file.close()

Paul Rubin http
Fri Jul 25 22:35:49 CEST 2003


bokr at oz.net (Bengt Richter) writes:
> >"done" here is a generic method that gets called on exiting a "with"
> >block.  
> First reaction == +1, but some questions...
> 
> 1) Is f.done() really necessary? I.e., doesn't an explicit del f
>    take care of it if the object has been coded with a __del__
>    method? I.e., the idea was to get the effect of CPython's
>    immediate effective del on ref count going to zero, right?

The ref count might not be zero.  Something inside the "with" block
might make a new reference and leave it around.

> 2) how about with two files (or other multiple resources)?
> 
>     with f1,f2 = file('f1'), file('f2'):
>         [do stuff with f1 & f2]
> 
> What is the canonical expansion?

I think f1.done and f2.done should both get called.

> Also, what about the attribute version, i.e.,
> 
>     ob.f = file(frob)
>     try:
>       [do stuff with ob.f]
>     finally:
>       del ob.f # calls f.__del__, which calls/does f.close()
> 
> I.e., ob.f = something could raise an exception (e.g., a read-only property)
> *after* file(frob) has succeeded. So I guess the easiest would be to limit
> the left hand side to plain names... 

The assignment should be inside the try.  If I had it on the outside
before, that was an error.




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