Re: BEGIN WHILE UNTIL THEN

From	Gerry Jackson <gerry@jackson9000.fsnet.co.uk>
Newsgroups	comp.lang.forth
Subject	Re: BEGIN WHILE UNTIL THEN
Date	2016-01-12 20:48 +0000
Organization	A noiseless patient Spider
Message-ID	<n73omj$63c$1@dont-email.me> (permalink)
References	(4 earlier) <d9ce8bc7-635a-4596-94f6-a29173edf95d@googlegroups.com> <568f9b94.1958323170@news.eternal-september.org> <ad7a5711-f46b-4362-ac85-166d82804be3@googlegroups.com> <n7059h$vai$1@dont-email.me> <1300bc89-75f3-4ac1-992d-0f0c2251deb0@googlegroups.com>

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On 11/01/2016 22:16, hughaguilar96@gmail.com wrote:
> On Monday, January 11, 2016 at 4:59:16 AM UTC-7, Gerry wrote:
>> In 2012 in a similar discussion I posted an ANS Forth implementation
>> NEXTCASE and other words that seem to meet your and Chris Curls
>> objections. Another opportunity for you to complain about 'ugly,
>> inefficient Forth code' :)
>
> Your code is just generating nested IF statements.

Tell me something I don't know.

>
> Did you read what I said about the jump-table? This is how C does their SWITCH statement (also HLA and most likely every other serious language). This is two or three orders of magnitude faster than your method, depending upon how many test values there are.
>

The specification for CASE etc permits code such as:
: foo  ( x -- )
    >r
    case
       aaa true of ( action a ) endof
       bbb true of ( action b ) endof
       ccc r@   of ( action c ) endof
       ddd wxyz of ( action d ) endof
       ...
    endcase
    ...
;
where aaa etc represent one or more Forth words. The values compared by 
OF may be repeated, calculated, passed in on the stack and may, 
therefore, be unknown at compile time. How would a jump-table handle 
those cases?

> Since you are so proud of your CASE NEXTCASE code, how about writing
>  a byte-code interpreter? A byte-code interpreter has upwards of 256
>  opcodes, so with your method that is upwards of 256 conditional tests
>  for every opcode before your program figures out which opcode it has
> and is able to emulate it. Your program should be about three orders
>  of magnitude slower than a comparable C program --- a great way to
>  disprove the C programmers' assertion that Forth is too slow to be
>  useful in the real world.

Surely you're not serious, are you being sarcastic? Anyway you're wrong, 
with a (large) tree of nested CASE statements it could be done in 8 
comparisons, e.g. testing opcode bit 7, then bit 6 etc. (this may not be 
a practical solution but suffices to refute your claim - in fact I'd 
hate to set it up and would use a jump table instead). Also look up the 
meaning of "upwards of".

-- 
Gerry

Thread

BEGIN WHILE UNTIL THEN Julian Fondren <julian.fondren@gmail.com> - 2016-01-04 14:50 -0800
  Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-05 11:24 +1100
    Re: BEGIN WHILE UNTIL THEN Julian Fondren <julian.fondren@gmail.com> - 2016-01-04 16:47 -0800
      Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-05 12:17 +1100
      Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-05 10:51 +0000
        Re: BEGIN WHILE UNTIL THEN stephen@mpeforth.com (Stephen Pelc) - 2016-01-05 15:06 +0000
  Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-04 17:25 -0800
    Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-05 13:06 +1100
      Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-04 21:42 -0800
        Re: BEGIN WHILE UNTIL THEN rickman <gnuarm@gmail.com> - 2016-01-05 01:48 -0500
        Re: BEGIN WHILE UNTIL THEN Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-01-05 11:15 +0000
        Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-06 14:35 +1100
  Re: BEGIN WHILE UNTIL THEN Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-01-05 02:04 +0000
  Re: BEGIN WHILE UNTIL THEN Julian Fondren <julian.fondren@gmail.com> - 2016-01-04 18:37 -0800
    Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-04 19:17 -0800
    Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-05 11:10 +0000
    Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-06 15:02 +1100
  Re: BEGIN WHILE UNTIL THEN november.nihal@gmail.com - 2016-01-05 08:03 -0800
    Re: BEGIN WHILE UNTIL THEN november.nihal@gmail.com - 2016-01-05 08:07 -0800
      Re: BEGIN WHILE UNTIL THEN november.nihal@gmail.com - 2016-01-05 08:18 -0800
      Re: BEGIN WHILE UNTIL THEN november.nihal@gmail.com - 2016-01-05 08:21 -0800
  Re: BEGIN WHILE UNTIL THEN Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-01-07 05:13 -0500
    Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-08 12:36 +1100
      Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-08 10:32 +0000
        Re: BEGIN WHILE UNTIL THEN Raimond Dragomir <raimond.dragomir@gmail.com> - 2016-01-08 02:55 -0800
          Re: BEGIN WHILE UNTIL THEN Coos Haak <chforth@hccnet.nl> - 2016-01-08 13:57 +0100
            Re: BEGIN WHILE UNTIL THEN Raimond Dragomir <raimond.dragomir@gmail.com> - 2016-01-08 06:55 -0800
              Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-08 15:06 -0800
              Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-08 16:59 -0800
                Re: BEGIN WHILE UNTIL THEN "Elizabeth D. Rather" <erather@forth.com> - 2016-01-08 16:15 -1000
                Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-08 22:23 -0800
                Re: BEGIN WHILE UNTIL THEN "Elizabeth D. Rather" <erather@forth.com> - 2016-01-08 21:12 -1000
                Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-09 08:04 -0800
                Re: BEGIN WHILE UNTIL THEN "Elizabeth D. Rather" <erather@forth.com> - 2016-01-09 09:16 -1000
                Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-10 15:31 +0000
                Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-10 08:11 -0800
                Re: BEGIN WHILE UNTIL THEN "Elizabeth D. Rather" <erather@forth.com> - 2016-01-10 09:42 -1000
                Re: BEGIN WHILE UNTIL THEN Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-01-11 13:02 +0000
                Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-13 16:20 +0000
                Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-10 14:10 -0800
                Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-11 18:38 -0800
                Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-14 08:47 +1100
                Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-13 17:24 -0800
                Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-13 19:25 -0800
                Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-14 22:09 +1100
                Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-14 16:21 +0000
                Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-16 11:34 +1100
                Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-16 03:43 +0100
                Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-19 18:01 +1100
                Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-19 23:07 +0100
                Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-21 14:29 +1100
                Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-21 22:25 +0100
                Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-24 13:28 +1100
                Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-25 01:31 +0100
                Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-25 21:45 +1100
                Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-25 10:24 -0800
                Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-25 20:41 +0100
                Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-28 20:39 +1100
                Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-28 16:05 +0100
                Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-21 20:52 -0800
                Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-24 13:16 +1100
                Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-14 08:46 -0800
                Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-16 11:34 +1100
                Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-15 20:53 -0800
                Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-13 19:31 -0800
                Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-11 09:29 +1100
                Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-10 21:18 -0800
                Re: BEGIN WHILE UNTIL THEN Paul Rubin <no.email@nospam.invalid> - 2016-01-10 21:29 -0800
                Re: BEGIN WHILE UNTIL THEN "Elizabeth D. Rather" <erather@forth.com> - 2016-01-10 20:37 -1000
                Re: BEGIN WHILE UNTIL THEN Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2016-01-11 09:05 +0000
                Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-12 12:26 +1100
                Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-10 14:18 -0800
                Re: BEGIN WHILE UNTIL THEN Raimond Dragomir <raimond.dragomir@gmail.com> - 2016-01-08 23:31 -0800
                Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-09 08:09 -0800
                Re: BEGIN WHILE UNTIL THEN Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-01-09 05:31 -0600
                Re: BEGIN WHILE UNTIL THEN Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-01-09 07:52 -0600
              Re: BEGIN WHILE UNTIL THEN Ron Aaron <rambamist@gmail.com> - 2016-01-09 18:22 +0200
              Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-09 16:29 +0000
          Re: BEGIN WHILE UNTIL THEN stephen@mpeforth.com (Stephen Pelc) - 2016-01-08 11:23 +0000
            Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-10 20:17 -0800
              Re: BEGIN WHILE UNTIL THEN stephen@mpeforth.com (Stephen Pelc) - 2016-01-11 11:56 +0000
              Re: BEGIN WHILE UNTIL THEN Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2016-01-11 11:59 +0000
                generalized CASE (was: BEGIN WHILE UNTIL THEN) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-11 12:30 +0000
                Re: generalized CASE (was: BEGIN WHILE UNTIL THEN) hughaguilar96@gmail.com - 2016-01-11 13:52 -0800
                Re: generalized CASE Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2016-01-11 22:00 +0000
                Re: generalized CASE Coos Haak <chforth@hccnet.nl> - 2016-01-12 01:50 +0100
                Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-11 14:16 -0800
                Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-11 16:17 -0800
                Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-12 13:07 +0000
                Re: BEGIN WHILE UNTIL THEN Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2016-01-12 20:48 +0000
                Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-12 14:16 -0800
          Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-08 16:21 +0000
            Re: BEGIN WHILE UNTIL THEN stephen@mpeforth.com (Stephen Pelc) - 2016-01-08 20:12 +0000
              Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-09 18:19 +0000
              Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-11 09:34 +1100
            Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-08 21:13 +0100
        Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-09 23:46 +1100
      Re: BEGIN WHILE UNTIL THEN Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-01-08 10:11 -0500
        Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-11 08:38 +1100
  Re: BEGIN WHILE UNTIL THEN november.nihal@gmail.com - 2016-01-08 03:04 -0800

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