Groups > comp.lang.forth > #19623

Re: Loop structures

From	"Ed" <invalid@nospam.com>
Newsgroups	comp.lang.forth
Subject	Re: Loop structures
Date	2013-02-11 12:56 +1100
Organization	Aioe.org NNTP Server
Message-ID	<kf9j5d$4ir$1@speranza.aioe.org> (permalink)
References	(2 earlier) <kevs3h$g9r$1@speranza.aioe.org> <13r63gqppixk2$.1bkjy6d3bg52m$.dlg@40tude.net> <1kxy635.1woc6vq18akrn7N%awegel@arcor.de> <kf569s$rg7$1@speranza.aioe.org> <1ky180m.kyfdfo1vhygioN%awegel@arcor.de>

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Alex Wegel wrote:
> ...
> But you *do* agree that infinite loops exist (even in forth), and that
> they differ from the other constructs having been mentioned?
...
> My original point wasn't so much about AGAIN, more about recognizing the
> infinite loop as a basic looping construct in general.

None of the CS texts I've read mention infinite loops as a fundamental
construct.  When they're discussed they're described in terms of the
classic loops, which in Forth would be BEGIN... 0 UNTIL or BEGIN...
1 WHILE...REPEAT.

"Starting FORTH" (first ed.) talks about creating infinite loops with
BEGIN...0 UNTIL.  AFAIK AGAIN is not referenced anywhere.

When this topic came up before some folks pointed out other
languages would optimize the equivalent of 0 UNTIL into an AGAIN.
Having a specific construct for infinite loops in these languages
would thus be redundant.

Some folks say BEGIN... AGAIN is faster that BEGIN...0 UNTIL
but I can't think of a scenario where this would be true.

Thread

 Loop structures kenney@cix.compulink.co.uk - 2013-02-06 03:55 -0600
  Re: Loop structures Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-06 04:24 -0600
  Re: Loop structures Pablo Hugo Reda <pabloreda@gmail.com> - 2013-02-06 05:38 -0800
  Re: Loop structures Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-02-06 10:43 -0800
    Re: Loop structures "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-08 03:46 -0500
  Re: Loop structures awegel@arcor.de (Alex Wegel) - 2013-02-06 20:19 +0100
    Re: Loop structures "Ed" <invalid@nospam.com> - 2013-02-07 20:27 +1100
      Re: Loop structures Coos Haak <chforth@hccnet.nl> - 2013-02-07 17:03 +0100
        Re: Loop structures awegel@arcor.de (Alex Wegel) - 2013-02-08 00:43 +0100
          Re: Loop structures "Ed" <invalid@nospam.com> - 2013-02-09 20:52 +1100
            Re: Loop structures Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-09 18:05 -0600
              Re: Loop structures "Ed" <invalid@nospam.com> - 2013-02-10 11:48 +1100
            Re: Loop structures awegel@arcor.de (Alex Wegel) - 2013-02-11 01:41 +0100
              Re: Loop structures "Ed" <invalid@nospam.com> - 2013-02-11 12:56 +1100
                Re: Loop structures "Elizabeth D. Rather" <erather@forth.com> - 2013-02-10 17:54 -1000
                Re: Loop structures "Ed" <invalid@nospam.com> - 2013-02-12 15:11 +1100
                Re: Loop structures Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-13 09:49 -0600
                Re: Loop structures Mark Wills <forthfreak@gmail.com> - 2013-02-11 23:32 -0800
                Re: Loop structures "Ed" <invalid@nospam.com> - 2013-02-13 12:34 +1100
                Re: Loop structures "Elizabeth D. Rather" <erather@forth.com> - 2013-02-12 15:49 -1000
                Re: Loop structures "Ed" <invalid@nospam.com> - 2013-02-13 14:48 +1100
                Re: Loop structures Alex McDonald <blog@rivadpm.com> - 2013-02-12 23:02 -0800
                Re: Loop structures Alex McDonald <blog@rivadpm.com> - 2013-02-12 23:29 -0800
                Re: Loop structures albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-13 13:35 +0000
                Re: Loop structures Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-13 15:17 +0100
                Re: Loop structures Alex McDonald <blog@rivadpm.com> - 2013-02-13 09:01 -0800
                Re: Loop structures albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-13 20:22 +0000
                Re: Loop structures anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-14 16:29 +0000
                Re: Loop structures albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-14 18:41 +0000
                Re: Loop structures Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-14 21:44 +0100
                Re: Loop structures albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-14 21:06 +0000
                Re: Loop structures Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-14 23:51 +0100
                Re: Loop structures mhx@iae.nl (Marcel Hendrix) - 2013-02-15 00:56 +0200
                Re: Loop structures anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-15 09:53 +0000
                Re: Loop structures m.a.m.hendrix@tue.nl - 2013-02-15 03:36 -0800
                Re: Loop structures anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-15 09:44 +0000
                Re: Loop structures Lars Brinkhoff <lars.spam@nocrew.org> - 2013-03-04 13:04 +0100
                Re: Loop structures albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-03-04 13:22 +0000
                Re: Loop structures "Ed" <invalid@nospam.com> - 2013-02-15 13:09 +1100
                Re: Loop structures Alex McDonald <blog@rivadpm.com> - 2013-02-14 19:21 -0800
                Re: Loop structures albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-15 13:01 +0000
                Re: Loop structures Alex McDonald <blog@rivadpm.com> - 2013-02-15 07:51 -0800
                Re: Loop structures Brad Eckert <hwfwguy@gmail.com> - 2013-02-13 10:51 -0800
                Re: Loop structures "Ed" <invalid@nospam.com> - 2013-02-15 13:11 +1100
                Re: Loop structures "Elizabeth D. Rather" <erather@forth.com> - 2013-02-14 21:31 -1000
                Re: Loop structures Mark Wills <forthfreak@gmail.com> - 2013-02-13 00:18 -0800
                Re: Loop structures alberto@hal-pc.org - 2013-02-13 14:27 +0000
                Re: Loop structures Mark Wills <forthfreak@gmail.com> - 2013-02-13 07:08 -0800
                Re: Loop structures m.a.m.hendrix@tue.nl - 2013-02-13 08:23 -0800
                Re: Loop structures stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-13 17:32 +0000
                Re: Loop structures Mark Wills <forthfreak@gmail.com> - 2013-02-13 23:17 -0800
                Re: Loop structures stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-14 10:53 +0000
                Re: Loop structures stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-14 13:42 +0000
                Re: Loop structures "Clyde W. Phillips Jr." <cwpjr02@gmail.com> - 2013-02-14 21:25 -0800
                Re: Loop structures "Clyde W. Phillips Jr." <cwpjr02@gmail.com> - 2013-02-14 21:18 -0800
                Re: Loop structures Mark Wills <forthfreak@gmail.com> - 2013-02-13 23:15 -0800
                Re: Loop structures mhx@iae.nl (Marcel Hendrix) - 2013-02-14 22:08 +0200
                Re: Loop structures Mark Wills <forthfreak@gmail.com> - 2013-02-14 22:53 -0800
                Re: Loop structures awegel@arcor.de (Alex Wegel) - 2013-02-12 16:00 +0100
  Re: Loop structures kenney@cix.compulink.co.uk - 2013-02-13 03:49 -0600

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