* Fixed regression from last commit: syntax highlighting works robustly again.

* Added option to ipythonqt for enabling text-based tab completion.

IPython/frontend/qt/console/console_widget.py

@@ -150,6 +150,7 b' class ConsoleWidget(QtGui.QWidget):'
         self._prompt = ''
         self._prompt_html = None
         self._prompt_pos = 0
+        self._prompt_sep = ''
         self._reading = False
         self._reading_callback = None
         self._tab_width = 8
@@ -282,24 +283,35 b' class ConsoleWidget(QtGui.QWidget):'
         --------
         A boolean indicating whether the source was executed.
         """
-        if not hidden:
-            # Do everything here inside an edit block so continuation prompts
-            # are removed seamlessly via undo/redo.
-            cursor = self._control.textCursor()
-            cursor.beginEditBlock()
-
-            if source is not None:
-                self.input_buffer = source
-
-            self._append_plain_text('\n')
-            self._executing_input_buffer = self.input_buffer
-            self._executing = True
-            self._prompt_finished()
+        # WARNING: The order in which things happen here is very particular, in
+        # large part because our syntax highlighting is fragile. If you change
+        # something, test carefully!
 
-        real_source = self.input_buffer if source is None else source
-        complete = self._is_complete(real_source, interactive)
-        if complete:
+        # Decide what to execute.
+        if source is None:
+            source = self.input_buffer
             if not hidden:
+                # A newline is appended later, but it should be considered part
+                # of the input buffer.
+                source += '\n'
+        elif not hidden:
+            self.input_buffer = source
+            
+        # Execute the source or show a continuation prompt if it is incomplete.
+        complete = self._is_complete(source, interactive)
+        if hidden:
+            if complete:
+                self._execute(source, hidden)
+            else:
+                error = 'Incomplete noninteractive input: "%s"'
+                raise RuntimeError(error % source)                
+        else:
+            if complete:
+                self._append_plain_text('\n')
+                self._executing_input_buffer = self.input_buffer
+                self._executing = True
+                self._prompt_finished()
+
                 # The maximum block count is only in effect during execution.
                 # This ensures that _prompt_pos does not become invalid due to
                 # text truncation.
@@ -309,14 +321,18 b' class ConsoleWidget(QtGui.QWidget):'
                 # disable the undo/redo history, but just to be safe:
                 self._control.setUndoRedoEnabled(False)
 
-            self._execute(real_source, hidden)
-        elif hidden:
-            raise RuntimeError('Incomplete noninteractive input: "%s"' % source)
-        else:
-            self._show_continuation_prompt()
+                self._execute(source, hidden)
+            
+            else:
+                # Do this inside an edit block so continuation prompts are
+                # removed seamlessly via undo/redo.
+                cursor = self._control.textCursor()
+                cursor.beginEditBlock()
 
-        if not hidden:
-            cursor.endEditBlock()
+                self._append_plain_text('\n')
+                self._show_continuation_prompt()
+
+                cursor.endEditBlock()
 
         return complete
 
@@ -1115,7 +1131,7 b' class ConsoleWidget(QtGui.QWidget):'
 
         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'
+            raise RuntimeError('Cannot synchronously read a line if the widget '
                                'is not visible!')
 
         self._reading = True
@@ -1212,6 +1228,7 b' class ConsoleWidget(QtGui.QWidget):'
                     self._append_plain_text('\n')
 
         # Write the prompt.
+        self._append_plain_text(self._prompt_sep)
         if prompt is None:
             if self._prompt_html is None:
                 self._append_plain_text(self._prompt)
@@ -1238,8 +1255,6 b' class ConsoleWidget(QtGui.QWidget):'
             self._continuation_prompt = self._append_html_fetching_plain_text(
                 self._continuation_prompt_html)
 
-        self._prompt_started()
-
 
 class HistoryConsoleWidget(ConsoleWidget):
     """ A ConsoleWidget that keeps a history of the commands that have been

IPython/frontend/qt/console/ipython_widget.py

@@ -179,7 +179,7 b' class IPythonWidget(FrontendWidget):'
 
         # Show a new prompt and save information about it so that it can be
         # updated later if the prompt number turns out to be wrong.
-        self._append_plain_text(input_sep)
+        self._prompt_sep = input_sep
         self._show_prompt(self._make_in_prompt(number), html=True)
         block = self._control.document().lastBlock()
         length = len(self._prompt)

IPython/frontend/qt/console/scripts/ipythonqt.py

@@ -22,7 +22,12 b' def main():'
     """
     # Parse command line arguments.
     parser = ArgumentParser()
-    parser.add_argument('-e', '--existing', action='store_true',
+    parser.add_argument('-r', '--rich', action='store_true',
+                        help='use a rich text frontend')
+    parser.add_argument('-t', '--tab-simple', action='store_true',
+                        help='do tab completion ala a Unix terminal')
+
+    parser.add_argument('--existing', action='store_true',
                         help='connect to an existing kernel')
     parser.add_argument('--ip', type=str, default=LOCALHOST,
                         help='set the kernel\'s IP address [default localhost]')
@@ -32,13 +37,13 b' def main():'
                         help='set the SUB channel port [default random]')
     parser.add_argument('--rep', type=int, metavar='PORT', default=0,
                         help='set the REP channel port [default random]')
+
     group = parser.add_mutually_exclusive_group()
     group.add_argument('--pure', action='store_true', help = \
                        'use a pure Python kernel instead of an IPython kernel')
     group.add_argument('--pylab', action='store_true',
                         help='use a kernel with PyLab enabled')
-    parser.add_argument('--rich', action='store_true',
-                        help='use a rich text frontend')
+    
     args = parser.parse_args()
     
     # Don't let Qt or ZMQ swallow KeyboardInterupts.
@@ -70,6 +75,7 b' def main():'
         widget = RichIPythonWidget()
     else:
         widget = IPythonWidget()
+    widget.gui_completion = not args.tab_simple
     widget.kernel_manager = kernel_manager
     widget.setWindowTitle('Python' if args.pure else 'IPython')
     widget.show()