[Python-Dev] context manager - generator interaction?

Guido van Rossum guido at python.org
Fri Apr 6 11:39:33 CEST 2007

On 4/5/07, Raymond Hettinger <python at rcn.com> wrote:
> > Guido van Rossum wrote:
> >> Isn't this violating the rule that a try/except should only enclose
> >> the smallest expression where the exception is expected?
> >
> > Yeah, and I keep finding myself wanting to hyperlink to that "rule" in
> > the official docs, but it only seems to be written down in developer's
> > heads. Can we get that into the Language Ref somewhere? Maybe on the
> > http://docs.python.org/ref/try.html page?
> I'll add a snippet to the tutorial with advice on try/except.
> I don't think it should go in the main documentation because it is
> really more of a suggestion or technique than an actual rule.
> Also, there are plenty of other situations where the "rule" doesn't apply.

I see a lot of code written by Googlers who are not (yet) experienced
Python users. Overly wide try/except clauses are a common mistake, and
it is nearly always easy to apply this rule. I would argue, as a style
issue, for making this rule the norm, and require deviations to be
thought through very carefully.

This rule has no place in a pure language *reference* manual. But it
certainly deserves mention in any form of more practical
documentation, be it a tutorial or a more advanced programming manual.

--Guido van Rossum (home page: http://www.python.org/~guido/)

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