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Python Source  |  2000-09-28  |  2.6 KB  |  86 lines
  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 close(self):
  16.         while self.top is not self.bottom:
  17.             self.removefilter(self.top)
  18.         self.top = None
  19.         self.bottom.setdelegate(None); self.bottom = None
  20.         self.redir.close(); self.redir = None
  21.         self.text = None
  22.  
  23.     def insert(self, index, chars, tags=None):
  24.         # Could go away if inheriting from Delegator
  25.         self.top.insert(index, chars, tags)
  26.  
  27.     def delete(self, index1, index2=None):
  28.         # Could go away if inheriting from Delegator
  29.         self.top.delete(index1, index2)
  30.  
  31.     def insertfilter(self, filter):
  32.         # Perhaps rename to pushfilter()?
  33.         assert isinstance(filter, Delegator)
  34.         assert filter.delegate is None
  35.         filter.setdelegate(self.top)
  36.         self.top = filter
  37.  
  38.     def removefilter(self, filter):
  39.         # XXX Perhaps should only support popfilter()?
  40.         assert isinstance(filter, Delegator)
  41.         assert filter.delegate is not None
  42.         f = self.top
  43.         if f is filter:
  44.             self.top = filter.delegate
  45.             filter.setdelegate(None)
  46.         else:
  47.             while f.delegate is not filter:
  48.                 assert f is not self.bottom
  49.                 f.resetcache()
  50.                 f = f.delegate
  51.             f.setdelegate(filter.delegate)
  52.             filter.setdelegate(None)
  53.  
  54.  
  55. def main():
  56.     class Tracer(Delegator):
  57.         def __init__(self, name):
  58.             self.name = name
  59.             Delegator.__init__(self, None)
  60.         def insert(self, *args):
  61.             print self.name, ": insert", args
  62.             apply(self.delegate.insert, args)
  63.         def delete(self, *args):
  64.             print self.name, ": delete", args
  65.             apply(self.delegate.delete, args)
  66.     from Tkinter import *
  67.     root = Tk()
  68.     root.wm_protocol("WM_DELETE_WINDOW", root.quit)
  69.     text = Text()
  70.     text.pack()
  71.     text.focus_set()
  72.     p = Percolator(text)
  73.     t1 = Tracer("t1")
  74.     t2 = Tracer("t2")
  75.     p.insertfilter(t1)
  76.     p.insertfilter(t2)
  77.     root.mainloop()
  78.     p.removefilter(t2)
  79.     root.mainloop()
  80.     p.insertfilter(t2)
  81.     p.removefilter(t1)
  82.     root.mainloop()
  83.  
  84. if __name__ == "__main__":
  85.     main()
  86.