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Groups > comp.lang.python > #93721

Re: 0 + not 0

From Gregory Ewing <greg.ewing@canterbury.ac.nz>
Newsgroups comp.lang.python
Subject Re: 0 + not 0
Date 2015-07-12 18:12 +1200
Message-ID <d0eepiFo9spU1@mid.individual.net> (permalink)
References <01ec6551-1f40-42b0-9406-036030591519@googlegroups.com> <mailman.420.1436621919.3674.python-list@python.org> <not-20150711180044@ram.dialup.fu-berlin.de> <mailman.428.1436633811.3674.python-list@python.org>

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Ian Kelly wrote:
> I must concur. The grammar as written does not actually produce 1 +
> not 0. I think it's still worthwhile opening a bug, because the
> behavior is surprising and possibly not intentional.

It's almost certainly intentional. If you want

    not a + b > c

to be interpreted as

    not (a + b > c)

rather than

    (not a) + b > c

then 'not' has to be higher up in the chain of
grammar productions than the arithmetic operations.
Maintaining that while allowing 'a + not b' would
require contortions in the grammar that wouldn't be
worth the very small benefit that would be obtained.

-- 
Greg

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Thread

0 + not 0 candide <c.candide@laposte.net> - 2015-07-11 03:26 -0700
  Re: 0 + not 0 Chris Angelico <rosuav@gmail.com> - 2015-07-11 20:38 +1000
  Re: 0 + not 0 Irmen de Jong <irmen.NOSPAM@xs4all.nl> - 2015-07-11 12:38 +0200
    Re: 0 + not 0 Luuk <luuk@invalid.lan> - 2015-07-11 13:12 +0200
      Re: 0 + not 0 Chris Angelico <rosuav@gmail.com> - 2015-07-11 21:20 +1000
        Re: 0 + not 0 Luuk <luuk@invalid.lan> - 2015-07-11 13:30 +0200
          Re: 0 + not 0 candide <c.candide@laposte.net> - 2015-07-11 04:54 -0700
            Re: 0 + not 0 Chris Angelico <rosuav@gmail.com> - 2015-07-11 22:05 +1000
              Re: 0 + not 0 candide <c.candide@laposte.net> - 2015-07-11 06:22 -0700
        Re: 0 + not 0 candide <c.candide@laposte.net> - 2015-07-11 04:48 -0700
      Re: 0 + not 0 random832@fastmail.us - 2015-07-11 16:46 -0400
  Re: 0 + not 0 Serhiy Storchaka <storchaka@gmail.com> - 2015-07-11 16:38 +0300
    Re: 0 + not 0 candide <c.candide@laposte.net> - 2015-07-11 08:07 -0700
    Re: 0 + not 0 MRAB <python@mrabarnett.plus.com> - 2015-07-11 17:20 +0100
    Re: 0 + not 0 Ian Kelly <ian.g.kelly@gmail.com> - 2015-07-11 10:56 -0600
      Re: 0 + not 0 Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2015-07-12 18:12 +1200
    Re: 0 + not 0 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-07-11 21:05 +0100

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