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From: Devin Jeanpierre <jeanpierreda@gmail.com>
Date: Fri, 26 Oct 2012 19:59:06 -0400
Subject: Re: while expression feature proposal
To: Cameron Simpson <cs@zip.com.au>
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Xref: csiph.com comp.lang.python:32249

On Fri, Oct 26, 2012 at 7:56 PM, Cameron Simpson <cs@zip.com.au> wrote:
> No. Separate _expressions_ are evaluated left to right.
>
> So this:
>
>   f(1), f(2)
>
> calls "f(1)" first, then "f(2)". But this:
>
>   f(1) + f(2)
>
> need not do so. Counter-documentation welcomed, but the doco you cite
> does not define an order for the second example above.

Actually, it does. Both f(1) and f(2) are separate (sub-)expressions
in f(1) + f(2). More to the point, it gives the following example:

    In the following lines, expressions will be evaluated in the
arithmetic order of their suffixes:
        ...
        expr1 + expr2 * (expr3 - expr4)

I sympathize with your concern, though. Order of evaluation is very
bitey, and it's better to be safe than sorry.

-- Devin