* Created an IPythonWidget subclass of FrontendWidget to contain IPython specific functionality.

* Added API for overriding magic commands to the above widget.
* Added a non-zero epsilon to time.sleep in the flush method of the kernel manager per Fernando's suggestion

IPython/frontend/qt/console/ipython_widget.py

@@ -0,0 +1,80 b''
+# Local imports.
+from frontend_widget import FrontendWidget
+
+
+class IPythonWidget(FrontendWidget):
+    """ A FrontendWidget for an IPython kernel.
+    """
+
+    #---------------------------------------------------------------------------
+    # 'FrontendWidget' interface
+    #---------------------------------------------------------------------------
+    
+    def __init__(self, kernel_manager, parent=None):
+        super(IPythonWidget, self).__init__(kernel_manager, parent)
+
+        self._magic_overrides = {}
+
+    def execute_source(self, source, hidden=False, interactive=False):
+        """ Reimplemented to override magic commands.
+        """
+        magic_source = source.strip()
+        if magic_source.startswith('%'):
+            magic_source = magic_source[1:]
+        magic, sep, arguments = magic_source.partition(' ')
+        if not magic:
+            magic = magic_source
+
+        callback = self._magic_overrides.get(magic)
+        if callback:
+            output = callback(arguments)
+            if output:
+                self.appendPlainText(output)
+            self._show_prompt('>>> ')
+            return True
+        else:
+            return super(IPythonWidget, self).execute_source(source, hidden,
+                                                             interactive)
+
+    #---------------------------------------------------------------------------
+    # 'IPythonWidget' interface
+    #---------------------------------------------------------------------------
+
+    def set_magic_override(self, magic, callback):
+        """ Overrides an IPython magic command. This magic will be intercepted
+            by the frontend rather than passed on to the kernel and 'callback'
+            will be called with a single argument: a string of argument(s) for
+            the magic. The callback can (optionally) return text to print to the
+            console.
+        """
+        self._magic_overrides[magic] = callback
+
+    def remove_magic_override(self, magic):
+        """ Removes the override for the specified magic, if there is one.
+        """
+        try:
+            del self._magic_overrides[magic]
+        except KeyError:
+            pass
+
+
+if __name__ == '__main__':
+    import sys
+    from IPython.frontend.qt.kernelmanager import QtKernelManager
+
+    # Create KernelManager
+    xreq_addr = ('127.0.0.1', 5575)
+    sub_addr = ('127.0.0.1', 5576)
+    rep_addr = ('127.0.0.1', 5577)
+    kernel_manager = QtKernelManager(xreq_addr, sub_addr, rep_addr)
+    kernel_manager.sub_channel.start()
+    kernel_manager.xreq_channel.start()
+
+    # Launch application
+    app = QtGui.QApplication(sys.argv)
+    widget = IPythonWidget(kernel_manager)
+    widget.setWindowTitle('Python')
+    widget.resize(640, 480)
+    widget.show()
+    sys.exit(app.exec_())
+    

IPython/frontend/qt/console/frontend_widget.py

@@ -1,324 +1,303 b''
 # Standard library imports
 from codeop import CommandCompiler
 from threading import Thread
 import time
 import types
 
 # System library imports
 from pygments.lexers import PythonLexer
 from PyQt4 import QtCore, QtGui
 import zmq
 
 # Local imports
 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 Python PygmentsHighlighter that can be turned on and off and which 
         knows about continuation prompts.
     """
 
     def __init__(self, frontend):
         PygmentsHighlighter.__init__(self, frontend.document(), PythonLexer())
         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 self.highlighting_on:
             for prompt in (self._frontend._prompt, 
                            self._frontend.continuation_prompt):
                 if qstring.startsWith(prompt):
                     qstring.remove(0, len(prompt))
                     self._current_offset = len(prompt)
                     break
             PygmentsHighlighter.highlightBlock(self, qstring)
 
     def setFormat(self, start, count, format):
         """ Reimplemented to avoid highlighting continuation prompts.
         """
         start += self._current_offset
         PygmentsHighlighter.setFormat(self, start, count, format)
 
 
 class FrontendWidget(HistoryConsoleWidget):
-    """ A Qt frontend for an IPython kernel.
+    """ A Qt frontend for a generic Python kernel.
     """
 
     # Emitted when an 'execute_reply' is received from the kernel.
     executed = QtCore.pyqtSignal(object)
 
     #---------------------------------------------------------------------------
     # 'QWidget' interface
     #---------------------------------------------------------------------------
     
     def __init__(self, kernel_manager, parent=None):
         super(FrontendWidget, self).__init__(parent)
 
         self._call_tip_widget = CallTipWidget(self)
         self._compile = CommandCompiler()
         self._completion_lexer = CompletionLexer(PythonLexer())
-        self._hidden = False
+        self._hidden = True
         self._highlighter = FrontendHighlighter(self)
         self._kernel_manager = None
 
         self.continuation_prompt = '... '
         self.kernel_manager = kernel_manager
 
         self.document().contentsChange.connect(self._document_contents_change)
 
     def focusOutEvent(self, event):
         """ Reimplemented to hide calltips.
         """
         self._call_tip_widget.hide()
         return super(FrontendWidget, self).focusOutEvent(event)
 
     def keyPressEvent(self, event):
         """ Reimplemented to hide calltips.
         """
         if event.key() == QtCore.Qt.Key_Escape:
             self._call_tip_widget.hide()
         return super(FrontendWidget, self).keyPressEvent(event)
 
     #---------------------------------------------------------------------------
     # 'ConsoleWidget' abstract interface
     #---------------------------------------------------------------------------
 
     def _execute(self, interactive):
         """ Called to execute the input buffer. When triggered by an the enter
             key press, 'interactive' is True; otherwise, it is False. Returns
             whether the input buffer was completely processed and a new prompt
             created.
         """
         return self.execute_source(self.input_buffer, interactive=interactive)
         
     def _prompt_started_hook(self):
         """ Called immediately after a new prompt is displayed.
         """
         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.
         """
         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.textCursor()
         if not self._complete():
             cursor.insertText('    ')
         return False
 
     #---------------------------------------------------------------------------
     # 'FrontendWidget' interface
     #---------------------------------------------------------------------------
 
     def execute_source(self, source, hidden=False, interactive=False):
         """ Execute a string containing Python code. If 'hidden', no output is
             shown. Returns whether the source executed (i.e., returns True only
             if no more input is necessary).
         """
+        # Use CommandCompiler to determine if more input is needed.
         try:
             code = self._compile(source, symbol='single')
         except (OverflowError, SyntaxError, ValueError):
             # Just let IPython deal with the syntax error.
             code = Exception
             
         # Only execute interactive multiline input if it ends with a blank line
         lines = source.splitlines()
         if interactive and len(lines) > 1 and lines[-1].strip() != '':
             code = None
             
         executed = code is not None
         if executed:
             self.kernel_manager.xreq_channel.execute(source)
             self._hidden = hidden
         else:
             space = 0
             for char in lines[-1]:
                 if char == '\t':
                     space += 4
                 elif char == ' ':
                     space += 1
                 else:
                     break
             if source.endswith(':') or source.endswith(':\n'):
                 space += 4
             self._show_continuation_prompt()
             self.appendPlainText(' ' * space)
 
         return executed
 
     def execute_file(self, path, hidden=False):
         """ Attempts to execute file with 'path'. If 'hidden', no output is
             shown.
         """
         self.execute_source('run %s' % path, hidden=hidden)
 
     def _get_kernel_manager(self):
         """ Returns the current kernel manager.
         """
         return self._kernel_manager
 
     def _set_kernel_manager(self, kernel_manager):
         """ Sets a new kernel manager, configuring its channels as necessary.
         """
         # Disconnect the old kernel manager.
         if self._kernel_manager is not None:
             sub = self._kernel_manager.sub_channel
             xreq = self._kernel_manager.xreq_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)
 
         # Connect the new kernel manager.
         self._kernel_manager = kernel_manager
         sub = kernel_manager.sub_channel
         xreq = kernel_manager.xreq_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)
         
         self._show_prompt('>>> ')
 
     kernel_manager = property(_get_kernel_manager, _set_kernel_manager)
 
     #---------------------------------------------------------------------------
     # '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.textCursor()
         cursor.movePosition(QtGui.QTextCursor.Left)
         document = self.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._calltip_id = self.kernel_manager.xreq_channel.object_info(name)
         self._calltip_pos = self.textCursor().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
         text = '.'.join(context)
         self._complete_id = self.kernel_manager.xreq_channel.complete(
             text, self.input_buffer_cursor_line, self.input_buffer)
         self._complete_pos = self.textCursor().position()
         return True
 
     def _get_context(self, cursor=None):
         """ Gets the context at the current cursor location.
         """
         if cursor is None:
             cursor = self.textCursor()
         cursor.movePosition(QtGui.QTextCursor.StartOfLine, 
                             QtGui.QTextCursor.KeepAnchor)
         text = unicode(cursor.selectedText())
         return self._completion_lexer.get_context(text)
 
     #------ Signal handlers ----------------------------------------------------
 
     def _document_contents_change(self, position, removed, added):
         """ Called whenever the document's content changes. Display a calltip
             if appropriate.
         """
         # Calculate where the cursor should be *after* the change:
         position += added
 
         document = self.document()
         if position == self.textCursor().position():
             self._call_tip()
 
     def _handle_sub(self, omsg):
         if not self._hidden:
             handler = getattr(self, '_handle_%s' % omsg['msg_type'], None)
             if handler is not None:
                 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')
 
     def _handle_stream(self, omsg):
         self.appendPlainText(omsg['content']['data'])
         
     def _handle_execute_reply(self, rep):
         # Make sure that all output from the SUB channel has been processed
         # before writing a new prompt.
         self.kernel_manager.sub_channel.flush()
 
         content = rep['content']
         status = content['status']
         if status == 'error':
             self.appendPlainText(content['traceback'][-1])
         elif status == 'aborted':
             text = "ERROR: ABORTED\n"
             self.appendPlainText(text)
-        self._hidden = False
+        self._hidden = True
         self._show_prompt('>>> ')
         self.executed.emit(rep)
 
     def _handle_complete_reply(self, rep):
         cursor = self.textCursor()
         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_object_info_reply(self, rep):
         cursor = self.textCursor()
         if rep['parent_header']['msg_id'] == self._calltip_id and \
                 cursor.position() == self._calltip_pos:
             doc = rep['content']['docstring']
             if doc:
                 self._call_tip_widget.show_tip(doc)
-
-
-if __name__ == '__main__':
-    import sys
-    from IPython.frontend.qt.kernelmanager import QtKernelManager
-
-    # Create KernelManager
-    xreq_addr = ('127.0.0.1', 5575)
-    sub_addr = ('127.0.0.1', 5576)
-    rep_addr = ('127.0.0.1', 5577)
-    kernel_manager = QtKernelManager(xreq_addr, sub_addr, rep_addr)
-    kernel_manager.sub_channel.start()
-    kernel_manager.xreq_channel.start()
-
-    # Launch application
-    app = QtGui.QApplication(sys.argv)
-    widget = FrontendWidget(kernel_manager)
-    widget.setWindowTitle('Python')
-    widget.resize(640, 480)
-    widget.show()
-    sys.exit(app.exec_())
-    

IPython/zmq/kernelmanager.py

@@ -1,335 +1,335 b''
 """Kernel frontend classes.
 
 TODO: Create logger to handle debugging and console messages.
 
 """
 
 # Standard library imports.
 from Queue import Queue, Empty
 from threading import Thread
 import time
 import traceback
 
 # 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, Int, Instance, Str, Type
 from session import Session
 
 
 class MissingHandlerError(Exception):
     pass
 
 
 class ZmqSocketChannel(Thread):
 
     socket = None
 
     def __init__(self, context, session, addr):
         self.context = context
         self.session = session
         self.addr = addr
         super(ZmqSocketChannel, self).__init__()
         self.daemon = True
 
 
 class SubSocketChannel(ZmqSocketChannel):
 
     handlers = None
     _overriden_call_handler = None
 
     def __init__(self, context, session, addr):
         self.handlers = {}
         super(SubSocketChannel, self).__init__(context, session, addr)
 
     def run(self):
         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.addr)
         self.ioloop = ioloop.IOLoop()
         self.ioloop.add_handler(self.socket, self._handle_events, 
                                 POLLIN|POLLERR)
         self.ioloop.start()
 
     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):
         raise zmq.ZmqError()
 
     def _handle_recv(self):
         msg = self.socket.recv_json()
         self.call_handlers(msg)
 
     def override_call_handler(self, func):
         """Permanently override the call_handler.
     
         The function func will be called as::
 
             func(handler, msg)
 
         And must call::
         
             handler(msg)
 
         in the main thread.
         """
         assert callable(func), "not a callable: %r" % func
         self._overriden_call_handler = func
 
     def call_handlers(self, msg):
         handler = self.handlers.get(msg['msg_type'], None)
         if handler is not None:
             try:
                 self.call_handler(handler, msg)
             except:
                 # XXX: This should be logged at least
                 traceback.print_last()
 
     def call_handler(self, handler, msg):
         if self._overriden_call_handler is not None:
             self._overriden_call_handler(handler, msg)
         elif hasattr(self, '_call_handler'):
            call_handler = getattr(self, '_call_handler')
            call_handler(handler, msg)
         else:
             raise RuntimeError('no handler!')
 
     def add_handler(self, callback, msg_type):
         """Register a callback for msg type."""
         self.handlers[msg_type] = callback
 
     def remove_handler(self, msg_type):
         """Remove the callback for msg type."""
         self.handlers.pop(msg_type, None)
 
     def flush(self):
         """Immediately processes all pending messages on the SUB channel. This
            method is thread safe.
         """
         self._flushed = False
         self.ioloop.add_callback(self._flush)
         while not self._flushed:
-            time.sleep(0)
+            time.sleep(0.01)
         
     def _flush(self):
         """Called in this thread by the IOLoop to indicate that all events have
            been processed.
         """
         self._flushed = True
 
 
 class XReqSocketChannel(ZmqSocketChannel):
 
     handler_queue = None
     command_queue = None
     handlers = None
     _overriden_call_handler = None
 
     def __init__(self, context, session, addr):
         self.handlers = {}
         self.handler_queue = Queue()
         self.command_queue = Queue()
         super(XReqSocketChannel, self).__init__(context, session, addr)
 
     def run(self):
         self.socket = self.context.socket(zmq.XREQ)
         self.socket.setsockopt(zmq.IDENTITY, self.session.session)
         self.socket.connect('tcp://%s:%i' % self.addr)
         self.ioloop = ioloop.IOLoop()
         self.ioloop.add_handler(self.socket, self._handle_events, 
                                 POLLIN|POLLOUT|POLLERR)
         self.ioloop.start()
 
     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 & 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)
 
     def _handle_err(self):
         raise zmq.ZmqError()
 
     def _queue_request(self, msg, callback):
         handler = self._find_handler(msg['msg_type'], callback)
         self.handler_queue.put(handler)
         self.command_queue.put(msg)
 
     def execute(self, code, callback=None):
         # Create class for content/msg creation. Related to, but possibly
         # not in Session.
         content = dict(code=code)
         msg = self.session.msg('execute_request', content)
         self._queue_request(msg, callback)
         return msg['header']['msg_id']
 
     def complete(self, text, line, block=None, callback=None):
         content = dict(text=text, line=line)
         msg = self.session.msg('complete_request', content)
         self._queue_request(msg, callback)
         return msg['header']['msg_id']
 
     def object_info(self, oname, callback=None):
         content = dict(oname=oname)
         msg = self.session.msg('object_info_request', content)
         self._queue_request(msg, callback)
         return msg['header']['msg_id']
 
     def _find_handler(self, name, callback):
         if callback is not None:
             return callback
         handler = self.handlers.get(name)
         if handler is None:
             raise MissingHandlerError(
                 'No handler defined for method: %s' % name)
         return handler
 
     def override_call_handler(self, func):
         """Permanently override the call_handler.
     
         The function func will be called as::
 
             func(handler, msg)
 
         And must call::
         
             handler(msg)
 
         in the main thread.
         """
         assert callable(func), "not a callable: %r" % func
         self._overriden_call_handler = func
 
     def call_handlers(self, msg):
         try:
             handler = self.handler_queue.get(False)
         except Empty:
             print "Message received with no handler!!!"
             print msg
         else:
             self.call_handler(handler, msg)
 
     def call_handler(self, handler, msg):
         if self._overriden_call_handler is not None:
             self._overriden_call_handler(handler, msg)
         elif hasattr(self, '_call_handler'):
            call_handler = getattr(self, '_call_handler')
            call_handler(handler, msg)
         else:
             raise RuntimeError('no handler!')
 
 
 class RepSocketChannel(ZmqSocketChannel):
 
     def on_raw_input():
         pass
 
 
 class KernelManager(HasTraits):
 
     # The addresses to use for the various channels. Should be tuples of form
     # (ip_address, port).
     sub_address = Any
     xreq_address = Any
     rep_address = Any
     # FIXME: Add Tuple to Traitlets.
     #sub_address = Tuple(Str, Int)
     #xreq_address = Tuple(Str, Int)
     #rep_address = Tuple(Str, Int)
 
     # 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 classes to use for the various channels.
     sub_channel_class = Type(SubSocketChannel)
     xreq_channel_class = Type(XReqSocketChannel)
     rep_channel_class = Type(RepSocketChannel)
 
     # Protected traits.
     _sub_channel = Any
     _xreq_channel = Any
     _rep_channel = Any
 
     def __init__(self, xreq_address, sub_address, rep_address, **traits):
         super(KernelManager, self).__init__()
 
         self.xreq_address = xreq_address
         self.sub_address = sub_address
         self.rep_address = rep_address
 
         # FIXME: This should be the business of HasTraits. The convention is:
         #        HasTraits.__init__(self, **traits_to_be_initialized.)
         for trait in traits:
             setattr(self, trait, traits[trait])
 
     def start_kernel(self):
         """Start a localhost kernel on ip and port.
         
         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.
         """
 
     def kill_kernel(self):
         """Kill the running kernel"""
 
     def is_alive(self):
         """Is the kernel alive?"""
         return True
 
     def signal_kernel(self, signum):
         """Send signum to the kernel."""
 
     @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 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 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