Re: bug in VFX --- IF does't work

From	anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups	comp.lang.forth
Subject	Re: bug in VFX --- IF does't work
Date	2017-03-30 15:45 +0000
Organization	Institut fuer Computersprachen, Technische Universitaet Wien
Message-ID	<2017Mar30.174535@mips.complang.tuwien.ac.at> (permalink)
References	(3 earlier) <48qdnYcMXuT0Ek7FnZ2dnUU7-fHNnZ2d@supernews.com> <ob0kgb$sa6$1@cherry.spenarnc.xs4all.nl> <WOadnbt3_5SwdU7FnZ2dnUU7-QudnZ2d@supernews.com> <obhqll$mq9$1@dont-email.me> <fM-dnSnYeqrsXkHFnZ2dnUU7-TGdnZ2d@supernews.com>

Show all headers | View raw

Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>Bernd Paysan <bernd@net2o.de> wrote:
>> It turned out that the original dual-xt (with two wordlists) cmForth
>> approach was not fully compatible with the Standard (with a literal
>> interpretation), and Chuck didn't care, and it didn't catch on,
>> either.
>
>That's how I remember it, too.  There were such severe disadvantages
>to dual-wordlist that it had to die.

I guess if it was more popular, even the cmForth variant would be
defended with the same argument that people use for defending
STATE-smart implementations of S": "Yes, it's not compatible with the
standard as written, but the intention was to allow this
implementation, so we should not use a literal reading of the standard
for this".

Apart from that, it is possible to make the dual-wordlist approach
(and also the STATE-smart S") fully compatible with a literal reading
of the standard, but the resulting dual-wordlist implementation is
more complicated than the single-wordlist/dual-xt implementation.

The main issue with the dual-wordlist approach is: AFAIK the compiler
wordlist is searched first in compile state, so an older IF in the
compiler wordlist will be found before (i.e., instead of) a newer IF
in the FORTH wordlist.  This can be fixed by searching both, and
returning the later-defined one (i.e., the one with the bigger
address).

Other issues are:

User-defined words with special compilation semantics need to be
defined with syntax specific to this model (but that's the same for
other models).

Supporting the search-order wordset gets quite complex, in particular
if you want to have special compilation semantics for words in other
wordsets than the Forth wordset; probably the best way would be if
each WORDLIST call creates a corresponding compilation wordlist, and
FIND searches the corresponding compilation wordlist along with the
general wordlist for each wordlist in the search order.

>Dual-xt gets rid of some of
>those disadvantages.

You need none of the comlexity outlined above.

- 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 2016: http://www.euroforth.org/ef16/

Thread

Re: bug in VFX --- IF does't work rickman <gnuarm@gmail.com> - 2017-03-18 17:37 -0400
  Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-03-18 15:08 -0700
  Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-03-18 15:17 -0700
    Re: bug in VFX --- IF does't work Alex <alex@rivadpm.com> - 2017-03-18 22:22 +0000
      Re: bug in VFX --- IF does't work rickman <gnuarm@gmail.com> - 2017-03-18 19:47 -0400
        Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-03-18 17:06 -0700
          Re: bug in VFX --- IF does't work rickman <gnuarm@gmail.com> - 2017-03-18 20:58 -0400
          Re: bug in VFX --- IF does't work Alex <alex@rivadpm.com> - 2017-03-19 18:04 +0000
  Re: bug in VFX --- IF does't work anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-03-19 10:53 +0000
    Re: bug in VFX --- IF does't work Cecil Bayona <cbayona@cbayona.com> - 2017-03-19 12:57 -0500
      Re: bug in VFX --- IF does't work Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-03-19 13:39 -0500
      Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-03-19 14:48 -0700
        Re: bug in VFX --- IF does't work Alex <alex@rivadpm.com> - 2017-03-19 22:05 +0000
    Re: bug in VFX --- IF does't work Alex <alex@rivadpm.com> - 2017-03-19 17:57 +0000
    Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-03-19 12:18 -0700
    Re: bug in VFX --- IF does't work Bernd Paysan <bernd@net2o.de> - 2017-03-22 22:57 +0000
      Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-03-22 17:18 -0700
      Re: bug in VFX --- IF does't work Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-03-23 04:03 -0500
        Re: bug in VFX --- IF does't work albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-03-23 15:01 +0100
          Re: bug in VFX --- IF does't work peter.m.falth@gmail.com - 2017-03-23 07:12 -0700
            Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-03-29 20:31 -0700
          Re: bug in VFX --- IF does't work Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-03-23 10:22 -0500
            Re: bug in VFX --- IF does't work Bernd Paysan <bernd@net2o.de> - 2017-03-30 02:31 +0000
              Re: bug in VFX --- IF does't work Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-03-30 03:36 -0500
                Re: bug in VFX --- IF does't work anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-03-30 15:45 +0000
                Re: bug in VFX --- IF does't work Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-03-30 12:03 -0500
                Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-03-30 14:04 -0700
                Re: bug in VFX --- IF does't work anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-03-31 09:23 +0000
                Re: bug in VFX --- IF does't work Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-03-31 07:43 -0500
                Re: bug in VFX --- IF does't work anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-01 12:55 +0000
                Re: bug in VFX --- IF does't work Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-01 11:52 -0500
      Re: bug in VFX --- IF does't work anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-03-23 12:23 +0000
        Re: bug in VFX --- IF does't work Alex <alex@rivadpm.com> - 2017-03-23 15:57 +0000
          Re: bug in VFX --- IF does't work anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-03-23 17:38 +0000
            Re: bug in VFX --- IF does't work Alex <alex@rivadpm.com> - 2017-03-23 17:58 +0000
              Re: bug in VFX --- IF does't work Alex <alex@rivadpm.com> - 2017-03-23 19:16 +0000
              Re: bug in VFX --- IF does't work anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-03-24 09:52 +0000
        Re: bug in VFX --- IF does't work anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-03-23 18:26 +0000
        Re: bug in VFX --- IF does't work Bernd Paysan <bernd@net2o.de> - 2017-03-30 02:55 +0000
          Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-03-29 20:49 -0700
          Re: bug in VFX --- IF does't work Mark Wills <markwills1970@gmail.com> - 2017-03-30 03:04 -0700
            Re: bug in VFX --- IF does't work Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-03-30 06:47 -0500
              Re: bug in VFX --- IF does't work Alex <alex@rivadpm.com> - 2017-03-30 12:56 +0100
                Re: bug in VFX --- IF does't work Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-03-30 09:41 -0500
              Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-03-30 13:59 -0700
              Re: bug in VFX --- IF does't work Bernd Paysan <bernd@net2o.de> - 2017-05-01 01:33 +0000
                Re: bug in VFX --- IF does't work "Elizabeth D. Rather" <erather@forth.com> - 2017-04-30 15:50 -1000
                Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-04-30 19:34 -0700
                Re: bug in VFX --- IF does't work albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-05-01 23:53 +0200
                Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-05-01 18:54 -0700
                Re: bug in VFX --- IF does't work Bernd Paysan <bernd@net2o.de> - 2017-05-02 15:01 +0000
                Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-05-02 11:30 -0700
                Re: bug in VFX --- IF does't work Cecil Bayona <cbayona@cbayona.com> - 2017-05-02 13:36 -0500
                Re: bug in VFX --- IF does't work Bernd Paysan <bernd@net2o.de> - 2017-05-02 22:57 +0000
          Re: bug in VFX --- IF does't work anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-03-31 09:45 +0000
            Re: bug in VFX --- IF does't work hughaguilar96@gmail.com - 2017-03-31 20:09 -0700

csiph-web