Merge pull request #388 from epatters/qt-kill-ring

Add Emacs-style kill ring to Qt console

IPython/frontend/qt/console/kill_ring.py

@@ -0,0 +1,128 b''
+""" A generic Emacs-style kill ring, as well as a Qt-specific version.
+"""
+#-----------------------------------------------------------------------------
+# Imports
+#-----------------------------------------------------------------------------
+
+# System library imports
+from IPython.external.qt import QtCore, QtGui
+
+#-----------------------------------------------------------------------------
+# Classes
+#-----------------------------------------------------------------------------
+
+class KillRing(object):
+    """ A generic Emacs-style kill ring.
+    """
+    
+    def __init__(self):
+        self.clear()
+
+    def clear(self):
+        """ Clears the kill ring.
+        """
+        self._index = -1
+        self._ring = []
+
+    def kill(self, text):
+        """ Adds some killed text to the ring.
+        """
+        self._ring.append(text)
+
+    def yank(self):
+        """ Yank back the most recently killed text.
+
+        Returns:
+        --------
+        A text string or None.
+        """
+        self._index = len(self._ring)
+        return self.rotate()
+
+    def rotate(self):
+        """ Rotate the kill ring, then yank back the new top.
+        
+        Returns:
+        --------
+        A text string or None.
+        """
+        self._index -= 1
+        if self._index >= 0:
+            return self._ring[self._index]
+        return None
+        
+class QtKillRing(QtCore.QObject):
+    """ A kill ring attached to Q[Plain]TextEdit.
+    """
+
+    #--------------------------------------------------------------------------
+    # QtKillRing interface
+    #--------------------------------------------------------------------------
+
+    def __init__(self, text_edit):
+        """ Create a kill ring attached to the specified Qt text edit.
+        """
+        assert isinstance(text_edit, (QtGui.QTextEdit, QtGui.QPlainTextEdit))
+        super(QtKillRing, self).__init__()
+
+        self._ring = KillRing()
+        self._prev_yank = None
+        self._skip_cursor = False
+        self._text_edit = text_edit
+
+        text_edit.cursorPositionChanged.connect(self._cursor_position_changed)
+
+    def clear(self):
+        """ Clears the kill ring.
+        """
+        self._ring.clear()
+        self._prev_yank = None
+
+    def kill(self, text):
+        """ Adds some killed text to the ring.
+        """
+        self._ring.kill(text)
+
+    def kill_cursor(self, cursor):
+        """ Kills the text selected by the give cursor.
+        """
+        text = cursor.selectedText()
+        if text:
+            cursor.removeSelectedText()
+            self.kill(text)
+
+    def yank(self):
+        """ Yank back the most recently killed text.
+        """
+        text = self._ring.yank()
+        if text:
+            self._skip_cursor = True
+            cursor = self._text_edit.textCursor()
+            cursor.insertText(text)
+            self._prev_yank = text
+
+    def rotate(self):
+        """ Rotate the kill ring, then yank back the new top.
+        """
+        if self._prev_yank:
+            text = self._ring.rotate()
+            if text:
+                self._skip_cursor = True
+                cursor = self._text_edit.textCursor()
+                cursor.movePosition(QtGui.QTextCursor.Left, 
+                                    QtGui.QTextCursor.KeepAnchor, 
+                                    n = len(self._prev_yank))
+                cursor.insertText(text)
+                self._prev_yank = text
+        
+    #--------------------------------------------------------------------------
+    # Protected interface
+    #--------------------------------------------------------------------------
+
+    #------ Signal handlers ----------------------------------------------------
+
+    def _cursor_position_changed(self):
+        if self._skip_cursor:
+            self._skip_cursor = False
+        else:
+            self._prev_yank = None

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

@@ -0,0 +1,83 b''
+# Standard library imports
+import unittest
+
+# System library imports
+from IPython.external.qt import QtCore, QtGui
+
+# Local imports
+from IPython.frontend.qt.console.kill_ring import KillRing, QtKillRing
+
+
+class TestKillRing(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        """ Create the application for the test case.
+        """
+        cls._app = QtGui.QApplication([])
+        cls._app.setQuitOnLastWindowClosed(False)
+
+    @classmethod
+    def tearDownClass(cls):
+        """ Exit the application.
+        """
+        QtGui.QApplication.quit()
+
+    def test_generic(self):
+        """ Does the generic kill ring work?
+        """
+        ring = KillRing()
+        self.assert_(ring.yank() is None)
+        self.assert_(ring.rotate() is None)
+
+        ring.kill('foo')
+        self.assertEqual(ring.yank(), 'foo')
+        self.assert_(ring.rotate() is None)
+        self.assertEqual(ring.yank(), 'foo')
+
+        ring.kill('bar')
+        self.assertEqual(ring.yank(), 'bar')
+        self.assertEqual(ring.rotate(), 'foo')
+
+        ring.clear()
+        self.assert_(ring.yank() is None)
+        self.assert_(ring.rotate() is None)
+
+    def test_qt_basic(self):
+        """ Does the Qt kill ring work?
+        """
+        text_edit = QtGui.QPlainTextEdit()
+        ring = QtKillRing(text_edit)
+
+        ring.kill('foo')
+        ring.kill('bar')
+        ring.yank()
+        ring.rotate()
+        ring.yank()
+        self.assertEqual(text_edit.toPlainText(), 'foobar')
+
+        text_edit.clear()
+        ring.kill('baz')
+        ring.yank()
+        ring.rotate()
+        ring.rotate()
+        ring.rotate()
+        self.assertEqual(text_edit.toPlainText(), 'foo')
+
+    def test_qt_cursor(self):
+        """ Does the Qt kill ring maintain state with cursor movement?
+        """
+        text_edit = QtGui.QPlainTextEdit()
+        ring = QtKillRing(text_edit)
+        
+        ring.kill('foo')
+        ring.kill('bar')
+        ring.yank()
+        text_edit.moveCursor(QtGui.QTextCursor.Left)
+        ring.rotate()
+        self.assertEqual(text_edit.toPlainText(), 'bar')
+
+
+if __name__ == '__main__':
+    import nose
+    nose.main()

IPython/frontend/qt/console/console_widget.py

@@ -22,6 +22,7 b' from IPython.frontend.qt.util import MetaQObjectHasTraits, get_font'
 from IPython.utils.traitlets import Bool, Enum, Int
 from ansi_code_processor import QtAnsiCodeProcessor
 from completion_widget import CompletionWidget
+from kill_ring import QtKillRing
 
 #-----------------------------------------------------------------------------
 # Functions
@@ -173,6 +174,7 b' class ConsoleWidget(Configurable, QtGui.QWidget):'
         self._filter_drag = False
         self._filter_resize = False
         self._html_exporter = HtmlExporter(self._control)
+        self._kill_ring = QtKillRing(self._control)
         self._prompt = ''
         self._prompt_html = None
         self._prompt_pos = 0
@@ -953,7 +955,7 b' class ConsoleWidget(Configurable, QtGui.QWidget):'
                         cursor.movePosition(QtGui.QTextCursor.Right,
                                             QtGui.QTextCursor.KeepAnchor,
                                             len(self._continuation_prompt))
-                    cursor.removeSelectedText()
+                    self._kill_ring.kill_cursor(cursor)
                 intercepted = True
 
             elif key == QtCore.Qt.Key_L:
@@ -976,11 +978,12 b' class ConsoleWidget(Configurable, QtGui.QWidget):'
                                         QtGui.QTextCursor.KeepAnchor)
                     cursor.movePosition(QtGui.QTextCursor.Right,
                                         QtGui.QTextCursor.KeepAnchor, offset)
-                    cursor.removeSelectedText()
+                    self._kill_ring.kill_cursor(cursor)
                 intercepted = True
 
             elif key == QtCore.Qt.Key_Y:
-                self.paste()
+                self._keep_cursor_in_buffer()
+                self._kill_ring.yank()
                 intercepted = True
 
             elif key in (QtCore.Qt.Key_Backspace, QtCore.Qt.Key_Delete):
@@ -1005,16 +1008,20 b' class ConsoleWidget(Configurable, QtGui.QWidget):'
                 self._set_cursor(self._get_word_end_cursor(position))
                 intercepted = True
 
+            elif key == QtCore.Qt.Key_Y:
+                self._kill_ring.rotate()
+                intercepted = True
+
             elif key == QtCore.Qt.Key_Backspace:
                 cursor = self._get_word_start_cursor(position)
                 cursor.setPosition(position, QtGui.QTextCursor.KeepAnchor)
-                cursor.removeSelectedText()
+                self._kill_ring.kill_cursor(cursor)
                 intercepted = True
 
             elif key == QtCore.Qt.Key_D:
                 cursor = self._get_word_end_cursor(position)
                 cursor.setPosition(position, QtGui.QTextCursor.KeepAnchor)
-                cursor.removeSelectedText()
+                self._kill_ring.kill_cursor(cursor)
                 intercepted = True
 
             elif key == QtCore.Qt.Key_Delete: