Yield inside try...finally

W Isaac Carroll icarroll at pobox.com
Thu Jun 5 12:13:43 CEST 2003


Jeremy Fincher wrote:
> I wonder if he's considered relaxing that restriction to allow at most
> *one* try: finally: block, or any number of try: finally: blocks whose
> finally: clauses are identical (which is effectively equivalent to a
> single finally: clause).  He could then just compile the finally code
> into an __del__ method on the generator-iterator.

I don't think it's that simple. For example:

     def finalgen():
         while not done:
             try:
                 foo = makefoo()
                 yield foo
             finally:
                 cleanup(foo)
             yield somethingelse

At the first yield statement, the generator would need a __del__ method 
that calls cleanup(foo). At the second yield statement, no __del__ 
method is needed because cleanup(foo) was called when the generator was 
resumed. Solving this problem, however, would lift your proposed 
restriction that only one finally block be allowed.

TTFN






More information about the Python-list mailing list