"""ParenMatch -- An IDLE extension 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.configHandler import idleConf
_openers = {')':'(',']':'[','}':'{'}
CHECK_DELAY = 100 # milliseconds
class ParenMatch:
"""Highlight matching parentheses
There are three supported style of paren matching, based loosely
on the Emacs options. The style is select based on the
HILITE_STYLE attribute; it can be changed used the set_style
method.
The supported styles are:
default -- When a right paren is typed, highlight the matching
left paren for 1/2 sec.
expression -- When a right paren is typed, highlight the entire
expression from the left paren to the right paren.
TODO:
- extend IDLE with configuration dialog to change options
- implement rest of Emacs highlight styles (see below)
- print mismatch warning in IDLE status window
Note: In Emacs, there are several styles of highlight where the
matching paren is highlighted whenever the cursor is immediately
to the right of a right paren. I don't know how to do that in Tk,
so I haven't bothered.
"""
menudefs = [
('edit', [
("Show surrounding parens", "<<flash-paren>>"),
])
]
STYLE = idleConf.GetOption('extensions','ParenMatch','style',
default='expression')
FLASH_DELAY = idleConf.GetOption('extensions','ParenMatch','flash-delay',
type='int',default=500)
HILITE_CONFIG = idleConf.GetHighlight(idleConf.CurrentTheme(),'hilite')
BELL = idleConf.GetOption('extensions','ParenMatch','bell',
type='bool',default=1)
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
self.set_style(self.STYLE)
def activate_restore(self):
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):
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 set_style(self, style):
self.STYLE = style
if style == "default":
self.create_tag = self.create_tag_default
self.set_timeout = self.set_timeout_last
elif style == "expression":
self.create_tag = self.create_tag_expression
self.set_timeout = self.set_timeout_none
def flash_paren_event(self, event):
indices = (HyperParser(self.editwin, "insert")
.get_surrounding_brackets())
if indices is None:
self.warn_mismatched()
return
self.activate_restore()
self.create_tag(indices)
self.set_timeout_last()
def paren_closed_event(self, event):
# If it was a shortcut and not really a closing paren, 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)
if indices is None:
self.warn_mismatched()
return
self.activate_restore()
self.create_tag(indices)
self.set_timeout()
def restore_event(self, event=None):
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()
def warn_mismatched(self):
if self.BELL:
self.text.bell()
# any one of the create_tag_XXX methods can be used depending on
# the style
def create_tag_default(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_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)
# 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 .5 sec"""
# 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))
if __name__ == '__main__':
import unittest
unittest.main('idlelib.idle_test.test_parenmatch', verbosity=2)
