Re: Case Statements

From	BartC <bc@freeuk.com>
Newsgroups	comp.lang.python
Subject	Re: Case Statements
Date	2016-03-16 12:53 +0000
Organization	A noiseless patient Spider
Message-ID	<ncbkr7$kj3$1@dont-email.me> (permalink)
References	(6 earlier) <ncbac2$qtk$1@ger.gmane.org> <56E93ADD.9040500@rece.vub.ac.be> <mailman.191.1458126480.12893.python-list@python.org> <ncbf5e$uq4$1@dont-email.me> <87vb4md362.fsf@elektro.pacujo.net>

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On 16/03/2016 12:21, Marko Rauhamaa wrote:
> BartC <bc@freeuk.com>:

>> That's the first time I've heard a language feature common in C
>> described as sexy.
>
> Scheme has a "switch" statement (a "case" form). However, it is slightly
> better equipped for it than Python:
>
>   * Scheme has an atom type ("symbol"). It corresponds to interned
>     strings and is supposed to be compared by reference.
>
>   * Scheme has defined three equality operators: "eq?", "eqv?" and
>     "equal?". Python only has two: "is" (~ "eq?") and "==" (~ "equal?").
>     The "case" form makes use of the operator "eqv?" that is missing from
>     Python ("eqv?" compares numbers numerically but is otherwise the same
>     as "eq?").
>

Yes, a few scripting languages can do interesting things with switch or 
case statements. Perl for example (where I think it is created out other 
language features, but it looks a regular part of the syntax).

Even Ruby has one. It doesn't do anything 'sexy' with it, but it does 
have this:

  case
  when this
     ....
  when that
     ....
  when other
     ...
  end

which is exactly equivalent to if this... elif that... (when the tests 
are ordered), with one difference:

Each test starts with "when", instead of "if" for the first and "elif" 
for subsequent ones. That makes it easier to reorder tests, temporarily 
comment out the first test, copy a test from elsewhere, insert a new 
first test (you get the idea).

-- 
Bartc

Thread

Case Statements jj0gen0info@gmail.com - 2016-03-15 13:46 -0700
  Re: Case Statements Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-15 23:11 +0000
  Re: Case Statements jj0gen0info@gmail.com - 2016-03-15 16:47 -0700
    Re: Case Statements Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-15 23:58 +0000
    Re: Case Statements BartC <bc@freeuk.com> - 2016-03-16 00:51 +0000
      Re: Case Statements Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-16 01:05 +0000
  Re: Case Statements jj0gen0info@gmail.com - 2016-03-15 18:55 -0700
    Re: Case Statements "Mario R. Osorio" <nimbiotics@gmail.com> - 2016-03-15 21:06 -0700
      Re: Case Statements BartC <bc@freeuk.com> - 2016-03-16 10:34 +0000
        Re: Case Statements Steven D'Aprano <steve@pearwood.info> - 2016-03-16 23:56 +1100
    Re: Case Statements Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-16 04:26 +0000
      Re: Case Statements Christian Gollwitzer <auriocus@gmx.de> - 2016-03-16 09:13 +0100
        Re: Case Statements Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-16 08:47 +0000
        Re: Case Statements Marko Rauhamaa <marko@pacujo.net> - 2016-03-16 11:16 +0200
        Re: Case Statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-16 10:35 +0100
        Re: Case Statements Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-16 09:51 +0000
          Re: Case Statements BartC <bc@freeuk.com> - 2016-03-16 19:41 +0000
            Re: Case Statements BartC <bc@freeuk.com> - 2016-03-16 22:30 +0000
        Re: Case Statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-16 11:52 +0100
        Re: Case Statements Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-16 11:07 +0000
          Re: Case Statements BartC <bc@freeuk.com> - 2016-03-16 11:16 +0000
            Re: Case Statements Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-16 11:33 +0000
            Re: Case Statements Marko Rauhamaa <marko@pacujo.net> - 2016-03-16 14:21 +0200
              Re: Case Statements BartC <bc@freeuk.com> - 2016-03-16 12:53 +0000
                Re: Case Statements Marko Rauhamaa <marko@pacujo.net> - 2016-03-16 16:31 +0200
                Re: Case Statements BartC <bc@freeuk.com> - 2016-03-16 15:00 +0000
                Re: Case Statements Marko Rauhamaa <marko@pacujo.net> - 2016-03-16 19:07 +0200
              Re: Case Statements Rustom Mody <rustompmody@gmail.com> - 2016-03-20 01:01 -0700
                Re: Case Statements Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-20 08:29 +0000
        Re: Case Statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-16 14:38 +0100
        Re: Case Statements Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-16 14:02 +0000
        Re: Case Statements Marko Rauhamaa <marko@pacujo.net> - 2016-03-16 21:27 +0200
          Re: Case Statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-17 09:22 +0100
            Re: Case Statements Marko Rauhamaa <marko@pacujo.net> - 2016-03-17 10:57 +0200
              Re: Case Statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-17 10:12 +0100
        Re: Case Statements Steven D'Aprano <steve@pearwood.info> - 2016-03-17 11:19 +1100
          Re: Case Statements Steven D'Aprano <steve@pearwood.info> - 2016-03-17 12:54 +1100
            Re: Case Statements Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-03-17 18:45 +1300
              Re: Case Statements Chris Angelico <rosuav@gmail.com> - 2016-03-17 17:30 +1100
                Re: Case Statements Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-03-18 18:59 +1300
              Re: Case Statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-03-17 17:29 +1100
                Re: Case Statements Chris Angelico <rosuav@gmail.com> - 2016-03-17 17:48 +1100
                Re: Case Statements Steven D'Aprano <steve@pearwood.info> - 2016-03-17 21:53 +1100
                Re: Case Statements Chris Angelico <rosuav@gmail.com> - 2016-03-17 22:49 +1100
            Re: Case Statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-17 10:23 +0100
            Re: Case Statements Chris Angelico <rosuav@gmail.com> - 2016-03-17 20:55 +1100
          Re: Case Statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-17 09:36 +0100
        Re: Case Statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-17 09:38 +0100
  Re: Case Statements l0r0m0a0i0l@gmail.com - 2016-03-16 06:15 -0700
    Re: Case Statements Steven D'Aprano <steve@pearwood.info> - 2016-03-17 00:27 +1100
      Re: Case Statements Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-16 14:00 +0000
    Re: Case Statements Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-16 13:59 +0000
  Re: Case Statements l0r0m0a0i0l@gmail.com - 2016-03-16 07:21 -0700
    Re: Case Statements Marko Rauhamaa <marko@pacujo.net> - 2016-03-16 16:33 +0200

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