from Tkinter import * class WidgetRedirector: """Support for redirecting arbitrary widget subcommands.""" def __init__(self, widget): self.dict = {} self.widget = widget self.tk = tk = widget.tk w = widget._w self.orig = w + "_orig" tk.call("rename", w, self.orig) tk.createcommand(w, self.dispatch) def __repr__(self): return "WidgetRedirector(%s<%s>)" % (self.widget.__class__.__name__, self.widget._w) def close(self): for name in self.dict.keys(): self.unregister(name) widget = self.widget; del self.widget orig = self.orig; del self.orig tk = widget.tk w = widget._w tk.deletecommand(w) tk.call("rename", orig, w) def register(self, name, function): if self.dict.has_key(name): previous = dict[name] else: previous = OriginalCommand(self, name) self.dict[name] = function setattr(self.widget, name, function) return previous def unregister(self, name): if self.dict.has_key(name): function = self.dict[name] del self.dict[name] if hasattr(self.widget, name): delattr(self.widget, name) return function else: return None def dispatch(self, cmd, *args): m = self.dict.get(cmd) try: if m: return apply(m, args) else: return self.tk.call((self.orig, cmd) + args) except TclError: return "" class OriginalCommand: def __init__(self, redir, name): self.redir = redir self.name = name self.tk = redir.tk self.orig = redir.orig self.tk_call = self.tk.call self.orig_and_name = (self.orig, self.name) def __repr__(self): return "OriginalCommand(%s, %s)" % (`self.redir`, `self.name`) def __call__(self, *args): return self.tk_call(self.orig_and_name + args) def main(): root = Tk() text = Text() text.pack() text.focus_set() redir = WidgetRedirector(text) global orig_insert def my_insert(*args): print "insert", args apply(orig_insert, args) orig_insert = redir.register("insert", my_insert) root.mainloop() if __name__ == "__main__": main()