[Python-Dev] Multiline with statement line continuation
steve at pearwood.info
Wed Aug 13 19:32:26 CEST 2014
On Wed, Aug 13, 2014 at 08:08:51PM +0300, yoav glazner wrote:
> Just a thought, would it bit wierd that:
> with (a as b, c as d): "works"
> with (a, c): "boom"
> with(a as b, c): ?
If this proposal is accepted, there is no need for the "boom". The
syntax should allow:
# Without parens, limited to a single line.
with a [as name], b [as name], c [as name], ...:
# With parens, not limited to a single line.
with (a [as name],
b [as name],
c [as name],
where the "as name" part is always optional. In both these cases,
whether there are parens or not, it will be interpreted as a series of
context managers and never as a single tuple.
Note two things:
(1) this means that even in the unlikely event that tuples become
context managers in the future, you won't be able to use a tuple
with (1, 2, 3): # won't work as expected
t = (1, 2, 3)
with t: # will work as expected
But I cannot imagine any circumstances where tuples will become context
(2) Also note that *this is already the case*, since tuples are made by
the commas, not the parentheses. E.g. this succeeds:
# Not a tuple, actually two context managers.
with open("/tmp/foo"), open("/tmp/bar", "w"):
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