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Groups > comp.lang.c++ > #89773

Re: "C++ on the Move" by Darryl K. Taft

From Ben Bacarisse <ben.lists@bsb.me.uk>
Newsgroups comp.lang.c++
Subject Re: "C++ on the Move" by Darryl K. Taft
Date 2023-03-15 00:10 +0000
Organization A noiseless patient Spider
Message-ID <87a60e98o4.fsf@bsb.me.uk> (permalink)
References (14 earlier) <tunqrv$3sq9s$1@dont-email.me> <tupekj$97ld$1@dont-email.me> <tuppcn$b454$1@dont-email.me> <tuq6lj$di5r$1@dont-email.me> <tuq8ig$dq70$1@dont-email.me>

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David Brown <david.brown@hesbynett.no> writes:

> On 14/03/2023 17:16, Muttley@dastardlyhq.com wrote:
>> On Tue, 14 Mar 2023 13:30:15 +0100
>> David Brown <david.brown@hesbynett.no> wrote:
<cut>
>>> Of course, you might /want/ infinite recursion.  Many (not all)
>>> functional programming languages support lazy evaluation, and so
>>> infinite lists are commonly used.
>> If you can infinite recursion then its not recursion, its a disguised
>> loop.
>
> In terms of computational theory, all loops are disguised recursion - loops
> can /always/ be re-written in terms of recursion.  And /simple/ recursion
> can be re-written in terms of loops (but more complicated cases cannot).
>
> A functional programming definition such as :
>
> 	nums = 1 : map (+1) nums
>
> is infinite recursion, generating an infinite list.

This discussion is going to go off the rails (if it hasn't already)
without some better terms.  "Infinite recursion", if it means anything
at all, should imply an unending computation.  In a lazy language, nums
is not "infinite recursion", it's just a recursive definition.  Lazy
evaluation just moves the place where the recursion is (usually!) made
finite somewhere higher-up in the program.

Likewise

  p n = if n == 0 then 1 else n * p (n-1)

is just a recursive definition.  It's not finite (or not "infinite
recursion") just because it has an if in it!

My point is that lazy evaluation is a red herring.  Infinite recursion
(like "sum nums" and "p (-1)") is always bad in this sort of context,
just as it sometimes good in the context of never-ending programs like
servers.

-- 
Ben.

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Thread

"C++ on the Move" by Darryl K. Taft Lynn McGuire <lynnmcguire5@gmail.com> - 2023-03-07 15:38 -0600
  Re: "C++ on the Move" by Darryl K. Taft legalize+jeeves@mail.xmission.com (Richard) - 2023-03-07 22:08 +0000
    Re: "C++ on the Move" by Darryl K. Taft Lynn McGuire <lynnmcguire5@gmail.com> - 2023-03-07 16:25 -0600
      Re: "C++ on the Move" by Darryl K. Taft legalize+jeeves@mail.xmission.com (Richard) - 2023-03-07 23:10 +0000
        Re: "C++ on the Move" by Darryl K. Taft Paavo Helde <eesnimi@osa.pri.ee> - 2023-03-08 08:40 +0200
        Re: "C++ on the Move" by Darryl K. Taft Lynn McGuire <lynnmcguire5@gmail.com> - 2023-04-05 19:30 -0500
      Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-07 23:21 -0800
        Re: "C++ on the Move" by Darryl K. Taft scott@slp53.sl.home (Scott Lurndal) - 2023-03-08 16:10 +0000
          Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-08 19:47 +0100
          Re: "C++ on the Move" by Darryl K. Taft Michael S <already5chosen@yahoo.com> - 2023-03-08 11:21 -0800
            Re: "C++ on the Move" by Darryl K. Taft scott@slp53.sl.home (Scott Lurndal) - 2023-03-08 19:49 +0000
              Re: "C++ on the Move" by Darryl K. Taft Michael S <already5chosen@yahoo.com> - 2023-03-08 12:08 -0800
        Re: "C++ on the Move" by Darryl K. Taft Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-03-08 09:52 -0800
          Re: "C++ on the Move" by Darryl K. Taft Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-03-08 10:18 -0800
            Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-08 20:45 +0100
          Re: "C++ on the Move" by Darryl K. Taft "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-03-08 19:20 +0100
            Re: "C++ on the Move" by Darryl K. Taft James Kuyper <jameskuyper@alumni.caltech.edu> - 2023-03-08 14:10 -0500
              Re: "C++ on the Move" by Darryl K. Taft "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-03-08 22:34 +0100
                Re: "C++ on the Move" by Darryl K. Taft Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-03-08 14:29 -0800
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-09 00:59 +0100
                Re: "C++ on the Move" by Darryl K. Taft James Kuyper <jameskuyper@alumni.caltech.edu> - 2023-03-08 18:11 -0500
            Re: "C++ on the Move" by Darryl K. Taft Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-03-08 12:28 -0800
              Re: "C++ on the Move" by Darryl K. Taft Michael S <already5chosen@yahoo.com> - 2023-03-08 12:48 -0800
                Re: "C++ on the Move" by Darryl K. Taft "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-03-08 22:40 +0100
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-09 01:12 +0100
                Re: "C++ on the Move" by Darryl K. Taft Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-03-08 16:27 -0800
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-09 13:52 +0100
                Re: "C++ on the Move" by Darryl K. Taft Michael S <already5chosen@yahoo.com> - 2023-03-09 12:47 -0800
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-09 01:08 +0100
                Re: "C++ on the Move" by Darryl K. Taft Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-03-09 02:08 -0800
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-09 14:06 +0100
                Re: "C++ on the Move" by Darryl K. Taft Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-03-09 07:14 -0800
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-09 20:32 +0100
                Re: "C++ on the Move" by Darryl K. Taft Michael S <already5chosen@yahoo.com> - 2023-03-09 12:42 -0800
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-10 00:30 +0100
                Re: "C++ on the Move" by Darryl K. Taft scott@slp53.sl.home (Scott Lurndal) - 2023-03-10 15:01 +0000
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-10 16:38 +0100
                Re: "C++ on the Move" by Darryl K. Taft scott@slp53.sl.home (Scott Lurndal) - 2023-03-10 16:36 +0000
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-11 10:43 +0100
          Re: "C++ on the Move" by Darryl K. Taft Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-03-08 12:59 -0800
          Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-09 03:03 -0800
            Re: "C++ on the Move" by Darryl K. Taft Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-03-09 12:12 -0800
              Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-09 19:20 -0800
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-10 10:36 +0100
                Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-10 04:27 -0800
                Re: "C++ on the Move" by Darryl K. Taft Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-03-10 05:13 -0800
                Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-10 06:05 -0800
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-10 15:59 +0100
                Re: "C++ on the Move" by Darryl K. Taft kalevi@kolttonen.fi (Kalevi Kolttonen) - 2023-03-10 15:14 +0000
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-10 16:45 +0100
                Re: "C++ on the Move" by Darryl K. Taft kalevi@kolttonen.fi (Kalevi Kolttonen) - 2023-03-10 16:02 +0000
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-13 11:45 +0100
                Re: "C++ on the Move" by Darryl K. Taft Muttley@dastardlyhq.com - 2023-03-13 12:00 +0000
                Re: "C++ on the Move" by Darryl K. Taft kalevi@kolttonen.fi (Kalevi Kolttonen) - 2023-03-13 12:26 +0000
                Re: "C++ on the Move" by Darryl K. Taft Muttley@dastardlyhq.com - 2023-03-13 15:00 +0000
                Re: "C++ on the Move" by Darryl K. Taft kalevi@kolttonen.fi (Kalevi Kolttonen) - 2023-03-13 15:18 +0000
                Re: "C++ on the Move" by Darryl K. Taft Muttley@dastardlyhq.com - 2023-03-13 16:00 +0000
                Re: "C++ on the Move" by Darryl K. Taft kalevi@kolttonen.fi (Kalevi Kolttonen) - 2023-03-13 18:43 +0000
                Re: "C++ on the Move" by Darryl K. Taft Muttley@dastardlyhq.com - 2023-03-14 09:26 +0000
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-14 13:30 +0100
                Re: "C++ on the Move" by Darryl K. Taft Muttley@dastardlyhq.com - 2023-03-14 16:16 +0000
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-14 17:49 +0100
                Re: "C++ on the Move" by Darryl K. Taft Muttley@dastardlyhq.com - 2023-03-14 17:14 +0000
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-14 23:05 +0100
                Re: "C++ on the Move" by Darryl K. Taft Muttley@dastardlyhq.com - 2023-03-15 08:39 +0000
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-15 17:31 +0100
                Re: "C++ on the Move" by Darryl K. Taft Muttley@dastardlyhq.com - 2023-03-15 17:11 +0000
                Re: "C++ on the Move" by Darryl K. Taft Ben Bacarisse <ben.lists@bsb.me.uk> - 2023-03-15 00:10 +0000
                Re: "C++ on the Move" by Darryl K. Taft Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-03-14 14:52 -0700
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-13 20:17 +0100
                Re: "C++ on the Move" by Darryl K. Taft kalevi@kolttonen.fi (Kalevi Kolttonen) - 2023-03-13 19:31 +0000
                Re: "C++ on the Move" by Darryl K. Taft Paavo Helde <eesnimi@osa.pri.ee> - 2023-03-14 00:01 +0200
                Re: "C++ on the Move" by Darryl K. Taft gst <g.starck@gmail.com> - 2023-03-13 23:49 -0700
                Re: "C++ on the Move" by Darryl K. Taft "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-03-14 11:04 +0100
                Re: "C++ on the Move" by Darryl K. Taft gst <g.starck@gmail.com> - 2023-03-14 03:26 -0700
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-14 09:08 +0100
                Re: "C++ on the Move" by Darryl K. Taft Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-03-14 01:21 -0700
                Re: "C++ on the Move" by Darryl K. Taft Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-03-14 15:12 -0700
                Re: "C++ on the Move" by Darryl K. Taft Muttley@dastardlyhq.com - 2023-03-14 09:31 +0000
                Re: "C++ on the Move" by Darryl K. Taft kalevi@kolttonen.fi (Kalevi Kolttonen) - 2023-03-14 09:51 +0000
                Re: "C++ on the Move" by Darryl K. Taft Muttley@dastardlyhq.com - 2023-03-14 09:56 +0000
                Re: "C++ on the Move" by Darryl K. Taft kalevi@kolttonen.fi (Kalevi Kolttonen) - 2023-03-14 10:30 +0000
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-14 13:41 +0100
                Re: "C++ on the Move" by Darryl K. Taft Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-03-14 14:50 -0700
                Re: "C++ on the Move" by Darryl K. Taft Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-03-14 14:13 -0700
                Re: "C++ on the Move" by Darryl K. Taft kalevi@kolttonen.fi (Kalevi Kolttonen) - 2023-03-14 21:53 +0000
                Re: "C++ on the Move" by Darryl K. Taft Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-04-04 23:21 -0700
                Re: "C++ on the Move" by Darryl K. Taft "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2023-04-05 08:44 -0700
                Re: "C++ on the Move" by Darryl K. Taft legalize+jeeves@mail.xmission.com (Richard) - 2023-04-05 15:47 +0000
                Re: "C++ on the Move" by Darryl K. Taft scott@slp53.sl.home (Scott Lurndal) - 2023-04-05 16:33 +0000
                Re: "C++ on the Move" by Darryl K. Taft richardthiebaud <thiebauddick2@aol.com> - 2023-04-05 12:53 -0400
                Re: "C++ on the Move" by Darryl K. Taft scott@slp53.sl.home (Scott Lurndal) - 2023-04-05 17:19 +0000
                Re: "C++ on the Move" by Darryl K. Taft Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-04-05 13:47 -0700
                Re: "C++ on the Move" by Darryl K. Taft Muttley@dastardlyhq.com - 2023-04-06 08:12 +0000
                Re: "C++ on the Move" by Darryl K. Taft Daniel <danielaparker@gmail.com> - 2023-04-06 05:23 -0700
                Re: "C++ on the Move" by Darryl K. Taft Muttley@dastardlyhq.com - 2023-04-06 08:09 +0000
                Re: "C++ on the Move" by Darryl K. Taft Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-07-20 10:02 -0700
                Re: "C++ on the Move" by Darryl K. Taft Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-04-05 21:04 +0100
                Re: "C++ on the Move" by Darryl K. Taft Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-07-20 09:52 -0700
                Re: "C++ on the Move" by Darryl K. Taft Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-07-20 21:01 +0100
                Re: "C++ on the Move" by Darryl K. Taft Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-03-14 08:57 -0700
                Re: "C++ on the Move" by Darryl K. Taft Muttley@dastardlyhq.com - 2023-03-14 16:20 +0000
                Re: "C++ on the Move" by Darryl K. Taft Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-03-10 07:23 -0800
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-10 16:48 +0100
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-10 15:54 +0100
                Re: "C++ on the Move" by Darryl K. Taft Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-03-10 07:12 -0800
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-10 16:53 +0100
                Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-10 08:20 -0800
                Re: "C++ on the Move" by Darryl K. Taft kalevi@kolttonen.fi (Kalevi Kolttonen) - 2023-03-10 16:48 +0000
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-12 11:54 +0100
                Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-12 09:29 -0700
                Re: "C++ on the Move" by Darryl K. Taft Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-03-12 09:57 -0700
                Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-12 10:26 -0700
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-13 14:40 +0100
                Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-13 08:59 -0700
                Re: "C++ on the Move" by Darryl K. Taft Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-03-12 14:17 -0700
                Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-12 16:18 -0700
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-13 14:30 +0100
                Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-13 08:25 -0700
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-13 17:54 +0100
                Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-14 13:27 -0700
                Re: "C++ on the Move" by Darryl K. Taft Paavo Helde <eesnimi@osa.pri.ee> - 2023-03-13 20:37 +0200
                Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-14 13:30 -0700
                Re: "C++ on the Move" by Darryl K. Taft Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-03-13 10:02 -0700
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-13 20:21 +0100
                Re: "C++ on the Move" by Darryl K. Taft Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-03-13 12:53 -0700
                Re: "C++ on the Move" by Darryl K. Taft Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-03-14 01:17 -0700
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-14 09:55 +0100
                Re: "C++ on the Move" by Darryl K. Taft scott@slp53.sl.home (Scott Lurndal) - 2023-03-10 16:27 +0000
                Re: "C++ on the Move" by Darryl K. Taft Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-03-10 11:33 -0800
                Re: "C++ on the Move" by Darryl K. Taft Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-03-10 11:14 -0800
                Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-11 04:10 -0800
                Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-12 12:06 +0100
                Re: "C++ on the Move" by Darryl K. Taft Öö Tiib <ootiib@hot.ee> - 2023-03-12 09:29 -0700
  Re: "C++ on the Move" by Darryl K. Taft Bonita Montero <Bonita.Montero@gmail.com> - 2023-03-09 15:26 +0100
    Re: "C++ on the Move" by Darryl K. Taft Lynn McGuire <lynnmcguire5@gmail.com> - 2023-03-09 16:59 -0600
      Re: "C++ on the Move" by Darryl K. Taft Bonita Montero <Bonita.Montero@gmail.com> - 2023-03-10 05:59 +0100
        Re: "C++ on the Move" by Darryl K. Taft "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-03-10 09:17 +0100
          Re: "C++ on the Move" by Darryl K. Taft Bonita Montero <Bonita.Montero@gmail.com> - 2023-03-10 13:38 +0100
            Re: "C++ on the Move" by Darryl K. Taft Michael S <already5chosen@yahoo.com> - 2023-03-10 05:10 -0800
              Re: "C++ on the Move" by Darryl K. Taft Bonita Montero <Bonita.Montero@gmail.com> - 2023-03-10 15:20 +0100
              Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-10 16:13 +0100
        Re: "C++ on the Move" by Darryl K. Taft David Brown <david.brown@hesbynett.no> - 2023-03-10 10:44 +0100
      Re: "C++ on the Move" by Darryl K. Taft Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-03-10 11:08 -0800
        Re: "C++ on the Move" by Darryl K. Taft "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-03-12 11:42 +0100
  Re: "C++ on the Move" by Darryl K. Taft "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-04-06 00:42 -0700

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