[Python-ideas] with statement syntax forces ugly line breaks?

[Gregory P. Smith]

On Wed, Sep 8, 2010 at 10:00 AM, Nathan Schneider <nathan at cmu.edu> wrote:

> Mark,
>
> I have approached these cases by using the backslash line-continuation
> operator:
>
> with FakeContext("a") as a, \
>   FakeContext("b") as b:
>   pass
>
> Nathan
>

I'm in the "\ is evil" at all costs camp so I'd suggest either the nested
with statements or alternatively do this:

fc = FakeContext
with fc("a") as a, fc("b") as b:
    pass


> On Wed, Sep 8, 2010 at 12:50 PM, Mark Summerfield <mark at qtrac.eu> wrote:
> > Hi,
> >
> > I can't see a _nice_ way of splitting a with statement over mulitple
> > lines:
> >
> > class FakeContext:
> >    def __init__(self, name):
> >        self.name = name
> >    def __enter__(self):
> >        print("enter", self.name)
> >    def __exit__(self, *args):
> >        print("exit", self.name)
> >
> > with FakeContext("a") as a, FakeContext("b") as b:
> >    pass # works fine
> >
> >
> > with FakeContext("a") as a,
> >     FakeContext("b") as b:
> >    pass # synax error
> >
> >
> > with (FakeContext("a") as a,
> >      FakeContext("b") as b):
> >    pass # synax error
> >
> > The use case where this mattered to me was this:
> >
> >    with open(args.actual, encoding="utf-8") as afh,
> >    open(args.expected, encoding="utf-8") as efh: actual =
> >    [line.rstrip("\n\r") for line in afh.readlines()] expected =
> >    [line.rstrip("\n\r") for line in efh.readlines()]
> >
> > Naturally, I could split the line in an ugly place:
> >
> >    with open(args.actual, encoding="utf-8") as afh, open(args.expected,
> >            encoding="utf-8") as efh:
> >
> > but it seems a shame to do so. Or am I missing something?
> >
> > I'm using Python 3.1.2.
> >
> > --
> > Mark Summerfield, Qtrac Ltd, www.qtrac.eu
> >    C++, Python, Qt, PyQt - training and consultancy
> >        "Rapid GUI Programming with Python and Qt" - ISBN 0132354187
> >            http://www.qtrac.eu/pyqtbook.html
> > _______________________________________________
> > Python-ideas mailing list
> > Python-ideas at python.org
> > http://mail.python.org/mailman/listinfo/python-ideas
> >
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