Use new prompt machinery to generate Out prompts

IPython/core/displayhook.py

@@ -1,293 +1,293 b''
 # -*- coding: utf-8 -*-
 """Displayhook for IPython.
 
 This defines a callable class that IPython uses for `sys.displayhook`.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 from __future__ import print_function
 
 import sys
 import io as _io
 import tokenize
 
 from traitlets.config.configurable import Configurable
 from IPython.utils.py3compat import builtin_mod, cast_unicode_py2
 from traitlets import Instance, Float
 from warnings import warn
 
 # TODO: Move the various attributes (cache_size, [others now moved]). Some
 # of these are also attributes of InteractiveShell. They should be on ONE object
 # only and the other objects should ask that one object for their values.
 
 class DisplayHook(Configurable):
     """The custom IPython displayhook to replace sys.displayhook.
 
     This class does many things, but the basic idea is that it is a callable
     that gets called anytime user code returns a value.
     """
 
     shell = Instance('IPython.core.interactiveshell.InteractiveShellABC',
                      allow_none=True)
     exec_result = Instance('IPython.core.interactiveshell.ExecutionResult',
                            allow_none=True)
     cull_fraction = Float(0.2)
 
     def __init__(self, shell=None, cache_size=1000, **kwargs):
         super(DisplayHook, self).__init__(shell=shell, **kwargs)
         cache_size_min = 3
         if cache_size <= 0:
             self.do_full_cache = 0
             cache_size = 0
         elif cache_size < cache_size_min:
             self.do_full_cache = 0
             cache_size = 0
             warn('caching was disabled (min value for cache size is %s).' %
                  cache_size_min,level=3)
         else:
             self.do_full_cache = 1
 
         self.cache_size = cache_size
 
         # we need a reference to the user-level namespace
         self.shell = shell
         
         self._,self.__,self.___ = '','',''
 
         # these are deliberately global:
         to_user_ns = {'_':self._,'__':self.__,'___':self.___}
         self.shell.user_ns.update(to_user_ns)
 
     @property
     def prompt_count(self):
         return self.shell.execution_count
 
     #-------------------------------------------------------------------------
     # Methods used in __call__. Override these methods to modify the behavior
     # of the displayhook.
     #-------------------------------------------------------------------------
 
     def check_for_underscore(self):
         """Check if the user has set the '_' variable by hand."""
         # If something injected a '_' variable in __builtin__, delete
         # ipython's automatic one so we don't clobber that.  gettext() in
         # particular uses _, so we need to stay away from it.
         if '_' in builtin_mod.__dict__:
             try:
                 del self.shell.user_ns['_']
             except KeyError:
                 pass
 
     def quiet(self):
         """Should we silence the display hook because of ';'?"""
         # do not print output if input ends in ';'
         
         try:
             cell = cast_unicode_py2(self.shell.history_manager.input_hist_parsed[-1])
         except IndexError:
             # some uses of ipshellembed may fail here
             return False
         
         sio = _io.StringIO(cell)
         tokens = list(tokenize.generate_tokens(sio.readline))
 
         for token in reversed(tokens):
             if token[0] in (tokenize.ENDMARKER, tokenize.NL, tokenize.NEWLINE, tokenize.COMMENT):
                 continue
             if (token[0] == tokenize.OP) and (token[1] == ';'):
                 return True
             else:
                 return False
 
     def start_displayhook(self):
         """Start the displayhook, initializing resources."""
         pass
 
     def write_output_prompt(self):
         """Write the output prompt.
 
         The default implementation simply writes the prompt to
         ``io.stdout``.
         """
         # Use write, not print which adds an extra space.
         sys.stdout.write(self.shell.separate_out)
-        outprompt = self.shell.prompt_manager.render('out')
+        outprompt = 'Out[{}]: '.format(self.shell.execution_count)
         if self.do_full_cache:
             sys.stdout.write(outprompt)
 
     def compute_format_data(self, result):
         """Compute format data of the object to be displayed.
 
         The format data is a generalization of the :func:`repr` of an object.
         In the default implementation the format data is a :class:`dict` of
         key value pair where the keys are valid MIME types and the values
         are JSON'able data structure containing the raw data for that MIME
         type. It is up to frontends to determine pick a MIME to to use and
         display that data in an appropriate manner.
 
         This method only computes the format data for the object and should
         NOT actually print or write that to a stream.
 
         Parameters
         ----------
         result : object
             The Python object passed to the display hook, whose format will be
             computed.
 
         Returns
         -------
         (format_dict, md_dict) : dict
             format_dict is a :class:`dict` whose keys are valid MIME types and values are
             JSON'able raw data for that MIME type. It is recommended that
             all return values of this should always include the "text/plain"
             MIME type representation of the object.
             md_dict is a :class:`dict` with the same MIME type keys
             of metadata associated with each output.
             
         """
         return self.shell.display_formatter.format(result)
 
     def write_format_data(self, format_dict, md_dict=None):
         """Write the format data dict to the frontend.
 
         This default version of this method simply writes the plain text
         representation of the object to ``io.stdout``. Subclasses should
         override this method to send the entire `format_dict` to the
         frontends.
 
         Parameters
         ----------
         format_dict : dict
             The format dict for the object passed to `sys.displayhook`.
         md_dict : dict (optional)
             The metadata dict to be associated with the display data.
         """
         if 'text/plain' not in format_dict:
             # nothing to do
             return
         # We want to print because we want to always make sure we have a
         # newline, even if all the prompt separators are ''. This is the
         # standard IPython behavior.
         result_repr = format_dict['text/plain']
         if '\n' in result_repr:
             # So that multi-line strings line up with the left column of
             # the screen, instead of having the output prompt mess up
             # their first line.
             # We use the prompt template instead of the expanded prompt
             # because the expansion may add ANSI escapes that will interfere
             # with our ability to determine whether or not we should add
             # a newline.
             prompt_template = self.shell.prompt_manager.out_template
             if prompt_template and not prompt_template.endswith('\n'):
                 # But avoid extraneous empty lines.
                 result_repr = '\n' + result_repr
 
         print(result_repr)
 
     def update_user_ns(self, result):
         """Update user_ns with various things like _, __, _1, etc."""
 
         # Avoid recursive reference when displaying _oh/Out
         if result is not self.shell.user_ns['_oh']:
             if len(self.shell.user_ns['_oh']) >= self.cache_size and self.do_full_cache:
                 self.cull_cache()
             # Don't overwrite '_' and friends if '_' is in __builtin__ (otherwise
             # we cause buggy behavior for things like gettext).
 
             if '_' not in builtin_mod.__dict__:
                 self.___ = self.__
                 self.__ = self._
                 self._ = result
                 self.shell.push({'_':self._,
                                  '__':self.__,
                                 '___':self.___}, interactive=False)
 
             # hackish access to top-level  namespace to create _1,_2... dynamically
             to_main = {}
             if self.do_full_cache:
                 new_result = '_'+repr(self.prompt_count)
                 to_main[new_result] = result
                 self.shell.push(to_main, interactive=False)
                 self.shell.user_ns['_oh'][self.prompt_count] = result
 
     def fill_exec_result(self, result):
         if self.exec_result is not None:
             self.exec_result.result = result
 
     def log_output(self, format_dict):
         """Log the output."""
         if 'text/plain' not in format_dict:
             # nothing to do
             return
         if self.shell.logger.log_output:
             self.shell.logger.log_write(format_dict['text/plain'], 'output')
         self.shell.history_manager.output_hist_reprs[self.prompt_count] = \
                                                     format_dict['text/plain']
 
     def finish_displayhook(self):
         """Finish up all displayhook activities."""
         sys.stdout.write(self.shell.separate_out2)
         sys.stdout.flush()
 
     def __call__(self, result=None):
         """Printing with history cache management.
 
         This is invoked everytime the interpreter needs to print, and is
         activated by setting the variable sys.displayhook to it.
         """
         self.check_for_underscore()
         if result is not None and not self.quiet():
             self.start_displayhook()
             self.write_output_prompt()
             format_dict, md_dict = self.compute_format_data(result)
             self.update_user_ns(result)
             self.fill_exec_result(result)
             if format_dict:
                 self.write_format_data(format_dict, md_dict)
                 self.log_output(format_dict)
             self.finish_displayhook()
 
     def cull_cache(self):
         """Output cache is full, cull the oldest entries"""
         oh = self.shell.user_ns.get('_oh', {})
         sz = len(oh)
         cull_count = max(int(sz * self.cull_fraction), 2)
         warn('Output cache limit (currently {sz} entries) hit.\n'
              'Flushing oldest {cull_count} entries.'.format(sz=sz, cull_count=cull_count))
         
         for i, n in enumerate(sorted(oh)):
             if i >= cull_count:
                 break
             self.shell.user_ns.pop('_%i' % n, None)
             oh.pop(n, None)
         
 
     def flush(self):
         if not self.do_full_cache:
             raise ValueError("You shouldn't have reached the cache flush "
                              "if full caching is not enabled!")
         # delete auto-generated vars from global namespace
 
         for n in range(1,self.prompt_count + 1):
             key = '_'+repr(n)
             try:
                 del self.shell.user_ns[key]
             except: pass
         # In some embedded circumstances, the user_ns doesn't have the
         # '_oh' key set up.
         oh = self.shell.user_ns.get('_oh', None)
         if oh is not None:
             oh.clear()
 
         # Release our own references to objects:
         self._, self.__, self.___ = '', '', ''
 
         if '_' not in builtin_mod.__dict__:
             self.shell.user_ns.update({'_':None,'__':None, '___':None})
         import gc
         # TODO: Is this really needed?
         # IronPython blocks here forever
         if sys.platform != "cli":
             gc.collect()

IPython/terminal/prompts.py

@@ -1,36 +1,50 b''
 from pygments.token import Token
+import sys
+
+from IPython.core.displayhook import DisplayHook
 
 class Prompts(object):
     def __init__(self, shell):
         self.shell = shell
 
     def in_prompt_tokens(self, cli=None):
         return [
             (Token.Prompt, 'In ['),
             (Token.PromptNum, str(self.shell.execution_count)),
             (Token.Prompt, ']: '),
         ]
 
     def _width(self):
         in_tokens = self.in_prompt_tokens()
         return sum(len(s) for (t, s) in in_tokens)
 
     def continuation_prompt_tokens(self, cli=None, width=None):
         if width is None:
             width = self._width()
         return [
             (Token.Prompt, (' ' * (width - 5)) + '...: '),
         ]
 
     def rewrite_prompt_tokens(self):
         width = self._width()
         return [
             (Token.Prompt, ('-' * (width - 2)) + '> '),
         ]
 
     def out_prompt_tokens(self):
         return [
             (Token.OutPrompt, 'Out['),
             (Token.OutPromptNum, str(self.shell.execution_count)),
             (Token.OutPrompt, ']: '),
         ]
+
+class RichPromptDisplayHook(DisplayHook):
+    """Subclass of base display hook using coloured prompt"""
+    def write_output_prompt(self):
+        sys.stdout.write(self.shell.separate_out)
+        if self.do_full_cache:
+            tokens = self.shell.prompts.out_prompt_tokens()
+            if self.shell.pt_cli:
+                self.shell.pt_cli.print_tokens(tokens)
+            else:
+                print(*(s for t, s in tokens), sep='')

IPython/terminal/ptshell.py

@@ -1,451 +1,456 b''
 """IPython terminal interface using prompt_toolkit in place of readline"""
 from __future__ import print_function
 
 import os
 import sys
 import signal
 from warnings import warn
 
 from IPython.core.error import TryNext
 from IPython.core.interactiveshell import InteractiveShell
 from IPython.utils.py3compat import 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
 
 from prompt_toolkit.enums import DEFAULT_BUFFER, SEARCH_BUFFER, EditingMode
 from prompt_toolkit.filters import HasFocus, HasSelection, Condition, ViInsertMode, EmacsInsertMode, IsDone
 from prompt_toolkit.history import InMemoryHistory
 from prompt_toolkit.shortcuts import create_prompt_application, create_eventloop, create_prompt_layout
 from prompt_toolkit.interface import CommandLineInterface
 from prompt_toolkit.key_binding.manager import KeyBindingManager
 from prompt_toolkit.keys import Keys
 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 .pt_inputhooks import get_inputhook_func
 from .interactiveshell import get_default_editor, TerminalMagics
-from .prompts import Prompts
+from .prompts import Prompts, RichPromptDisplayHook
 from .ptutils import IPythonPTCompleter, IPythonPTLexer
 
 _use_simple_prompt = 'IPY_TEST_SIMPLE_PROMPT' in os.environ or not sys.stdin.isatty()
 
 class TerminalInteractiveShell(InteractiveShell):
     colors_force = True
 
     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
 
     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
 
     autoedit_syntax = Bool(False,
         help="auto editing of files with syntax errors.",
     ).tag(config=True)
 
 
     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('default',
             help="The name of a Pygments style to use for syntax highlighting: \n %s" % ', '.join(get_all_styles())
     ).tag(config=True)
 
     
     @observe('highlighting_style')
     def _highlighting_style_changed(self, change):
         self._style = self._make_style_from_name(self.highlighting_style)
 
     highlighting_style_overrides = Dict(
         help="Override highlighting format for specific tokens"
     ).tag(config=True)
 
     editor = Unicode(get_default_editor(),
         help="Set the editor used by IPython (default to $EDITOR/vi/notepad)."
     ).tag(config=True)
 
     prompts = Instance(Prompts)
 
     def _prompts_default(self):
         return Prompts(self)
-    
+
+    def _displayhook_class_default(self):
+        return RichPromptDisplayHook
+
     term_title = Bool(True,
         help="Automatically set the terminal title"
     ).tag(config=True)
 
     display_completions_in_columns = Bool(False,
         help="Display a multi column completion menu.",
     ).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_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
 
         kbmanager = KeyBindingManager.for_prompt()
         insert_mode = ViInsertMode() | EmacsInsertMode()
         # Ctrl+J == Enter, seemingly
         @kbmanager.registry.add_binding(Keys.ControlJ,
                             filter=(HasFocus(DEFAULT_BUFFER)
                                     & ~HasSelection()
                                     & insert_mode
                                    ))
         def _(event):
             b = event.current_buffer
             d = b.document
             if not (d.on_last_line or d.cursor_position_row >= d.line_count
                                            - d.empty_line_count_at_the_end()):
                 b.newline()
                 return
 
             status, indent = self.input_splitter.check_complete(d.text)
 
             if (status != 'incomplete') and b.accept_action.is_returnable:
                 b.accept_action.validate_and_handle(event.cli, b)
             else:
                 b.insert_text('\n' + (' ' * (indent or 0)))
 
         @kbmanager.registry.add_binding(Keys.ControlC, filter=HasFocus(DEFAULT_BUFFER))
         def _reset_buffer(event):
             event.current_buffer.reset()
 
         @kbmanager.registry.add_binding(Keys.ControlC, filter=HasFocus(SEARCH_BUFFER))
         def _reset_search_buffer(event):
             if event.current_buffer.document.text:
                 event.current_buffer.reset()
             else:
                 event.cli.push_focus(DEFAULT_BUFFER)
 
         supports_suspend = Condition(lambda cli: hasattr(signal, 'SIGTSTP'))
 
         @kbmanager.registry.add_binding(Keys.ControlZ, filter=supports_suspend)
         def _suspend_to_bg(event):
             event.cli.suspend_to_background()
 
         @Condition
         def cursor_in_leading_ws(cli):
             before = cli.application.buffer.document.current_line_before_cursor
             return (not before) or before.isspace()
 
         # Ctrl+I == Tab
         @kbmanager.registry.add_binding(Keys.ControlI,
                             filter=(HasFocus(DEFAULT_BUFFER)
                                     & ~HasSelection()
                                     & insert_mode
                                     & cursor_in_leading_ws
                                    ))
         def _indent_buffer(event):
             event.current_buffer.insert_text(' ' * 4)
 
         # 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._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._app, eventloop=self._eventloop)
 
     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_cls = get_style_by_name(name)
         style_overrides = {
             Token.Prompt: '#009900',
             Token.PromptNum: '#00ff00 bold',
+            Token.OutPrompt: '#990000',
+            Token.OutPromptNum: '#ff0000 bold',
         }
         if name == 'default':
             style_cls = get_style_by_name('default')
             # 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_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',
             })
         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_in_columns,
 
                 # 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.
         """
         self._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 init_io(self):
         if sys.platform not in {'win32', 'cli'}:
             return
 
         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
         from IPython.utils import io
         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):
         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)
                     if self.autoedit_syntax and self.SyntaxTB.last_syntax_error:
                         self.edit_syntax_error()
 
     def mainloop(self):
         # An extra layer of protection in case someone mashing Ctrl-C breaks
         # out of our internal code.
         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
 
     # 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:
                     with open(err.filename) as f:
                         # This should be inside a display_trap block and I
                         # think it is.
                         sys.displayhook(f.read())
                 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
 
     # 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='')
 
 
 if __name__ == '__main__':
     TerminalInteractiveShell.instance().interact()