Le Wed, 16 Oct 2013 13:42:34 +0200,
Victor Stinner <victor.stin...@gmail.com> a écrit :
> I might agree with idea of contextlib.ignore() (I'm still opposed to
> the idea), but I don't understand the purpose of adding a new syntax
> doing exactly the same than try/except:
>
> > with trap(OSError) as cm:
> > os.unlink('missing.txt')
> > if cm.exc:
> > do_something()
>
> Nobody noticed that this can be written:
>
> try:
> os.unlink('missing.txt')
> except OSError as err:
> # do something with err
>
> ?? What happened with the Zen Principle "There should be one-- and
> preferably only one --obvious way to do it." I don't understand why I
> would import contextlib and use a new context manager, whereas
> try/except is already a builtin feature of Python.
>
> By the way, what are the performances of contextlib.ignore()?
> Exceptions can be slow in some cases. Adding something even slower
> would not be a good idea.
A "try" block which succeeds is fast. A context manager will always be
slower, especially when written in pure Python with a generator wrapped
in a contextlib.contextmanager.
Regards
Antoine.
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