"""ParenMatch -- for parenthesis matching.
When you hit a right paren, the cursor should move briefly to the left
paren. Paren here is used generically; the matching applies to
parentheses, square brackets, and curly braces.
"""
from idlelib.hyperparser import HyperParser
from idlelib.config import idleConf
_openers = {')':'(',']':'[','}':'{'}
CHECK_DELAY = 100 # milliseconds
class ParenMatch:
"""Highlight matching openers and closers, (), [], and {}.
There are three supported styles of paren matching. When a right
paren (opener) is typed:
opener -- highlight the matching left paren (closer);
parens -- highlight the left and right parens (opener and closer);
expression -- highlight the entire expression from opener to closer.
(For back compatibility, 'default' is a synonym for 'opener').
Flash-delay is the maximum milliseconds the highlighting remains.
Any cursor movement (key press or click) before that removes the
highlight. If flash-delay is 0, there is no maximum.
TODO:
- Augment bell() with mismatch warning in status window.
- Highlight when cursor is moved to the right of a closer.
This might be too expensive to check.
"""
RESTORE_VIRTUAL_EVENT_NAME = "<<parenmatch-check-restore>>"
# We want the restore event be called before the usual return and
# backspace events.
RESTORE_SEQUENCES = ("<KeyPress>", "<ButtonPress>",
"<Key-Return>", "<Key-BackSpace>")
def __init__(self, editwin):
self.editwin = editwin
self.text = editwin.text
# Bind the check-restore event to the function restore_event,
# so that we can then use activate_restore (which calls event_add)
# and deactivate_restore (which calls event_delete).
editwin.text.bind(self.RESTORE_VIRTUAL_EVENT_NAME,
self.restore_event)
self.counter = 0
self.is_restore_active = 0
@classmethod
def reload(cls):
cls.STYLE = idleConf.GetOption(
'extensions','ParenMatch','style', default='opener')
cls.FLASH_DELAY = idleConf.GetOption(
'extensions','ParenMatch','flash-delay', type='int',default=500)
cls.BELL = idleConf.GetOption(
'extensions','ParenMatch','bell', type='bool', default=1)
cls.HILITE_CONFIG = idleConf.GetHighlight(idleConf.CurrentTheme(),
'hilite')
def activate_restore(self):
"Activate mechanism to restore text from highlighting."
if not self.is_restore_active:
for seq in self.RESTORE_SEQUENCES:
self.text.event_add(self.RESTORE_VIRTUAL_EVENT_NAME, seq)
self.is_restore_active = True
def deactivate_restore(self):
"Remove restore event bindings."
if self.is_restore_active:
for seq in self.RESTORE_SEQUENCES:
self.text.event_delete(self.RESTORE_VIRTUAL_EVENT_NAME, seq)
self.is_restore_active = False
def flash_paren_event(self, event):
"Handle editor 'show surrounding parens' event (menu or shortcut)."
indices = (HyperParser(self.editwin, "insert")
.get_surrounding_brackets())
self.finish_paren_event(indices)
return "break"
def paren_closed_event(self, event):
"Handle user input of closer."
# If user bound non-closer to <<paren-closed>>, quit.
closer = self.text.get("insert-1c")
if closer not in _openers:
return
hp = HyperParser(self.editwin, "insert-1c")
if not hp.is_in_code():
return
indices = hp.get_surrounding_brackets(_openers[closer], True)
self.finish_paren_event(indices)
return # Allow calltips to see ')'
def finish_paren_event(self, indices):
if indices is None and self.BELL:
self.text.bell()
return
self.activate_restore()
# self.create_tag(indices)
self.tagfuncs.get(self.STYLE, self.create_tag_expression)(self, indices)
# self.set_timeout()
(self.set_timeout_last if self.FLASH_DELAY else
self.set_timeout_none)()
def restore_event(self, event=None):
"Remove effect of doing match."
self.text.tag_delete("paren")
self.deactivate_restore()
self.counter += 1 # disable the last timer, if there is one.
def handle_restore_timer(self, timer_count):
if timer_count == self.counter:
self.restore_event()
# any one of the create_tag_XXX methods can be used depending on
# the style
def create_tag_opener(self, indices):
"""Highlight the single paren that matches"""
self.text.tag_add("paren", indices[0])
self.text.tag_config("paren", self.HILITE_CONFIG)
def create_tag_parens(self, indices):
"""Highlight the left and right parens"""
if self.text.get(indices[1]) in (')', ']', '}'):
rightindex = indices[1]+"+1c"
else:
rightindex = indices[1]
self.text.tag_add("paren", indices[0], indices[0]+"+1c", rightindex+"-1c", rightindex)
self.text.tag_config("paren", self.HILITE_CONFIG)
def create_tag_expression(self, indices):
"""Highlight the entire expression"""
if self.text.get(indices[1]) in (')', ']', '}'):
rightindex = indices[1]+"+1c"
else:
rightindex = indices[1]
self.text.tag_add("paren", indices[0], rightindex)
self.text.tag_config("paren", self.HILITE_CONFIG)
tagfuncs = {
'opener': create_tag_opener,
'default': create_tag_opener,
'parens': create_tag_parens,
'expression': create_tag_expression,
}
# any one of the set_timeout_XXX methods can be used depending on
# the style
def set_timeout_none(self):
"""Highlight will remain until user input turns it off
or the insert has moved"""
# After CHECK_DELAY, call a function which disables the "paren" tag
# if the event is for the most recent timer and the insert has changed,
# or schedules another call for itself.
self.counter += 1
def callme(callme, self=self, c=self.counter,
index=self.text.index("insert")):
if index != self.text.index("insert"):
self.handle_restore_timer(c)
else:
self.editwin.text_frame.after(CHECK_DELAY, callme, callme)
self.editwin.text_frame.after(CHECK_DELAY, callme, callme)
def set_timeout_last(self):
"""The last highlight created will be removed after FLASH_DELAY millisecs"""
# associate a counter with an event; only disable the "paren"
# tag if the event is for the most recent timer.
self.counter += 1
self.editwin.text_frame.after(
self.FLASH_DELAY,
lambda self=self, c=self.counter: self.handle_restore_timer(c))
ParenMatch.reload()
if __name__ == '__main__':
from unittest import main
main('idlelib.idle_test.test_parenmatch', verbosity=2)
