prompt"""
         if not self.show_rewritten_input:
             return
 
         tokens = self.prompts.rewrite_prompt_tokens()
         if self.pt_cli:
             self.pt_cli.print_tokens(tokens)
             print(cmd)
         else:
             prompt = ''.join(s for t, s in tokens)
             print(prompt, cmd, sep='')
 
     _prompts_before = None
     def switch_doctest_mode(self, mode):
         """Switch prompts to classic for %doctest_mode"""
         if mode:
             self._prompts_before = self.prompts
             self.prompts = ClassicPrompts(self)
         elif self._prompts_before:
             self.prompts = self._prompts_before
             self._prompts_before = None
         self._update_layout()
 
 
 InteractiveShellABC.register(TerminalInteractiveShell)
 
 if __name__ == '__main__':
     TerminalInteractiveShell.instance().interact()