Merge pull request ipython#1089 from mdboom/qtconsole-carriage-return

Support carriage return ('\r') and beep ('\b') characters in the qtconsole, providing text-mode 'scroll bars' and terminal bell in the console.

It extends AnsiCodeProcessor to understand the '\r' character and move the cursor back to the start of the line. It also understands the '\b' character and calls QTApplication::beep(). Neither are strictly speaking ANSI code sequences, of course, but they seem related enough and was simple enough to do it this way.

Closes ipython#629.

IPython/frontend/qt/console/ansi_code_processor.py

@@ -26,12 +26,19 @@
 # An action for scroll requests (SU and ST) and form feeds.
 ScrollAction = namedtuple('ScrollAction', ['action', 'dir', 'unit', 'count'])
 
+# An action for the carriage return character
+CarriageReturnAction = namedtuple('CarriageReturnAction', ['action'])
+
+# An action for the beep character
+BeepAction = namedtuple('BeepAction', ['action'])
+
 # Regular expressions.
 CSI_COMMANDS = 'ABCDEFGHJKSTfmnsu'
 CSI_SUBPATTERN = '\[(.*?)([%s])' % CSI_COMMANDS
 OSC_SUBPATTERN = '\](.*?)[\x07\x1b]'
-ANSI_PATTERN = re.compile('\x01?\x1b(%s|%s)\x02?' % \
-                              (CSI_SUBPATTERN, OSC_SUBPATTERN))
+ANSI_PATTERN = ('\x01?\x1b(%s|%s)\x02?' % \
+                (CSI_SUBPATTERN, OSC_SUBPATTERN))
+ANSI_OR_SPECIAL_PATTERN = re.compile('(\b|\r)|(?:%s)' % ANSI_PATTERN)
 SPECIAL_PATTERN = re.compile('([\f])')
 
 #-----------------------------------------------------------------------------
@@ -76,7 +83,7 @@ def split_string(self, string):
         self.actions = []
         start = 0
 
-        for match in ANSI_PATTERN.finditer(string):
+        for match in ANSI_OR_SPECIAL_PATTERN.finditer(string):
             raw = string[start:match.start()]
             substring = SPECIAL_PATTERN.sub(self._replace_special, raw)
             if substring or self.actions:
@@ -85,20 +92,27 @@ def split_string(self, string):
 
             self.actions = []
             groups = filter(lambda x: x is not None, match.groups())
-            params = [ param for param in groups[1].split(';') if param ]
-            if groups[0].startswith('['):
-                # Case 1: CSI code.
-                try:
-                    params = map(int, params)
-                except ValueError:
-                    # Silently discard badly formed codes.
-                    pass
-                else:
-                    self.set_csi_code(groups[2], params)
-
-            elif groups[0].startswith(']'):
-                # Case 2: OSC code.
-                self.set_osc_code(params)
+            if groups[0] == '\r':
+                self.actions.append(CarriageReturnAction('carriage-return'))
+                yield ''
+            elif groups[0] == '\b':
+                self.actions.append(BeepAction('beep'))
+                yield ''
+            else:
+                params = [ param for param in groups[1].split(';') if param ]
+                if groups[0].startswith('['):
+                    # Case 1: CSI code.
+                    try:
+                        params = map(int, params)
+                    except ValueError:
+                        # Silently discard badly formed codes.
+                        pass
+                    else:
+                        self.set_csi_code(groups[2], params)
+
+                elif groups[0].startswith(']'):
+                    # Case 2: OSC code.
+                    self.set_osc_code(params)
 
         raw = string[start:]
         substring = SPECIAL_PATTERN.sub(self._replace_special, raw)

IPython/frontend/qt/console/console_widget.py

@@ -1513,6 +1513,13 @@ def _insert_plain_text(self, cursor, text):
                         cursor.joinPreviousEditBlock()
                         cursor.deletePreviousChar()
 
+                    elif act.action == 'carriage-return':
+                        cursor.movePosition(
+                            cursor.StartOfLine, cursor.KeepAnchor)
+
+                    elif act.action == 'beep':
+                        QtGui.qApp.beep()
+
                 format = self._ansi_processor.get_format()
                 cursor.insertText(substring, format)
         else:

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

@@ -90,8 +90,8 @@ def test_scroll(self):
                 self.fail('Too many substrings.')
         self.assertEquals(i, 1, 'Too few substrings.')
 
-    def test_specials(self):
-        """ Are special characters processed correctly?
+    def test_formfeed(self):
+        """ Are formfeed characters processed correctly?
         """
         string = '\f' # form feed
         self.assertEquals(list(self.processor.split_string(string)), [''])
@@ -102,6 +102,26 @@ def test_specials(self):
         self.assertEquals(action.unit, 'page')
         self.assertEquals(action.count, 1)
 
+    def test_carriage_return(self):
+        """ Are carriage return characters processed correctly?
+        """
+        string = 'foo\rbar' # form feed
+        self.assertEquals(list(self.processor.split_string(string)), ['foo', '', 'bar'])
+        self.assertEquals(len(self.processor.actions), 1)
+        action = self.processor.actions[0]
+        self.assertEquals(action.action, 'carriage-return')
+        self.assertEquals(action.count, 1)
+
+    def test_beep(self):
+        """ Are beep characters processed correctly?
+        """
+        string = 'foo\bbar' # form feed
+        self.assertEquals(list(self.processor.split_string(string)), ['foo', '', 'bar'])
+        self.assertEquals(len(self.processor.actions), 1)
+        action = self.processor.actions[0]
+        self.assertEquals(action.action, 'beep')
+        self.assertEquals(action.count, 1)
+
 
 if __name__ == '__main__':
     unittest.main()