[Python-Dev] Acquire/release functionality

[holger krekel]

Moore, Paul wrote:
> Paul Moore <lists@morpheus.demon.co.uk> writes:
> 
> > As far as the acquire/release case is concerned, I think that there is
> > definitely a strong case for syntactic support for this. The
> > equivalent idiom in C++ is "resource acquisition is initialisation"
> > which, while not having syntax support, does rely on the existence of
> > deterministic destructors, and on the ability to introduce a new scope
> > at will. Python has neither of these, and the try...finally construct
> > is verbose enough to make something better worth having.
> 
> In trying to draw a parallel between "with" and the C++ RAII idiom, I
> hit a funny, best illustrated by an example:
> 
>     class autoclose(file):
>         __exit__ = close
> 
>     with f = autoclose("blah.txt", "r"):
>         # Let's get sneaky
>         g = f
>         # Main code here
> 
>     # File now gets closed
>     with g:

I haven't found a way to make assignments optional (in recent
experiments).  Is this possible with Python's Parser? 

    holger