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Groups > comp.lang.forth > #44682

Re: Is WHILE allowed within DO .. LOOP ?

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"Elizabeth D. Rather" <erather@forth.com> writes:
>The reason is that not only that a do-sys may be a 
>different size from origs and dests, but more importantly, the DO ... 
>LOOP family of words has stuff on the Return Stack, while the indefinite 
>loop words do not.

Yes, although that would not really be a problem with regards to the
specification: If we allow CS-ROLL to also deal with do-sys, and a
program makes use of that, there is the loop-sys around at run-time on
the irregular exit from the counted loop, and just like for EXIT
inside the counted loop, the program has to get rid of that with
UNLOOP.

Hmm, another way to deal with the loop-sys would be to consume it in
another counted loop, e.g.,

do ... while ... loop
...
do ... [ 1 cs-roll ] then ... loop

Here the WHILE jumps to the THEN in the other counted loop.  But given
that this should work in Gforth and, to my knowledge, has not been
used, it will probably not be a frequent construct.

- anton
-- 
M. Anton Ertl  http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
     New standard: http://www.forth200x.org/forth200x.html
   EuroForth 2015: http://www.rigwit.co.uk/EuroForth2015/

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Is WHILE allowed within DO .. LOOP ? Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-01-06 16:28 +0000
  Re: Is WHILE allowed within DO .. LOOP ? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2016-01-06 17:20 +0000
  Is WHILE allowed within DO .. LOOP ? JennyB <jennybrien@googlemail.com> - 2016-01-06 09:24 -0800
    Re: Is WHILE allowed within DO .. LOOP ? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-01-06 16:06 -0600
      Re: Is WHILE allowed within DO .. LOOP ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-07 08:36 +0000
        Re: Is WHILE allowed within DO .. LOOP ? Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-01-07 13:13 +0000
          Re: Is WHILE allowed within DO .. LOOP ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-07 13:33 +0000
            Re: Is WHILE allowed within DO .. LOOP ? "Elizabeth D. Rather" <erather@forth.com> - 2016-01-07 18:42 -1000
              Re: Is WHILE allowed within DO .. LOOP ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-08 10:19 +0000
                Re: Is WHILE allowed within DO .. LOOP ? Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-08 22:09 +0100
                Re: Is WHILE allowed within DO .. LOOP ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-09 16:51 +0000
                Re: Is WHILE allowed within DO .. LOOP ? Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-09 19:49 +0100
                Re: Is WHILE allowed within DO .. LOOP ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-10 15:44 +0000
              Re: Is WHILE allowed within DO .. LOOP ? Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-01-08 11:22 +0000
    Re: Is WHILE allowed within DO .. LOOP ? hughaguilar96@gmail.com - 2016-01-06 22:33 -0800
      Re: Is WHILE allowed within DO .. LOOP ? Raimond Dragomir <raimond.dragomir@gmail.com> - 2016-01-06 22:47 -0800
  Re: Is WHILE allowed within DO .. LOOP ? hughaguilar96@gmail.com - 2016-01-11 19:46 -0800
    Re: Is WHILE allowed within DO .. LOOP ? Raimond Dragomir <raimond.dragomir@gmail.com> - 2016-01-11 22:37 -0800

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