Lib/idlelib/WidgetRedirector.py

   1 from Tkinter import *
   2
   3
   4 class WidgetRedirector:
   5
   6     """Support for redirecting arbitrary widget subcommands."""
   7
   8     def __init__(self, widget):
   9         self.dict = {}
  10         self.widget = widget
  11         self.tk = tk = widget.tk
  12         w = widget._w
  13         self.orig = w + "_orig"
  14         tk.call("rename", w, self.orig)
  15         tk.createcommand(w, self.dispatch)
  16
  17     def __repr__(self):
  18         return "WidgetRedirector(%s<%s>)" % (self.widget.__class__.__name__,
  19                                              self.widget._w)
  20
  21     def close(self):
  22         for name in self.dict.keys():
  23             self.unregister(name)
  24         widget = self.widget; del self.widget
  25         orig = self.orig; del self.orig
  26         tk = widget.tk
  27         w = widget._w
  28         tk.deletecommand(w)
  29         tk.call("rename", orig, w)
  30
  31     def register(self, name, function):
  32         if self.dict.has_key(name):
  33             previous = dict[name]
  34         else:
  35             previous = OriginalCommand(self, name)
  36         self.dict[name] = function
  37         setattr(self.widget, name, function)
  38         return previous
  39
  40     def unregister(self, name):
  41         if self.dict.has_key(name):
  42             function = self.dict[name]
  43             del self.dict[name]
  44             if hasattr(self.widget, name):
  45                 delattr(self.widget, name)
  46             return function
  47         else:
  48             return None
  49
  50     def dispatch(self, cmd, *args):
  51         m = self.dict.get(cmd)
  52         try:
  53             if m:
  54                 return apply(m, args)
  55             else:
  56                 return self.tk.call((self.orig, cmd) + args)
  57         except TclError:
  58             return ""
  59
  60
  61 class OriginalCommand:
  62
  63     def __init__(self, redir, name):
  64         self.redir = redir
  65         self.name = name
  66         self.tk = redir.tk
  67         self.orig = redir.orig
  68         self.tk_call = self.tk.call
  69         self.orig_and_name = (self.orig, self.name)
  70
  71     def __repr__(self):
  72         return "OriginalCommand(%s, %s)" % (`self.redir`, `self.name`)
  73
  74     def __call__(self, *args):
  75         return self.tk_call(self.orig_and_name + args)
  76
  77
  78 def main():
  79     root = Tk()
  80     text = Text()
  81     text.pack()
  82     text.focus_set()
  83     redir = WidgetRedirector(text)
  84     global orig_insert
  85     def my_insert(*args):
  86         print "insert", args
  87         apply(orig_insert, args)
  88     orig_insert = redir.register("insert", my_insert)
  89     root.mainloop()
  90
  91 if __name__ == "__main__":
  92     main()