Tools/idle/Percolator.py

   1 from WidgetRedirector import WidgetRedirector
   2 from Delegator import Delegator
   3
   4 class Percolator:
   5
   6     def __init__(self, text):
   7         # XXX would be nice to inherit from Delegator
   8         self.text = text
   9         self.redir = WidgetRedirector(text)
  10         self.top = self.bottom = Delegator(text)
  11         self.bottom.insert = self.redir.register("insert", self.insert)
  12         self.bottom.delete = self.redir.register("delete", self.delete)
  13         self.filters = []
  14
  15     def insert(self, index, chars, tags=None):
  16         # Could go away if inheriting from Delegator
  17         self.top.insert(index, chars, tags)
  18
  19     def delete(self, index1, index2=None):
  20         # Could go away if inheriting from Delegator
  21         self.top.delete(index1, index2)
  22
  23     def insertfilter(self, filter):
  24         # Perhaps rename to pushfilter()?
  25         assert isinstance(filter, Delegator)
  26         assert filter.delegate is None
  27         filter.setdelegate(self.top)
  28         self.top = filter
  29
  30     def removefilter(self, filter):
  31         # XXX Perhaps should only support popfilter()?
  32         assert isinstance(filter, Delegator)
  33         assert filter.delegate is not None
  34         f = self.top
  35         if f is filter:
  36             self.top = filter.delegate
  37             filter.setdelegate(None)
  38         else:
  39             while f.delegate is not filter:
  40                 assert f is not self.bottom
  41                 f.resetcache()
  42                 f = f.delegate
  43             f.setdelegate(filter.delegate)
  44             filter.setdelegate(None)
  45
  46
  47 def main():
  48     class Tracer(Delegator):
  49         def __init__(self, name):
  50             self.name = name
  51             Delegator.__init__(self, None)
  52         def insert(self, *args):
  53             print self.name, ": insert", args
  54             apply(self.delegate.insert, args)
  55         def delete(self, *args):
  56             print self.name, ": delete", args
  57             apply(self.delegate.delete, args)
  58     from Tkinter import *
  59     root = Tk()
  60     root.wm_protocol("WM_DELETE_WINDOW", root.quit)
  61     text = Text()
  62     text.pack()
  63     text.focus_set()
  64     p = Percolator(text)
  65     t1 = Tracer("t1")
  66     t2 = Tracer("t2")
  67     p.insertfilter(t1)
  68     p.insertfilter(t2)
  69     root.mainloop()
  70     p.removefilter(t2)
  71     root.mainloop()
  72     p.insertfilter(t2)
  73     p.removefilter(t1)
  74     root.mainloop()
  75
  76 if __name__ == "__main__":
  77     main()