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from __future__ import print_function
# Standard library imports
from collections import namedtuple
import sys
import time
# System library imports
from pygments.lexers import PythonLexer
from PyQt4 import QtCore, QtGui
# Local imports
from IPython.core.inputsplitter import InputSplitter, transform_classic_prompt
from IPython.core.oinspect import call_tip
from IPython.frontend.qt.base_frontend_mixin import BaseFrontendMixin
from IPython.utils.traitlets import Bool
from bracket_matcher import BracketMatcher
from call_tip_widget import CallTipWidget
from completion_lexer import CompletionLexer
from history_console_widget import HistoryConsoleWidget
from pygments_highlighter import PygmentsHighlighter
class FrontendHighlighter(PygmentsHighlighter):
""" A PygmentsHighlighter that can be turned on and off and that ignores
def __init__(self, frontend):
super(FrontendHighlighter, self).__init__(frontend._control.document())
self._current_offset = 0
self._frontend = frontend
self.highlighting_on = False
def highlightBlock(self, qstring):
""" Highlight a block of text. Reimplemented to highlight selectively.
if not self.highlighting_on:
# The input to this function is unicode string that may contain
# paragraph break characters, non-breaking spaces, etc. Here we acquire
# the string as plain text so we can compare it.
current_block = self.currentBlock()
string = self._frontend._get_block_plain_text(current_block)
# Decide whether to check for the regular or continuation prompt.
if current_block.contains(self._frontend._prompt_pos):
prompt = self._frontend._prompt
prompt = self._frontend._continuation_prompt
# Don't highlight the part of the string that contains the prompt.
if string.startswith(prompt):
self._current_offset = len(prompt)
qstring.remove(0, len(prompt))
self._current_offset = 0
PygmentsHighlighter.highlightBlock(self, qstring)
def rehighlightBlock(self, block):
""" Reimplemented to temporarily enable highlighting if disabled.
old = self.highlighting_on
self.highlighting_on = True
super(FrontendHighlighter, self).rehighlightBlock(block)
self.highlighting_on = old
def setFormat(self, start, count, format):
""" Reimplemented to highlight selectively.
start += self._current_offset
PygmentsHighlighter.setFormat(self, start, count, format)
class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):
""" A Qt frontend for a generic Python kernel.
# An option and corresponding signal for overriding the default kernel
# interrupt behavior.
custom_interrupt = Bool(False)
custom_interrupt_requested = QtCore.pyqtSignal()
# An option and corresponding signals for overriding the default kernel
# restart behavior.
custom_restart = Bool(False)
custom_restart_kernel_died = QtCore.pyqtSignal(float)
custom_restart_requested = QtCore.pyqtSignal()
# Emitted when an 'execute_reply' has been received from the kernel and
# processed by the FrontendWidget.
executed = QtCore.pyqtSignal(object)
# Emitted when an exit request has been received from the kernel.
exit_requested = QtCore.pyqtSignal()
# Protected class variables.
_CallTipRequest = namedtuple('_CallTipRequest', ['id', 'pos'])
_CompletionRequest = namedtuple('_CompletionRequest', ['id', 'pos'])
_ExecutionRequest = namedtuple('_ExecutionRequest', ['id', 'kind'])
_input_splitter_class = InputSplitter
_local_kernel = False
# 'object' interface
def __init__(self, *args, **kw):
super(FrontendWidget, self).__init__(*args, **kw)
# FrontendWidget protected variables.
self._bracket_matcher = BracketMatcher(self._control)
self._call_tip_widget = CallTipWidget(self._control)
self._completion_lexer = CompletionLexer(PythonLexer())
self._copy_raw_action = QtGui.QAction('Copy (Raw Text)', None)
self._hidden = False
self._highlighter = FrontendHighlighter(self)
self._input_splitter = self._input_splitter_class(input_mode='cell')
self._kernel_manager = None
self._request_info = {}
# Configure the ConsoleWidget.
self.tab_width = 4
self._set_continuation_prompt('... ')
# Configure the CallTipWidget.
# Configure actions.
action = self._copy_raw_action
key = QtCore.Qt.CTRL | QtCore.Qt.SHIFT | QtCore.Qt.Key_C
# Connect signal handlers.
document = self._control.document()
# set flag for whether we are connected via localhost
self._local_kernel = kw.get('local_kernel', FrontendWidget._local_kernel)
# 'ConsoleWidget' public interface
def copy(self):
""" Copy the currently selected text to the clipboard, removing prompts.
text = unicode(self._control.textCursor().selection().toPlainText())
if text:
lines = map(transform_classic_prompt, text.splitlines())
text = '\n'.join(lines)
# 'ConsoleWidget' abstract interface
def _is_complete(self, source, interactive):
""" Returns whether 'source' can be completely processed and a new
prompt created. When triggered by an Enter/Return key press,
'interactive' is True; otherwise, it is False.
complete = self._input_splitter.push(source)
if interactive:
complete = not self._input_splitter.push_accepts_more()
return complete
def _execute(self, source, hidden):
""" Execute 'source'. If 'hidden', do not show any output.
See parent class :meth:`execute` docstring for full details.
msg_id = self.kernel_manager.xreq_channel.execute(source, hidden)
self._request_info['execute'] = self._ExecutionRequest(msg_id, 'user')
self._hidden = hidden
def _prompt_started_hook(self):
""" Called immediately after a new prompt is displayed.
if not self._reading:
self._highlighter.highlighting_on = True
def _prompt_finished_hook(self):
""" Called immediately after a prompt is finished, i.e. when some input
will be processed and a new prompt displayed.
if not self._reading:
self._highlighter.highlighting_on = False
def _tab_pressed(self):
""" Called when the tab key is pressed. Returns whether to continue
processing the event.
# Perform tab completion if:
# 1) The cursor is in the input buffer.
# 2) There is a non-whitespace character before the cursor.
text = self._get_input_buffer_cursor_line()
if text is None:
return False
complete = bool(text[:self._get_input_buffer_cursor_column()].strip())
if complete:
return not complete
# 'ConsoleWidget' protected interface
def _context_menu_make(self, pos):
""" Reimplemented to add an action for raw copy.
menu = super(FrontendWidget, self)._context_menu_make(pos)
for before_action in menu.actions():
if before_action.shortcut().matches(QtGui.QKeySequence.Paste) == \
menu.insertAction(before_action, self._copy_raw_action)
return menu
def _event_filter_console_keypress(self, event):
""" Reimplemented for execution interruption and smart backspace.
key = event.key()
if self._control_key_down(event.modifiers(), include_command=False):
if key == QtCore.Qt.Key_C and self._executing:
return True
elif key == QtCore.Qt.Key_Period:
message = 'Are you sure you want to restart the kernel?'
self.restart_kernel(message, now=False)
return True
elif not event.modifiers() & QtCore.Qt.AltModifier:
# Smart backspace: remove four characters in one backspace if:
# 1) everything left of the cursor is whitespace
# 2) the four characters immediately left of the cursor are spaces
if key == QtCore.Qt.Key_Backspace:
col = self._get_input_buffer_cursor_column()
cursor = self._control.textCursor()
if col > 3 and not cursor.hasSelection():
text = self._get_input_buffer_cursor_line()[:col]
if text.endswith(' ') and not text.strip():
QtGui.QTextCursor.KeepAnchor, 4)
return True
return super(FrontendWidget, self)._event_filter_console_keypress(event)
def _insert_continuation_prompt(self, cursor):
""" Reimplemented for auto-indentation.
super(FrontendWidget, self)._insert_continuation_prompt(cursor)
cursor.insertText(' ' * self._input_splitter.indent_spaces)
# 'BaseFrontendMixin' abstract interface
def _handle_complete_reply(self, rep):
""" Handle replies for tab completion.
cursor = self._get_cursor()
info = self._request_info.get('complete')
if info and == rep['parent_header']['msg_id'] and \
info.pos == cursor.position():
text = '.'.join(self._get_context())
cursor.movePosition(QtGui.QTextCursor.Left, n=len(text))
self._complete_with_items(cursor, rep['content']['matches'])
def _handle_execute_reply(self, msg):
""" Handles replies for code execution.
info = self._request_info.get('execute')
if info and == msg['parent_header']['msg_id'] and \
info.kind == 'user' and not self._hidden:
# Make sure that all output from the SUB channel has been processed
# before writing a new prompt.
# Reset the ANSI style information to prevent bad text in stdout
# from messing up our colors. We're not a true terminal so we're
# allowed to do this.
if self.ansi_codes:
content = msg['content']
status = content['status']
if status == 'ok':
elif status == 'error':
elif status == 'abort':
def _handle_input_request(self, msg):
""" Handle requests for raw_input.
if self._hidden:
raise RuntimeError('Request for raw input during hidden execution.')
# Make sure that all output from the SUB channel has been processed
# before entering readline mode.
def callback(line):
self._readline(msg['content']['prompt'], callback=callback)
def _handle_kernel_died(self, since_last_heartbeat):
""" Handle the kernel's death by asking if the user wants to restart.
if self.custom_restart:
message = 'The kernel heartbeat has been inactive for %.2f ' \
'seconds. Do you want to restart the kernel? You may ' \
'first want to check the network connection.' % \
self.restart_kernel(message, now=True)
def _handle_object_info_reply(self, rep):
""" Handle replies for call tips.
cursor = self._get_cursor()
info = self._request_info.get('call_tip')
if info and == rep['parent_header']['msg_id'] and \
info.pos == cursor.position():
# Get the information for a call tip. For now we format the call
# line as string, later we can pass False to format_call and
# syntax-highlight it ourselves for nicer formatting in the
# calltip.
call_info, doc = call_tip(rep['content'], format_call=True)
if call_info or doc:
self._call_tip_widget.show_call_info(call_info, doc)
def _handle_pyout(self, msg):
""" Handle display hook output.
if not self._hidden and self._is_from_this_session(msg):
self._append_plain_text(msg['content']['data'] + '\n')
def _handle_stream(self, msg):
""" Handle stdout, stderr, and stdin.
if not self._hidden and self._is_from_this_session(msg):
# Most consoles treat tabs as being 8 space characters. Convert tabs
# to spaces so that output looks as expected regardless of this
# widget's tab width.
text = msg['content']['data'].expandtabs(8)
def _handle_shutdown_reply(self, msg):
""" Handle shutdown signal, only if from other console.
if not self._hidden and not self._is_from_this_session(msg):
if self._local_kernel:
if not msg['content']['restart']:
# we just got notified of a restart!
time.sleep(0.25) # wait 1/4 sec to reset
# lest the request for a new prompt
# goes to the old kernel
else: # remote kernel, prompt on Kernel shutdown/reset
title = self.window().windowTitle()
if not msg['content']['restart']:
reply = QtGui.QMessageBox.question(self, title,
"Kernel has been shutdown permanently. Close the Console?",
if reply == QtGui.QMessageBox.Yes:
reply = QtGui.QMessageBox.question(self, title,
"Kernel has been reset. Clear the Console?",
if reply == QtGui.QMessageBox.Yes:
time.sleep(0.25) # wait 1/4 sec to reset
# lest the request for a new prompt
# goes to the old kernel
def _started_channels(self):
""" Called when the KernelManager channels have started listening or
when the frontend is assigned an already listening KernelManager.
# 'FrontendWidget' public interface
def copy_raw(self):
""" Copy the currently selected text to the clipboard without attempting
to remove prompts or otherwise alter the text.
def execute_file(self, path, hidden=False):
""" Attempts to execute file with 'path'. If 'hidden', no output is
self.execute('execfile("%s")' % path, hidden=hidden)
def interrupt_kernel(self):
""" Attempts to interrupt the running kernel.
if self.custom_interrupt:
elif self.kernel_manager.has_kernel:
self._append_plain_text('Kernel process is either remote or '
'unspecified. Cannot interrupt.\n')
def reset(self):
""" Resets the widget to its initial state. Similar to ``clear``, but
also re-writes the banner and aborts execution if necessary.
if self._executing:
self._executing = False
self._request_info['execute'] = None
self._reading = False
self._highlighter.highlighting_on = False
def restart_kernel(self, message, now=False):
""" Attempts to restart the running kernel.
# FIXME: now should be configurable via a checkbox in the dialog. Right
# now at least the heartbeat path sets it to True and the manual restart
# to False. But those should just be the pre-selected states of a
# checkbox that the user could override if so desired. But I don't know
# enough Qt to go implementing the checkbox now.
if self.custom_restart:
elif self.kernel_manager.has_kernel:
# Pause the heart beat channel to prevent further warnings.
# Prompt the user to restart the kernel. Un-pause the heartbeat if
# they decline. (If they accept, the heartbeat will be un-paused
# automatically when the kernel is restarted.)
buttons = QtGui.QMessageBox.Yes | QtGui.QMessageBox.No
result = QtGui.QMessageBox.question(self, 'Restart kernel?',
message, buttons)
if result == QtGui.QMessageBox.Yes:
except RuntimeError:
self._append_plain_text('Kernel started externally. '
'Cannot restart.\n')
self._append_plain_text('Kernel process is either remote or '
'unspecified. Cannot restart.\n')
# 'FrontendWidget' protected interface
def _call_tip(self):
""" Shows a call tip, if appropriate, at the current cursor location.
# Decide if it makes sense to show a call tip
cursor = self._get_cursor()
if cursor.document().characterAt(cursor.position()).toAscii() != '(':
return False
context = self._get_context(cursor)
if not context:
return False
# Send the metadata request to the kernel
name = '.'.join(context)
msg_id = self.kernel_manager.xreq_channel.object_info(name)
pos = self._get_cursor().position()
self._request_info['call_tip'] = self._CallTipRequest(msg_id, pos)
return True
def _complete(self):
""" Performs completion at the current cursor location.
context = self._get_context()
if context:
# Send the completion request to the kernel
msg_id = self.kernel_manager.xreq_channel.complete(
'.'.join(context), # text
self._get_input_buffer_cursor_line(), # line
self._get_input_buffer_cursor_column(), # cursor_pos
self.input_buffer) # block
pos = self._get_cursor().position()
info = self._CompletionRequest(msg_id, pos)
self._request_info['complete'] = info
def _get_banner(self):
""" Gets a banner to display at the beginning of a session.
banner = 'Python %s on %s\nType "help", "copyright", "credits" or ' \
'"license" for more information.'
return banner % (sys.version, sys.platform)
def _get_context(self, cursor=None):
""" Gets the context for the specified cursor (or the current cursor
if none is specified).
if cursor is None:
cursor = self._get_cursor()
text = unicode(cursor.selection().toPlainText())
return self._completion_lexer.get_context(text)
def _process_execute_abort(self, msg):
""" Process a reply for an aborted execution request.
self._append_plain_text("ERROR: execution aborted\n")
def _process_execute_error(self, msg):
""" Process a reply for an execution request that resulted in an error.
content = msg['content']
traceback = ''.join(content['traceback'])
def _process_execute_ok(self, msg):
""" Process a reply for a successful execution equest.
payload = msg['content']['payload']
for item in payload:
if not self._process_execute_payload(item):
warning = 'Warning: received unknown payload of type %s'
print(warning % repr(item['source']))
def _process_execute_payload(self, item):
""" Process a single payload item from the list of payload items in an
execution reply. Returns whether the payload was handled.
# The basic FrontendWidget doesn't handle payloads, as they are a
# mechanism for going beyond the standard Python interpreter model.
return False
def _show_interpreter_prompt(self):
""" Shows a prompt for the interpreter.
self._show_prompt('>>> ')
def _show_interpreter_prompt_for_reply(self, msg):
""" Shows a prompt for the interpreter given an 'execute_reply' message.
#------ Signal handlers ----------------------------------------------------
def _document_contents_change(self, position, removed, added):
""" Called whenever the document's content changes. Display a call tip
if appropriate.
# Calculate where the cursor should be *after* the change:
position += added
document = self._control.document()
if position == self._get_cursor().position():
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