Merge branch 'epatters-qtfrontend' into kernelmanager

Conflicts:
	IPython/frontend/qt/kernelmanager.py
	IPython/frontend/qt/util.py

IPython/frontend/qt/console/ansi_code_processor.py

@@ -0,0 +1,131 b''
+# Standard library imports
+import re
+
+# System library imports
+from PyQt4 import QtCore, QtGui
+
+
+class AnsiCodeProcessor(object):
+    """ Translates ANSI escape codes into readable attributes.
+    """
+
+    # Protected class variables.
+    _ansi_commands = 'ABCDEFGHJKSTfmnsu'
+    _ansi_pattern = re.compile('\x01?\x1b\[(.*?)([%s])\x02?' % _ansi_commands)
+
+    def __init__(self):
+        self.reset()
+
+    def reset(self):
+        """ Reset attributs to their default values.
+        """
+        self.intensity = 0
+        self.italic = False
+        self.bold = False
+        self.underline = False
+        self.foreground_color = None
+        self.background_color = None
+
+    def split_string(self, string):
+        """ Yields substrings for which the same escape code applies.
+        """
+        start = 0
+
+        for match in self._ansi_pattern.finditer(string):
+            substring = string[start:match.start()]
+            if substring:
+                yield substring
+            start = match.end()
+
+            params = map(int, match.group(1).split(';'))
+            self.set_csi_code(match.group(2), params)
+
+        substring = string[start:]
+        if substring:
+            yield substring
+
+    def set_csi_code(self, command, params=[]):
+        """ Set attributes based on CSI (Control Sequence Introducer) code.
+
+        Parameters
+        ----------
+        command : str
+            The code identifier, i.e. the final character in the sequence.
+        
+        params : sequence of integers, optional
+            The parameter codes for the command.
+        """
+        if command == 'm': # SGR - Select Graphic Rendition
+            for code in params:
+                self.set_sgr_code(code)
+        
+    def set_sgr_code(self, code):
+        """ Set attributes based on SGR (Select Graphic Rendition) code.
+        """
+        if code == 0:
+            self.reset()
+        elif code == 1:
+            self.intensity = 1
+            self.bold = True
+        elif code == 2:
+            self.intensity = 0
+        elif code == 3:
+            self.italic = True
+        elif code == 4:
+            self.underline = True
+        elif code == 22:
+            self.intensity = 0
+            self.bold = False
+        elif code == 23:
+            self.italic = False
+        elif code == 24:
+            self.underline = False
+        elif code >= 30 and code <= 37:
+            self.foreground_color = code - 30
+        elif code == 39:
+            self.foreground_color = None
+        elif code >= 40 and code <= 47:
+            self.background_color = code - 40
+        elif code == 49:
+            self.background_color = None
+        
+
+class QtAnsiCodeProcessor(AnsiCodeProcessor):
+    """ Translates ANSI escape codes into QTextCharFormats.
+    """
+
+    # A map from color codes to RGB colors.
+    ansi_colors = ( # Normal, Bright/Light
+                   ('#000000', '#7f7f7f'), # 0: black
+                   ('#cd0000', '#ff0000'), # 1: red
+                   ('#00cd00', '#00ff00'), # 2: green
+                   ('#cdcd00', '#ffff00'), # 3: yellow
+                   ('#0000ee', '#0000ff'), # 4: blue
+                   ('#cd00cd', '#ff00ff'), # 5: magenta
+                   ('#00cdcd', '#00ffff'), # 6: cyan
+                   ('#e5e5e5', '#ffffff')) # 7: white
+    
+    def get_format(self):
+        """ Returns a QTextCharFormat that encodes the current style attributes.
+        """
+        format = QtGui.QTextCharFormat()
+
+        # Set foreground color
+        if self.foreground_color is not None:
+            color = self.ansi_colors[self.foreground_color][self.intensity]
+            format.setForeground(QtGui.QColor(color))
+
+        # Set background color
+        if self.background_color is not None:
+            color = self.ansi_colors[self.background_color][self.intensity]
+            format.setBackground(QtGui.QColor(color))
+
+        # Set font weight/style options
+        if self.bold:
+            format.setFontWeight(QtGui.QFont.Bold)
+        else:
+            format.setFontWeight(QtGui.QFont.Normal)
+        format.setFontItalic(self.italic)
+        format.setFontUnderline(self.underline)
+
+        return format

IPython/frontend/qt/console/tests/test_ansi_code_processor.py

@@ -0,0 +1,32 b''
+# Standard library imports
+import unittest
+
+# Local imports
+from IPython.frontend.qt.console.ansi_code_processor import AnsiCodeProcessor
+
+
+class TestAnsiCodeProcessor(unittest.TestCase):
+
+    def setUp(self):
+        self.processor = AnsiCodeProcessor()
+
+    def testColors(self):
+        string = "first\x1b[34mblue\x1b[0mlast"
+        i = -1
+        for i, substring in enumerate(self.processor.split_string(string)):
+            if i == 0:
+                self.assertEquals(substring, 'first')
+                self.assertEquals(self.processor.foreground_color, None)
+            elif i == 1:
+                self.assertEquals(substring, 'blue')
+                self.assertEquals(self.processor.foreground_color, 4)
+            elif i == 2:
+                self.assertEquals(substring, 'last')
+                self.assertEquals(self.processor.foreground_color, None)
+            else:
+                self.fail("Too many substrings.")
+        self.assertEquals(i, 2, "Too few substrings.")
+
+
+if __name__ == '__main__':
+    unittest.main()

IPython/frontend/qt/console/completion_lexer.py

@@ -31,7 +31,7 b' class CompletionLexer(object):'
                 not string.endswith('\n'):
             reversed_tokens.pop(0)
         
-        current_op = unicode()
+        current_op = ''
         for token, text in reversed_tokens:
 
             if is_token_subtype(token, Token.Name):
@@ -39,14 +39,14 b' class CompletionLexer(object):'
                 # Handle a trailing separator, e.g 'foo.bar.'
                 if current_op in self._name_separators:
                     if not context:
-                        context.insert(0, unicode())
+                        context.insert(0, '')
 
                 # Handle non-separator operators and punction.
                 elif current_op:
                     break
 
                 context.insert(0, text)
-                current_op = unicode()
+                current_op = ''
 
             # Pygments doesn't understand that, e.g., '->' is a single operator
             # in C++. This is why we have to build up an operator from

IPython/frontend/qt/console/completion_widget.py

@@ -112,7 +112,7 b' class CompletionWidget(QtGui.QListWidget):'
     def _update_current(self):
         """ Updates the current item based on the current text.
         """
-        prefix = self._current_text_cursor().selectedText()
+        prefix = self._current_text_cursor().selection().toPlainText()
         if prefix:
             items = self.findItems(prefix, (QtCore.Qt.MatchStartsWith | 
                                             QtCore.Qt.MatchCaseSensitive))

IPython/frontend/qt/console/console_widget.py

@@ -1,99 +1,14 b''
 # Standard library imports
-import re
 import sys
 
 # System library imports
 from PyQt4 import QtCore, QtGui
 
 # Local imports
+from ansi_code_processor import QtAnsiCodeProcessor
 from completion_widget import CompletionWidget
 
 
-class AnsiCodeProcessor(object):
-    """ Translates ANSI escape codes into readable attributes.
-    """
-
-    def __init__(self):
-        self.ansi_colors = ( # Normal, Bright/Light
-                             ('#000000', '#7f7f7f'), # 0: black
-                             ('#cd0000', '#ff0000'), # 1: red
-                             ('#00cd00', '#00ff00'), # 2: green
-                             ('#cdcd00', '#ffff00'), # 3: yellow
-                             ('#0000ee', '#0000ff'), # 4: blue
-                             ('#cd00cd', '#ff00ff'), # 5: magenta
-                             ('#00cdcd', '#00ffff'), # 6: cyan
-                             ('#e5e5e5', '#ffffff')) # 7: white
-        self.reset()
-        
-    def set_code(self, code):
-        """ Set attributes based on code.
-        """
-        if code == 0:
-            self.reset()
-        elif code == 1:
-            self.intensity = 1
-            self.bold = True
-        elif code == 3:
-            self.italic = True
-        elif code == 4:
-            self.underline = True
-        elif code == 22:
-            self.intensity = 0
-            self.bold = False
-        elif code == 23:
-            self.italic = False
-        elif code == 24:
-            self.underline = False
-        elif code >= 30 and code <= 37:
-            self.foreground_color = code - 30
-        elif code == 39:
-            self.foreground_color = None
-        elif code >= 40 and code <= 47:
-            self.background_color = code - 40
-        elif code == 49:
-            self.background_color = None
-        
-    def reset(self):
-        """ Reset attributs to their default values.
-        """
-        self.intensity = 0
-        self.italic = False
-        self.bold = False
-        self.underline = False
-        self.foreground_color = None
-        self.background_color = None
-
-
-class QtAnsiCodeProcessor(AnsiCodeProcessor):
-    """ Translates ANSI escape codes into QTextCharFormats.
-    """
-    
-    def get_format(self):
-        """ Returns a QTextCharFormat that encodes the current style attributes.
-        """
-        format = QtGui.QTextCharFormat()
-
-        # Set foreground color
-        if self.foreground_color is not None:
-            color = self.ansi_colors[self.foreground_color][self.intensity]
-            format.setForeground(QtGui.QColor(color))
-
-        # Set background color
-        if self.background_color is not None:
-            color = self.ansi_colors[self.background_color][self.intensity]
-            format.setBackground(QtGui.QColor(color))
-
-        # Set font weight/style options
-        if self.bold:
-            format.setFontWeight(QtGui.QFont.Bold)
-        else:
-            format.setFontWeight(QtGui.QFont.Normal)
-        format.setFontItalic(self.italic)
-        format.setFontUnderline(self.underline)
-
-        return format
-
-
 class ConsoleWidget(QtGui.QPlainTextEdit):
     """ Base class for console-type widgets. This class is mainly concerned with
         dealing with the prompt, keeping the cursor inside the editing line, and
@@ -115,7 +30,6 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
     override_shortcuts = False
 
     # Protected class variables.
-    _ansi_pattern = re.compile('\x01?\x1b\[(.*?)m\x02?')
     _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,
@@ -133,14 +47,19 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
     def __init__(self, parent=None):
         QtGui.QPlainTextEdit.__init__(self, parent)
 
-        # Initialize protected variables.
+        # 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)
         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()
@@ -191,6 +110,11 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
         
         self._context_menu.exec_(event.globalPos())
 
+    def dragMoveEvent(self, event):
+        """ Reimplemented to disable moving text by drag and drop.
+        """
+        event.ignore()
+
     def keyPressEvent(self, event):
         """ Reimplemented to create a console-like interface.
         """
@@ -257,7 +181,10 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
         else:
             if key in (QtCore.Qt.Key_Return, QtCore.Qt.Key_Enter):
                 if self._reading:
+                    self.appendPlainText('\n')
                     self._reading = False
+                    if self._reading_callback:
+                        self._reading_callback()
                 elif not self._executing:
                     self.execute(interactive=True)
                 intercepted = True
@@ -303,7 +230,8 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
 
                 # Line deletion (remove continuation prompt)
                 len_prompt = len(self._continuation_prompt)
-                if cursor.columnNumber() == len_prompt and \
+                if not self._reading and \
+                        cursor.columnNumber() == len_prompt and \
                         position != self._prompt_pos:
                     cursor.setPosition(position - len_prompt, 
                                        QtGui.QTextCursor.KeepAnchor)
@@ -333,24 +261,38 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
     # 'QPlainTextEdit' interface
     #--------------------------------------------------------------------------
 
+    def appendHtml(self, html):
+        """ Reimplemented to not append HTML as a new paragraph, which doesn't
+            make sense for a console widget.
+        """
+        cursor = self._get_end_cursor()
+        cursor.insertHtml(html)
+
+        # After appending HTML, the text document "remembers" the current
+        # formatting, which means that subsequent calls to 'appendPlainText'
+        # will be formatted similarly, a behavior that we do not want. To
+        # prevent this, we make sure that the last character has no formatting.
+        cursor.movePosition(QtGui.QTextCursor.Left, 
+                            QtGui.QTextCursor.KeepAnchor)
+        if cursor.selection().toPlainText().trimmed().isEmpty():
+            # If the last character is whitespace, it doesn't matter how it's
+            # formatted, so just clear the formatting.
+            cursor.setCharFormat(QtGui.QTextCharFormat())
+        else:
+            # Otherwise, add an unformatted space.
+            cursor.movePosition(QtGui.QTextCursor.Right)
+            cursor.insertText(' ', QtGui.QTextCharFormat())
+
     def appendPlainText(self, text):
         """ Reimplemented to not append text as a new paragraph, which doesn't
             make sense for a console widget. Also, if enabled, handle ANSI
             codes.
         """
-        cursor = self.textCursor()
-        cursor.movePosition(QtGui.QTextCursor.End)
-
+        cursor = self._get_end_cursor()
         if self.ansi_codes:
-            format = QtGui.QTextCharFormat()
-            previous_end = 0
-            for match in self._ansi_pattern.finditer(text):
-                cursor.insertText(text[previous_end:match.start()], format)
-                previous_end = match.end()
-                for code in match.group(1).split(';'):
-                    self._ansi_processor.set_code(int(code))
+            for substring in self._ansi_processor.split_string(text):
                 format = self._ansi_processor.get_format()
-            cursor.insertText(text[previous_end:], format)
+                cursor.insertText(substring, format)
         else:
             cursor.insertText(text)
 
@@ -358,8 +300,7 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
         """ Reimplemented to write a new prompt. If 'keep_input' is set,
             restores the old input buffer when the new prompt is written.
         """
-        super(ConsoleWidget, self).clear()
-
+        QtGui.QPlainTextEdit.clear(self)
         if keep_input:
             input_buffer = self.input_buffer
         self._show_prompt()
@@ -451,9 +392,6 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
 
         cursor = self._get_end_cursor()
         cursor.setPosition(self._prompt_pos, QtGui.QTextCursor.KeepAnchor)
-
-        # Use QTextDocumentFragment intermediate object because it strips
-        # out the Unicode line break characters that Qt insists on inserting.
         input_buffer = str(cursor.selection().toPlainText())
 
         # Strip out continuation prompts.
@@ -462,16 +400,21 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
     def _set_input_buffer(self, string):
         """ Replaces the text in the input buffer with 'string'.
         """
-        # Add continuation prompts where necessary.
-        lines = string.splitlines()
-        for i in xrange(1, len(lines)):
-            lines[i] = self._continuation_prompt + lines[i]
-        string = '\n'.join(lines)
-
-        # Replace buffer with new text.
+        # Remove old text.
         cursor = self._get_end_cursor()
         cursor.setPosition(self._prompt_pos, QtGui.QTextCursor.KeepAnchor)
-        cursor.insertText(string)
+        cursor.removeSelectedText()
+
+        # Insert new text with continuation prompts.
+        lines = string.splitlines(True)
+        if lines:
+            self.appendPlainText(lines[0])
+            for i in xrange(1, len(lines)):
+                if self._continuation_prompt_html is None:
+                    self.appendPlainText(self._continuation_prompt)
+                else:
+                    self.appendHtml(self._continuation_prompt_html)
+                self.appendPlainText(lines[i])
         self.moveCursor(QtGui.QTextCursor.End)
 
     input_buffer = property(_get_input_buffer, _set_input_buffer)
@@ -484,7 +427,7 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
             return None
         cursor = self.textCursor()
         if cursor.position() >= self._prompt_pos:
-            text = str(cursor.block().text())
+            text = self._get_block_plain_text(cursor.block())
             if cursor.blockNumber() == self._get_prompt_cursor().blockNumber():
                 return text[len(self._prompt):]
             else:
@@ -502,6 +445,9 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
     def _set_font(self, font):
         """ Sets the base font for the ConsoleWidget to the specified QFont.
         """
+        font_metrics = QtGui.QFontMetrics(font)
+        self.setTabStopWidth(self.tab_width * font_metrics.width(' '))
+
         self._completion_widget.setFont(font)
         self.document().setDefaultFont(font)
 
@@ -519,6 +465,21 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
         font = QtGui.QFont(name, QtGui.qApp.font().pointSize())
         font.setStyleHint(QtGui.QFont.TypeWriter)
         self._set_font(font)
+
+    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.setTabStopWidth(tab_width * font_metrics.width(' '))
+
+        self._tab_width = tab_width
+
+    tab_width = property(_get_tab_width, _set_tab_width)
         
     #---------------------------------------------------------------------------
     # 'ConsoleWidget' abstract interface
@@ -569,6 +530,27 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
     # 'ConsoleWidget' protected interface
     #--------------------------------------------------------------------------
 
+    def _append_html_fetching_plain_text(self, html):
+        """ Appends 'html', then returns the plain text version of it.
+        """
+        anchor = self._get_end_cursor().position()
+        self.appendHtml(html)
+        cursor = self._get_end_cursor()
+        cursor.setPosition(anchor, QtGui.QTextCursor.KeepAnchor)
+        return str(cursor.selection().toPlainText())
+
+    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.appendPlainText('\n')
+        self._prompt_finished()
+
+        self.appendPlainText(text)
+        self._show_prompt()
+        self.input_buffer = input_buffer
+
     def _control_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
@@ -594,8 +576,84 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
             if self.gui_completion:
                 self._completion_widget.show_items(cursor, items) 
             else:
-                text = '\n'.join(items) + '\n'
-                self._write_text_keeping_prompt(text)
+                text = self.format_as_columns(items)
+                self._append_plain_text_keeping_prompt(text)
+
+    def format_as_columns(self, items, separator='  '):
+        """ Transform a list of strings into a single string with columns.
+
+        Parameters
+        ----------
+        items : sequence [str]
+            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/
+
+        font_metrics = QtGui.QFontMetrics(self.font)
+        displaywidth = max(5, (self.width() / font_metrics.width(' ')) - 1)
+
+        # 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_end_cursor(self):
         """ Convenience method that returns a cursor for the last character.
@@ -677,6 +735,70 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
         self.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 _reset(self):
+        """ Clears the console and resets internal state variables.
+        """
+        QtGui.QPlainTextEdit.clear(self)
+        self._executing = self._reading = False
+
+    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_position(self, position):
         """ Convenience method to set the position of the cursor.
         """
@@ -689,33 +811,60 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
         """
         self.setTextCursor(self._get_selection_cursor(start, end))
 
-    def _show_prompt(self, prompt=None):
-        """ Writes a new prompt at the end of the buffer. If 'prompt' is not
-            specified, uses the previous prompt.
-        """
-        if prompt is not None:
-            self._prompt = prompt
-        self.appendPlainText('\n' + self._prompt)
+    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.appendPlainText('\n')
+
+        # Write the prompt.
+        if prompt is None:
+            if self._prompt_html is None:
+                self.appendPlainText(self._prompt)
+            else:
+                self.appendHtml(self._prompt_html)
+        else:
+            if html:
+                self._prompt = self._append_html_fetching_plain_text(prompt)
+                self._prompt_html = prompt
+            else:
+                self.appendPlainText(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.
         """
-        self.appendPlainText(self._continuation_prompt)
-        self._prompt_started()
-
-    def _write_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.appendPlainText('\n')
-        self._prompt_finished()
+        if self._continuation_prompt_html is None:
+            self.appendPlainText(self._continuation_prompt)
+        else:
+            self._continuation_prompt = self._append_html_fetching_plain_text(
+                self._continuation_prompt_html)
 
-        self.appendPlainText(text)
-        self._show_prompt()
-        self.input_buffer = input_buffer
+        self._prompt_started()
 
     def _in_buffer(self, position):
         """ Returns whether the given position is inside the editing region.

IPython/frontend/qt/console/frontend_widget.py

@@ -1,5 +1,6 b''
 # Standard library imports
 import signal
+import sys
 
 # System library imports
 from pygments.lexers import PythonLexer
@@ -15,12 +16,12 b' from pygments_highlighter import PygmentsHighlighter'
 
 
 class FrontendHighlighter(PygmentsHighlighter):
-    """ A Python PygmentsHighlighter that can be turned on and off and which 
-        knows about continuation prompts.
+    """ A PygmentsHighlighter that can be turned on and off and that ignores
+        prompts.
     """
 
     def __init__(self, frontend):
-        PygmentsHighlighter.__init__(self, frontend.document(), PythonLexer())
+        super(FrontendHighlighter, self).__init__(frontend.document())
         self._current_offset = 0
         self._frontend = frontend
         self.highlighting_on = False
@@ -28,17 +29,32 b' class FrontendHighlighter(PygmentsHighlighter):'
     def highlightBlock(self, qstring):
         """ Highlight a block of text. Reimplemented to highlight selectively.
         """
-        if self.highlighting_on:
-            for prompt in (self._frontend._continuation_prompt,
-                           self._frontend._prompt):                           
-                if qstring.startsWith(prompt):
-                    qstring.remove(0, len(prompt))
-                    self._current_offset = len(prompt)
-                    break
-            PygmentsHighlighter.highlightBlock(self, qstring)
+        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 setFormat(self, start, count, format):
-        """ Reimplemented to avoid highlighting continuation prompts.
+        """ Reimplemented to highlight selectively.
         """
         start += self._current_offset
         PygmentsHighlighter.setFormat(self, start, count, format)
@@ -47,7 +63,7 b' class FrontendHighlighter(PygmentsHighlighter):'
 class FrontendWidget(HistoryConsoleWidget):
     """ A Qt frontend for a generic Python kernel.
     """
-
+   
     # Emitted when an 'execute_reply' is received from the kernel.
     executed = QtCore.pyqtSignal(object)
 
@@ -58,10 +74,6 b' class FrontendWidget(HistoryConsoleWidget):'
     def __init__(self, parent=None):
         super(FrontendWidget, self).__init__(parent)
 
-        # ConsoleWidget protected variables.
-        self._continuation_prompt = '... '
-        self._prompt = '>>> '
-
         # FrontendWidget protected variables.
         self._call_tip_widget = CallTipWidget(self)
         self._completion_lexer = CompletionLexer(PythonLexer())
@@ -70,6 +82,10 b' class FrontendWidget(HistoryConsoleWidget):'
         self._input_splitter = InputSplitter(input_mode='replace')
         self._kernel_manager = None
 
+        # Configure the ConsoleWidget.
+        self.tab_width = 4
+        self._set_continuation_prompt('... ')
+
         self.document().contentsChange.connect(self._document_contents_change)
 
     #---------------------------------------------------------------------------
@@ -103,7 +119,7 b' class FrontendWidget(HistoryConsoleWidget):'
             prompt created. When triggered by an Enter/Return key press,
             'interactive' is True; otherwise, it is False.
         """
-        complete = self._input_splitter.push(source)
+        complete = self._input_splitter.push(source.expandtabs(4))
         if interactive:
             complete = not self._input_splitter.push_accepts_more()
         return complete
@@ -117,18 +133,22 b' class FrontendWidget(HistoryConsoleWidget):'
     def _prompt_started_hook(self):
         """ Called immediately after a new prompt is displayed.
         """
-        self._highlighter.highlighting_on = True
+        if not self._reading:
+            self._highlighter.highlighting_on = True
 
-        # Auto-indent if this is a continuation prompt.
-        if self._get_prompt_cursor().blockNumber() != \
-                self._get_end_cursor().blockNumber():
-            self.appendPlainText(' ' * self._input_splitter.indent_spaces)
+            # Auto-indent if this is a continuation prompt.
+            if self._get_prompt_cursor().blockNumber() != \
+                    self._get_end_cursor().blockNumber():
+                spaces = self._input_splitter.indent_spaces
+                self.appendPlainText('\t' * (spaces / self.tab_width))
+                self.appendPlainText(' ' * (spaces % self.tab_width))
 
     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.
         """
-        self._highlighter.highlighting_on = False
+        if not self._reading:
+            self._highlighter.highlighting_on = False
 
     def _tab_pressed(self):
         """ Called when the tab key is pressed. Returns whether to continue
@@ -136,9 +156,7 b' class FrontendWidget(HistoryConsoleWidget):'
         """
         self._keep_cursor_in_buffer()
         cursor = self.textCursor()
-        if not self._complete():
-            cursor.insertText('    ')
-        return False
+        return not self._complete()
 
     #---------------------------------------------------------------------------
     # 'FrontendWidget' interface
@@ -161,22 +179,24 b' class FrontendWidget(HistoryConsoleWidget):'
         """
         # Disconnect the old kernel manager, if necessary.
         if self._kernel_manager is not None:
-            self._kernel_manager.started_listening.disconnect(
-                self._started_listening)
-            self._kernel_manager.stopped_listening.disconnect(
-                self._stopped_listening)
+            self._kernel_manager.started_channels.disconnect(
+                self._started_channels)
+            self._kernel_manager.stopped_channels.disconnect(
+                self._stopped_channels)
 
             # Disconnect the old kernel manager's channels.
             sub = self._kernel_manager.sub_channel
             xreq = self._kernel_manager.xreq_channel
+            rep = self._kernel_manager.rep_channel
             sub.message_received.disconnect(self._handle_sub)
             xreq.execute_reply.disconnect(self._handle_execute_reply)
             xreq.complete_reply.disconnect(self._handle_complete_reply)
             xreq.object_info_reply.disconnect(self._handle_object_info_reply)
+            rep.readline_requested.disconnect(self._handle_req)
 
             # Handle the case where the old kernel manager is still listening.
             if self._kernel_manager.channels_running:
-                self._stopped_listening()
+                self._stopped_channels()
 
         # Set the new kernel manager.
         self._kernel_manager = kernel_manager
@@ -184,21 +204,23 b' class FrontendWidget(HistoryConsoleWidget):'
             return
 
         # Connect the new kernel manager.
-        kernel_manager.started_listening.connect(self._started_listening)
-        kernel_manager.stopped_listening.connect(self._stopped_listening)
+        kernel_manager.started_channels.connect(self._started_channels)
+        kernel_manager.stopped_channels.connect(self._stopped_channels)
 
         # Connect the new kernel manager's channels.
         sub = kernel_manager.sub_channel
         xreq = kernel_manager.xreq_channel
+        rep = kernel_manager.rep_channel
         sub.message_received.connect(self._handle_sub)
         xreq.execute_reply.connect(self._handle_execute_reply)
         xreq.complete_reply.connect(self._handle_complete_reply)
         xreq.object_info_reply.connect(self._handle_object_info_reply)
+        rep.readline_requested.connect(self._handle_req)
         
-        # Handle the case where the kernel manager started listening before
+        # Handle the case where the kernel manager started channels before
         # we connected.
         if kernel_manager.channels_running:
-            self._started_listening()
+            self._started_channels()
 
     kernel_manager = property(_get_kernel_manager, _set_kernel_manager)
 
@@ -240,6 +262,13 b' class FrontendWidget(HistoryConsoleWidget):'
         self._complete_pos = self.textCursor().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.
         """
@@ -247,7 +276,7 b' class FrontendWidget(HistoryConsoleWidget):'
             cursor = self.textCursor()
         cursor.movePosition(QtGui.QTextCursor.StartOfLine, 
                             QtGui.QTextCursor.KeepAnchor)
-        text = unicode(cursor.selectedText())
+        text = str(cursor.selection().toPlainText())
         return self._completion_lexer.get_context(text)
 
     def _interrupt_kernel(self):
@@ -259,8 +288,26 b' class FrontendWidget(HistoryConsoleWidget):'
             self.appendPlainText('Kernel process is either remote or '
                                  'unspecified. Cannot interrupt.\n')
 
+    def _show_interpreter_prompt(self):
+        """ Shows a prompt for the interpreter.
+        """
+        self._show_prompt('>>> ')
+
     #------ Signal handlers ----------------------------------------------------
 
+    def _started_channels(self):
+        """ Called when the kernel manager has started listening.
+        """
+        self._reset()
+        self.appendPlainText(self._get_banner())
+        self._show_interpreter_prompt()
+
+    def _stopped_channels(self):
+        """ Called when the kernel manager has stopped listening.
+        """
+        # FIXME: Print a message here?
+        pass
+
     def _document_contents_change(self, position, removed, added):
         """ Called whenever the document's content changes. Display a calltip
             if appropriate.
@@ -272,6 +319,15 b' class FrontendWidget(HistoryConsoleWidget):'
         if position == self.textCursor().position():
             self._call_tip()
 
+    def _handle_req(self, req):
+        # 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.readline(line)
+        self._readline(callback=callback)
+
     def _handle_sub(self, omsg):
         if self._hidden:
             return
@@ -280,15 +336,13 b' class FrontendWidget(HistoryConsoleWidget):'
             handler(omsg)
 
     def _handle_pyout(self, omsg):
-        session = omsg['parent_header']['session']
-        if session == self.kernel_manager.session.session:
-            self.appendPlainText(omsg['content']['data'] + '\n')
+        self.appendPlainText(omsg['content']['data'] + '\n')
 
     def _handle_stream(self, omsg):
         self.appendPlainText(omsg['content']['data'])
         self.moveCursor(QtGui.QTextCursor.End)
         
-    def _handle_execute_reply(self, rep):
+    def _handle_execute_reply(self, reply):
         if self._hidden:
             return
 
@@ -296,16 +350,20 b' class FrontendWidget(HistoryConsoleWidget):'
         # before writing a new prompt.
         self.kernel_manager.sub_channel.flush()
 
-        content = rep['content']
-        status = content['status']
+        status = reply['content']['status']
         if status == 'error':
-            self.appendPlainText(content['traceback'][-1])
+            self._handle_execute_error(reply)
         elif status == 'aborted':
             text = "ERROR: ABORTED\n"
             self.appendPlainText(text)
         self._hidden = True
-        self._show_prompt()
-        self.executed.emit(rep)
+        self._show_interpreter_prompt()
+        self.executed.emit(reply)
+
+    def _handle_execute_error(self, reply):
+        content = reply['content']
+        traceback = ''.join(content['traceback'])
+        self.appendPlainText(traceback)
 
     def _handle_complete_reply(self, rep):
         cursor = self.textCursor()
@@ -322,9 +380,3 b' class FrontendWidget(HistoryConsoleWidget):'
             doc = rep['content']['docstring']
             if doc:
                 self._call_tip_widget.show_docstring(doc)
-
-    def _started_listening(self):
-        self.clear()
-
-    def _stopped_listening(self):
-        pass

IPython/frontend/qt/console/ipython_widget.py

@@ -2,6 +2,7 b''
 from PyQt4 import QtCore, QtGui
 
 # Local imports
+from IPython.core.usage import default_banner
 from frontend_widget import FrontendWidget
 
 
@@ -9,6 +10,15 b' class IPythonWidget(FrontendWidget):'
     """ A FrontendWidget for an IPython kernel.
     """
 
+    # The default stylesheet for prompts, colors, etc.
+    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; }
+    """
+
     #---------------------------------------------------------------------------
     # 'QObject' interface
     #---------------------------------------------------------------------------
@@ -16,7 +26,12 b' class IPythonWidget(FrontendWidget):'
     def __init__(self, parent=None):
         super(IPythonWidget, self).__init__(parent)
 
+        # Initialize protected variables.
         self._magic_overrides = {}
+        self._prompt_count = 0
+
+        # Set a default stylesheet.
+        self.set_style_sheet(self.default_stylesheet)
 
     #---------------------------------------------------------------------------
     # 'ConsoleWidget' abstract interface
@@ -37,7 +52,7 b' class IPythonWidget(FrontendWidget):'
             output = callback(arguments)
             if output:
                 self.appendPlainText(output)
-            self._show_prompt()
+            self._show_interpreter_prompt()
         else:
             super(IPythonWidget, self)._execute(source, hidden)
 
@@ -51,6 +66,56 b' class IPythonWidget(FrontendWidget):'
         self.execute('run %s' % path, hidden=hidden)
 
     #---------------------------------------------------------------------------
+    # 'FrontendWidget' protected interface
+    #---------------------------------------------------------------------------
+
+    def _get_banner(self):
+        """ Reimplemented to return IPython's default banner.
+        """
+        return default_banner
+
+    def _show_interpreter_prompt(self):
+        """ Reimplemented for IPython-style prompts.
+        """
+        self._prompt_count += 1
+        prompt_template = '<span class="in-prompt">%s</span>'
+        prompt_body = '<br/>In [<span class="in-prompt-number">%i</span>]: '
+        prompt = (prompt_template % prompt_body) % self._prompt_count
+        self._show_prompt(prompt, html=True)
+
+        # Update continuation prompt to reflect (possibly) new prompt length.
+        cont_prompt_chars = '...: '
+        space_count = len(self._prompt.lstrip()) - len(cont_prompt_chars)
+        cont_prompt_body = '&nbsp;' * space_count + cont_prompt_chars
+        self._continuation_prompt_html = prompt_template % cont_prompt_body
+
+    #------ Signal handlers ----------------------------------------------------
+
+    def _handle_execute_error(self, reply):
+        """ Reimplemented for IPython-style traceback formatting.
+        """
+        content = reply['content']
+        traceback_lines = content['traceback'][:]
+        traceback = ''.join(traceback_lines)
+        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.appendHtml(traceback)
+
+    def _handle_pyout(self, omsg):
+        """ Reimplemented for IPython-style "display hook".
+        """
+        prompt_template = '<span class="out-prompt">%s</span>'
+        prompt_body = 'Out[<span class="out-prompt-number">%i</span>]: '
+        prompt = (prompt_template % prompt_body) % self._prompt_count
+        self.appendHtml(prompt)
+        self.appendPlainText(omsg['content']['data'] + '\n')
+
+    #---------------------------------------------------------------------------
     # 'IPythonWidget' interface
     #---------------------------------------------------------------------------
 
@@ -71,32 +136,26 b' class IPythonWidget(FrontendWidget):'
         except KeyError:
             pass
 
+    def set_style_sheet(self, stylesheet):
+        """ Sets the style sheet.
+        """
+        self.document().setDefaultStyleSheet(stylesheet)
+
 
 if __name__ == '__main__':
-    import signal
     from IPython.frontend.qt.kernelmanager import QtKernelManager
 
+    # Don't let Qt or ZMQ swallow KeyboardInterupts.
+    import signal
+    signal.signal(signal.SIGINT, signal.SIG_DFL)
+
     # Create a KernelManager.
     kernel_manager = QtKernelManager()
     kernel_manager.start_kernel()
     kernel_manager.start_channels()
 
-    # Don't let Qt or ZMQ swallow KeyboardInterupts.
-    # FIXME: Gah, ZMQ swallows even custom signal handlers. So for now we leave 
-    #        behind a kernel process when Ctrl-C is pressed.
-    #def sigint_hook(signum, frame):
-    #    QtGui.qApp.quit()
-    #signal.signal(signal.SIGINT, sigint_hook)
-    signal.signal(signal.SIGINT, signal.SIG_DFL)
-
-    # Create the application, making sure to clean up nicely when we exit.
-    app = QtGui.QApplication([])
-    def quit_hook():
-        kernel_manager.stop_channels()
-        kernel_manager.kill_kernel()
-    app.aboutToQuit.connect(quit_hook)
-
     # Launch the application.
+    app = QtGui.QApplication([])
     widget = IPythonWidget()
     widget.kernel_manager = kernel_manager
     widget.setWindowTitle('Python')

IPython/frontend/qt/console/pygments_highlighter.py

@@ -1,7 +1,7 b''
 # System library imports.
 from PyQt4 import QtGui
 from pygments.lexer import RegexLexer, _TokenType, Text, Error
-from pygments.lexers import CLexer, CppLexer, PythonLexer
+from pygments.lexers import PythonLexer
 from pygments.styles.default import DefaultStyle
 from pygments.token import Comment
 
@@ -133,7 +133,7 b' class PygmentsHighlighter(QtGui.QSyntaxHighlighter):'
         if token in self._formats:
             return self._formats[token]
         result = None
-        for key, value in self._style.style_for_token(token) .items():
+        for key, value in self._style.style_for_token(token).items():
             if value:
                 if result is None:
                     result = QtGui.QTextCharFormat()
@@ -171,12 +171,11 b' class PygmentsHighlighter(QtGui.QSyntaxHighlighter):'
             qcolor = self._get_color(color)
             result = QtGui.QBrush(qcolor)
             self._brushes[color] = result
-
         return result
 
     def _get_color(self, color):
         qcolor = QtGui.QColor()
-        qcolor.setRgb(int(color[:2],base=16),
+        qcolor.setRgb(int(color[:2], base=16),
                       int(color[2:4], base=16),
                       int(color[4:6], base=16))
         return qcolor

IPython/frontend/qt/kernelmanager.py

@@ -17,6 +17,9 b' from util import MetaQObjectHasTraits'
 # * QtCore.QObject.__init__ takes 1 argument, the parent. So if you are going
 #   to use super, any class that comes before QObject must pass it something
 #   reasonable.
+# In summary, I don't think using super in these situations will work.
+# Instead we will need to call the __init__ methods of both parents
+# by hand.  Not pretty, but it works.
 
 class QtSubSocketChannel(SubSocketChannel, QtCore.QObject):
 
@@ -102,6 +105,12 b' class QtXReqSocketChannel(XReqSocketChannel, QtCore.QObject):'
 
 class QtRepSocketChannel(RepSocketChannel, QtCore.QObject):
 
+    # Emitted when any message is received.
+    message_received = QtCore.pyqtSignal(object)
+
+    # Emitted when a readline request is received.
+    readline_requested = QtCore.pyqtSignal(object)
+
     #---------------------------------------------------------------------------
     # 'object' interface
     #---------------------------------------------------------------------------
@@ -112,6 +121,22 b' class QtRepSocketChannel(RepSocketChannel, QtCore.QObject):'
         QtCore.QObject.__init__(self)
         RepSocketChannel.__init__(self, *args, **kw)
 
+    #---------------------------------------------------------------------------
+    # 'RepSocketChannel' interface
+    #---------------------------------------------------------------------------
+
+    def call_handlers(self, msg):
+        """ Reimplemented to emit signals instead of making callbacks.
+        """
+        # Emit the generic signal.
+        self.message_received.emit(msg)
+        
+        # Emit signals for specialized message types.
+        msg_type = msg['msg_type']
+        if msg_type == 'readline_request':
+            self.readline_requested.emit(msg)
+
+
 class QtKernelManager(KernelManager, QtCore.QObject):
     """ A KernelManager that provides signals and slots.
     """
@@ -119,10 +144,10 b' class QtKernelManager(KernelManager, QtCore.QObject):'
     __metaclass__ = MetaQObjectHasTraits
 
     # Emitted when the kernel manager has started listening.
-    started_listening = QtCore.pyqtSignal()
+    started_channels = QtCore.pyqtSignal()
 
     # Emitted when the kernel manager has stopped listening.
-    stopped_listening = QtCore.pyqtSignal()
+    stopped_channels = QtCore.pyqtSignal()
 
     # Use Qt-specific channel classes that emit signals.
     sub_channel_class = QtSubSocketChannel
@@ -134,6 +159,16 b' class QtKernelManager(KernelManager, QtCore.QObject):'
         KernelManager.__init__(self, *args, **kw)
 
     #---------------------------------------------------------------------------
+    # 'object' interface
+    #---------------------------------------------------------------------------
+    
+    def __init__(self, *args, **kw):
+        """ Reimplemented to ensure that QtCore.QObject is initialized first.
+        """
+        QtCore.QObject.__init__(self)
+        KernelManager.__init__(self, *args, **kw)
+
+    #---------------------------------------------------------------------------
     # 'KernelManager' interface
     #---------------------------------------------------------------------------
     
@@ -141,10 +176,10 b' class QtKernelManager(KernelManager, QtCore.QObject):'
         """ Reimplemented to emit signal.
         """
         super(QtKernelManager, self).start_channels()
-        self.started_listening.emit()
+        self.started_channels.emit()
 
     def stop_channels(self):
         """ Reimplemented to emit signal.
         """ 
         super(QtKernelManager, self).stop_channels()
-        self.stopped_listening.emit()
+        self.stopped_channels.emit()

IPython/frontend/qt/util.py

@@ -11,7 +11,7 b' from IPython.utils.traitlets import HasTraits'
 MetaHasTraits = type(HasTraits)
 MetaQObject = type(QtCore.QObject)
 
-# You can switch the order of the parents here.
+# You can switch the order of the parents here and it doesn't seem to matter.
 class MetaQObjectHasTraits(MetaQObject, MetaHasTraits):
     """ A metaclass that inherits from the metaclasses of both HasTraits and
         QObject. 
@@ -19,9 +19,4 b' class MetaQObjectHasTraits(MetaQObject, MetaHasTraits):'
         Using this metaclass allows a class to inherit from both HasTraits and
         QObject. See QtKernelManager for an example.
     """
-    # pass
-    # ???You can get rid of this, but only if the order above is MetaQObject, MetaHasTraits
-    # def __init__(cls, name, bases, dct):
-    #     MetaQObject.__init__(cls, name, bases, dct)
-    #     MetaHasTraits.__init__(cls, name, bases, dct)
-
+    pass

IPython/zmq/kernel.py

@@ -11,12 +11,19 b' Things to do:'
 * Implement event loop and poll version.
 """
 
+#-----------------------------------------------------------------------------
+# Imports
+#-----------------------------------------------------------------------------
+
 # Standard library imports.
 import __builtin__
+from code import CommandCompiler
+from cStringIO import StringIO
+import os
 import sys
+from threading import Thread
 import time
 import traceback
-from code import CommandCompiler
 
 # System library imports.
 import zmq
@@ -26,18 +33,109 b' from IPython.external.argparse import ArgumentParser'
 from session import Session, Message, extract_header
 from completer import KernelCompleter
 
+#-----------------------------------------------------------------------------
+# Kernel and stream classes
+#-----------------------------------------------------------------------------
+
+class InStream(object):
+    """ A file like object that reads from a 0MQ XREQ socket."""
+
+    def __init__(self, session, socket):
+        self.session = session
+        self.socket = socket
+
+    def close(self):
+        self.socket = None
+
+    def flush(self):
+        if self.socket is None:
+            raise ValueError('I/O operation on closed file')
+        
+    def isatty(self):
+        return False
+
+    def next(self):
+        raise IOError('Seek not supported.')
+
+    def read(self, size=-1):
+        # FIXME: Do we want another request for this?
+        string = '\n'.join(self.readlines())
+        return self._truncate(string, size)
+
+    def readline(self, size=-1):
+        if self.socket is None:
+            raise ValueError('I/O operation on closed file')
+        else:
+            content = dict(size=size)
+            msg = self.session.msg('readline_request', content=content) 
+            reply = self._request(msg)
+            line = reply['content']['line']
+            return self._truncate(line, size)
+
+    def readlines(self, sizehint=-1):
+        # Sizehint is ignored, as is permitted.
+        if self.socket is None:
+            raise ValueError('I/O operation on closed file')
+        else:
+            lines = []
+            while True:
+                line = self.readline()
+                if line:
+                    lines.append(line)
+                else:
+                    break
+            return lines
+
+    def seek(self, offset, whence=None):
+        raise IOError('Seek not supported.')
+
+    def write(self, string):
+        raise IOError('Write not supported on a read only stream.')
+
+    def writelines(self, sequence):
+        raise IOError('Write not supported on a read only stream.')
+    
+    def _request(self, msg):
+        # Flush output before making the request. This ensures, for example,
+        # that raw_input(prompt) actually gets a prompt written.
+        sys.stderr.flush()
+        sys.stdout.flush()
+
+        self.socket.send_json(msg)
+        while True:
+            try:
+                reply = self.socket.recv_json(zmq.NOBLOCK)
+            except zmq.ZMQError, e:
+                if e.errno == zmq.EAGAIN:
+                    pass
+                else:
+                    raise
+            else:
+                break
+        return reply
+
+    def _truncate(self, string, size):
+        if size >= 0:
+            if isinstance(string, str):
+                return string[:size]
+            elif isinstance(string, unicode):
+                encoded = string.encode('utf-8')[:size]
+                return encoded.decode('utf-8', 'ignore')
+        return string
+
 
 class OutStream(object):
     """A file like object that publishes the stream to a 0MQ PUB socket."""
 
-    def __init__(self, session, pub_socket, name, max_buffer=200):
+    # The time interval between automatic flushes, in seconds.
+    flush_interval = 0.05
+
+    def __init__(self, session, pub_socket, name):
         self.session = session
         self.pub_socket = pub_socket
         self.name = name
-        self._buffer = []
-        self._buffer_len = 0
-        self.max_buffer = max_buffer
         self.parent_header = {}
+        self._new_buffer()
 
     def set_parent(self, parent):
         self.parent_header = extract_header(parent)
@@ -49,47 +147,50 b' class OutStream(object):'
         if self.pub_socket is None:
             raise ValueError(u'I/O operation on closed file')
         else:
-            if self._buffer:
-                data = ''.join(self._buffer)
+            data = self._buffer.getvalue()
+            if data:
                 content = {u'name':self.name, u'data':data}
                 msg = self.session.msg(u'stream', content=content,
                                        parent=self.parent_header)
                 print>>sys.__stdout__, Message(msg)
                 self.pub_socket.send_json(msg)
-                self._buffer_len = 0
-                self._buffer = []
+                
+                self._buffer.close()
+                self._new_buffer()
 
-    def isattr(self):
+    def isatty(self):
         return False
 
     def next(self):
         raise IOError('Read not supported on a write only stream.')
 
-    def read(self, size=None):
+    def read(self, size=-1):
         raise IOError('Read not supported on a write only stream.')
 
-    readline=read
+    def readline(self, size=-1):
+        raise IOError('Read not supported on a write only stream.')
 
-    def write(self, s):
+    def write(self, string):
         if self.pub_socket is None:
             raise ValueError('I/O operation on closed file')
         else:
-            self._buffer.append(s)
-            self._buffer_len += len(s)
-            self._maybe_send()
-
-    def _maybe_send(self):
-        if '\n' in self._buffer[-1]:
-            self.flush()
-        if self._buffer_len > self.max_buffer:
-            self.flush()
+            self._buffer.write(string)
+            current_time = time.time()
+            if self._start <= 0:
+                self._start = current_time
+            elif current_time - self._start > self.flush_interval:
+                self.flush()
 
     def writelines(self, sequence):
         if self.pub_socket is None:
             raise ValueError('I/O operation on closed file')
         else:
-            for s in sequence:
-                self.write(s)
+            for string in sequence:
+                self.write(string)
+
+    def _new_buffer(self):
+        self._buffer = StringIO()
+        self._start = -1
 
 
 class DisplayHook(object):
@@ -112,28 +213,6 b' class DisplayHook(object):'
         self.parent_header = extract_header(parent)
 
 
-class RawInput(object):
-
-    def __init__(self, session, socket):
-        self.session = session
-        self.socket = socket
-
-    def __call__(self, prompt=None):
-        msg = self.session.msg(u'raw_input')
-        self.socket.send_json(msg)
-        while True:
-            try:
-                reply = self.socket.recv_json(zmq.NOBLOCK)
-            except zmq.ZMQError, e:
-                if e.errno == zmq.EAGAIN:
-                    pass
-                else:
-                    raise
-            else:
-                break
-        return reply[u'content'][u'data']
-
-
 class Kernel(object):
 
     def __init__(self, session, reply_socket, pub_socket):
@@ -183,6 +262,7 b' class Kernel(object):'
             return
         pyin_msg = self.session.msg(u'pyin',{u'code':code}, parent=parent)
         self.pub_socket.send_json(pyin_msg)
+
         try:
             comp_code = self.compiler(code, '<zmq-kernel>')
             sys.displayhook.set_parent(parent)
@@ -194,7 +274,7 b' class Kernel(object):'
             exc_content = {
                 u'status' : u'error',
                 u'traceback' : tb,
-                u'etype' : unicode(etype),
+                u'ename' : unicode(etype.__name__),
                 u'evalue' : unicode(evalue)
             }
             exc_msg = self.session.msg(u'pyerr', exc_content, parent)
@@ -202,6 +282,12 b' class Kernel(object):'
             reply_content = exc_content
         else:
             reply_content = {'status' : 'ok'}
+            
+        # 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)
@@ -270,19 +356,62 b' class Kernel(object):'
             else:
                 handler(ident, omsg)
 
+#-----------------------------------------------------------------------------
+# Kernel main and launch functions
+#-----------------------------------------------------------------------------
+
+class ExitPollerUnix(Thread):
+    """ A Unix-specific daemon thread that terminates the program immediately 
+    when this process' parent process no longer exists.
+    """
+
+    def __init__(self):
+        super(ExitPollerUnix, self).__init__()
+        self.daemon = True
+    
+    def run(self):
+        # We cannot use os.waitpid because it works only for child processes.
+        from errno import EINTR
+        while True:
+            try:
+                if os.getppid() == 1:
+                    os._exit(1)
+                time.sleep(1.0)
+            except OSError, e:
+                if e.errno == EINTR:
+                    continue
+                raise
+
+class ExitPollerWindows(Thread):
+    """ A Windows-specific daemon thread that terminates the program immediately
+    when a Win32 handle is signaled.
+    """ 
+    
+    def __init__(self, handle):
+        super(ExitPollerWindows, self).__init__()
+        self.daemon = True
+        self.handle = handle
+
+    def run(self):
+        from _subprocess import WaitForSingleObject, WAIT_OBJECT_0, INFINITE
+        result = WaitForSingleObject(self.handle, INFINITE)
+        if result == WAIT_OBJECT_0:
+            os._exit(1)
+
 
 def bind_port(socket, ip, port):
     """ Binds the specified ZMQ socket. If the port is less than zero, a random
     port is chosen. Returns the port that was bound.
     """
     connection = 'tcp://%s' % ip
-    if port < 0:
+    if port <= 0:
         port = socket.bind_to_random_port(connection)
     else:
         connection += ':%i' % port
         socket.bind(connection)
     return port
 
+
 def main():
     """ Main entry point for launching a kernel.
     """
@@ -291,12 +420,21 b' def main():'
     parser.add_argument('--ip', type=str, default='127.0.0.1',
                         help='set the kernel\'s IP address [default: local]')
     parser.add_argument('--xrep', type=int, metavar='PORT', default=0,
-                        help='set the XREP Channel port [default: random]')
+                        help='set the XREP channel port [default: random]')
     parser.add_argument('--pub', type=int, metavar='PORT', default=0,
-                        help='set the PUB Channel port [default: random]')
+                        help='set the PUB channel port [default: random]')
+    parser.add_argument('--req', type=int, metavar='PORT', default=0,
+                        help='set the REQ channel port [default: random]')
+    if sys.platform == 'win32':
+        parser.add_argument('--parent', type=int, metavar='HANDLE', 
+                            default=0, help='kill this process if the process '
+                            'with HANDLE dies')
+    else:
+        parser.add_argument('--parent', action='store_true', 
+                            help='kill this process if its parent dies')
     namespace = parser.parse_args()
 
-    # Create context, session, and kernel sockets.
+    # Create a context, a session, and the kernel sockets.
     print >>sys.__stdout__, "Starting the kernel..."
     context = zmq.Context()
     session = Session(username=u'kernel')
@@ -309,34 +447,63 b' def main():'
     pub_port = bind_port(pub_socket, namespace.ip, namespace.pub)
     print >>sys.__stdout__, "PUB Channel on port", pub_port
 
+    req_socket = context.socket(zmq.XREQ)
+    req_port = bind_port(req_socket, namespace.ip, namespace.req)
+    print >>sys.__stdout__, "REQ Channel on port", req_port
+
     # Redirect input streams and set a display hook.
+    sys.stdin = InStream(session, req_socket)
     sys.stdout = OutStream(session, pub_socket, u'stdout')
     sys.stderr = OutStream(session, pub_socket, u'stderr')
     sys.displayhook = DisplayHook(session, pub_socket)
 
+    # Create the kernel.
     kernel = Kernel(session, reply_socket, pub_socket)
 
-    # For debugging convenience, put sleep and a string in the namespace, so we
-    # have them every time we start.
-    kernel.user_ns['sleep'] = time.sleep
-    kernel.user_ns['s'] = 'Test string'
-    
-    print >>sys.__stdout__, "Use Ctrl-\\ (NOT Ctrl-C!) to terminate."
+    # Configure this kernel/process to die on parent termination, if necessary.
+    if namespace.parent:
+        if sys.platform == 'win32':
+            poller = ExitPollerWindows(namespace.parent)
+        else:
+            poller = ExitPollerUnix()
+        poller.start()
+
+    # Start the kernel mainloop.
     kernel.start()
 
-def launch_kernel(xrep_port=0, pub_port=0):
-    """ Launches a localhost kernel, binding to the specified ports. For any
-    port that is left unspecified, a port is chosen by the operating system.
 
-    Returns a tuple of form:
-        (kernel_process [Popen], rep_port [int], sub_port [int])
+def launch_kernel(xrep_port=0, pub_port=0, req_port=0, independent=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.
+
+    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.
     """
     import socket
     from subprocess import Popen
 
     # Find open ports as necessary.
     ports = []
-    ports_needed = int(xrep_port == 0) + int(pub_port == 0)
+    ports_needed = int(xrep_port <= 0) + int(pub_port <= 0) + int(req_port <= 0)
     for i in xrange(ports_needed):
         sock = socket.socket()
         sock.bind(('', 0))
@@ -345,16 +512,35 b' def launch_kernel(xrep_port=0, pub_port=0):'
         port = sock.getsockname()[1]
         sock.close()
         ports[i] = port
-    if xrep_port == 0:
-        xrep_port = ports.pop()
-    if pub_port == 0:
-        pub_port = ports.pop()
+    if xrep_port <= 0:
+        xrep_port = ports.pop(0)
+    if pub_port <= 0:
+        pub_port = ports.pop(0)
+    if req_port <= 0:
+        req_port = ports.pop(0)
         
     # Spawn a kernel.
     command = 'from IPython.zmq.kernel import main; main()'
-    proc = Popen([ sys.executable, '-c', command, 
-                   '--xrep', str(xrep_port), '--pub', str(pub_port) ])
-    return proc, xrep_port, pub_port
+    arguments = [ sys.executable, '-c', command, '--xrep', str(xrep_port), 
+                  '--pub', str(pub_port), '--req', str(req_port) ]
+    if independent:
+        if sys.platform == 'win32':
+            proc = Popen(['start', '/b'] + arguments, shell=True)
+        else:
+            proc = Popen(arguments, preexec_fn=lambda: os.setsid())
+    else:
+        if sys.platform == 'win32':
+            from _subprocess import DuplicateHandle, GetCurrentProcess, \
+                DUPLICATE_SAME_ACCESS
+            pid = GetCurrentProcess()
+            handle = DuplicateHandle(pid, pid, pid, 0, 
+                                     True, # Inheritable by new  processes.
+                                     DUPLICATE_SAME_ACCESS)
+            proc = Popen(arguments + ['--parent', str(int(handle))])
+        else:
+            proc = Popen(arguments + ['--parent'])
+
+    return proc, xrep_port, pub_port, req_port
     
 
 if __name__ == '__main__':

IPython/zmq/kernelmanager.py

@@ -74,7 +74,8 b' class ZmqSocketChannel(Thread):'
         self.context = context
         self.session = session
         if address[1] == 0:
-            raise InvalidPortNumber('The port number for a channel cannot be 0.')
+            message = 'The port number for a channel cannot be 0.'
+            raise InvalidPortNumber(message)
         self._address = address
 
     def stop(self):
@@ -198,7 +199,6 b' class XReqSocketChannel(ZmqSocketChannel):'
         Returns
         -------
         The msg_id of the message sent.
-
         """
         content = dict(text=text, line=line)
         msg = self.session.msg('complete_request', content)
@@ -217,7 +217,6 b' class XReqSocketChannel(ZmqSocketChannel):'
         -------
         The msg_id of the message sent.
         """
-        print oname
         content = dict(oname=oname)
         msg = self.session.msg('object_info_request', content)
         self._queue_request(msg)
@@ -338,15 +337,84 b' class SubSocketChannel(ZmqSocketChannel):'
 class RepSocketChannel(ZmqSocketChannel):
     """A reply channel to handle raw_input requests that the kernel makes."""
 
-    def on_raw_input(self):
-        pass
+    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 readline(self, line):
+        """A send a line of raw input to the kernel.
+
+        Parameters
+        ----------
+        line : str
+            The line of the input.
+        """
+        content = dict(line=line)
+        msg = self.session.msg('readline_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.
 
@@ -380,6 +448,7 b' class KernelManager(HasTraits):'
 
     def __init__(self, xreq_address=None, sub_address=None, rep_address=None,
                  context=None, session=None):
+        super(KernelManager, self).__init__()
         self._xreq_address = (LOCALHOST, 0) if xreq_address is None else xreq_address
         self._sub_address = (LOCALHOST, 0) if sub_address is None else sub_address
         self._rep_address = (LOCALHOST, 0) if rep_address is None else rep_address
@@ -430,21 +499,18 b' class KernelManager(HasTraits):'
         If random ports (port=0) are being used, this method must be called
         before the channels are created.
         """
-        xreq, sub = self.xreq_address, self.sub_address
-        if xreq[0] != LOCALHOST or sub[0] != LOCALHOST:
+        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.")
 
-        kernel, xrep, pub = launch_kernel(xrep_port=xreq[1], pub_port=sub[1])
+        kernel, xrep, pub, req = launch_kernel(
+            xrep_port=xreq[1], pub_port=sub[1], req_port=rep[1])
         self._kernel = kernel
-        print xrep, pub
         self._xreq_address = (LOCALHOST, xrep)
         self._sub_address = (LOCALHOST, pub)
-        # The rep channel is not fully working yet, but its base class makes
-        # sure the port is not 0. We set to -1 for now until the rep channel
-        # is fully working.
-        self._rep_address = (LOCALHOST, -1)
+        self._rep_address = (LOCALHOST, req)
 
     @property
     def has_kernel(self):