* Added support for prompt and history requests to the kernel manager and Qt console frontend.

* Updated message spec to be consistent with the IPython kernel implementation.

IPython/frontend/qt/console/console_widget.py

@@ -1,1279 +1,1290 b''
 # Standard library imports
 import re
 import sys
 from textwrap import dedent
 
 # System library imports
 from PyQt4 import QtCore, QtGui
 
 # Local imports
 from ansi_code_processor import QtAnsiCodeProcessor
 from completion_widget import CompletionWidget
 
 
 class ConsoleWidget(QtGui.QWidget):
     """ An abstract base class for console-type widgets. This class has 
         functionality for:
 
             * Maintaining a prompt and editing region
             * Providing the traditional Unix-style console keyboard shortcuts 
             * Performing tab completion
             * Paging text
             * Handling ANSI escape codes
 
         ConsoleWidget also provides a number of utility methods that will be
         convenient to implementors of a console-style widget.
     """
 
     # Whether to process ANSI escape codes.
     ansi_codes = True
 
     # The maximum number of lines of text before truncation.
     buffer_size = 500
 
     # Whether to use a list widget or plain text output for tab completion.
     gui_completion = True
 
     # Whether to override ShortcutEvents for the keybindings defined by this
     # widget (Ctrl+n, Ctrl+a, etc). Enable this if you want this widget to take
     # priority (when it has focus) over, e.g., window-level menu shortcuts.
     override_shortcuts = False
 
     # Signals that indicate ConsoleWidget state.
     copy_available = QtCore.pyqtSignal(bool)
     redo_available = QtCore.pyqtSignal(bool)
     undo_available = QtCore.pyqtSignal(bool)
 
     # Signal emitted when paging is needed and the paging style has been
     # specified as 'custom'.
     custom_page_requested = QtCore.pyqtSignal(object)
 
     # Protected class variables.
     _ctrl_down_remap = { QtCore.Qt.Key_B : QtCore.Qt.Key_Left,
                          QtCore.Qt.Key_F : QtCore.Qt.Key_Right,
                          QtCore.Qt.Key_A : QtCore.Qt.Key_Home,
                          QtCore.Qt.Key_E : QtCore.Qt.Key_End,
                          QtCore.Qt.Key_P : QtCore.Qt.Key_Up,
                          QtCore.Qt.Key_N : QtCore.Qt.Key_Down,
                          QtCore.Qt.Key_D : QtCore.Qt.Key_Delete, }
     _shortcuts = set(_ctrl_down_remap.keys() +
                      [ QtCore.Qt.Key_C, QtCore.Qt.Key_V ])
 
     #---------------------------------------------------------------------------
     # 'QObject' interface
     #---------------------------------------------------------------------------
 
     def __init__(self, kind='plain', paging='inside', parent=None):
         """ Create a ConsoleWidget.
         
         Parameters
         ----------
         kind : str, optional [default 'plain']            
             The type of underlying text widget to use. Valid values are 'plain',
             which specifies a QPlainTextEdit, and 'rich', which specifies a
             QTextEdit.
 
         paging : str, optional [default 'inside']
             The type of paging to use. Valid values are:
                 'inside' : The widget pages like a traditional terminal pager.
                 'hsplit' : When paging is requested, the widget is split 
                            horizontally. The top pane contains the console,
                            and the bottom pane contains the paged text.
                 'vsplit' : Similar to 'hsplit', except that a vertical splitter
                            used.
                 'custom' : No action is taken by the widget beyond emitting a
                            'custom_page_requested(str)' signal.
                 'none'   : The text is written directly to the console.
 
         parent : QWidget, optional [default None]
             The parent for this widget.
         """
         super(ConsoleWidget, self).__init__(parent)
 
         # Create the layout and underlying text widget.
         layout = QtGui.QStackedLayout(self)
         layout.setMargin(0)
         self._control = self._create_control(kind)
         self._page_control = None
         self._splitter = None
         if paging in ('hsplit', 'vsplit'):
             self._splitter = QtGui.QSplitter()
             if paging == 'hsplit':
                 self._splitter.setOrientation(QtCore.Qt.Horizontal)
             else:
                 self._splitter.setOrientation(QtCore.Qt.Vertical)
             self._splitter.addWidget(self._control)
             layout.addWidget(self._splitter)
         else:
             layout.addWidget(self._control)
 
         # Create the paging widget, if necessary.
         self._page_style = paging
         if paging in ('inside', 'hsplit', 'vsplit'):
             self._page_control = self._create_page_control()
             if self._splitter:
                 self._page_control.hide()
                 self._splitter.addWidget(self._page_control)
             else:
                 layout.addWidget(self._page_control)
         elif paging not in ('custom', 'none'):
             raise ValueError('Paging style %s unknown.' % repr(paging))
 
         # Initialize protected variables. Some variables contain useful state
         # information for subclasses; they should be considered read-only.
         self._ansi_processor = QtAnsiCodeProcessor()
         self._completion_widget = CompletionWidget(self._control)
         self._continuation_prompt = '> '
         self._continuation_prompt_html = None
         self._executing = False
         self._prompt = ''
         self._prompt_html = None
         self._prompt_pos = 0
         self._reading = False
         self._reading_callback = None
         self._tab_width = 8
 
         # Set a monospaced font.
         self.reset_font()
 
     def eventFilter(self, obj, event):
         """ Reimplemented to ensure a console-like behavior in the underlying
             text widget.
         """
         # Re-map keys for all filtered widgets.
         etype = event.type()
         if etype == QtCore.QEvent.KeyPress and \
                 self._control_key_down(event.modifiers()) and \
                 event.key() in self._ctrl_down_remap:
             new_event = QtGui.QKeyEvent(QtCore.QEvent.KeyPress, 
                                         self._ctrl_down_remap[event.key()],
                                         QtCore.Qt.NoModifier)
             QtGui.qApp.sendEvent(obj, new_event)
             return True
 
         # Override shortucts for all filtered widgets. Note that on Mac OS it is
         # always unnecessary to override shortcuts, hence the check below (users
         # should just use the Control key instead of the Command key).
         elif etype == QtCore.QEvent.ShortcutOverride and \
                 sys.platform != 'darwin' and \
                 self._control_key_down(event.modifiers()) and \
                 event.key() in self._shortcuts:
             event.accept()
             return False
 
         elif obj == self._control:
             # Disable moving text by drag and drop.
             if etype == QtCore.QEvent.DragMove:
                 return True
 
             elif etype == QtCore.QEvent.KeyPress:
                 return self._event_filter_console_keypress(event)
 
         elif obj == self._page_control:
             if etype == QtCore.QEvent.KeyPress:
                 return self._event_filter_page_keypress(event)
 
         return super(ConsoleWidget, self).eventFilter(obj, event)
 
     #---------------------------------------------------------------------------
     # 'QWidget' interface
     #---------------------------------------------------------------------------
 
     def sizeHint(self):
         """ Reimplemented to suggest a size that is 80 characters wide and
             25 lines high.
         """
         style = self.style()
         opt = QtGui.QStyleOptionHeader()
         font_metrics = QtGui.QFontMetrics(self.font)
         splitwidth = style.pixelMetric(QtGui.QStyle.PM_SplitterWidth, opt, self)
 
         width = font_metrics.width(' ') * 80
         width += style.pixelMetric(QtGui.QStyle.PM_ScrollBarExtent, opt, self)
         if self._page_style == 'hsplit':
             width = width * 2 + splitwidth
 
         height = font_metrics.height() * 25
         if self._page_style == 'vsplit':
             height = height * 2 + splitwidth
 
         return QtCore.QSize(width, height)
 
     #---------------------------------------------------------------------------
     # 'ConsoleWidget' public interface
     #---------------------------------------------------------------------------
 
     def can_paste(self):
         """ Returns whether text can be pasted from the clipboard.
         """
         # Accept only text that can be ASCII encoded.
         if self._control.textInteractionFlags() & QtCore.Qt.TextEditable:
             text = QtGui.QApplication.clipboard().text()
             if not text.isEmpty():
                 try:
                     str(text)
                     return True
                 except UnicodeEncodeError:
                     pass
         return False
 
     def clear(self, keep_input=True):
         """ Clear the console, then write a new prompt. If 'keep_input' is set,
             restores the old input buffer when the new prompt is written.
         """
         if keep_input:
             input_buffer = self.input_buffer
         self._control.clear()
         self._show_prompt()
         if keep_input:
             self.input_buffer = input_buffer
 
     def copy(self):
         """ Copy the current selected text to the clipboard.
         """
         self._control.copy()
 
     def execute(self, source=None, hidden=False, interactive=False):
         """ Executes source or the input buffer, possibly prompting for more
         input.
 
         Parameters:
         -----------     
         source : str, optional
 
             The source to execute. If not specified, the input buffer will be
             used. If specified and 'hidden' is False, the input buffer will be
             replaced with the source before execution.
 
         hidden : bool, optional (default False)
 
             If set, no output will be shown and the prompt will not be modified.
             In other words, it will be completely invisible to the user that
             an execution has occurred.
 
         interactive : bool, optional (default False)
 
             Whether the console is to treat the source as having been manually
             entered by the user. The effect of this parameter depends on the
             subclass implementation.
 
         Raises:
         -------
         RuntimeError
             If incomplete input is given and 'hidden' is True. In this case,
             it is not possible to prompt for more input.
 
         Returns:
         --------
         A boolean indicating whether the source was executed.
         """
         if not hidden:
             if source is not None:
                 self.input_buffer = source
 
             self._append_plain_text('\n')
             self._executing_input_buffer = self.input_buffer
             self._executing = True
             self._prompt_finished()
 
         real_source = self.input_buffer if source is None else source
         complete = self._is_complete(real_source, interactive)
         if complete:
             if not hidden:
                 # The maximum block count is only in effect during execution.
                 # This ensures that _prompt_pos does not become invalid due to
                 # text truncation.
                 self._control.document().setMaximumBlockCount(self.buffer_size)
             self._execute(real_source, hidden)
         elif hidden:
             raise RuntimeError('Incomplete noninteractive input: "%s"' % source)
         else:
             self._show_continuation_prompt()
 
         return complete
 
     def _get_input_buffer(self):
         """ The text that the user has entered entered at the current prompt.
         """
         # If we're executing, the input buffer may not even exist anymore due to
         # the limit imposed by 'buffer_size'. Therefore, we store it.
         if self._executing:
             return self._executing_input_buffer
 
         cursor = self._get_end_cursor()
         cursor.setPosition(self._prompt_pos, QtGui.QTextCursor.KeepAnchor)
         input_buffer = str(cursor.selection().toPlainText())
 
         # Strip out continuation prompts.
         return input_buffer.replace('\n' + self._continuation_prompt, '\n')
 
     def _set_input_buffer(self, string):
         """ Replaces the text in the input buffer with 'string'.
         """
         # For now, it is an error to modify the input buffer during execution.
         if self._executing:
             raise RuntimeError("Cannot change input buffer during execution.")
 
         # Remove old text.
         cursor = self._get_end_cursor()
         cursor.beginEditBlock()
         cursor.setPosition(self._prompt_pos, QtGui.QTextCursor.KeepAnchor)
         cursor.removeSelectedText()
 
         # Insert new text with continuation prompts.
         lines = string.splitlines(True)
         if lines:
             self._append_plain_text(lines[0])
             for i in xrange(1, len(lines)):
                 if self._continuation_prompt_html is None:
                     self._append_plain_text(self._continuation_prompt)
                 else:
                     self._append_html(self._continuation_prompt_html)
                 self._append_plain_text(lines[i])
         cursor.endEditBlock()
         self._control.moveCursor(QtGui.QTextCursor.End)
 
     input_buffer = property(_get_input_buffer, _set_input_buffer)
 
     def _get_font(self):
         """ The base font being used by the ConsoleWidget.
         """
         return self._control.document().defaultFont()
 
     def _set_font(self, font):
         """ Sets the base font for the ConsoleWidget to the specified QFont.
         """
         font_metrics = QtGui.QFontMetrics(font)
         self._control.setTabStopWidth(self.tab_width * font_metrics.width(' '))
 
         self._completion_widget.setFont(font)
         self._control.document().setDefaultFont(font)
         if self._page_control:
             self._page_control.document().setDefaultFont(font)
 
     font = property(_get_font, _set_font)
 
     def paste(self):
         """ Paste the contents of the clipboard into the input region.
         """
         if self._control.textInteractionFlags() & QtCore.Qt.TextEditable:
             try:
                 text = str(QtGui.QApplication.clipboard().text())
             except UnicodeEncodeError:
                 pass
             else:
                 self._insert_plain_text_into_buffer(dedent(text))
 
     def print_(self, printer):
         """ Print the contents of the ConsoleWidget to the specified QPrinter.
         """
         self._control.print_(printer)
 
     def redo(self):
         """ Redo the last operation. If there is no operation to redo, nothing
             happens.
         """
         self._control.redo()
 
     def reset_font(self):
         """ Sets the font to the default fixed-width font for this platform.
         """
         if sys.platform == 'win32':
             name = 'Courier'
         elif sys.platform == 'darwin':
             name = 'Monaco'
         else:
             name = 'Monospace'
         font = QtGui.QFont(name, QtGui.qApp.font().pointSize())
         font.setStyleHint(QtGui.QFont.TypeWriter)
         self._set_font(font)
 
     def select_all(self):
         """ Selects all the text in the buffer.
         """
         self._control.selectAll()
 
     def _get_tab_width(self):
         """ The width (in terms of space characters) for tab characters.
         """
         return self._tab_width
 
     def _set_tab_width(self, tab_width):
         """ Sets the width (in terms of space characters) for tab characters.
         """
         font_metrics = QtGui.QFontMetrics(self.font)
         self._control.setTabStopWidth(tab_width * font_metrics.width(' '))
 
         self._tab_width = tab_width
 
     tab_width = property(_get_tab_width, _set_tab_width)
 
     def undo(self):
         """ Undo the last operation. If there is no operation to undo, nothing
             happens.
         """
         self._control.undo()
 
     #---------------------------------------------------------------------------
     # 'ConsoleWidget' abstract interface
     #---------------------------------------------------------------------------
 
     def _is_complete(self, source, interactive):
         """ Returns whether 'source' can be executed. When triggered by an
             Enter/Return key press, 'interactive' is True; otherwise, it is
             False.
         """
         raise NotImplementedError
 
     def _execute(self, source, hidden):
         """ Execute 'source'. If 'hidden', do not show any output.
         """
         raise NotImplementedError
 
     def _execute_interrupt(self):
         """ Attempts to stop execution. Returns whether this method has an
             implementation.
         """
         return False
 
     def _prompt_started_hook(self):
         """ Called immediately after a new prompt is displayed.
         """
         pass
 
     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.
         """
         pass
 
     def _up_pressed(self):
         """ Called when the up key is pressed. Returns whether to continue
             processing the event.
         """
         return True
 
     def _down_pressed(self):
         """ Called when the down key is pressed. Returns whether to continue
             processing the event.
         """
         return True
 
     def _tab_pressed(self):
         """ Called when the tab key is pressed. Returns whether to continue
             processing the event.
         """
         return False
 
     #--------------------------------------------------------------------------
     # 'ConsoleWidget' protected interface
     #--------------------------------------------------------------------------
 
     def _append_html(self, html):
         """ Appends html at the end of the console buffer.
         """
         cursor = self._get_end_cursor()
         self._insert_html(cursor, html)
 
     def _append_html_fetching_plain_text(self, html):
         """ Appends 'html', then returns the plain text version of it.
         """
         cursor = self._get_end_cursor()
         return self._insert_html_fetching_plain_text(cursor, html)
 
     def _append_plain_text(self, text):
         """ Appends plain text at the end of the console buffer, processing
             ANSI codes if enabled.
         """
         cursor = self._get_end_cursor()
         self._insert_plain_text(cursor, text)
 
     def _append_plain_text_keeping_prompt(self, text):
         """ Writes 'text' after the current prompt, then restores the old prompt
             with its old input buffer.
         """
         input_buffer = self.input_buffer
         self._append_plain_text('\n')
         self._prompt_finished()
 
         self._append_plain_text(text)
         self._show_prompt()
         self.input_buffer = input_buffer
 
     def _complete_with_items(self, cursor, items):
         """ Performs completion with 'items' at the specified cursor location.
         """
         if len(items) == 1:
             cursor.setPosition(self._control.textCursor().position(), 
                                QtGui.QTextCursor.KeepAnchor)
             cursor.insertText(items[0])
         elif len(items) > 1:
             if self.gui_completion:
                 self._completion_widget.show_items(cursor, items) 
             else:
                 text = self._format_as_columns(items)
                 self._append_plain_text_keeping_prompt(text)
 
     def _control_key_down(self, modifiers):
         """ Given a KeyboardModifiers flags object, return whether the Control
             key is down (on Mac OS, treat the Command key as a synonym for
             Control).
         """
         down = bool(modifiers & QtCore.Qt.ControlModifier)
 
         # Note: on Mac OS, ControlModifier corresponds to the Command key while
         # MetaModifier corresponds to the Control key.
         if sys.platform == 'darwin':
             down = down ^ bool(modifiers & QtCore.Qt.MetaModifier)
             
         return down
 
     def _create_control(self, kind):
         """ Creates and connects the underlying text widget.
         """
         if kind == 'plain':
             control = QtGui.QPlainTextEdit()
         elif kind == 'rich':
             control = QtGui.QTextEdit()
             control.setAcceptRichText(False)
         else:
             raise ValueError("Kind %s unknown." % repr(kind))
         control.installEventFilter(self)
         control.setContextMenuPolicy(QtCore.Qt.CustomContextMenu)
         control.customContextMenuRequested.connect(self._show_context_menu)
         control.copyAvailable.connect(self.copy_available)
         control.redoAvailable.connect(self.redo_available)
         control.undoAvailable.connect(self.undo_available)
+        control.setReadOnly(True)
         control.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn)
         return control
 
     def _create_page_control(self):
         """ Creates and connects the underlying paging widget.
         """
         control = QtGui.QPlainTextEdit()
         control.installEventFilter(self)
         control.setReadOnly(True)
         control.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn)
         return control
 
     def _event_filter_console_keypress(self, event):
         """ Filter key events for the underlying text widget to create a
             console-like interface.
         """
         intercepted = False
         cursor = self._control.textCursor()
         position = cursor.position()
         key = event.key()
         ctrl_down = self._control_key_down(event.modifiers())
         alt_down = event.modifiers() & QtCore.Qt.AltModifier
         shift_down = event.modifiers() & QtCore.Qt.ShiftModifier
 
         if event.matches(QtGui.QKeySequence.Paste):
             # Call our paste instead of the underlying text widget's.
             self.paste()
             intercepted = True
 
         elif ctrl_down:
             if key == QtCore.Qt.Key_C:
                 intercepted = self._executing and self._execute_interrupt()
 
             elif key == QtCore.Qt.Key_K:
                 if self._in_buffer(position):
                     cursor.movePosition(QtGui.QTextCursor.EndOfLine,
                                         QtGui.QTextCursor.KeepAnchor)
                     cursor.removeSelectedText()
                 intercepted = True
 
             elif key == QtCore.Qt.Key_X:
                 intercepted = True
 
             elif key == QtCore.Qt.Key_Y:
                 self.paste()
                 intercepted = True
 
         elif alt_down:
             if key == QtCore.Qt.Key_B:
                 self._set_cursor(self._get_word_start_cursor(position))
                 intercepted = True
                 
             elif key == QtCore.Qt.Key_F:
                 self._set_cursor(self._get_word_end_cursor(position))
                 intercepted = True
 
             elif key == QtCore.Qt.Key_Backspace:
                 cursor = self._get_word_start_cursor(position)
                 cursor.setPosition(position, QtGui.QTextCursor.KeepAnchor)
                 cursor.removeSelectedText()
                 intercepted = True
 
             elif key == QtCore.Qt.Key_D:
                 cursor = self._get_word_end_cursor(position)
                 cursor.setPosition(position, QtGui.QTextCursor.KeepAnchor)
                 cursor.removeSelectedText()
                 intercepted = True
 
         else:
             if key in (QtCore.Qt.Key_Return, QtCore.Qt.Key_Enter):
                 if self._reading:
                     self._append_plain_text('\n')
                     self._reading = False
                     if self._reading_callback:
                         self._reading_callback()
                 elif not self._executing:
                     self.execute(interactive=True)
                 intercepted = True
 
             elif key == QtCore.Qt.Key_Up:
                 if self._reading or not self._up_pressed():
                     intercepted = True
                 else:
                     prompt_line = self._get_prompt_cursor().blockNumber()
                     intercepted = cursor.blockNumber() <= prompt_line
 
             elif key == QtCore.Qt.Key_Down:
                 if self._reading or not self._down_pressed():
                     intercepted = True
                 else:
                     end_line = self._get_end_cursor().blockNumber()
                     intercepted = cursor.blockNumber() == end_line
 
             elif key == QtCore.Qt.Key_Tab:
                 if self._reading:
                     intercepted = False
                 else:
                     intercepted = not self._tab_pressed()
 
             elif key == QtCore.Qt.Key_Left:
                 intercepted = not self._in_buffer(position - 1)
 
             elif key == QtCore.Qt.Key_Home:
                 cursor.movePosition(QtGui.QTextCursor.StartOfBlock)
                 start_line = cursor.blockNumber()
                 if start_line == self._get_prompt_cursor().blockNumber():
                     start_pos = self._prompt_pos
                 else:
                     start_pos = cursor.position()
                     start_pos += len(self._continuation_prompt)
                 if shift_down and self._in_buffer(position):
                     self._set_selection(position, start_pos)
                 else:
                     self._set_position(start_pos)
                 intercepted = True
 
             elif key == QtCore.Qt.Key_Backspace:
 
                 # Line deletion (remove continuation prompt)
                 len_prompt = len(self._continuation_prompt)
                 if not self._reading and \
                         cursor.columnNumber() == len_prompt and \
                         position != self._prompt_pos:
                     cursor.movePosition(QtGui.QTextCursor.StartOfBlock,
                                         QtGui.QTextCursor.KeepAnchor)
                     cursor.removeSelectedText()
                     cursor.deletePreviousChar()
                     intercepted = True
 
                 # Regular backwards deletion
                 else:
                     anchor = cursor.anchor()
                     if anchor == position:
                         intercepted = not self._in_buffer(position - 1)
                     else:
                         intercepted = not self._in_buffer(min(anchor, position))
 
             elif key == QtCore.Qt.Key_Delete:
                 anchor = cursor.anchor()
                 intercepted = not self._in_buffer(min(anchor, position))
 
         # Don't move the cursor if control is down to allow copy-paste using
         # the keyboard in any part of the buffer.
         if not ctrl_down:
             self._keep_cursor_in_buffer()
 
         return intercepted
 
     def _event_filter_page_keypress(self, event):
         """ Filter key events for the paging widget to create console-like 
             interface.
         """
         key = event.key()
 
         if key in (QtCore.Qt.Key_Q, QtCore.Qt.Key_Escape):
             if self._splitter:
                 self._page_control.hide()
             else:
                 self.layout().setCurrentWidget(self._control)
             return True
 
         elif key in (QtCore.Qt.Key_Enter, QtCore.Qt.Key_Return):
             new_event = QtGui.QKeyEvent(QtCore.QEvent.KeyPress, 
                                         QtCore.Qt.Key_Down, 
                                         QtCore.Qt.NoModifier)
             QtGui.qApp.sendEvent(self._page_control, new_event)
             return True
 
         return False
 
     def _format_as_columns(self, items, separator='  '):
         """ Transform a list of strings into a single string with columns.
 
         Parameters
         ----------
         items : sequence of strings
             The strings to process.
 
         separator : str, optional [default is two spaces]
             The string that separates columns.
 
         Returns
         -------
         The formatted string.
         """
         # Note: this code is adapted from columnize 0.3.2.
         # See http://code.google.com/p/pycolumnize/
 
         width = self._control.viewport().width()
         char_width = QtGui.QFontMetrics(self.font).width(' ')
         displaywidth = max(5, width / char_width)
 
         # Some degenerate cases.
         size = len(items)
         if size == 0: 
             return '\n'
         elif size == 1:
             return '%s\n' % str(items[0])
 
         # Try every row count from 1 upwards
         array_index = lambda nrows, row, col: nrows*col + row
         for nrows in range(1, size):
             ncols = (size + nrows - 1) // nrows
             colwidths = []
             totwidth = -len(separator)
             for col in range(ncols):
                 # Get max column width for this column
                 colwidth = 0
                 for row in range(nrows):
                     i = array_index(nrows, row, col)
                     if i >= size: break
                     x = items[i]
                     colwidth = max(colwidth, len(x))
                 colwidths.append(colwidth)
                 totwidth += colwidth + len(separator)
                 if totwidth > displaywidth: 
                     break
             if totwidth <= displaywidth: 
                 break
 
         # The smallest number of rows computed and the max widths for each
         # column has been obtained. Now we just have to format each of the rows.
         string = ''
         for row in range(nrows):
             texts = []
             for col in range(ncols):
                 i = row + nrows*col
                 if i >= size:
                     texts.append('')
                 else:
                     texts.append(items[i])
             while texts and not texts[-1]:
                 del texts[-1]
             for col in range(len(texts)):
                 texts[col] = texts[col].ljust(colwidths[col])
             string += '%s\n' % str(separator.join(texts))
         return string
 
     def _get_block_plain_text(self, block):
         """ Given a QTextBlock, return its unformatted text.
         """
         cursor = QtGui.QTextCursor(block)
         cursor.movePosition(QtGui.QTextCursor.StartOfBlock)
         cursor.movePosition(QtGui.QTextCursor.EndOfBlock, 
                             QtGui.QTextCursor.KeepAnchor)
         return str(cursor.selection().toPlainText())
 
     def _get_cursor(self):
         """ Convenience method that returns a cursor for the current position.
         """
         return self._control.textCursor()
                 
     def _get_end_cursor(self):
         """ Convenience method that returns a cursor for the last character.
         """
         cursor = self._control.textCursor()
         cursor.movePosition(QtGui.QTextCursor.End)
         return cursor
 
     def _get_input_buffer_cursor_column(self):
         """ Returns the column of the cursor in the input buffer, excluding the
             contribution by the prompt, or -1 if there is no such column.
         """
         prompt = self._get_input_buffer_cursor_prompt()
         if prompt is None:
             return -1
         else:
             cursor = self._control.textCursor()
             return cursor.columnNumber() - len(prompt)
 
     def _get_input_buffer_cursor_line(self):
         """ Returns line of the input buffer that contains the cursor, or None
             if there is no such line.
         """
         prompt = self._get_input_buffer_cursor_prompt()
         if prompt is None:
             return None
         else:
             cursor = self._control.textCursor()
             text = self._get_block_plain_text(cursor.block())
             return text[len(prompt):]
 
     def _get_input_buffer_cursor_prompt(self):
         """ Returns the (plain text) prompt for line of the input buffer that
             contains the cursor, or None if there is no such line.
         """
         if self._executing:
             return None
         cursor = self._control.textCursor()
         if cursor.position() >= self._prompt_pos:
             if cursor.blockNumber() == self._get_prompt_cursor().blockNumber():
                 return self._prompt
             else:
                 return self._continuation_prompt
         else:
             return None
 
     def _get_prompt_cursor(self):
         """ Convenience method that returns a cursor for the prompt position.
         """
         cursor = self._control.textCursor()
         cursor.setPosition(self._prompt_pos)
         return cursor
 
     def _get_selection_cursor(self, start, end):
         """ Convenience method that returns a cursor with text selected between
             the positions 'start' and 'end'.
         """
         cursor = self._control.textCursor()
         cursor.setPosition(start)
         cursor.setPosition(end, QtGui.QTextCursor.KeepAnchor)
         return cursor
 
     def _get_word_start_cursor(self, position):
         """ Find the start of the word to the left the given position. If a
             sequence of non-word characters precedes the first word, skip over
             them. (This emulates the behavior of bash, emacs, etc.)
         """
         document = self._control.document()
         position -= 1
         while position >= self._prompt_pos and \
                 not document.characterAt(position).isLetterOrNumber():
             position -= 1
         while position >= self._prompt_pos and \
                 document.characterAt(position).isLetterOrNumber():
             position -= 1
         cursor = self._control.textCursor()
         cursor.setPosition(position + 1)
         return cursor
 
     def _get_word_end_cursor(self, position):
         """ Find the end of the word to the right the given position. If a
             sequence of non-word characters precedes the first word, skip over
             them. (This emulates the behavior of bash, emacs, etc.)
         """
         document = self._control.document()
         end = self._get_end_cursor().position()
         while position < end and \
                 not document.characterAt(position).isLetterOrNumber():
             position += 1
         while position < end and \
                 document.characterAt(position).isLetterOrNumber():
             position += 1
         cursor = self._control.textCursor()
         cursor.setPosition(position)
         return cursor
 
     def _insert_html(self, cursor, html):
         """ Inserts HTML using the specified cursor in such a way that future
             formatting is unaffected.
         """
         cursor.beginEditBlock()
         cursor.insertHtml(html)
 
         # After inserting HTML, the text document "remembers" it's in "html
         # mode", which means that subsequent calls adding plain text will result
         # in unwanted formatting, lost tab characters, etc. The following code
         # hacks around this behavior, which I consider to be a bug in Qt, by
         # (crudely) resetting the document's style state.
         cursor.movePosition(QtGui.QTextCursor.Left,
                             QtGui.QTextCursor.KeepAnchor)
         if cursor.selection().toPlainText() == ' ':
             cursor.removeSelectedText()
         else:
             cursor.movePosition(QtGui.QTextCursor.Right)
         cursor.insertText(' ', QtGui.QTextCharFormat())
         cursor.endEditBlock()
 
     def _insert_html_fetching_plain_text(self, cursor, html):
         """ Inserts HTML using the specified cursor, then returns its plain text
             version.
         """
         cursor.beginEditBlock()
         cursor.removeSelectedText()
 
         start = cursor.position()
         self._insert_html(cursor, html)
         end = cursor.position()
         cursor.setPosition(start, QtGui.QTextCursor.KeepAnchor)
         text = str(cursor.selection().toPlainText())
 
         cursor.setPosition(end)
         cursor.endEditBlock()
         return text
 
     def _insert_plain_text(self, cursor, text):
         """ Inserts plain text using the specified cursor, processing ANSI codes
             if enabled.
         """
         cursor.beginEditBlock()
         if self.ansi_codes:
             for substring in self._ansi_processor.split_string(text):
                 for action in self._ansi_processor.actions:
                     if action.kind == 'erase' and action.area == 'screen':
                         cursor.select(QtGui.QTextCursor.Document)
                         cursor.removeSelectedText()
                 format = self._ansi_processor.get_format()
                 cursor.insertText(substring, format)
         else:
             cursor.insertText(text)
         cursor.endEditBlock()
 
     def _insert_plain_text_into_buffer(self, text):
         """ Inserts text into the input buffer at the current cursor position,
             ensuring that continuation prompts are inserted as necessary.
         """
         lines = str(text).splitlines(True)
         if lines:
             self._keep_cursor_in_buffer()
             cursor = self._control.textCursor()
             cursor.beginEditBlock()
             cursor.insertText(lines[0])
             for line in lines[1:]:
                 if self._continuation_prompt_html is None:
                     cursor.insertText(self._continuation_prompt)
                 else:
                     self._continuation_prompt = \
                         self._insert_html_fetching_plain_text(
                             cursor, self._continuation_prompt_html)
                 cursor.insertText(line)
             cursor.endEditBlock()
             self._control.setTextCursor(cursor)
 
     def _in_buffer(self, position):
         """ Returns whether the given position is inside the editing region.
         """
         cursor = self._control.textCursor()
         cursor.setPosition(position)
         line = cursor.blockNumber()
         prompt_line = self._get_prompt_cursor().blockNumber()
         if line == prompt_line:
             return position >= self._prompt_pos
         elif line > prompt_line:
             cursor.movePosition(QtGui.QTextCursor.StartOfBlock)
             prompt_pos = cursor.position() + len(self._continuation_prompt)
             return position >= prompt_pos
         return False
 
     def _keep_cursor_in_buffer(self):
         """ Ensures that the cursor is inside the editing region. Returns
             whether the cursor was moved.
         """
         cursor = self._control.textCursor()
         if self._in_buffer(cursor.position()):
             return False
         else:
             cursor.movePosition(QtGui.QTextCursor.End)
             self._control.setTextCursor(cursor)
             return True
         
     def _page(self, text):
         """ Displays text using the pager if it exceeds the height of the
             visible area.
         """
         if self._page_style == 'none':
             self._append_plain_text(text)
         else:
             line_height = QtGui.QFontMetrics(self.font).height()
             minlines = self._control.viewport().height() / line_height
             if re.match("(?:[^\n]*\n){%i}" % minlines, text):
                 if self._page_style == 'custom':
                     self.custom_page_requested.emit(text)
                 else:
                     self._page_control.clear()
                     cursor = self._page_control.textCursor()
                     self._insert_plain_text(cursor, text)
                     self._page_control.moveCursor(QtGui.QTextCursor.Start)
 
                     self._page_control.viewport().resize(self._control.size())
                     if self._splitter:
                         self._page_control.show()
                         self._page_control.setFocus()
                     else:
                         self.layout().setCurrentWidget(self._page_control)
             else:
                 self._append_plain_text(text)
 
     def _prompt_started(self):
         """ Called immediately after a new prompt is displayed.
         """
         # Temporarily disable the maximum block count to permit undo/redo and 
         # to ensure that the prompt position does not change due to truncation.
         self._control.document().setMaximumBlockCount(0)
         self._control.setUndoRedoEnabled(True)
 
         self._control.setReadOnly(False)
         self._control.moveCursor(QtGui.QTextCursor.End)
 
         self._executing = False
         self._prompt_started_hook()
 
     def _prompt_finished(self):
         """ Called immediately after a prompt is finished, i.e. when some input
             will be processed and a new prompt displayed.
         """
         self._control.setUndoRedoEnabled(False)
         self._control.setReadOnly(True)
         self._prompt_finished_hook()
 
     def _readline(self, prompt='', callback=None):
         """ Reads one line of input from the user. 
 
         Parameters
         ----------
         prompt : str, optional
             The prompt to print before reading the line.
 
         callback : callable, optional
             A callback to execute with the read line. If not specified, input is
             read *synchronously* and this method does not return until it has
             been read.
 
         Returns
         -------
         If a callback is specified, returns nothing. Otherwise, returns the
         input string with the trailing newline stripped.
         """
         if self._reading:
             raise RuntimeError('Cannot read a line. Widget is already reading.')
 
         if not callback and not self.isVisible():
             # If the user cannot see the widget, this function cannot return.
             raise RuntimeError('Cannot synchronously read a line if the widget'
                                'is not visible!')
 
         self._reading = True
         self._show_prompt(prompt, newline=False)
 
         if callback is None:
             self._reading_callback = None
             while self._reading:
                 QtCore.QCoreApplication.processEvents()
             return self.input_buffer.rstrip('\n')
 
         else:
             self._reading_callback = lambda: \
                 callback(self.input_buffer.rstrip('\n'))
 
     def _set_continuation_prompt(self, prompt, html=False):
         """ Sets the continuation prompt.
 
         Parameters
         ----------
         prompt : str
             The prompt to show when more input is needed.
 
         html : bool, optional (default False)
             If set, the prompt will be inserted as formatted HTML. Otherwise,
             the prompt will be treated as plain text, though ANSI color codes
             will be handled.
         """
         if html:
             self._continuation_prompt_html = prompt
         else:
             self._continuation_prompt = prompt
             self._continuation_prompt_html = None
             
     def _set_cursor(self, cursor):
         """ Convenience method to set the current cursor.
         """
         self._control.setTextCursor(cursor)
 
     def _set_position(self, position):
         """ Convenience method to set the position of the cursor.
         """
         cursor = self._control.textCursor()
         cursor.setPosition(position)
         self._control.setTextCursor(cursor)
 
     def _set_selection(self, start, end):
         """ Convenience method to set the current selected text.
         """
         self._control.setTextCursor(self._get_selection_cursor(start, end))
 
     def _show_context_menu(self, pos):
         """ Shows a context menu at the given QPoint (in widget coordinates).
         """
         menu = QtGui.QMenu()
 
         copy_action = menu.addAction('Copy', self.copy)
         copy_action.setEnabled(self._get_cursor().hasSelection())
         copy_action.setShortcut(QtGui.QKeySequence.Copy)
 
         paste_action = menu.addAction('Paste', self.paste)
         paste_action.setEnabled(self.can_paste())
         paste_action.setShortcut(QtGui.QKeySequence.Paste)
 
         menu.addSeparator()
         menu.addAction('Select All', self.select_all)
 
         menu.exec_(self._control.mapToGlobal(pos))
 
     def _show_prompt(self, prompt=None, html=False, newline=True):
         """ Writes a new prompt at the end of the buffer.
 
         Parameters
         ----------
         prompt : str, optional
             The prompt to show. If not specified, the previous prompt is used.
 
         html : bool, optional (default False)
             Only relevant when a prompt is specified. If set, the prompt will
             be inserted as formatted HTML. Otherwise, the prompt will be treated
             as plain text, though ANSI color codes will be handled.
 
         newline : bool, optional (default True)
             If set, a new line will be written before showing the prompt if 
             there is not already a newline at the end of the buffer.
         """
         # Insert a preliminary newline, if necessary.
         if newline:
             cursor = self._get_end_cursor()
             if cursor.position() > 0:
                 cursor.movePosition(QtGui.QTextCursor.Left, 
                                     QtGui.QTextCursor.KeepAnchor)
                 if str(cursor.selection().toPlainText()) != '\n':
                     self._append_plain_text('\n')
 
         # Write the prompt.
         if prompt is None:
             if self._prompt_html is None:
                 self._append_plain_text(self._prompt)
             else:
                 self._append_html(self._prompt_html)
         else:
             if html:
                 self._prompt = self._append_html_fetching_plain_text(prompt)
                 self._prompt_html = prompt
             else:
                 self._append_plain_text(prompt)
                 self._prompt = prompt
                 self._prompt_html = None
 
         self._prompt_pos = self._get_end_cursor().position()
         self._prompt_started()
 
     def _show_continuation_prompt(self):
         """ Writes a new continuation prompt at the end of the buffer.
         """
         if self._continuation_prompt_html is None:
             self._append_plain_text(self._continuation_prompt)
         else:
             self._continuation_prompt = self._append_html_fetching_plain_text(
                 self._continuation_prompt_html)
 
         self._prompt_started()
 
 
 class HistoryConsoleWidget(ConsoleWidget):
     """ A ConsoleWidget that keeps a history of the commands that have been
         executed.
     """
     
     #---------------------------------------------------------------------------
     # 'object' interface
     #---------------------------------------------------------------------------
 
     def __init__(self, *args, **kw):
         super(HistoryConsoleWidget, self).__init__(*args, **kw)
         self._history = []
         self._history_index = 0
 
     #---------------------------------------------------------------------------
     # 'ConsoleWidget' public interface
     #---------------------------------------------------------------------------
 
     def execute(self, source=None, hidden=False, interactive=False):
         """ Reimplemented to the store history.
         """
         if not hidden:
             history = self.input_buffer if source is None else source
 
         executed = super(HistoryConsoleWidget, self).execute(
             source, hidden, interactive)
 
         if executed and not hidden:
             self._history.append(history.rstrip())
             self._history_index = len(self._history)
 
         return executed
 
     #---------------------------------------------------------------------------
     # 'ConsoleWidget' abstract interface
     #---------------------------------------------------------------------------
 
     def _up_pressed(self):
         """ Called when the up key is pressed. Returns whether to continue
             processing the event.
         """
         prompt_cursor = self._get_prompt_cursor()
         if self._get_cursor().blockNumber() == prompt_cursor.blockNumber():
             self.history_previous()
 
             # Go to the first line of prompt for seemless history scrolling.
             cursor = self._get_prompt_cursor()
             cursor.movePosition(QtGui.QTextCursor.EndOfLine)
             self._set_cursor(cursor)
 
             return False
         return True
 
     def _down_pressed(self):
         """ Called when the down key is pressed. Returns whether to continue
             processing the event.
         """
         end_cursor = self._get_end_cursor()
         if self._get_cursor().blockNumber() == end_cursor.blockNumber():
             self.history_next()
             return False
         return True
 
     #---------------------------------------------------------------------------
-    # 'HistoryConsoleWidget' interface
+    # 'HistoryConsoleWidget' public interface
     #---------------------------------------------------------------------------
 
     def history_previous(self):
         """ If possible, set the input buffer to the previous item in the
             history.
         """
         if self._history_index > 0:
             self._history_index -= 1
             self.input_buffer = self._history[self._history_index]
 
     def history_next(self):
         """ Set the input buffer to the next item in the history, or a blank
             line if there is no subsequent item.
         """
         if self._history_index < len(self._history):
             self._history_index += 1
             if self._history_index < len(self._history):
                 self.input_buffer = self._history[self._history_index]
             else:
                 self.input_buffer = ''
+
+    #---------------------------------------------------------------------------
+    # 'HistoryConsoleWidget' protected interface
+    #---------------------------------------------------------------------------
+
+    def _set_history(self, history):
+        """ Replace the current history with a sequence of history items.
+        """
+        self._history = list(history)
+        self._history_index = len(self._history)

IPython/frontend/qt/console/frontend_widget.py

@@ -1,379 +1,379 b''
 # Standard library imports
 import signal
 import sys
 
 # System library imports
 from pygments.lexers import PythonLexer
 from PyQt4 import QtCore, QtGui
 import zmq
 
 # Local imports
 from IPython.core.inputsplitter import InputSplitter
 from IPython.frontend.qt.base_frontend_mixin import BaseFrontendMixin
 from call_tip_widget import CallTipWidget
 from completion_lexer import CompletionLexer
 from console_widget import HistoryConsoleWidget
 from pygments_highlighter import PygmentsHighlighter
 
 
 class FrontendHighlighter(PygmentsHighlighter):
     """ A PygmentsHighlighter that can be turned on and off and that ignores
         prompts.
     """
 
     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:
             return
 
         # 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
         else:
             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))
         else:
             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.
     """
    
     # Emitted when an 'execute_reply' has been received from the kernel and
     # processed by the FrontendWidget.
     executed = QtCore.pyqtSignal(object)
 
     # Protected class attributes.
     _highlighter_class = FrontendHighlighter
     _input_splitter_class = InputSplitter
 
     #---------------------------------------------------------------------------
     # 'object' interface
     #---------------------------------------------------------------------------
     
     def __init__(self, *args, **kw):
         super(FrontendWidget, self).__init__(*args, **kw)
 
         # FrontendWidget protected variables.
         self._call_tip_widget = CallTipWidget(self._control)
         self._completion_lexer = CompletionLexer(PythonLexer())
         self._hidden = False
         self._highlighter = self._highlighter_class(self)
         self._input_splitter = self._input_splitter_class(input_mode='replace')
         self._kernel_manager = None
 
         # Configure the ConsoleWidget.
         self.tab_width = 4
         self._set_continuation_prompt('... ')
 
         # Connect signal handlers.
         document = self._control.document()
         document.contentsChange.connect(self._document_contents_change)
 
     #---------------------------------------------------------------------------
     # '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.expandtabs(4))
         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.
         """
-        self.kernel_manager.xreq_channel.execute(source)
+        self.kernel_manager.xreq_channel.execute(source, hidden)
         self._hidden = hidden
 
     def _execute_interrupt(self):
         """ Attempts to stop execution. Returns whether this method has an
             implementation.
         """
         self._interrupt_kernel()
         return True
         
     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.
         """
         self._keep_cursor_in_buffer()
         cursor = self._get_cursor()
         return not self._complete()
 
     #---------------------------------------------------------------------------
     # 'ConsoleWidget' protected interface
     #---------------------------------------------------------------------------
 
     def _show_continuation_prompt(self):
         """ Reimplemented for auto-indentation.
         """
         super(FrontendWidget, self)._show_continuation_prompt()
         spaces = self._input_splitter.indent_spaces
         self._append_plain_text('\t' * (spaces / self.tab_width))
         self._append_plain_text(' ' * (spaces % self.tab_width))
 
     #---------------------------------------------------------------------------
     # 'BaseFrontendMixin' abstract interface
     #---------------------------------------------------------------------------
 
     def _handle_complete_reply(self, rep):
         """ Handle replies for tab completion.
         """
         cursor = self._get_cursor()
         if rep['parent_header']['msg_id'] == self._complete_id and \
                 cursor.position() == self._complete_pos:
             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.
         """
         if not self._hidden:
             # Make sure that all output from the SUB channel has been processed
             # before writing a new prompt.
             self.kernel_manager.sub_channel.flush()
 
             content = msg['content']
             status = content['status']
             if status == 'ok':
                 self._process_execute_ok(msg)
             elif status == 'error':
                 self._process_execute_error(msg)
             elif status == 'abort':
                 self._process_execute_abort(msg)
 
             self._show_interpreter_prompt_for_reply(msg)
             self.executed.emit(msg)
 
     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.
         self.kernel_manager.sub_channel.flush()
 
         def callback(line):
             self.kernel_manager.rep_channel.input(line)
         self._readline(msg['content']['prompt'], callback=callback)
 
     def _handle_object_info_reply(self, rep):
         """ Handle replies for call tips.
         """
         cursor = self._get_cursor()
         if rep['parent_header']['msg_id'] == self._call_tip_id and \
                 cursor.position() == self._call_tip_pos:
             doc = rep['content']['docstring']
             if doc:
                 self._call_tip_widget.show_docstring(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):
             self._append_plain_text(msg['content']['data'])
             self._control.moveCursor(QtGui.QTextCursor.End)
     
     def _started_channels(self):
         """ Called when the KernelManager channels have started listening or 
             when the frontend is assigned an already listening KernelManager.
         """
         self._control.clear()
         self._append_plain_text(self._get_banner())
         self._show_interpreter_prompt()
 
     def _stopped_channels(self):
         """ Called when the KernelManager channels have stopped listening or
             when a listening KernelManager is removed from the frontend.
         """
         self._executing = self._reading = False
         self._highlighter.highlighting_on = False
 
     #---------------------------------------------------------------------------
     # 'FrontendWidget' interface
     #---------------------------------------------------------------------------
 
     def execute_file(self, path, hidden=False):
         """ Attempts to execute file with 'path'. If 'hidden', no output is
             shown.
         """
         self.execute('execfile("%s")' % path, hidden=hidden)
 
     #---------------------------------------------------------------------------
     # '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()
         cursor.movePosition(QtGui.QTextCursor.Left)
         document = self._control.document()
         if 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)
         self._call_tip_id = self.kernel_manager.xreq_channel.object_info(name)
         self._call_tip_pos = self._get_cursor().position()
         return True
 
     def _complete(self):
         """ Performs completion at the current cursor location.
         """
         # Decide if it makes sense to do completion
         context = self._get_context()
         if not context:
             return False
 
         # Send the completion request to the kernel
         self._complete_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 
         self._complete_pos = self._get_cursor().position()
         return True
 
     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 at the current cursor location.
         """
         if cursor is None:
             cursor = self._get_cursor()
         cursor.movePosition(QtGui.QTextCursor.StartOfBlock, 
                             QtGui.QTextCursor.KeepAnchor)
         text = str(cursor.selection().toPlainText())
         return self._completion_lexer.get_context(text)
 
     def _interrupt_kernel(self):
         """ Attempts to the interrupt the kernel.
         """
         if self.kernel_manager.has_kernel:
             self.kernel_manager.signal_kernel(signal.SIGINT)
         else:
             self._append_plain_text('Kernel process is either remote or '
                                     'unspecified. Cannot interrupt.\n')
 
     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'])
         self._append_plain_text(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 = 'Received unknown payload of type %s\n'
                 self._append_plain_text(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.
         """
         self._show_interpreter_prompt()
 
     #------ 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():
             self._call_tip()

IPython/frontend/qt/console/ipython_widget.py

@@ -1,299 +1,323 b''
 # Standard library imports
 from subprocess import Popen
 
 # System library imports
 from PyQt4 import QtCore, QtGui
 
 # Local imports
 from IPython.core.inputsplitter import IPythonInputSplitter
 from IPython.core.usage import default_banner
 from frontend_widget import FrontendWidget
 
 
 class IPythonPromptBlock(object):
     """ An internal storage object for IPythonWidget.
     """
     def __init__(self, block, length, number):
         self.block = block
         self.length = length
         self.number = number
 
 
 class IPythonWidget(FrontendWidget):
     """ A FrontendWidget for an IPython kernel.
     """
 
     # Signal emitted when an editor is needed for a file and the editor has been
     # specified as 'custom'. See 'set_editor' for more information.
     custom_edit_requested = QtCore.pyqtSignal(object, object)
 
     # The default stylesheet: black text on a white background.
     default_stylesheet = """
         .error { color: red; }
         .in-prompt { color: navy; }
         .in-prompt-number { font-weight: bold; }
         .out-prompt { color: darkred; }
         .out-prompt-number { font-weight: bold; }
     """
 
     # A dark stylesheet: white text on a black background.
     dark_stylesheet = """
         QPlainTextEdit, QTextEdit { background-color: black; color: white }
         QFrame { border: 1px solid grey; }
         .error { color: red; }
         .in-prompt { color: lime; }
         .in-prompt-number { color: lime; font-weight: bold; }
         .out-prompt { color: red; }
         .out-prompt-number { color: red; font-weight: bold; }
     """
 
     # Default prompts.
     in_prompt = 'In [<span class="in-prompt-number">%i</span>]: '
     out_prompt = 'Out[<span class="out-prompt-number">%i</span>]: '
 
     # FrontendWidget protected class variables.
     #_input_splitter_class = IPythonInputSplitter
 
     # IPythonWidget protected class variables.
     _payload_source_edit = 'IPython.zmq.zmqshell.ZMQInteractiveShell.edit_magic'
     _payload_source_page = 'IPython.zmq.page.page'
 
     #---------------------------------------------------------------------------
     # 'object' interface
     #---------------------------------------------------------------------------
     
     def __init__(self, *args, **kw):
         super(IPythonWidget, self).__init__(*args, **kw)
 
         # IPythonWidget protected variables.
         self._previous_prompt_obj = None
 
         # Set a default editor and stylesheet.
         self.set_editor('default')
         self.reset_styling()
 
     #---------------------------------------------------------------------------
     # 'BaseFrontendMixin' abstract interface
     #---------------------------------------------------------------------------
 
+    def _handle_history_reply(self, msg):
+        """ Implemented to handle history replies, which are only supported by
+            the IPython kernel.
+        """
+        history_dict = msg['content']['history']
+        items = [ history_dict[key] for key in sorted(history_dict.keys()) ]
+        self._set_history(items)
+
+    def _handle_prompt_reply(self, msg):
+        """ Implemented to handle prompt number replies, which are only
+            supported by the IPython kernel.
+        """
+        content = msg['content']
+        self._show_interpreter_prompt(content['prompt_number'], 
+                                      content['input_sep'])
+
     def _handle_pyout(self, msg):
         """ Reimplemented for IPython-style "display hook".
         """
         if not self._hidden and self._is_from_this_session(msg):
             content = msg['content']
             prompt_number = content['prompt_number']
             self._append_plain_text(content['output_sep'])
             self._append_html(self._make_out_prompt(prompt_number))
             self._append_plain_text(content['data'] + '\n' + 
                                     content['output_sep2'])
 
+    def _started_channels(self):
+        """ Reimplemented to make a history request.
+        """
+        super(IPythonWidget, self)._started_channels()
+        # FIXME: Disabled until history requests are properly implemented.
+        #self.kernel_manager.xreq_channel.history(raw=True, output=False)
+
     #---------------------------------------------------------------------------
     # 'FrontendWidget' interface
     #---------------------------------------------------------------------------
 
     def execute_file(self, path, hidden=False):
         """ Reimplemented to use the 'run' magic.
         """
         self.execute('%%run %s' % path, hidden=hidden)
 
     #---------------------------------------------------------------------------
     # 'FrontendWidget' protected interface
     #---------------------------------------------------------------------------
 
     def _get_banner(self):
         """ Reimplemented to return IPython's default banner.
         """
         return default_banner + '\n'
 
     def _process_execute_error(self, msg):
         """ Reimplemented for IPython-style traceback formatting.
         """
         content = msg['content']
         traceback = '\n'.join(content['traceback']) + '\n'
         if False:
             # FIXME: For now, tracebacks come as plain text, so we can't use
             # the html renderer yet.  Once we refactor ultratb to produce
             # properly styled tracebacks, this branch should be the default
             traceback = traceback.replace(' ', '&nbsp;')
             traceback = traceback.replace('\n', '<br/>')
 
             ename = content['ename']
             ename_styled = '<span class="error">%s</span>' % ename
             traceback = traceback.replace(ename, ename_styled)
 
             self._append_html(traceback)
         else:
             # This is the fallback for now, using plain text with ansi escapes
             self._append_plain_text(traceback)
 
     def _process_execute_payload(self, item):
         """ Reimplemented to handle %edit and paging payloads.
         """
         if item['source'] == self._payload_source_edit:
             self.edit(item['filename'], item['line_number'])
             return True
         elif item['source'] == self._payload_source_page:
             self._page(item['data'])
             return True
         else:
             return False
 
     def _show_interpreter_prompt(self, number=None, input_sep='\n'):
         """ Reimplemented for IPython-style prompts.
         """
-        # TODO: If a number was not specified, make a prompt number request.
+        # If a number was not specified, make a prompt number request.
         if number is None:
-            number = 0
+            self.kernel_manager.xreq_channel.prompt()
+            return
 
         # Show a new prompt and save information about it so that it can be
         # updated later if the prompt number turns out to be wrong.
         self._append_plain_text(input_sep)
         self._show_prompt(self._make_in_prompt(number), html=True)
         block = self._control.document().lastBlock()
         length = len(self._prompt)
         self._previous_prompt_obj = IPythonPromptBlock(block, length, number)
 
         # Update continuation prompt to reflect (possibly) new prompt length.
         self._set_continuation_prompt(
             self._make_continuation_prompt(self._prompt), html=True)
 
     def _show_interpreter_prompt_for_reply(self, msg):
         """ Reimplemented for IPython-style prompts.
         """
         # Update the old prompt number if necessary.
         content = msg['content']
         previous_prompt_number = content['prompt_number']
         if self._previous_prompt_obj and \
                 self._previous_prompt_obj.number != previous_prompt_number:
             block = self._previous_prompt_obj.block
             if block.isValid():
 
                 # Remove the old prompt and insert a new prompt.
                 cursor = QtGui.QTextCursor(block)
                 cursor.movePosition(QtGui.QTextCursor.Right,
                                     QtGui.QTextCursor.KeepAnchor, 
                                     self._previous_prompt_obj.length)
                 prompt = self._make_in_prompt(previous_prompt_number)
                 self._prompt = self._insert_html_fetching_plain_text(
                     cursor, prompt)
 
                 # When the HTML is inserted, Qt blows away the syntax
                 # highlighting for the line, so we need to rehighlight it.
                 self._highlighter.rehighlightBlock(cursor.block())
 
             self._previous_prompt_obj = None
 
         # Show a new prompt with the kernel's estimated prompt number.
         next_prompt = content['next_prompt']
         self._show_interpreter_prompt(next_prompt['prompt_number'], 
                                       next_prompt['input_sep'])
 
     #---------------------------------------------------------------------------
     # 'IPythonWidget' interface
     #---------------------------------------------------------------------------
 
     def edit(self, filename, line=None):
         """ Opens a Python script for editing.
 
         Parameters:
         -----------
         filename : str
             A path to a local system file.
 
         line : int, optional
             A line of interest in the file.
         
         Raises:
         -------
         OSError
             If the editor command cannot be executed.
         """
         if self._editor == 'default':
             url = QtCore.QUrl.fromLocalFile(filename)
             if not QtGui.QDesktopServices.openUrl(url):
                 message = 'Failed to open %s with the default application'
                 raise OSError(message % repr(filename))
         elif self._editor is None:
             self.custom_edit_requested.emit(filename, line)
         else:
             Popen(self._editor + [filename])
 
     def reset_styling(self):
         """ Restores the default IPythonWidget styling.
         """
         self.set_styling(self.default_stylesheet, syntax_style='default')
         #self.set_styling(self.dark_stylesheet, syntax_style='monokai')
 
     def set_editor(self, editor):
         """ Sets the editor to use with the %edit magic.
 
         Parameters:
         -----------
         editor : str or sequence of str
             A command suitable for use with Popen. This command will be executed
             with a single argument--a filename--when editing is requested.
 
             This parameter also takes two special values:
                 'default' : Files will be edited with the system default 
                             application for Python files.
                 'custom'  : Emit a 'custom_edit_requested(str, int)' signal 
                             instead of opening an editor.
         """
         if editor == 'default':
             self._editor = 'default'
         elif editor == 'custom':
             self._editor = None
         elif isinstance(editor, basestring):
             self._editor = [ editor ]
         else:
             self._editor = list(editor)
 
     def set_styling(self, stylesheet, syntax_style=None):
         """ Sets the IPythonWidget styling.
 
         Parameters:
         -----------
         stylesheet : str
             A CSS stylesheet. The stylesheet can contain classes for:
                 1. Qt: QPlainTextEdit, QFrame, QWidget, etc
                 2. Pygments: .c, .k, .o, etc (see PygmentsHighlighter)
                 3. IPython: .error, .in-prompt, .out-prompt, etc.
 
         syntax_style : str or None [default None]
             If specified, use the Pygments style with given name. Otherwise, 
             the stylesheet is queried for Pygments style information.
         """
         self.setStyleSheet(stylesheet)
         self._control.document().setDefaultStyleSheet(stylesheet)
         if self._page_control:
             self._page_control.document().setDefaultStyleSheet(stylesheet)
 
         if syntax_style is None:
             self._highlighter.set_style_sheet(stylesheet)
         else:
             self._highlighter.set_style(syntax_style)
 
     #---------------------------------------------------------------------------
     # 'IPythonWidget' protected interface
     #---------------------------------------------------------------------------
 
     def _make_in_prompt(self, number):
         """ Given a prompt number, returns an HTML In prompt.
         """
         body = self.in_prompt % number
         return '<span class="in-prompt">%s</span>' % body
 
     def _make_continuation_prompt(self, prompt):
         """ Given a plain text version of an In prompt, returns an HTML
             continuation prompt.
         """
         end_chars = '...: '
         space_count = len(prompt.lstrip('\n')) - len(end_chars)
         body = '&nbsp;' * space_count + end_chars
         return '<span class="in-prompt">%s</span>' % body
         
     def _make_out_prompt(self, number):
         """ Given a prompt number, returns an HTML Out prompt.
         """
         body = self.out_prompt % number
         return '<span class="out-prompt">%s</span>' % body

IPython/zmq/ipkernel.py

@@ -1,398 +1,399 b''
 #!/usr/bin/env python
 """A simple interactive kernel that talks to a frontend over 0MQ.
 
 Things to do:
 
 * Implement `set_parent` logic. Right before doing exec, the Kernel should
   call set_parent on all the PUB objects with the message about to be executed.
 * Implement random port and security key logic.
 * Implement control messages.
 * Implement event loop and poll version.
 """
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # Standard library imports.
 import __builtin__
 import sys
 import time
 import traceback
 
 # System library imports.
 import zmq
 
 # Local imports.
 from IPython.config.configurable import Configurable
 from IPython.utils.traitlets import Instance
 from completer import KernelCompleter
 from entry_point import base_launch_kernel, make_argument_parser, make_kernel, \
     start_kernel
 from iostream import OutStream
 from session import Session, Message
 from zmqshell import ZMQInteractiveShell
 
 #-----------------------------------------------------------------------------
 # Main kernel class
 #-----------------------------------------------------------------------------
 
 class Kernel(Configurable):
 
     #---------------------------------------------------------------------------
     # Kernel interface
     #---------------------------------------------------------------------------
 
     shell = Instance('IPython.core.interactiveshell.InteractiveShellABC')
     session = Instance(Session)
     reply_socket = Instance('zmq.Socket')
     pub_socket = Instance('zmq.Socket')
     req_socket = Instance('zmq.Socket')
 
     # Maps user-friendly backend names to matplotlib backend identifiers.
     _pylab_map = { 'tk': 'TkAgg',
                    'gtk': 'GTKAgg',
                    'wx': 'WXAgg',
                    'qt': 'Qt4Agg', # qt3 not supported
                    'qt4': 'Qt4Agg',
                    'payload-svg' : \
                        'module://IPython.zmq.pylab.backend_payload_svg' }
 
     def __init__(self, **kwargs):
         super(Kernel, self).__init__(**kwargs)
 
         # Initialize the InteractiveShell subclass
         self.shell = ZMQInteractiveShell.instance()
         self.shell.displayhook.session = self.session
         self.shell.displayhook.pub_socket = self.pub_socket
 
         # TMP - hack while developing
         self.shell._reply_content = None
 
         # Build dict of handlers for message types
         msg_types = [ 'execute_request', 'complete_request', 
                       'object_info_request', 'prompt_request',
                       'history_request' ]
         self.handlers = {}
         for msg_type in msg_types:
             self.handlers[msg_type] = getattr(self, msg_type)
 
     def activate_pylab(self, backend=None, import_all=True):
         """ Activates pylab in this kernel's namespace.
 
         Parameters:
         -----------
         backend : str, optional
             A valid backend name.
 
         import_all : bool, optional
             If true, an 'import *' is done from numpy and pylab.
         """
         # FIXME: This is adapted from IPython.lib.pylabtools.pylab_activate.
         #        Common functionality should be refactored.
 
         # We must set the desired backend before importing pylab.
         import matplotlib
         if backend:
             backend_id = self._pylab_map[backend]
             if backend_id.startswith('module://'):
                 # Work around bug in matplotlib: matplotlib.use converts the
                 # backend_id to lowercase even if a module name is specified!
                 matplotlib.rcParams['backend'] = backend_id
             else:
                 matplotlib.use(backend_id)
 
         # Import numpy as np/pyplot as plt are conventions we're trying to
         # somewhat standardize on. Making them available to users by default
         # will greatly help this.
         exec ("import numpy\n"
               "import matplotlib\n"
               "from matplotlib import pylab, mlab, pyplot\n"
               "np = numpy\n"
               "plt = pyplot\n"
               ) in self.shell.user_ns
 
         if import_all:
             exec("from matplotlib.pylab import *\n"
                  "from numpy import *\n") in self.shell.user_ns
 
         matplotlib.interactive(True)
 
     def start(self):
         """ Start the kernel main loop.
         """
         while True:
             ident = self.reply_socket.recv()
             assert self.reply_socket.rcvmore(), "Missing message part."
             msg = self.reply_socket.recv_json()
             omsg = Message(msg)
             print>>sys.__stdout__
             print>>sys.__stdout__, omsg
             handler = self.handlers.get(omsg.msg_type, None)
             if handler is None:
                 print >> sys.__stderr__, "UNKNOWN MESSAGE TYPE:", omsg
             else:
                 handler(ident, omsg)
 
     #---------------------------------------------------------------------------
     # Kernel request handlers
     #---------------------------------------------------------------------------
 
     def execute_request(self, ident, parent):
         try:
             code = parent[u'content'][u'code']
         except:
             print>>sys.__stderr__, "Got bad msg: "
             print>>sys.__stderr__, Message(parent)
             return
         pyin_msg = self.session.msg(u'pyin',{u'code':code}, parent=parent)
         self.pub_socket.send_json(pyin_msg)
 
         try:
             # Replace raw_input. Note that is not sufficient to replace 
             # raw_input in the user namespace.
             raw_input = lambda prompt='': self._raw_input(prompt, ident, parent)
             __builtin__.raw_input = raw_input
 
             # Set the parent message of the display hook and out streams.
             self.shell.displayhook.set_parent(parent)
             sys.stdout.set_parent(parent)
             sys.stderr.set_parent(parent)
 
             # FIXME: runlines calls the exception handler itself.  We should
             # clean this up.
             self.shell._reply_content = None
             self.shell.runlines(code)
         except:
             # FIXME: this code right now isn't being used yet by default,
             # because the runlines() call above directly fires off exception
             # reporting.  This code, therefore, is only active in the scenario
             # where runlines itself has an unhandled exception.  We need to
             # uniformize this, for all exception construction to come from a
             # single location in the codbase.
             etype, evalue, tb = sys.exc_info()
             tb_list = traceback.format_exception(etype, evalue, tb)
             reply_content = self.shell._showtraceback(etype, evalue, tb_list)
         else:
             payload = self.shell.payload_manager.read_payload()
             # Be agressive about clearing the payload because we don't want
             # it to sit in memory until the next execute_request comes in.
             self.shell.payload_manager.clear_payload()
             reply_content = { 'status' : 'ok', 'payload' : payload }
 
         # Compute the prompt information
         prompt_number = self.shell.displayhook.prompt_count
         reply_content['prompt_number'] = prompt_number        
         prompt_string = self.shell.displayhook.prompt1.peek_next_prompt()
         next_prompt = {'prompt_string' : prompt_string,
                        'prompt_number' : prompt_number+1,
                        'input_sep'     : self.shell.displayhook.input_sep}
         reply_content['next_prompt'] = next_prompt
 
         # TMP - fish exception info out of shell, possibly left there by
         # runlines
         if self.shell._reply_content is not None:
             reply_content.update(self.shell._reply_content)
 
         # Flush output before sending the reply.
         sys.stderr.flush()
         sys.stdout.flush()
 
         # Send the reply.
         reply_msg = self.session.msg(u'execute_reply', reply_content, parent)
         print>>sys.__stdout__, Message(reply_msg)
         self.reply_socket.send(ident, zmq.SNDMORE)
         self.reply_socket.send_json(reply_msg)
         if reply_msg['content']['status'] == u'error':
             self._abort_queue()
 
     def complete_request(self, ident, parent):
         matches = {'matches' : self._complete(parent),
                    'status' : 'ok'}
         completion_msg = self.session.send(self.reply_socket, 'complete_reply',
                                            matches, parent, ident)
         print >> sys.__stdout__, completion_msg
 
     def object_info_request(self, ident, parent):
         context = parent['content']['oname'].split('.')
         object_info = self._object_info(context)
         msg = self.session.send(self.reply_socket, 'object_info_reply',
                                 object_info, parent, ident)
         print >> sys.__stdout__, msg
 
     def prompt_request(self, ident, parent):
         prompt_number = self.shell.displayhook.prompt_count
         prompt_string = self.shell.displayhook.prompt1.peek_next_prompt()
         content = {'prompt_string' : prompt_string,
-                   'prompt_number' : prompt_number+1}
+                   'prompt_number' : prompt_number+1,
+                   'input_sep'     : self.shell.displayhook.input_sep}
         msg = self.session.send(self.reply_socket, 'prompt_reply',
                                 content, parent, ident)
         print >> sys.__stdout__, msg
 
     def history_request(self, ident, parent):
-        output = parent['content'].get('output', True)
-        index = parent['content'].get('index')
-        raw = parent['content'].get('raw', False)
+        output = parent['content']['output']
+        index = parent['content']['index']
+        raw = parent['content']['raw']
         hist = self.shell.get_history(index=index, raw=raw, output=output)
         content = {'history' : hist}
         msg = self.session.send(self.reply_socket, 'history_reply',
                                 content, parent, ident)
         print >> sys.__stdout__, msg
         
     #---------------------------------------------------------------------------
     # Protected interface
     #---------------------------------------------------------------------------
 
     def _abort_queue(self):
         while True:
             try:
                 ident = self.reply_socket.recv(zmq.NOBLOCK)
             except zmq.ZMQError, e:
                 if e.errno == zmq.EAGAIN:
                     break
             else:
                 assert self.reply_socket.rcvmore(), "Unexpected missing message part."
                 msg = self.reply_socket.recv_json()
             print>>sys.__stdout__, "Aborting:"
             print>>sys.__stdout__, Message(msg)
             msg_type = msg['msg_type']
             reply_type = msg_type.split('_')[0] + '_reply'
             reply_msg = self.session.msg(reply_type, {'status' : 'aborted'}, msg)
             print>>sys.__stdout__, Message(reply_msg)
             self.reply_socket.send(ident,zmq.SNDMORE)
             self.reply_socket.send_json(reply_msg)
             # We need to wait a bit for requests to come in. This can probably
             # be set shorter for true asynchronous clients.
             time.sleep(0.1)
 
     def _raw_input(self, prompt, ident, parent):
         # Flush output before making the request.
         sys.stderr.flush()
         sys.stdout.flush()
 
         # Send the input request.
         content = dict(prompt=prompt)
         msg = self.session.msg(u'input_request', content, parent)
         self.req_socket.send_json(msg)
 
         # Await a response.
         reply = self.req_socket.recv_json()
         try:
             value = reply['content']['value']
         except:
             print>>sys.__stderr__, "Got bad raw_input reply: "
             print>>sys.__stderr__, Message(parent)
             value = ''
         return value
     
     def _complete(self, msg):
         #from IPython.utils.io import rprint  # dbg
         #rprint('\n\n**MSG**\n\n', msg)  # dbg
         #import traceback; rprint(''.join(traceback.format_stack())) # dbg
         c = msg['content']
         try:
             cpos = int(c['cursor_pos'])
         except:
             # If we don't get something that we can convert to an integer, at
             # leasat attempt the completion guessing the cursor is at the end
             # of the text
             cpos = len(c['text'])
         return self.shell.complete(c['text'], c['line'], cpos)
 
     def _object_info(self, context):
         symbol, leftover = self._symbol_from_context(context)
         if symbol is not None and not leftover:
             doc = getattr(symbol, '__doc__', '')
         else:
             doc = ''
         object_info = dict(docstring = doc)
         return object_info
 
     def _symbol_from_context(self, context):
         if not context:
             return None, context
 
         base_symbol_string = context[0]
         symbol = self.shell.user_ns.get(base_symbol_string, None)
         if symbol is None:
             symbol = __builtin__.__dict__.get(base_symbol_string, None)
         if symbol is None:
             return None, context
 
         context = context[1:]
         for i, name in enumerate(context):
             new_symbol = getattr(symbol, name, None)
             if new_symbol is None:
                 return symbol, context[i:]
             else:
                 symbol = new_symbol
 
         return symbol, []
 
 #-----------------------------------------------------------------------------
 # Kernel main and launch functions
 #-----------------------------------------------------------------------------
 
 def launch_kernel(xrep_port=0, pub_port=0, req_port=0, independent=False,
                   pylab=False):
     """ Launches a localhost kernel, binding to the specified ports.
 
     Parameters
     ----------
     xrep_port : int, optional
         The port to use for XREP channel.
 
     pub_port : int, optional
         The port to use for the SUB channel.
 
     req_port : int, optional
         The port to use for the REQ (raw input) channel.
 
     independent : bool, optional (default False) 
         If set, the kernel process is guaranteed to survive if this process
         dies. If not set, an effort is made to ensure that the kernel is killed
         when this process dies. Note that in this case it is still good practice
         to kill kernels manually before exiting.
 
     pylab : bool or string, optional (default False)
         If not False, the kernel will be launched with pylab enabled. If a
         string is passed, matplotlib will use the specified backend. Otherwise,
         matplotlib's default backend will be used.
 
     Returns
     -------
     A tuple of form:
         (kernel_process, xrep_port, pub_port, req_port)
     where kernel_process is a Popen object and the ports are integers.
     """
     extra_arguments = []
     if pylab:
         extra_arguments.append('--pylab')
         if isinstance(pylab, basestring):
             extra_arguments.append(pylab)
     return base_launch_kernel('from IPython.zmq.ipkernel import main; main()',
                               xrep_port, pub_port, req_port, independent, 
                               extra_arguments)
 
 def main():
     """ The IPython kernel main entry point.
     """
     parser = make_argument_parser()
     parser.add_argument('--pylab', type=str, metavar='GUI', nargs='?', 
                         const='auto', help = \
 "Pre-load matplotlib and numpy for interactive use. If GUI is not \
 given, the GUI backend is matplotlib's, otherwise use one of: \
 ['tk', 'gtk', 'qt', 'wx', 'payload-svg'].")
     namespace = parser.parse_args()
 
     kernel = make_kernel(namespace, Kernel, OutStream)
     if namespace.pylab:
         if namespace.pylab == 'auto':
             kernel.activate_pylab()
         else:
             kernel.activate_pylab(namespace.pylab)
     
     start_kernel(namespace, kernel)
 
 if __name__ == '__main__':
     main()

IPython/zmq/kernelmanager.py

@@ -1,581 +1,617 b''
 """Base classes to manage the interaction with a running kernel.
 
 Todo
 ====
 
 * Create logger to handle debugging and console messages.
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2010  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
 #-----------------------------------------------------------------------------
 
 # Standard library imports.
 from Queue import Queue, Empty
 from subprocess import Popen
 from threading import Thread
 import time
 
 # System library imports.
 import zmq
 from zmq import POLLIN, POLLOUT, POLLERR
 from zmq.eventloop import ioloop
 
 # Local imports.
 from IPython.utils.traitlets import HasTraits, Any, Instance, Type, TCPAddress
 from session import Session
 
 #-----------------------------------------------------------------------------
 # Constants and exceptions
 #-----------------------------------------------------------------------------
 
 LOCALHOST = '127.0.0.1'
 
 class InvalidPortNumber(Exception):
     pass
 
 #-----------------------------------------------------------------------------
 # ZMQ Socket Channel classes
 #-----------------------------------------------------------------------------
 
 class ZmqSocketChannel(Thread):
     """The base class for the channels that use ZMQ sockets.
     """
     context = None
     session = None
     socket = None
     ioloop = None
     iostate = None
     _address = None
 
     def __init__(self, context, session, address):
         """Create a channel
 
         Parameters
         ----------
         context : :class:`zmq.Context`
             The ZMQ context to use.
         session : :class:`session.Session`
             The session to use.
         address : tuple
             Standard (ip, port) tuple that the kernel is listening on.
         """
         super(ZmqSocketChannel, self).__init__()
         self.daemon = True
 
         self.context = context
         self.session = session
         if address[1] == 0:
             message = 'The port number for a channel cannot be 0.'
             raise InvalidPortNumber(message)
         self._address = address
 
     def stop(self):
         """Stop the channel's activity.
 
         This calls :method:`Thread.join` and returns when the thread
         terminates. :class:`RuntimeError` will be raised if 
         :method:`self.start` is called again.
         """
         self.join()
 
     @property
     def address(self):
         """Get the channel's address as an (ip, port) tuple.
         
         By the default, the address is (localhost, 0), where 0 means a random
         port.
         """
         return self._address
 
     def add_io_state(self, state):
         """Add IO state to the eventloop.
 
         Parameters
         ----------
         state : zmq.POLLIN|zmq.POLLOUT|zmq.POLLERR
             The IO state flag to set.
 
         This is thread safe as it uses the thread safe IOLoop.add_callback.
         """
         def add_io_state_callback():
             if not self.iostate & state:
                 self.iostate = self.iostate | state
                 self.ioloop.update_handler(self.socket, self.iostate)
         self.ioloop.add_callback(add_io_state_callback)
 
     def drop_io_state(self, state):
         """Drop IO state from the eventloop.
 
         Parameters
         ----------
         state : zmq.POLLIN|zmq.POLLOUT|zmq.POLLERR
             The IO state flag to set.
 
         This is thread safe as it uses the thread safe IOLoop.add_callback.
         """
         def drop_io_state_callback():
             if self.iostate & state:
                 self.iostate = self.iostate & (~state)
                 self.ioloop.update_handler(self.socket, self.iostate)
         self.ioloop.add_callback(drop_io_state_callback)
 
 
 class XReqSocketChannel(ZmqSocketChannel):
     """The XREQ channel for issues request/replies to the kernel.
     """
 
     command_queue = None
 
     def __init__(self, context, session, address):
         self.command_queue = Queue()
         super(XReqSocketChannel, self).__init__(context, session, address)
 
     def run(self):
         """The thread's main activity.  Call start() instead."""
         self.socket = self.context.socket(zmq.XREQ)
         self.socket.setsockopt(zmq.IDENTITY, self.session.session)
         self.socket.connect('tcp://%s:%i' % self.address)
         self.ioloop = ioloop.IOLoop()
         self.iostate = POLLERR|POLLIN
         self.ioloop.add_handler(self.socket, self._handle_events, 
                                 self.iostate)
         self.ioloop.start()
 
     def stop(self):
         self.ioloop.stop()
         super(XReqSocketChannel, self).stop()
 
     def call_handlers(self, msg):
         """This method is called in the ioloop thread when a message arrives.
 
         Subclasses should override this method to handle incoming messages.
         It is important to remember that this method is called in the thread
         so that some logic must be done to ensure that the application leve
         handlers are called in the application thread.
         """
         raise NotImplementedError('call_handlers must be defined in a subclass.')
 
-    def execute(self, code):
+    def execute(self, code, silent=False):
         """Execute code in the kernel.
 
         Parameters
         ----------
         code : str
             A string of Python code.
+        silent : bool, optional (default False)
+            If set, the kernel will execute the code as quietly possible.
 
         Returns
         -------
         The msg_id of the message sent.
         """
         # Create class for content/msg creation. Related to, but possibly
         # not in Session.
-        content = dict(code=code)
+        content = dict(code=code, silent=silent)
         msg = self.session.msg('execute_request', content)
         self._queue_request(msg)
         return msg['header']['msg_id']
 
     def complete(self, text, line, cursor_pos, block=None):
         """Tab complete text in the kernel's namespace.
 
         Parameters
         ----------
         text : str
             The text to complete.
         line : str
             The full line of text that is the surrounding context for the 
             text to complete.
         cursor_pos : int
             The position of the cursor in the line where the completion was
             requested.
         block : str, optional
             The full block of code in which the completion is being requested.
 
         Returns
         -------
         The msg_id of the message sent.
         """
         content = dict(text=text, line=line, block=block, cursor_pos=cursor_pos)
         msg = self.session.msg('complete_request', content)
         self._queue_request(msg)
         return msg['header']['msg_id']
 
     def object_info(self, oname):
         """Get metadata information about an object.
 
         Parameters
         ----------
         oname : str
             A string specifying the object name.
         
         Returns
         -------
         The msg_id of the message sent.
         """
         content = dict(oname=oname)
         msg = self.session.msg('object_info_request', content)
         self._queue_request(msg)
         return msg['header']['msg_id']
 
+    def history(self, index=None, raw=False, output=True):
+        """Get the history list.
+
+        Parameters
+        ----------
+        index : n or (n1, n2) or None
+            If n, then the last entries. If a tuple, then all in
+            range(n1, n2). If None, then all entries. Raises IndexError if
+            the format of index is incorrect.
+        raw : bool
+            If True, return the raw input.
+        output : bool
+            If True, then return the output as well.
+
+        Returns
+        -------
+        The msg_id of the message sent.
+        """
+        content = dict(index=index, raw=raw, output=output)
+        msg = self.session.msg('history_request', content)
+        self._queue_request(msg)
+        return msg['header']['msg_id']
+
+    def prompt(self):
+        """Requests a prompt number from the kernel.
+
+        Returns
+        -------
+        The msg_id of the message sent.
+        """
+        msg = self.session.msg('prompt_request')
+        self._queue_request(msg)
+        return msg['header']['msg_id']
+
     def _handle_events(self, socket, events):
         if events & POLLERR:
             self._handle_err()
         if events & POLLOUT:
             self._handle_send()
         if events & POLLIN:
             self._handle_recv()
 
     def _handle_recv(self):
         msg = self.socket.recv_json()
         self.call_handlers(msg)
 
     def _handle_send(self):
         try:
             msg = self.command_queue.get(False)
         except Empty:
             pass
         else:
             self.socket.send_json(msg)
         if self.command_queue.empty():
             self.drop_io_state(POLLOUT)
 
     def _handle_err(self):
         # We don't want to let this go silently, so eventually we should log.
         raise zmq.ZMQError()
 
     def _queue_request(self, msg):
         self.command_queue.put(msg)
         self.add_io_state(POLLOUT)
 
 
 class SubSocketChannel(ZmqSocketChannel):
     """The SUB channel which listens for messages that the kernel publishes.
     """
 
     def __init__(self, context, session, address):
         super(SubSocketChannel, self).__init__(context, session, address)
 
     def run(self):
         """The thread's main activity.  Call start() instead."""
         self.socket = self.context.socket(zmq.SUB)
         self.socket.setsockopt(zmq.SUBSCRIBE,'')
         self.socket.setsockopt(zmq.IDENTITY, self.session.session)
         self.socket.connect('tcp://%s:%i' % self.address)
         self.ioloop = ioloop.IOLoop()
         self.iostate = POLLIN|POLLERR
         self.ioloop.add_handler(self.socket, self._handle_events, 
                                 self.iostate)
         self.ioloop.start()
 
     def stop(self):
         self.ioloop.stop()
         super(SubSocketChannel, self).stop()
 
     def call_handlers(self, msg):
         """This method is called in the ioloop thread when a message arrives.
 
         Subclasses should override this method to handle incoming messages.
         It is important to remember that this method is called in the thread
         so that some logic must be done to ensure that the application leve
         handlers are called in the application thread.
         """
         raise NotImplementedError('call_handlers must be defined in a subclass.')
 
     def flush(self, timeout=1.0):
         """Immediately processes all pending messages on the SUB channel.
 
         Callers should use this method to ensure that :method:`call_handlers`
         has been called for all messages that have been received on the
         0MQ SUB socket of this channel.
 
         This method is thread safe.
 
         Parameters
         ----------
         timeout : float, optional
             The maximum amount of time to spend flushing, in seconds. The
             default is one second.
         """
         # We do the IOLoop callback process twice to ensure that the IOLoop
         # gets to perform at least one full poll.
         stop_time = time.time() + timeout
         for i in xrange(2):
             self._flushed = False
             self.ioloop.add_callback(self._flush)
             while not self._flushed and time.time() < stop_time:
                 time.sleep(0.01)
 
     def _handle_events(self, socket, events):
         # Turn on and off POLLOUT depending on if we have made a request
         if events & POLLERR:
             self._handle_err()
         if events & POLLIN:
             self._handle_recv()
 
     def _handle_err(self):
         # We don't want to let this go silently, so eventually we should log.
         raise zmq.ZMQError()
 
     def _handle_recv(self):
         # Get all of the messages we can
         while True:
             try:
                 msg = self.socket.recv_json(zmq.NOBLOCK)
             except zmq.ZMQError:
                 # Check the errno?
                 # Will this trigger POLLERR?
                 break
             else:
                 self.call_handlers(msg)
 
     def _flush(self):
         """Callback for :method:`self.flush`."""
         self._flushed = True
 
 
 class RepSocketChannel(ZmqSocketChannel):
     """A reply channel to handle raw_input requests that the kernel makes."""
 
     msg_queue = None
 
     def __init__(self, context, session, address):
         self.msg_queue = Queue()
         super(RepSocketChannel, self).__init__(context, session, address)
 
     def run(self):
         """The thread's main activity.  Call start() instead."""
         self.socket = self.context.socket(zmq.XREQ)
         self.socket.setsockopt(zmq.IDENTITY, self.session.session)
         self.socket.connect('tcp://%s:%i' % self.address)
         self.ioloop = ioloop.IOLoop()
         self.iostate = POLLERR|POLLIN
         self.ioloop.add_handler(self.socket, self._handle_events, 
                                 self.iostate)
         self.ioloop.start()
 
     def stop(self):
         self.ioloop.stop()
         super(RepSocketChannel, self).stop()
 
     def call_handlers(self, msg):
         """This method is called in the ioloop thread when a message arrives.
 
         Subclasses should override this method to handle incoming messages.
         It is important to remember that this method is called in the thread
         so that some logic must be done to ensure that the application leve
         handlers are called in the application thread.
         """
         raise NotImplementedError('call_handlers must be defined in a subclass.')
 
     def input(self, string):
         """Send a string of raw input to the kernel."""
         content = dict(value=string)
         msg = self.session.msg('input_reply', content)
         self._queue_reply(msg)
 
     def _handle_events(self, socket, events):
         if events & POLLERR:
             self._handle_err()
         if events & POLLOUT:
             self._handle_send()
         if events & POLLIN:
             self._handle_recv()
 
     def _handle_recv(self):
         msg = self.socket.recv_json()
         self.call_handlers(msg)
 
     def _handle_send(self):
         try:
             msg = self.msg_queue.get(False)
         except Empty:
             pass
         else:
             self.socket.send_json(msg)
         if self.msg_queue.empty():
             self.drop_io_state(POLLOUT)
 
     def _handle_err(self):
         # We don't want to let this go silently, so eventually we should log.
         raise zmq.ZMQError()
 
     def _queue_reply(self, msg):
         self.msg_queue.put(msg)
         self.add_io_state(POLLOUT)
 
 
 #-----------------------------------------------------------------------------
 # Main kernel manager class
 #-----------------------------------------------------------------------------
 
 class KernelManager(HasTraits):
     """ Manages a kernel for a frontend.
 
     The SUB channel is for the frontend to receive messages published by the
     kernel.
         
     The REQ channel is for the frontend to make requests of the kernel.
     
     The REP channel is for the kernel to request stdin (raw_input) from the
     frontend.
     """
     # The PyZMQ Context to use for communication with the kernel.
     context = Instance(zmq.Context,(),{})
 
     # The Session to use for communication with the kernel.
     session = Instance(Session,(),{})
 
     # The kernel process with which the KernelManager is communicating.
     kernel = Instance(Popen)
 
     # The addresses for the communication channels. 
     xreq_address = TCPAddress((LOCALHOST, 0))
     sub_address = TCPAddress((LOCALHOST, 0))
     rep_address = TCPAddress((LOCALHOST, 0))
 
     # The classes to use for the various channels.
     xreq_channel_class = Type(XReqSocketChannel)
     sub_channel_class = Type(SubSocketChannel)
     rep_channel_class = Type(RepSocketChannel)
     
     # Protected traits.
     _xreq_channel = Any
     _sub_channel = Any
     _rep_channel = Any
 
     #--------------------------------------------------------------------------
     # Channel management methods:
     #--------------------------------------------------------------------------
 
     def start_channels(self):
         """Starts the channels for this kernel.
 
         This will create the channels if they do not exist and then start
         them. If port numbers of 0 are being used (random ports) then you
         must first call :method:`start_kernel`. If the channels have been
         stopped and you call this, :class:`RuntimeError` will be raised.
         """
         self.xreq_channel.start()
         self.sub_channel.start()
         self.rep_channel.start()
 
     def stop_channels(self):
         """Stops the channels for this kernel.
 
         This stops the channels by joining their threads. If the channels
         were not started, :class:`RuntimeError` will be raised.
         """
         self.xreq_channel.stop()
         self.sub_channel.stop()
         self.rep_channel.stop()
 
     @property
     def channels_running(self):
         """Are all of the channels created and running?"""
         return self.xreq_channel.is_alive() \
             and self.sub_channel.is_alive() \
             and self.rep_channel.is_alive()
 
     #--------------------------------------------------------------------------
     # Kernel process management methods:
     #--------------------------------------------------------------------------
 
     def start_kernel(self, ipython=True, **kw):
         """Starts a kernel process and configures the manager to use it.
 
         If random ports (port=0) are being used, this method must be called
         before the channels are created.
 
         Parameters:
         -----------
         ipython : bool, optional (default True)
              Whether to use an IPython kernel instead of a plain Python kernel.
         """
         xreq, sub, rep = self.xreq_address, self.sub_address, self.rep_address
         if xreq[0] != LOCALHOST or sub[0] != LOCALHOST or rep[0] != LOCALHOST:
             raise RuntimeError("Can only launch a kernel on localhost."
                                "Make sure that the '*_address' attributes are "
                                "configured properly.")
 
         if ipython:
             from ipkernel import launch_kernel as launch
         else:
             from pykernel import launch_kernel as launch
         self.kernel, xrep, pub, req = launch(xrep_port=xreq[1], pub_port=sub[1],
                                              req_port=rep[1], **kw)
         self.xreq_address = (LOCALHOST, xrep)
         self.sub_address = (LOCALHOST, pub)
         self.rep_address = (LOCALHOST, req)
 
     @property
     def has_kernel(self):
         """Returns whether a kernel process has been specified for the kernel
         manager.
         """
         return self.kernel is not None
 
     def kill_kernel(self):
         """ Kill the running kernel. """
         if self.kernel is not None:
             self.kernel.kill()
             self.kernel = None
         else:
             raise RuntimeError("Cannot kill kernel. No kernel is running!")
 
     def signal_kernel(self, signum):
         """ Sends a signal to the kernel. """
         if self.kernel is not None:
             self.kernel.send_signal(signum)
         else:
             raise RuntimeError("Cannot signal kernel. No kernel is running!")
 
     @property
     def is_alive(self):
         """Is the kernel process still running?"""
         if self.kernel is not None:
             if self.kernel.poll() is None:
                 return True
             else:
                 return False
         else:
             # We didn't start the kernel with this KernelManager so we don't
             # know if it is running. We should use a heartbeat for this case.
             return True
 
     #--------------------------------------------------------------------------
     # Channels used for communication with the kernel:
     #--------------------------------------------------------------------------
 
     @property
     def xreq_channel(self):
         """Get the REQ socket channel object to make requests of the kernel."""
         if self._xreq_channel is None:
             self._xreq_channel = self.xreq_channel_class(self.context, 
                                                          self.session,
                                                          self.xreq_address)
         return self._xreq_channel
 
     @property
     def sub_channel(self):
         """Get the SUB socket channel object."""
         if self._sub_channel is None:
             self._sub_channel = self.sub_channel_class(self.context,
                                                        self.session,
                                                        self.sub_address)
         return self._sub_channel
 
     @property
     def rep_channel(self):
         """Get the REP socket channel object to handle stdin (raw_input)."""
         if self._rep_channel is None:
             self._rep_channel = self.rep_channel_class(self.context, 
                                                        self.session,
                                                        self.rep_address)
         return self._rep_channel

docs/source/development/messaging.txt

@@ -1,590 +1,587 b''
 .. _messaging:
 
 ======================
  Messaging in IPython
 ======================
 
 
 Introduction
 ============
 
 This document explains the basic communications design and messaging
 specification for how the various IPython objects interact over a network
 transport.  The current implementation uses the ZeroMQ_ library for messaging
 within and between hosts.
 
 .. Note::
 
    This document should be considered the authoritative description of the
    IPython messaging protocol, and all developers are strongly encouraged to
    keep it updated as the implementation evolves, so that we have a single
    common reference for all protocol details.
    
 The basic design is explained in the following diagram:
 
 .. image:: frontend-kernel.png
    :width: 450px
    :alt: IPython kernel/frontend messaging architecture.
    :align: center
    :target: ../_images/frontend-kernel.png
 
 A single kernel can be simultaneously connected to one or more frontends.  The
 kernel has three sockets that serve the following functions:
 
 1. REQ: this socket is connected to a *single* frontend at a time, and it allows
    the kernel to request input from a frontend when :func:`raw_input` is called.
    The frontend holding the matching REP socket acts as a 'virtual keyboard'
    for the kernel while this communication is happening (illustrated in the
    figure by the black outline around the central keyboard).  In practice,
    frontends may display such kernel requests using a special input widget or
    otherwise indicating that the user is to type input for the kernel instead
    of normal commands in the frontend.
 
 2. XREP: this single sockets allows multiple incoming connections from
    frontends, and this is the socket where requests for code execution, object
    information, prompts, etc. are made to the kernel by any frontend.  The
    communication on this socket is a sequence of request/reply actions from
    each frontend and the kernel.
 
 3. PUB: this socket is the 'broadcast channel' where the kernel publishes all
    side effects (stdout, stderr, etc.) as well as the requests coming from any
    client over the XREP socket and its own requests on the REP socket.  There
    are a number of actions in Python which generate side effects: :func:`print`
    writes to ``sys.stdout``, errors generate tracebacks, etc.  Additionally, in
    a multi-client scenario, we want all frontends to be able to know what each
    other has sent to the kernel (this can be useful in collaborative scenarios,
    for example).  This socket allows both side effects and the information
    about communications taking place with one client over the XREQ/XREP channel
    to be made available to all clients in a uniform manner.
 
    All messages are tagged with enough information (details below) for clients
    to know which messages come from their own interaction with the kernel and
    which ones are from other clients, so they can display each type
    appropriately.
 
 The actual format of the messages allowed on each of these channels is
 specified below.  Messages are dicts of dicts with string keys and values that
 are reasonably representable in JSON.  Our current implementation uses JSON
 explicitly as its message format, but this shouldn't be considered a permanent
 feature.  As we've discovered that JSON has non-trivial performance issues due
 to excessive copying, we may in the future move to a pure pickle-based raw
 message format.  However, it should be possible to easily convert from the raw
 objects to JSON, since we may have non-python clients (e.g. a web frontend).
 As long as it's easy to make a JSON version of the objects that is a faithful
 representation of all the data, we can communicate with such clients.
 
 .. Note::
 
    Not all of these have yet been fully fleshed out, but the key ones are, see
    kernel and frontend files for actual implementation details.
 
    
 Python functional API
 =====================
 
 As messages are dicts, they map naturally to a ``func(**kw)`` call form.  We
 should develop, at a few key points, functional forms of all the requests that
 take arguments in this manner and automatically construct the necessary dict
 for sending.
 
 
 General Message Format
 ======================
 
 All messages send or received by any IPython process should have the following
 generic structure::
     
     {
       # The message header contains a pair of unique identifiers for the
       # originating session and the actual message id, in addition to the
       # username for the process that generated the message.  This is useful in
       # collaborative settings where multiple users may be interacting with the
       # same kernel simultaneously, so that frontends can label the various
       # messages in a meaningful way.
       'header' : { 'msg_id' : uuid,
                    'username' : str,
            'session' : uuid
          },
 
       # In a chain of messages, the header from the parent is copied so that
       # clients can track where messages come from.
       'parent_header' : dict,
 
       # All recognized message type strings are listed below.
       'msg_type' : str,
 
       # The actual content of the message must be a dict, whose structure
       # depends on the message type.x
       'content' : dict,
     }
 
 For each message type, the actual content will differ and all existing message
 types are specified in what follows of this document.
 
 
 Messages on the XREP/XREQ socket
 ================================
 
 .. _execute:
 
 Execute
 -------
 
 The execution request contains a single string, but this may be a multiline
 string.  The kernel is responsible for splitting this into possibly more than
 one block and deciding whether to compile these in 'single' or 'exec' mode.
 We're still sorting out this policy.  The current inputsplitter is capable of
 splitting the input for blocks that can all be run as 'single', but in the long
 run it may prove cleaner to only use 'single' mode for truly single-line
 inputs, and run all multiline input in 'exec' mode.  This would preserve the
 natural behavior of single-line inputs while allowing long cells to behave more
 likea a script.  This design will be refined as we complete the implementation.
 
 Message type: ``execute_request``::
 
     content = {
         # Source code to be executed by the kernel, one or more lines.
     'code' : str,
 
     # A boolean flag which, if True, signals the kernel to execute this
     # code as quietly as possible.  This means that the kernel will compile
     # the code with 'exec' instead of 'single' (so sys.displayhook will not
     # fire), and will *not*:
     #   - broadcast exceptions on the PUB socket
     #   - do any logging
     #   - populate any history
     # The default is False.
     'silent' : bool,
     }
 
 Upon execution, the kernel *always* sends a reply, with a status code
 indicating what happened and additional data depending on the outcome.
 
 Message type: ``execute_reply``::
 
     content = {
       # One of: 'ok' OR 'error' OR 'abort'
       'status' : str,
 
       # This has the same structure as the output of a prompt request, but is
       # for the client to set up the *next* prompt (with identical limitations
       # to a prompt request)
       'next_prompt' : {
             'prompt_string' : str,
             'prompt_number' : int,
             'input_sep'     : str
       },
 
       # The prompt number of the actual execution for this code, which may be
       # different from the one used when the code was typed, which was the
       # 'next_prompt' field of the *previous* request.  They will differ in the
       # case where there is more than one client talking simultaneously to a
       # kernel, since the numbers can go out of sync.  GUI clients can use this
       # to correct the previously written number in-place, terminal ones may
       # re-print a corrected one if desired.
       'prompt_number' : int,
     }
 
 When status is 'ok', the following extra fields are present::
 
     {
       # The kernel will often transform the input provided to it.  This
       # contains the transformed code, which is what was actually executed.
       'transformed_code' : str,
 
       # The execution payload is a dict with string keys that may have been
       # produced by the code being executed.  It is retrieved by the kernel at
       # the end of the execution and sent back to the front end, which can take
       # action on it as needed.  See main text for further details.
       'payload' : dict,
     }
 
 .. admonition:: Execution payloads
     
    The notion of an 'execution payload' is different from a return value of a
    given set of code, which normally is just displayed on the pyout stream
    through the PUB socket.  The idea of a payload is to allow special types of
    code, typically magics, to populate a data container in the IPython kernel
    that will be shipped back to the caller via this channel.  The kernel will
    have an API for this, probably something along the lines of::
 
        ip.exec_payload_add(key, value)
 
    though this API is still in the design stages.  The data returned in this
    payload will allow frontends to present special views of what just happened.
 
    
 When status is 'error', the following extra fields are present::
 
     {
       'exc_name' : str,   # Exception name, as a string
       'exc_value' : str,  # Exception value, as a string
 
       # The traceback will contain a list of frames, represented each as a
       # string.  For now we'll stick to the existing design of ultraTB, which
       # controls exception level of detail statefully.  But eventually we'll
       # want to grow into a model where more information is collected and
       # packed into the traceback object, with clients deciding how little or
       # how much of it to unpack.  But for now, let's start with a simple list
       # of strings, since that requires only minimal changes to ultratb as
       # written.
       'traceback' : list,
     }
 
 
 When status is 'abort', there are for now no additional data fields.  This
 happens when the kernel was interrupted by a signal.
 
 
 Prompt
 ------
 
 A simple request for a current prompt string.
 
 Message type: ``prompt_request``::
 
     content = {}
 
 In the reply, the prompt string comes back with the prompt number placeholder
 *unevaluated*.  The message format is:
     
 Message type: ``prompt_reply``::
 
     content = {
       'prompt_string' : str,
       'prompt_number' : int,
+      'input_sep'     : str
     }
 
 Clients can produce a prompt with ``prompt_string.format(prompt_number)``, but
 they should be aware that the actual prompt number for that input could change
 later, in the case where multiple clients are interacting with a single
 kernel. 
 
 
 Object information
 ------------------
 
 One of IPython's most used capabilities is the introspection of Python objects
 in the user's namespace, typically invoked via the ``?`` and ``??`` characters
 (which in reality are shorthands for the ``%pinfo`` magic).  This is used often
 enough that it warrants an explicit message type, especially because frontends
 may want to get object information in response to user keystrokes (like Tab or
 F1) besides from the user explicitly typing code like ``x??``.
 
 Message type: ``object_info_request``::
 
     content = {
         # The (possibly dotted) name of the object to be searched in all
     # relevant namespaces
     'name' : str,
 
     # The level of detail desired.  The default (0) is equivalent to typing
     # 'x?' at the prompt, 1 is equivalent to 'x??'.
     'detail_level' : int,
     }
 
 The returned information will be a dictionary with keys very similar to the
 field names that IPython prints at the terminal.
     
 Message type: ``object_info_reply``::
 
     content = {
         # Flags for magics and system aliases
     'ismagic' : bool,
     'isalias' : bool,
 
     # The name of the namespace where the object was found ('builtin',
     # 'magics', 'alias', 'interactive', etc.)
     'namespace' : str,
 
     # The type name will be type.__name__ for normal Python objects, but it
     # can also be a string like 'Magic function' or 'System alias'
     'type_name' : str,
 
     'string_form' : str,
 
     # For objects with a __class__ attribute this will be set
     'base_class' : str,
 
     # For objects with a __len__ attribute this will be set
     'length' : int,
 
     # If the object is a function, class or method whose file we can find,
     # we give its full path
     'file' : str,
 
     # For pure Python callable objects, we can reconstruct the object
     # definition line which provides its call signature
     'definition' : str,
 
     # For instances, provide the constructor signature (the definition of
     # the __init__ method):
     'init_definition' : str,
     
     # Docstrings: for any object (function, method, module, package) with a
     # docstring, we show it.  But in addition, we may provide additional
     # docstrings.  For example, for instances we will show the constructor
     # and class docstrings as well, if available.
     'docstring' : str,
 
     # For instances, provide the constructor and class docstrings
     'init_docstring' : str,
     'class_docstring' : str,
 
     # If detail_level was 1, we also try to find the source code that
     # defines the object, if possible.  The string 'None' will indicate
     # that no source was found.
     'source' : str,
     }
 
     
 Complete
 --------
 
 Message type: ``complete_request``::
 
     content = {
         # The text to be completed, such as 'a.is'
     'text' : str,
 
     # The full line, such as 'print a.is'.  This allows completers to
     # make decisions that may require information about more than just the
     # current word.
     'line' : str,
 
     # The entire block of text where the line is.  This may be useful in the
     # case of multiline completions where more context may be needed.  Note: if
     # in practice this field proves unnecessary, remove it to lighten the
     # messages.
     
     'block' : str,
 
     # The position of the cursor where the user hit 'TAB' on the line.
     'cursor_pos' : int,
     }
 
 Message type: ``complete_reply``::
 
     content = {
         # The list of all matches to the completion request, such as
     # ['a.isalnum', 'a.isalpha'] for the above example.
     'matches' : list
     }
 
     
 History
 -------
 
 For clients to explicitly request history from a kernel.  The kernel has all
 the actual execution history stored in a single location, so clients can
 request it from the kernel when needed.
 
 Message type: ``history_request``::
 
     content = {
     
       # If True, also return output history in the resulting dict.
       'output' : bool,
 
       # If True, return the raw input history, else the transformed input.
       'raw' : bool,
 
       # This parameter can be one of: A number,  a pair of numbers, None
       # If not given, last 40 are returned.
       #  - number n: return the last n entries.
       #  - pair n1, n2: return entries in the range(n1, n2).
       #  - None: return all history
-      'range' : n or (n1, n2) or None,
-
-      # If a filter is given, it is  treated as a regular expression and only
-      #  matching entries are returned.  re.search() is used to find matches.
-      'filter' : str,
+      'index' : n or (n1, n2) or None,
     }
 
 Message type: ``history_reply``::
 
     content = {
       # A dict with prompt numbers as keys and either (input, output) or input
       # as the value depending on whether output was True or False,
       # respectively.
       'history' : dict,
     }
 Messages on the PUB/SUB socket
 ==============================
 
 Streams (stdout,  stderr, etc)
 ------------------------------
 
 Message type: ``stream``::
 
     content = {
         # The name of the stream is one of 'stdin', 'stdout', 'stderr'
     'name' : str,
     
     # The data is an arbitrary string to be written to that stream
     'data' : str,
     }
 
 When a kernel receives a raw_input call, it should also broadcast it on the pub
 socket with the names 'stdin' and 'stdin_reply'.  This will allow other clients
 to monitor/display kernel interactions and possibly replay them to their user
 or otherwise expose them.
 
 Python inputs
 -------------
 
 These messages are the re-broadcast of the ``execute_request``.
 
 Message type: ``pyin``::
 
     content = {
         # Source code to be executed, one or more lines
     'code' : str
     }
 
 Python outputs
 --------------
 
 When Python produces output from code that has been compiled in with the
 'single' flag to :func:`compile`, any expression that produces a value (such as
 ``1+1``) is passed to ``sys.displayhook``, which is a callable that can do with
 this value whatever it wants.  The default behavior of ``sys.displayhook`` in
 the Python interactive prompt is to print to ``sys.stdout`` the :func:`repr` of
 the value as long as it is not ``None`` (which isn't printed at all).  In our
 case, the kernel instantiates as ``sys.displayhook`` an object which has
 similar behavior, but which instead of printing to stdout, broadcasts these
 values as ``pyout`` messages for clients to display appropriately.
 
 Message type: ``pyout``::
 
     content = {
         # The data is typically the repr() of the object.
     'data' : str,
     
     # The prompt number for this execution is also provided so that clients
     # can display it, since IPython automatically creates variables called
     # _N (for prompt N).
     'prompt_number' : int,
     }
     
 Python errors
 -------------
 
 When an error occurs during code execution
 
 Message type: ``pyerr``::
 
     content = {
        # Similar content to the execute_reply messages for the 'error' case,
        # except the 'status' field is omitted.
     }
 
 Kernel crashes
 --------------
 
 When the kernel has an unexpected exception, caught by the last-resort
 sys.excepthook, we should broadcast the crash handler's output before exiting.
 This will allow clients to notice that a kernel died, inform the user and
 propose further actions.
 
 Message type: ``crash``::
 
     content = {
        # Similarly to the 'error' case for execute_reply messages, this will
        # contain exc_name, exc_type and traceback fields.
 
        # An additional field with supplementary information such as where to
        # send the crash message
        'info' : str,
     }
 
 
 Future ideas
 ------------
     
 Other potential message types, currently unimplemented, listed below as ideas.
     
 Message type: ``file``::
 
     content = {
     'path' : 'cool.jpg',
     'mimetype' : str,
     'data' : str,
     }
 
     
 Messages on the REQ/REP socket
 ==============================
 
 This is a socket that goes in the opposite direction: from the kernel to a
 *single* frontend, and its purpose is to allow ``raw_input`` and similar
 operations that read from ``sys.stdin`` on the kernel to be fulfilled by the
 client.  For now we will keep these messages as simple as possible, since they
 basically only mean to convey the ``raw_input(prompt)`` call.
 
 Message type: ``input_request``::
 
     content = { 'prompt' : str }
 
 Message type: ``input_reply``::
 
     content = { 'value' : str }
     
 .. Note::
 
    We do not explicitly try to forward the raw ``sys.stdin`` object, because in
    practice the kernel should behave like an interactive program.  When a
    program is opened on the console, the keyboard effectively takes over the
    ``stdin`` file descriptor, and it can't be used for raw reading anymore.
    Since the IPython kernel effectively behaves like a console program (albeit
    one whose "keyboard" is actually living in a separate process and
    transported over the zmq connection), raw ``stdin`` isn't expected to be
    available.
 
    
 Heartbeat for kernels
 =====================
 
 Initially we had considered using messages like those above over ZMQ for a
 kernel 'heartbeat' (a way to detect quickly and reliably whether a kernel is
 alive at all, even if it may be busy executing user code).  But this has the
 problem that if the kernel is locked inside extension code, it wouldn't execute
 the python heartbeat code.  But it turns out that we can implement a basic
 heartbeat with pure ZMQ, without using any Python messaging at all.
 
 The monitor sends out a single zmq message (right now, it is a str of the
 monitor's lifetime in seconds), and gets the same message right back, prefixed
 with the zmq identity of the XREQ socket in the heartbeat process. This can be
 a uuid, or even a full message, but there doesn't seem to be a need for packing
 up a message when the sender and receiver are the exact same Python object.
 
 The model is this::
 
     monitor.send(str(self.lifetime)) # '1.2345678910'
 
 and the monitor receives some number of messages of the form::
 
     ['uuid-abcd-dead-beef', '1.2345678910']
 
 where the first part is the zmq.IDENTITY of the heart's XREQ on the engine, and
 the rest is the message sent by the monitor.  No Python code ever has any
 access to the message between the monitor's send, and the monitor's recv.
 
 
 ToDo
 ====
 
 Missing things include:
 
 * Important: finish thinking through the payload concept and API.
 
 * Important: ensure that we have a good solution for magics like %edit.  It's
   likely that with the payload concept we can build a full solution, but not
   100% clear yet.
 
 * Finishing the details of the heartbeat protocol.
 
 * Signal handling: specify what kind of information kernel should broadcast (or
   not) when it receives signals.
 
 .. include:: ../links.rst