[Python-Dev] With statement

[John Williams]

Michael Hudson wrote:
> Oren Tirosh <oren-py-d@hishome.net> writes:
>>Let's assume that a new 'local' statement is added to Python. At the end 
>>of the current block the __del__ method of any references declared local 
>>is guaranteed to be called. [snip]
> 
> Two comments:
> 
> 1) The resource-allocation-is-initialization pattern works very well
>    in C++, but I'm unconvinced that we should aim to copy it exactly
>    -- it's a nice solution to the problem, but not the only possible
>    or best one, IMHO.
> 
> 2) Without the ability to define a scope at will, RAiI becomes less useful.


Why not combine the "with" and "local" statement ideas?  Change the 
"with" statement so that there is no __enter__ method, and call __del__ 
where there current proposal calls __exit__.  Now you have

   with f = file(...):
     # Do something with f.

meaning something similar to

   f = file(...)
   try:
     # Do something with f.
   finally:
     assert sys.getrefcount(f) == 2
     del f
     # f is guaranteed dead, so f.__del__ is called