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Re: Loop structures

From "Ed" <invalid@nospam.com>
Newsgroups comp.lang.forth
Subject Re: Loop structures
Date 2013-02-09 20:52 +1100
Organization Aioe.org NNTP Server
Message-ID <kf569s$rg7$1@speranza.aioe.org> (permalink)
References <lridnZcasu89tY_MnZ2dnUVZ8lqdnZ2d@giganews.com> <1kxw08b.1e79yo2kdx9d1N%awegel@arcor.de> <kevs3h$g9r$1@speranza.aioe.org> <13r63gqppixk2$.1bkjy6d3bg52m$.dlg@40tude.net> <1kxy635.1woc6vq18akrn7N%awegel@arcor.de>

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Alex Wegel wrote:
> Coos Haak <chforth@hccnet.nl> wrote:
>
> > Op Thu, 7 Feb 2013 20:27:39 +1100 schreef Ed:
> >
> > > Alex Wegel wrote:
> > >> <kenney@cix.compulink.co.uk> wrote:
> > >>
> > >>>  The discussions about do lops triggered an interest in loop structures.
> > >>> I can think of three
> > >>>  "for-next" unconditional
> > >>>  "repeat-until" conditional is checked at the end of each run through
> > >>> the loop as a result the code will be run at least once
> > >>>
> > >>>  "While-next" conditional is checked at the start of each run through
> > >>> the loop
> > >>>
> > >>>  As far as I can tell any other structures are variants of the above
> > >>> with the possibility of multiple exits is this correct?
> > >>
> > >> No, there's also "forever", or -in forth- "begin ... again".
> > >
> > > AGAIN is optional in ANS-Forth as infinite loops are readily implemented
> > > using indefinite loops e.g.  BEGIN .. 0 UNTIL.
> >
> > Does it matter? The OP mentioned REPEAT .. UNTIL. That's not Forth either.
>
> Well - i think AGAIN being optional in ans forth should be proof enough
> that it actually *is* forth, and that it has been for quite a while ;-)
>
> BTW: It is the most basic looping construct, and often the basis of
> (high-level definitions of) the words UNTIL and REPEAT. The OP didn't
> mention "no exits", so this wasn't covered.

My understanding is that infinite loops are not counted among the classic
looping constructs - hence my comment.  It is true AGAIN is useful as a
primitive but generally it is not required.

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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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