[Python-Dev] multi-with statement

[Alex Martelli]

FWIW, I prefer Fredrik's wish too.
Alex

On Sat, May 2, 2009 at 12:26 PM, Fredrik Johansson <
fredrik.johansson at gmail.com> wrote:

> On Sat, May 2, 2009 at 9:01 PM, Georg Brandl <g.brandl at gmx.net> wrote:
> > Hi,
> >
> > this is just a short notice that Mattias Brändström and I have finished a
> > patch to implement the previously discussed and mostly warmly welcomed
> > extension to with's syntax, allowing
> >
> >   with A() as a, B() as b:
> >
> > to be written instead of
> >
> >   with A() as a:
> >       with B() as b:
> >
> > This syntax was chosen (over "with A(), B() as a, b:") because it has
> more
> > syntactical similarity to the written-out version.  Also, our current
> uses
> > of "as" all have only one expression on the right.
> >
> > The patch implements it as a simple AST transformation, which guarantees
> > semantic equivalence.  It is at <http://codereview.appspot.com/53094>.
> >
> > If there is no strong opposition, I will commit it and port it to py3k
> > before 3.1 enters beta stage.
> >
> > cheers,
> > Georg
>
> I was hoping for the other syntax in order to be able to create a
> nested context in advance as a simple tuple:
>
> with A, B:
>    pass
>
> context = A, B
> with context:
>    pass
>
> (I.e. a tuple, or perhaps any iterable, would be a valid context manager.)
>
> With the syntax in the patch, I will still have to implement a custom
> nesting context manager to do this, which sort of defeats the purpose.
>
> Fredrik
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