Groups > comp.lang.python > #32076

Re: while expression feature proposal

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From	Ian Kelly <ian.g.kelly@gmail.com>
Date	Wed, 24 Oct 2012 16:54:14 -0600
Subject	Re: while expression feature proposal
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On Wed, Oct 24, 2012 at 3:54 PM, Tim Chase
<python.list@tim.thechases.com> wrote:
> It may be idiomatic, but that doesn't stop it from being pretty
> ugly.  I must say I really like the parity of Dan's
>
>   while EXPR as VAR:
>      BLOCK
>
> proposal with the "with" statement.  It also doesn't fall prey to
> the "mistaken-assignment vs. intentional-assignment" found in most
> C-like languages.  I could see a pretty reasonable PEP coming from this.

Often though the while test is not a simple boolean test of VAR.  For example:

j = int(random() * n)
while j in selected:
    j = int(random() * n)

It also doesn't flow quite as naturally.  "with x as y" is
grammatically correct English.  "while x as y" is not, and I wonder
how easily it might be confused for "while x is y", which is valid
Python and means something completely different.

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Re: while expression feature proposal Ian Kelly <ian.g.kelly@gmail.com> - 2012-10-24 16:54 -0600
  Re: while expression feature proposal Paul Rubin <no.email@nospam.invalid> - 2012-10-24 16:08 -0700
    Re: while expression feature proposal Ian Kelly <ian.g.kelly@gmail.com> - 2012-10-24 17:39 -0600
      Re: while expression feature proposal Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2012-10-25 09:21 +0200
        Re: while expression feature proposal Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2012-10-25 12:12 +0200
        Re: while expression feature proposal Ian Kelly <ian.g.kelly@gmail.com> - 2012-10-25 10:36 -0600
          Re: while expression feature proposal Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2012-10-25 22:49 +0200
            Re: while expression feature proposal Dan Loewenherz <dloewenherz@gmail.com> - 2012-10-25 22:12 -0700
              Re: while expression feature proposal Paul Rubin <no.email@nospam.invalid> - 2012-10-25 23:06 -0700
                Re: while expression feature proposal Chris Angelico <rosuav@gmail.com> - 2012-10-26 17:23 +1100
                Re: while expression feature proposal Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-10-26 09:43 +0000
                Re: while expression feature proposal Dan Loewenherz <dloewenherz@gmail.com> - 2012-10-26 08:29 -0700
                Re: while expression feature proposal Ian Kelly <ian.g.kelly@gmail.com> - 2012-10-26 09:42 -0600
                Re: while expression feature proposal Paul Rubin <no.email@nospam.invalid> - 2012-10-26 09:10 -0700
                Re: while expression feature proposal Cameron Simpson <cs@zip.com.au> - 2012-10-27 09:03 +1100
                Re: while expression feature proposal Ian Kelly <ian.g.kelly@gmail.com> - 2012-10-26 16:48 -0600
                Re: while expression feature proposal Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-10-27 00:07 +0000
                Re: while expression feature proposal Paul Rubin <no.email@nospam.invalid> - 2012-10-26 20:43 -0700
                Re: while expression feature proposal Tim Chase <sed@thechases.com> - 2012-10-26 18:26 -0500
                Re: while expression feature proposal Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-10-26 19:41 -0400
                Re: while expression feature proposal Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-10-26 19:19 -0400
                Re: while expression feature proposal Chris Angelico <rosuav@gmail.com> - 2012-10-27 11:42 +1100
              Re: while expression feature proposal Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-10-26 19:12 -0400
                Re: while expression feature proposal Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-10-27 00:18 +0000
                Re: while expression feature proposal Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-10-26 20:27 -0400
                Re: while expression feature proposal Tim Chase <python.list@tim.thechases.com> - 2012-10-27 14:15 -0500
              Re: while expression feature proposal Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-10-26 19:51 -0400
        Re: while expression feature proposal Ian Kelly <ian.g.kelly@gmail.com> - 2012-10-25 10:47 -0600
    Re: while expression feature proposal Paul Rudin <paul.nospam@rudin.co.uk> - 2012-10-25 10:35 +0100

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