Add trace methods to class Variable

diff --git a/Lib/lib-tk/Tkinter.py b/Lib/lib-tk/Tkinter.py
index fbf90e446d52eca3bccd80e38647f2d1dc2ddd39..5220c9d5565ad25105ddf53a604c491fb6035f9f 100644 (file)
--- a/Lib/lib-tk/Tkinter.py
+++ b/Lib/lib-tk/Tkinter.py
@@ -63,12 +63,11 @@ _varnum = 0
 class Variable:
        _default = ""
        def __init__(self, master=None):
-               global _default_root
                global _varnum
-               if master:
-                       self._tk = master.tk
-               else:
-                       self._tk = _default_root.tk
+               if not master:
+                       master = _default_root
+               self._master = master
+               self._tk = master.tk
                self._name = 'PY_VAR' + `_varnum`
                _varnum = _varnum + 1
                self.set(self._default)
@@ -78,6 +77,17 @@ class Variable:
                return self._name
        def set(self, value):
                return self._tk.globalsetvar(self._name, value)
+       def trace_variable(self, mode, callback):
+               cbname = self._master._register(callback)
+               self._tk.call("trace", "variable", self._name, mode, cbname)
+               return cbname
+       trace = trace_variable
+       def trace_vdelete(self, mode, cbname):
+               self._tk.call("trace", "vdelete", self._name, mode, cbname)
+               self._tk.deletecommand(cbname)
+       def trace_vinfo(self):
+               return map(self._tk.split, self._tk.splitlist(
+                       self._tk.call("trace", "vinfo", self._name)))
 
 class StringVar(Variable):
        _default = ""