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Groups > comp.lang.python > #111509

Re: Operator Precedence/Boolean Logic

From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Subject Re: Operator Precedence/Boolean Logic
Date 2016-07-16 20:46 +1000
Message-ID <mailman.33.1468665977.2307.python-list@python.org> (permalink)
References (16 earlier) <d60e179a-c244-48c1-8438-03ad63292897@googlegroups.com> <5775555f$0$22140$c3e8da3$5496439d@news.astraweb.com> <7ecde6d0-d3db-4a7a-8de6-65b398fedafe@googlegroups.com> <578a0992$0$1610$c3e8da3$5496439d@news.astraweb.com> <CAPTjJmpRO+V+6s8RebvTkUu=7DqWPbM5ycgSZkhsZ7ebsPz6Dw@mail.gmail.com>

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On Sat, Jul 16, 2016 at 8:16 PM, Steven D'Aprano <steve@pearwood.info> wrote:
>> If both you and Chris tripped up on a right definition of an “empty”
>> automaton and regex respectively, I believe it demonstrates that getting
>> boolishness for an arbitrary type right is at least non-trivial. [FWIW My
>> belief: In general its nonsensical]
>
> Firstly, I disagree that I tripped up on anything. You haven't given any
> reason to think that Automata objects shouldn't be truthy, and even if you
> do, isn't that just a matter of opinion?

I also disagree that I "tripped up", but there is room for differing
decisions in API design, and this is one of them. I can't say
perfectly, from my armchair (which I'm not in anyway - way too
cumbersome for a desktop computer), which objects are capable of being
"empty" and which are not. The implementer of the automaton class or
the regex class has to decide what counts as "empty". As Steven says,
the default is that they're all truthy, and onus is on the implementer
to demonstrate that this object is functionally equivalent to 0 or an
empty collection. (And it's possible for ANYONE to get that wrong - cf
timedelta.)

ChrisA

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Thread

Operator Precedence/Boolean Logic Elizabeth Weiss <cake240@gmail.com> - 2016-06-21 20:40 -0700
  Re: Operator Precedence/Boolean Logic Ben Finney <ben+python@benfinney.id.au> - 2016-06-22 13:59 +1000
    Re: Operator Precedence/Boolean Logic Elizabeth Weiss <cake240@gmail.com> - 2016-06-22 21:19 -0700
    Re: Operator Precedence/Boolean Logic Elizabeth Weiss <cake240@gmail.com> - 2016-06-22 21:20 -0700
  Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-22 16:02 +1000
  Re: Operator Precedence/Boolean Logic Christian Gollwitzer <auriocus@gmx.de> - 2016-06-22 08:26 +0200
    Re: Operator Precedence/Boolean Logic Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-06-22 10:14 +0300
      Re: Operator Precedence/Boolean Logic Elizabeth Weiss <cake240@gmail.com> - 2016-06-22 21:21 -0700
  Re: Operator Precedence/Boolean Logic Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-22 00:42 -0700
    Re: Operator Precedence/Boolean Logic Larry Hudson <orgnut@yahoo.com> - 2016-06-22 20:12 -0700
      Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-06-23 13:59 +1000
        Re: Operator Precedence/Boolean Logic Elizabeth Weiss <cake240@gmail.com> - 2016-06-22 21:23 -0700
        Re: Operator Precedence/Boolean Logic Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-06-23 09:58 +0200
          Re: Operator Precedence/Boolean Logic Marko Rauhamaa <marko@pacujo.net> - 2016-06-23 11:16 +0300
            Re: Operator Precedence/Boolean Logic Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-23 01:53 -0700
              Re: Operator Precedence/Boolean Logic Marko Rauhamaa <marko@pacujo.net> - 2016-06-23 12:10 +0300
                Re: Operator Precedence/Boolean Logic Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-06-23 11:27 +0200
                Re: Operator Precedence/Boolean Logic Marko Rauhamaa <marko@pacujo.net> - 2016-06-23 12:53 +0300
                Re: Operator Precedence/Boolean Logic Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-06-23 12:54 +0200
                Re: Operator Precedence/Boolean Logic Marko Rauhamaa <marko@pacujo.net> - 2016-06-23 13:59 +0300
                Re: Operator Precedence/Boolean Logic Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-06-23 13:15 +0200
                Re: Operator Precedence/Boolean Logic Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-06-23 15:05 +0300
                Re: Operator Precedence/Boolean Logic Chris Angelico <rosuav@gmail.com> - 2016-06-23 22:13 +1000
                Re: Operator Precedence/Boolean Logic Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-23 02:44 -0700
                Re: Operator Precedence/Boolean Logic Marko Rauhamaa <marko@pacujo.net> - 2016-06-23 12:57 +0300
                Re: Operator Precedence/Boolean Logic Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-24 22:38 -0700
                Re: Operator Precedence/Boolean Logic Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-06-25 09:46 +0300
            Re: Operator Precedence/Boolean Logic Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-06-23 11:01 +0200
          Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-23 19:39 +1000
            Re: Operator Precedence/Boolean Logic Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-06-23 12:21 +0200
              Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-06-23 22:37 +1000
                Re: Operator Precedence/Boolean Logic Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-06-23 15:24 +0200
                Re: Operator Precedence/Boolean Logic Random832 <random832@fastmail.com> - 2016-06-23 09:26 -0400
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-06-24 02:43 +1000
                Re: Operator Precedence/Boolean Logic Chris Angelico <rosuav@gmail.com> - 2016-06-24 01:49 +1000
        Re: Operator Precedence/Boolean Logic Marko Rauhamaa <marko@pacujo.net> - 2016-06-25 11:56 +0300
      Re: Operator Precedence/Boolean Logic Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-22 21:47 -0700
        Re: Operator Precedence/Boolean Logic Rustom Mody <rustompmody@gmail.com> - 2016-06-22 22:00 -0700
        Re: Operator Precedence/Boolean Logic Andreas Röhler <andreas.roehler@online.de> - 2016-06-23 08:34 +0200
          Re: Operator Precedence/Boolean Logic Marko Rauhamaa <marko@pacujo.net> - 2016-06-23 09:46 +0300
          Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-23 17:05 +1000
            Re: Operator Precedence/Boolean Logic Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-06-23 10:17 +0200
              Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-23 18:48 +1000
                Re: Operator Precedence/Boolean Logic Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-06-23 11:23 +0200
                Re: Operator Precedence/Boolean Logic Chris Angelico <rosuav@gmail.com> - 2016-06-23 21:45 +1000
                Re: Operator Precedence/Boolean Logic Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-06-23 14:08 +0200
                Re: Operator Precedence/Boolean Logic Andreas Röhler <andreas.roehler@online.de> - 2016-06-23 14:22 +0200
            Re: Operator Precedence/Boolean Logic Andreas Röhler <andreas.roehler@online.de> - 2016-06-23 10:23 +0200
            Re: Operator Precedence/Boolean Logic Andreas Röhler <andreas.roehler@online.de> - 2016-06-23 10:32 +0200
              Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-23 19:17 +1000
                Re: Operator Precedence/Boolean Logic Marko Rauhamaa <marko@pacujo.net> - 2016-06-23 12:46 +0300
                Re: Operator Precedence/Boolean Logic Andreas Röhler <andreas.roehler@online.de> - 2016-06-23 12:19 +0200
                Re: Operator Precedence/Boolean Logic Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-26 11:01 +1200
                Re: Operator Precedence/Boolean Logic Rustom Mody <rustompmody@gmail.com> - 2016-06-29 03:21 -0700
                Re: Operator Precedence/Boolean Logic Chris Angelico <rosuav@gmail.com> - 2016-06-29 21:06 +1000
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-06-29 23:08 +1000
                Re: Operator Precedence/Boolean Logic Rustom Mody <rustompmody@gmail.com> - 2016-06-29 06:30 -0700
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-06-30 09:40 +1000
                Re: Operator Precedence/Boolean Logic Rustom Mody <rustompmody@gmail.com> - 2016-06-30 09:01 -0700
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-07-01 03:22 +1000
                Re: Operator Precedence/Boolean Logic Rustom Mody <rustompmody@gmail.com> - 2016-07-15 22:48 -0700
                Re: Operator Precedence/Boolean Logic Rustom Mody <rustompmody@gmail.com> - 2016-07-15 22:58 -0700
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-07-16 19:14 +1000
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-07-16 20:16 +1000
                Re: Operator Precedence/Boolean Logic Chris Angelico <rosuav@gmail.com> - 2016-07-16 20:46 +1000
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-07-16 21:02 +1000
                Re: Operator Precedence/Boolean Logic Chris Angelico <rosuav@gmail.com> - 2016-07-17 00:26 +1000
                Re: Operator Precedence/Boolean Logic Rustom Mody <rustompmody@gmail.com> - 2016-07-16 05:33 -0700
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-07-17 02:27 +1000
                Re: Operator Precedence/Boolean Logic MRAB <python@mrabarnett.plus.com> - 2016-07-16 17:58 +0100
                Re: Operator Precedence/Boolean Logic Rustom Mody <rustompmody@gmail.com> - 2016-07-16 20:43 -0700
                Re: Operator Precedence/Boolean Logic Chris Angelico <rosuav@gmail.com> - 2016-07-17 14:05 +1000
                Re: Operator Precedence/Boolean Logic Rustom Mody <rustompmody@gmail.com> - 2016-07-16 23:44 -0700
                Re: Operator Precedence/Boolean Logic Rustom Mody <rustompmody@gmail.com> - 2016-07-16 23:59 -0700
                Re: Operator Precedence/Boolean Logic Chris Angelico <rosuav@gmail.com> - 2016-07-17 17:33 +1000
                Re: Operator Precedence/Boolean Logic Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-17 00:44 -0700
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-07-17 20:04 +1000
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-07-17 21:02 +1000
                Re: Operator Precedence/Boolean Logic Rustom Mody <rustompmody@gmail.com> - 2016-07-17 08:00 -0700
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-07-18 01:58 +1000
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-07-18 02:01 +1000
                Re: Operator Precedence/Boolean Logic Chris Angelico <rosuav@gmail.com> - 2016-07-17 03:06 +1000
                Re: Operator Precedence/Boolean Logic Rustom Mody <rustompmody@gmail.com> - 2016-07-16 05:15 -0700
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-07-17 02:36 +1000
                Re: Operator Precedence/Boolean Logic Grant Edwards <grant.b.edwards@gmail.com> - 2016-06-29 15:00 +0000
                Re: Operator Precedence/Boolean Logic Jon Ribbens <jon+usenet@unequivocal.eu> - 2016-06-29 15:05 +0000
                Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve@pearwood.info> - 2016-06-30 09:44 +1000
                Re: Operator Precedence/Boolean Logic Andreas Röhler <andreas.roehler@online.de> - 2016-06-23 11:51 +0200
        Re: Operator Precedence/Boolean Logic Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-23 17:20 +1000
        Re: Operator Precedence/Boolean Logic Random832 <random832@fastmail.com> - 2016-06-23 09:18 -0400
      Re: Operator Precedence/Boolean Logic Christian Gollwitzer <auriocus@gmx.de> - 2016-06-23 09:11 +0200
    Re: Operator Precedence/Boolean Logic Elizabeth Weiss <cake240@gmail.com> - 2016-06-22 21:22 -0700
  Fwd: Operator Precedence/Boolean Logic Jorge Gimeno <jlgimeno71@gmail.com> - 2016-06-21 20:56 -0700
  Re: Operator Precedence/Boolean Logic Random832 <random832@fastmail.com> - 2016-06-22 10:10 -0400
  Re: Operator Precedence/Boolean Logic Erik <python@lucidity.plus.com> - 2016-06-22 20:43 +0100

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