/
kill_ring.py
128 lines (105 loc) · 3.72 KB
/
kill_ring.py
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""" 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