Re: Is WHILE allowed within DO .. LOOP ?

From	anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups	comp.lang.forth
Subject	Re: Is WHILE allowed within DO .. LOOP ?
Date	2016-01-10 15:44 +0000
Organization	Institut fuer Computersprachen, Technische Universitaet Wien
Message-ID	<2016Jan10.164404@mips.complang.tuwien.ac.at> (permalink)
References	(6 earlier) <J5qdncTosM7boxLLnZ2dnUU7-KudnZ2d@supernews.com> <2016Jan8.111957@mips.complang.tuwien.ac.at> <n6p8dq$e15$1@dont-email.me> <2016Jan9.175121@mips.complang.tuwien.ac.at> <n6rkj5$u2o$1@dont-email.me>

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Bernd Paysan <bernd.paysan@gmx.de> writes:
>Anton Ertl wrote:
>
>> The stack effect looks suspicious, but I'll ignore that for now.
>> 
>> : capscomp  ( c_addr1 u c_addr2 -- -1|0|1 )
>> swap bounds ?do
>> dup c@ toupper i c@ toupper - dup if
>> sgn unloop exit then
>> 1+ loop
>> drop 0 ;
>> 
>> (untested) Simpler and cleaner.  Not sure how slow TOUPPER is, it
>> might also be faster.  It certainly saves a bit by not applying SGN to
>> 0.
>
>If you don't have sgn on 0, you could unfold it; sgn on non-0 is pretty 
>easy.  Tested:
>
>: capscomp  ( c_addr1 u c_addr2 -- -1|0|1 )
>    swap bounds ?do
>	count toupper i c@ toupper - ?dup-if
>	    nip 0< 2* 1+ unloop exit then
>    loop
>    drop 0 ;
>
>Since this is for tab completion, I suppose that it's not really that 
>performance critical.  The -1|0|1 is probably overblow, compare returns an n 
>as well.

Yes.  If you want it, and since performance is not paramount, using
SGN is clearer than the optimized inlined version (as well as shorter
in the current Gforth implementation).  Using C@+ is clearer than
using COUNT.

- 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/

Thread

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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