Make qtconsole aware of clear_output.

IPython/qt/console/frontend_widget.py

@@ -197,6 +197,9 b' class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):'
         self._local_kernel = kw.get('local_kernel',
                                     FrontendWidget._local_kernel)
 
+        # Whether or not a clear_output call is pending new output.
+        self._pending_clearoutput = False
+
     #---------------------------------------------------------------------------
     # 'ConsoleWidget' public interface
     #---------------------------------------------------------------------------
@@ -339,6 +342,14 b' class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):'
     #---------------------------------------------------------------------------
     # 'BaseFrontendMixin' abstract interface
     #---------------------------------------------------------------------------
+    def _handle_clear_output(self, msg):
+        """Handle clear output messages."""
+        if not self._hidden and self._is_from_this_session(msg):
+            wait = msg['content'].get('wait', True)
+            if wait:
+                self._pending_clearoutput = True
+            else:
+                self.clear_output()
 
     def _handle_complete_reply(self, rep):
         """ Handle replies for tab completion.
@@ -520,6 +531,7 b' class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):'
         """
         self.log.debug("pyout: %s", msg.get('content', ''))
         if not self._hidden and self._is_from_this_session(msg):
+            self.flush_clearoutput()
             text = msg['content']['data']
             self._append_plain_text(text + '\n', before_prompt=True)
 
@@ -528,13 +540,8 b' class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):'
         """
         self.log.debug("stream: %s", msg.get('content', ''))
         if not self._hidden and self._is_from_this_session(msg):
-            # Most consoles treat tabs as being 8 space characters. Convert tabs
-            # to spaces so that output looks as expected regardless of this
-            # widget's tab width.
-            text = msg['content']['data'].expandtabs(8)
-
-            self._append_plain_text(text, before_prompt=True)
-            self._control.moveCursor(QtGui.QTextCursor.End)
+            self.flush_clearoutput()
+            self.append_stream(msg['content']['data'])
 
     def _handle_shutdown_reply(self, msg):
         """ Handle shutdown signal, only if from other console.
@@ -685,6 +692,31 b' class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):'
                 before_prompt=True
             )
 
+    def append_stream(self, text):
+        """Appends text to the output stream."""
+        # Most consoles treat tabs as being 8 space characters. Convert tabs
+        # to spaces so that output looks as expected regardless of this
+        # widget's tab width.
+        text = text.expandtabs(8)
+
+        print([ord(c) for c in text])
+        self._append_plain_text(text, before_prompt=True)
+        self._control.moveCursor(QtGui.QTextCursor.End)
+
+    def flush_clearoutput(self):
+        """If a clearoutput is pending, execute it."""
+        if self._pending_clearoutput:
+            self._pending_clearoutput = False
+            self.clear_output()
+
+    def clear_output(self):
+        """Clear the output area."""
+        cursor = self._control.textCursor()
+        cursor.beginEditBlock()
+        cursor.movePosition(cursor.StartOfLine, cursor.KeepAnchor)
+        cursor.insertText('')
+        cursor.endEditBlock()
+
     #---------------------------------------------------------------------------
     # 'FrontendWidget' protected interface
     #---------------------------------------------------------------------------

IPython/qt/console/ipython_widget.py

@@ -140,7 +140,6 b' class IPythonWidget(FrontendWidget):'
     #---------------------------------------------------------------------------
     # 'BaseFrontendMixin' abstract interface
     #---------------------------------------------------------------------------
-
     def _handle_complete_reply(self, rep):
         """ Reimplemented to support IPython's improved completion machinery.
         """
@@ -223,6 +222,7 b' class IPythonWidget(FrontendWidget):'
         """
         self.log.debug("pyout: %s", msg.get('content', ''))
         if not self._hidden and self._is_from_this_session(msg):
+            self.flush_clearoutput()
             content = msg['content']
             prompt_number = content.get('execution_count', 0)
             data = content['data']
@@ -250,6 +250,7 b' class IPythonWidget(FrontendWidget):'
         # eventually will as this allows all frontends to monitor the display
         # data. But we need to figure out how to handle this in the GUI.
         if not self._hidden and self._is_from_this_session(msg):
+            self.flush_clearoutput()
             source = msg['content']['source']
             data = msg['content']['data']
             metadata = msg['content']['metadata']

IPython/qt/console/rich_ipython_widget.py

@@ -114,6 +114,7 b' class RichIPythonWidget(IPythonWidget):'
         """ Overridden to handle rich data types, like SVG.
         """
         if not self._hidden and self._is_from_this_session(msg):
+            self.flush_clearoutput()
             content = msg['content']
             prompt_number = content.get('execution_count', 0)
             data = content['data']
@@ -140,6 +141,7 b' class RichIPythonWidget(IPythonWidget):'
         """ Overridden to handle rich data types, like SVG.
         """
         if not self._hidden and self._is_from_this_session(msg):
+            self.flush_clearoutput()
             source = msg['content']['source']
             data = msg['content']['data']
             metadata = msg['content']['metadata']