Lib/idlelib/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 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             self.delegate.insert(*args)
  63         def delete(self, *args):
  64             print self.name, ": delete", args
  65             self.delegate.delete(*args)
  66     root = Tk()
  67     root.wm_protocol("WM_DELETE_WINDOW", root.quit)
  68     text = Text()
  69     text.pack()
  70     text.focus_set()
  71     p = Percolator(text)
  72     t1 = Tracer("t1")
  73     t2 = Tracer("t2")
  74     p.insertfilter(t1)
  75     p.insertfilter(t2)
  76     root.mainloop()
  77     p.removefilter(t2)
  78     root.mainloop()
  79     p.insertfilter(t2)
  80     p.removefilter(t1)
  81     root.mainloop()
  82
  83 if __name__ == "__main__":
  84     from Tkinter import *
  85     main()