[Python-ideas] with statement vs. try...except...finally

[Scott David Daniels]

Gerald Britton wrote:
> I'm wondering if the "with" statement should have exception clauses
> like the "try" statement, even though this seems to defeat part of the
> reason for the "with" statement....
> something like:
>     try:
>         f = open('foo')
>         line = f.readline()
>         f.close()
>     except IOError:
>         line = 'default'
> ... Fine so far, but what if I want to be more granular? ...
> I can't see how to replace the above try-triplet with a "with"
> encapsulation. Or, do I have to wrap the "with" statement in try like
> this:

How about using the error information?:
     try:
         with open('pov_export/.hg/requires') as src:
             line = src.read(30)
     except IOError, why:
         line = 'Problem: %s' % why

--Scott David Daniels
Scott.Daniels at Acm.Org