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Groups > comp.lang.c > #18809

Re: Regression testing for pointers

From Malcolm McLean <malcolm.mclean5@btinternet.com>
Newsgroups comp.lang.c
Subject Re: Regression testing for pointers
Date 2012-03-15 13:10 -0700
Organization http://groups.google.com
Message-ID <6706525.36.1331842255566.JavaMail.geo-discussion-forums@ynej9> (permalink)
References (2 earlier) <jjiqj7$o37$1@speranza.aioe.org> <11081707.4444.1331671421048.JavaMail.geo-discussion-forums@vbiz13> <jjplr6$7df$1@speranza.aioe.org> <7764287.7283.1331763333360.JavaMail.geo-discussion-forums@vbgu10> <20120314154825.834@kylheku.com>

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בתאריך יום רביעי, 14 במרס 2012 22:57:11 UTC, מאת Kaz Kylheku:
>
> What crap!  Pure functions in pure functional languages allocate memory.  E.g.
> mapping a list to a different list. The different list has to come from
> somewhere.
> 
You need to learn to express yourself in a more cultured manner. Not everyone who disagrees with you is talking crap, and even if they are, often it's better not to say it.

We implement median(const double *x, int N) inthe obvious way, by copying to a temporary and sorting. So if we run out of memory, what do we do? Returning nan would seem a reasonable idea.
So median will sometimes return the mid point of x, sometimes nan, for identical values of x. So it's not, strictly, a pure function of x. It's a pure function of x and th state of the memory allocator. For indetical x and identical states of the free list, it will always return the same result.

However it's not easy to peep into the memory allocator, nor is it usually useful to do so. It does mean that we're treating the memory allocation system as something special. But that's reasonable. It's the infinite tape in our Turing machine.
-- 
MiniBasic - how to write a script interpreter
http://www.malcolmmclean.site11.com/www

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Thread

Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-09 16:43 -0700
  Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-10 12:56 +1300
    Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-09 19:40 -0700
      Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-10 17:53 +1300
        Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-10 18:12 +1300
        Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-10 02:05 -0700
          Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-10 23:17 +1300
            Re: Regression testing for pointers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-03-10 12:00 +0000
              Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-11 11:00 +1300
                Re: Regression testing for pointers Ike Naar <ike@iceland.freeshell.org> - 2012-03-10 22:23 +0000
                Re: Regression testing for pointers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-03-10 22:40 +0000
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-11 12:12 +1300
                Re: Regression testing for pointers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-03-11 00:42 +0000
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-11 14:26 +1300
                Re: Regression testing for pointers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-03-11 03:09 +0000
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-11 18:16 +1300
            Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-10 12:01 -0700
              Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-11 10:35 +1300
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-12 09:19 -0700
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-13 07:23 +1300
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-12 16:23 -0700
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-13 17:25 +1300
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-13 00:19 -0700
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-13 20:34 +1300
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-13 01:00 -0700
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-13 21:22 +1300
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-13 10:19 -0700
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-14 07:25 +1300
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-14 02:00 -0700
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-14 22:18 +1300
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-14 11:32 -0700
                Re: Regression testing for pointers nick_keighley_nospam@hotmail.com - 2012-03-15 05:58 -0700
                Re: Regression testing for pointers nick_keighley_nospam@hotmail.com - 2012-03-15 05:55 -0700
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-15 11:32 -0700
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-16 18:14 +1300
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-20 01:43 -0700
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-20 21:59 +1300
                Re: Regression testing for pointers nick_keighley_nospam@hotmail.com - 2012-03-16 03:05 -0700
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-20 02:33 -0700
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-24 11:49 +1300
          Re: Regression testing for pointers nick_keighley_nospam@hotmail.com - 2012-03-11 05:01 -0700
            Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-11 09:44 -0700
              Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-12 09:56 +1300
    Re: Regression testing for pointers nick_keighley_nospam@hotmail.com - 2012-03-10 02:28 -0800
      Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-10 11:09 -0700
      Re: Regression testing for pointers Kaz Kylheku <kaz@kylheku.com> - 2012-03-10 18:29 +0000
        Re: Regression testing for pointers nick_keighley_nospam@hotmail.com - 2012-03-11 05:22 -0700
          Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-11 09:50 -0700
            Re: Regression testing for pointers "io_x" <a@b.c.invalid> - 2012-03-13 13:09 +0100
  Re: Regression testing for pointers Kaz Kylheku <kaz@kylheku.com> - 2012-03-10 03:14 +0000
    Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-10 12:42 -0700
  Re: Regression testing for pointers Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-03-10 08:42 +0000
    Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-10 02:19 -0700
      Re: Regression testing for pointers "BartC" <bc@freeuk.com> - 2012-03-10 15:54 +0000
        Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-10 11:49 -0700
          Re: Regression testing for pointers nick_keighley_nospam@hotmail.com - 2012-03-11 06:09 -0700
            Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-11 12:33 -0700
              Re: Regression testing for pointers nick_keighley_nospam@hotmail.com - 2012-03-12 03:29 -0700
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-12 10:01 -0700
                Re: Regression testing for pointers "BartC" <bc@freeuk.com> - 2012-03-13 18:56 +0000
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-13 16:31 -0700
      Re: Regression testing for pointers Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-03-12 00:30 +0000
        Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-12 16:41 -0700
      Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-12 13:39 +1300
        Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-12 09:36 -0700
          Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-13 07:25 +1300
            Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-12 16:28 -0700
              Re: Regression testing for pointers Kaz Kylheku <kaz@kylheku.com> - 2012-03-13 04:20 +0000
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-13 17:34 +1300
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-13 00:29 -0700
              Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-13 17:31 +1300
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-13 01:05 -0700
                Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-13 21:30 +1300
                Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-13 10:43 -0700
  Re: Regression testing for pointers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-10 15:41 -0800
    Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-11 11:23 -0700
      Re: Regression testing for pointers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-13 13:43 -0700
        Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-14 01:45 -0700
          Re: Regression testing for pointers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-14 15:15 -0700
            Re: Regression testing for pointers Kaz Kylheku <kaz@kylheku.com> - 2012-03-14 22:57 +0000
              Re: Regression testing for pointers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-15 13:10 -0700
                Re: Regression testing for pointers jgk@panix.com (Joe keane) - 2012-03-16 22:20 +0000
                Re: Regression testing for pointers "io_x" <a@b.c.invalid> - 2012-03-18 07:15 +0100
            Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-14 23:13 -0700
  Re: Regression testing for pointers gordonb.b29ri@burditt.org (Gordon Burditt) - 2012-03-12 19:37 -0500
    Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-12 19:23 -0700
  Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-14 13:12 +1300
    Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-14 01:54 -0700
      Re: Regression testing for pointers Ian Collins <ian-news@hotmail.com> - 2012-03-14 22:05 +1300
        Re: Regression testing for pointers Don Y <this@isnotme.com> - 2012-03-14 11:54 -0700

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