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Date: Wed, 17 Aug 2011 18:25:12 +0100
Subject: Re: Syntactic sugar for assignment statements: one value to multiple targets?
From: Chris Angelico <rosuav@gmail.com>
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:11702

On Wed, Aug 17, 2011 at 5:55 PM, MRAB <python@mrabarnett.plus.com> wrote:
> x, y, z = lazy copies(SuperComplexClass(param1, etc, ...))
>

This assumes that you can construct it once and then copy it reliably,
which may mean that the class implement copying correctly. It also
wouldn't work with:

a, b, c, d = *random.randint(1,20)

which would roll 4d20 and get the results in separate variables. The
OP's idea of separately evaluating the expression would; but to do it
with copying would require a special "randint" object that functions
exactly as an integer but, when copied, would re-randomize.

Perhaps * is the wrong syntactic element to use. Maybe it needs a
special assignment operator:

a, b, c, d @= random.randint(1,20)

which would evaluate its left operand as a tuple of lvalues, then
evaluate its right operand once for each element in the left operand,
and assign to each element in turn. (I've no idea what form of
assignment operator would be suitable, but @= is currently illegal, so
it ought to be safe at least for discussion purposes.)

Chris Angelico