Lib/idlelib/ParenMatch.py

   1 """ParenMatch -- An IDLE extension for parenthesis matching.
   2
   3 When you hit a right paren, the cursor should move briefly to the left
   4 paren.  Paren here is used generically; the matching applies to
   5 parentheses, square brackets, and curly braces.
   6 """
   7
   8 from HyperParser import HyperParser
   9 from configHandler import idleConf
  10
  11 _openers = {')':'(',']':'[','}':'{'}
  12 CHECK_DELAY = 100 # miliseconds
  13
  14 class ParenMatch:
  15     """Highlight matching parentheses
  16
  17     There are three supported style of paren matching, based loosely
  18     on the Emacs options.  The style is select based on the
  19     HILITE_STYLE attribute; it can be changed used the set_style
  20     method.
  21
  22     The supported styles are:
  23
  24     default -- When a right paren is typed, highlight the matching
  25         left paren for 1/2 sec.
  26
  27     expression -- When a right paren is typed, highlight the entire
  28         expression from the left paren to the right paren.
  29
  30     TODO:
  31         - extend IDLE with configuration dialog to change options
  32         - implement rest of Emacs highlight styles (see below)
  33         - print mismatch warning in IDLE status window
  34
  35     Note: In Emacs, there are several styles of highlight where the
  36     matching paren is highlighted whenever the cursor is immediately
  37     to the right of a right paren.  I don't know how to do that in Tk,
  38     so I haven't bothered.
  39     """
  40     menudefs = [
  41         ('edit', [
  42             ("Show surrounding parens", "<<flash-paren>>"),
  43         ])
  44     ]
  45     STYLE = idleConf.GetOption('extensions','ParenMatch','style',
  46             default='expression')
  47     FLASH_DELAY = idleConf.GetOption('extensions','ParenMatch','flash-delay',
  48             type='int',default=500)
  49     HILITE_CONFIG = idleConf.GetHighlight(idleConf.CurrentTheme(),'hilite')
  50     BELL = idleConf.GetOption('extensions','ParenMatch','bell',
  51             type='bool',default=1)
  52
  53     RESTORE_VIRTUAL_EVENT_NAME = "<<parenmatch-check-restore>>"
  54     # We want the restore event be called before the usual return and
  55     # backspace events.
  56     RESTORE_SEQUENCES = ("<KeyPress>", "<ButtonPress>",
  57                          "<Key-Return>", "<Key-BackSpace>")
  58
  59     def __init__(self, editwin):
  60         self.editwin = editwin
  61         self.text = editwin.text
  62         # Bind the check-restore event to the function restore_event,
  63         # so that we can then use activate_restore (which calls event_add)
  64         # and deactivate_restore (which calls event_delete).
  65         editwin.text.bind(self.RESTORE_VIRTUAL_EVENT_NAME,
  66                           self.restore_event)
  67         self.counter = 0
  68         self.is_restore_active = 0
  69         self.set_style(self.STYLE)
  70
  71     def activate_restore(self):
  72         if not self.is_restore_active:
  73             for seq in self.RESTORE_SEQUENCES:
  74                 self.text.event_add(self.RESTORE_VIRTUAL_EVENT_NAME, seq)
  75             self.is_restore_active = True
  76
  77     def deactivate_restore(self):
  78         if self.is_restore_active:
  79             for seq in self.RESTORE_SEQUENCES:
  80                 self.text.event_delete(self.RESTORE_VIRTUAL_EVENT_NAME, seq)
  81             self.is_restore_active = False
  82
  83     def set_style(self, style):
  84         self.STYLE = style
  85         if style == "default":
  86             self.create_tag = self.create_tag_default
  87             self.set_timeout = self.set_timeout_last
  88         elif style == "expression":
  89             self.create_tag = self.create_tag_expression
  90             self.set_timeout = self.set_timeout_none
  91
  92     def flash_paren_event(self, event):
  93         indices = HyperParser(self.editwin, "insert").get_surrounding_brackets()
  94         if indices is None:
  95             self.warn_mismatched()
  96             return
  97         self.activate_restore()
  98         self.create_tag(indices)
  99         self.set_timeout_last()
 100
 101     def paren_closed_event(self, event):
 102         # If it was a shortcut and not really a closing paren, quit.
 103         closer = self.text.get("insert-1c")
 104         if closer not in _openers:
 105             return
 106         hp = HyperParser(self.editwin, "insert-1c")
 107         if not hp.is_in_code():
 108             return
 109         indices = hp.get_surrounding_brackets(_openers[closer], True)
 110         if indices is None:
 111             self.warn_mismatched()
 112             return
 113         self.activate_restore()
 114         self.create_tag(indices)
 115         self.set_timeout()
 116
 117     def restore_event(self, event=None):
 118         self.text.tag_delete("paren")
 119         self.deactivate_restore()
 120         self.counter += 1   # disable the last timer, if there is one.
 121
 122     def handle_restore_timer(self, timer_count):
 123         if timer_count == self.counter:
 124             self.restore_event()
 125
 126     def warn_mismatched(self):
 127         if self.BELL:
 128             self.text.bell()
 129
 130     # any one of the create_tag_XXX methods can be used depending on
 131     # the style
 132
 133     def create_tag_default(self, indices):
 134         """Highlight the single paren that matches"""
 135         self.text.tag_add("paren", indices[0])
 136         self.text.tag_config("paren", self.HILITE_CONFIG)
 137
 138     def create_tag_expression(self, indices):
 139         """Highlight the entire expression"""
 140         if self.text.get(indices[1]) in (')', ']', '}'):
 141             rightindex = indices[1]+"+1c"
 142         else:
 143             rightindex = indices[1]
 144         self.text.tag_add("paren", indices[0], rightindex)
 145         self.text.tag_config("paren", self.HILITE_CONFIG)
 146
 147     # any one of the set_timeout_XXX methods can be used depending on
 148     # the style
 149
 150     def set_timeout_none(self):
 151         """Highlight will remain until user input turns it off
 152         or the insert has moved"""
 153         # After CHECK_DELAY, call a function which disables the "paren" tag
 154         # if the event is for the most recent timer and the insert has changed,
 155         # or schedules another call for itself.
 156         self.counter += 1
 157         def callme(callme, self=self, c=self.counter,
 158                    index=self.text.index("insert")):
 159             if index != self.text.index("insert"):
 160                 self.handle_restore_timer(c)
 161             else:
 162                 self.editwin.text_frame.after(CHECK_DELAY, callme, callme)
 163         self.editwin.text_frame.after(CHECK_DELAY, callme, callme)
 164
 165     def set_timeout_last(self):
 166         """The last highlight created will be removed after .5 sec"""
 167         # associate a counter with an event; only disable the "paren"
 168         # tag if the event is for the most recent timer.
 169         self.counter += 1
 170         self.editwin.text_frame.after(self.FLASH_DELAY,
 171                                       lambda self=self, c=self.counter: \
 172                                       self.handle_restore_timer(c))