|
|
""" Provides bracket matching for Q[Plain]TextEdit widgets.
|
|
|
"""
|
|
|
|
|
|
# System library imports
|
|
|
from IPython.external.qt import QtCore, QtGui
|
|
|
|
|
|
|
|
|
class BracketMatcher(QtCore.QObject):
|
|
|
""" Matches square brackets, braces, and parentheses based on cursor
|
|
|
position.
|
|
|
"""
|
|
|
|
|
|
# Protected class variables.
|
|
|
_opening_map = { '(':')', '{':'}', '[':']' }
|
|
|
_closing_map = { ')':'(', '}':'{', ']':'[' }
|
|
|
|
|
|
#--------------------------------------------------------------------------
|
|
|
# 'QObject' interface
|
|
|
#--------------------------------------------------------------------------
|
|
|
|
|
|
def __init__(self, text_edit):
|
|
|
""" Create a call tip manager that is attached to the specified Qt
|
|
|
text edit widget.
|
|
|
"""
|
|
|
assert isinstance(text_edit, (QtGui.QTextEdit, QtGui.QPlainTextEdit))
|
|
|
super(BracketMatcher, self).__init__()
|
|
|
|
|
|
# The format to apply to matching brackets.
|
|
|
self.format = QtGui.QTextCharFormat()
|
|
|
self.format.setBackground(QtGui.QColor('silver'))
|
|
|
|
|
|
self._text_edit = text_edit
|
|
|
text_edit.cursorPositionChanged.connect(self._cursor_position_changed)
|
|
|
|
|
|
#--------------------------------------------------------------------------
|
|
|
# Protected interface
|
|
|
#--------------------------------------------------------------------------
|
|
|
|
|
|
def _find_match(self, position):
|
|
|
""" Given a valid position in the text document, try to find the
|
|
|
position of the matching bracket. Returns -1 if unsuccessful.
|
|
|
"""
|
|
|
# Decide what character to search for and what direction to search in.
|
|
|
document = self._text_edit.document()
|
|
|
start_char = document.characterAt(position)
|
|
|
search_char = self._opening_map.get(start_char)
|
|
|
if search_char:
|
|
|
increment = 1
|
|
|
else:
|
|
|
search_char = self._closing_map.get(start_char)
|
|
|
if search_char:
|
|
|
increment = -1
|
|
|
else:
|
|
|
return -1
|
|
|
|
|
|
# Search for the character.
|
|
|
char = start_char
|
|
|
depth = 0
|
|
|
while position >= 0 and position < document.characterCount():
|
|
|
if char == start_char:
|
|
|
depth += 1
|
|
|
elif char == search_char:
|
|
|
depth -= 1
|
|
|
if depth == 0:
|
|
|
break
|
|
|
position += increment
|
|
|
char = document.characterAt(position)
|
|
|
else:
|
|
|
position = -1
|
|
|
return position
|
|
|
|
|
|
def _selection_for_character(self, position):
|
|
|
""" Convenience method for selecting a character.
|
|
|
"""
|
|
|
selection = QtGui.QTextEdit.ExtraSelection()
|
|
|
cursor = self._text_edit.textCursor()
|
|
|
cursor.setPosition(position)
|
|
|
cursor.movePosition(QtGui.QTextCursor.NextCharacter,
|
|
|
QtGui.QTextCursor.KeepAnchor)
|
|
|
selection.cursor = cursor
|
|
|
selection.format = self.format
|
|
|
return selection
|
|
|
|
|
|
#------ Signal handlers ----------------------------------------------------
|
|
|
|
|
|
def _cursor_position_changed(self):
|
|
|
""" Updates the document formatting based on the new cursor position.
|
|
|
"""
|
|
|
# Clear out the old formatting.
|
|
|
self._text_edit.setExtraSelections([])
|
|
|
|
|
|
# Attempt to match a bracket for the new cursor position.
|
|
|
cursor = self._text_edit.textCursor()
|
|
|
if not cursor.hasSelection():
|
|
|
position = cursor.position() - 1
|
|
|
match_position = self._find_match(position)
|
|
|
if match_position != -1:
|
|
|
extra_selections = [ self._selection_for_character(pos)
|
|
|
for pos in (position, match_position) ]
|
|
|
self._text_edit.setExtraSelections(extra_selections)
|
|
|
|
