Re: ?EXEC

From	Bernd Paysan <bernd.paysan@gmx.de>
Newsgroups	comp.lang.forth
Subject	Re: ?EXEC
Date	2012-06-19 02:11 +0200
Organization	1&1 Internet AG
Message-ID	<jrog44$jsi$1@online.de> (permalink)
References	(1 earlier) <b445b94c-64c5-4773-be56-ee8c75f24f4d@h10g2000yqn.googlegroups.com> <m5qr30.n40@spenarnc.xs4all.nl> <2012Jun17.142751@mips.complang.tuwien.ac.at> <m5s4bd.5r0@spenarnc.xs4all.nl> <2012Jun18.153125@mips.complang.tuwien.ac.at>

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Anton Ertl wrote:
> Try <http://www.complang.tuwien.ac.at/forth/postponetest.fs> and see
> how IF and DO with ?COMP are broken.

I think this is a misunderstanding what "compilation semantics" could 
possibly mean - it's a literal reading of the standard.  Compilation 
semantics is what the text interpreter does with a word it encounters, 
which is

FIND 0< IF  COMPILE,  ELSE  EXECUTE  THEN

So what POSTPONE does is essentially (minus the self-reference, but I 
assume this is the cross compiler's POSTPONE):

FIND SWAP POSTPONE LITERAL 0< IF POSTPONE COMPILE, ELSE POSTPONE EXECUTE 
THEN

with some opportunity to optimize (lit+execute is call).  POSTPONE was 
introduced so that the implementer can choose to make some words 
immediate or not.

For an immediate word, the compilation semantics is to EXECUTE that 
word, for an non-immediate word, it is to COMPILE, this word.  POSTPONE 
embeds this into the current definition.  Unfortunately, for an 
immediate word, EXECUTE is also used to get the interpretation semantics 
fo that word.  The interpretation semantics of a word like IF is 
undefined, and the only standard way IF has to find out if it's 
interpretation or compilation semantics are requested is STATE.

postponetest.fs tests if the compiler uses non-standard features to 
implement these things.  You always argued that the standard would 
mandate postponetest.fs to pass.  It reads that way, but our recent 
discussion about semantics has revealed that things are a bit more 
complicated (or maybe let's say a bit more simplistic).

ANS Forth mandates that you implement CORE, but it also intents that 
CORE is a good minimal set of words which can be used as tools for the 
implementer himself.  If you have dual-xt name tokens, a compile-only 
flag, or an intelligent COMPILE,, you have no problems to implement 
?COMP in a way that postponetest.fs passes.  But the standard does not 
mandate these extensions, they are quality-of-implementation issues (and 
not having too many features is considered as quality of implementation 
by some people in the Forth community).

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/

Thread

?EXEC Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-15 20:40 +0000
  Re: ?EXEC "Ed" <invalid@nospam.com> - 2012-06-16 11:14 +1000
  Re: ?EXEC BruceMcF <agila61@netscape.net> - 2012-06-16 07:10 -0700
    Re: ?EXEC Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-17 03:01 +0000
      Re: ?EXEC "Ed" <invalid@nospam.com> - 2012-06-17 13:36 +1000
      Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-17 12:27 +0000
        Re: ?EXEC Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-17 20:45 +0000
          Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-18 13:31 +0000
            Re: ?EXEC Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-18 18:29 +0000
              Re: ?EXEC "Elizabeth D. Rather" <erather@forth.com> - 2012-06-18 08:01 -1000
              Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-19 14:09 +0000
                Re: ?EXEC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-19 10:51 -0500
                Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-19 16:04 +0000
                Re: ?EXEC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-19 12:45 -0500
                Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-20 10:50 +0000
                Re: ?EXEC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-20 07:10 -0500
                Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-20 12:47 +0000
                Re: ?EXEC Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-19 22:52 +0000
                Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-20 10:59 +0000
                Defining Compilation Behaviour - was Re: ?EXEC JennyB <jennybrien@googlemail.com> - 2012-06-21 04:58 -0700
                Re: Defining Compilation Behaviour - was Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-21 15:44 +0000
            Re: ?EXEC Bernd Paysan <bernd.paysan@gmx.de> - 2012-06-19 02:11 +0200
              Re: ?EXEC "Elizabeth D. Rather" <erather@forth.com> - 2012-06-18 14:45 -1000
                Re: ?EXEC Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-19 10:48 +0000
                Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-19 15:53 +0000
                Re: ?EXEC Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-19 23:00 +0000
                Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-20 11:09 +0000
                Re: ?EXEC BruceMcF <agila61@netscape.net> - 2012-06-20 07:39 -0700
                Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-20 15:32 +0000
                Re: ?EXEC BruceMcF <agila61@netscape.net> - 2012-06-21 11:24 -0700
                Re: ?EXEC Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-20 22:43 +0000
                Re: ?EXEC Bernd Paysan <bernd.paysan@gmx.de> - 2012-06-21 21:39 +0200
                Re: ?EXEC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-22 02:33 -0500
                Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-22 11:12 +0000
                Re: ?EXEC Bernd Paysan <bernd.paysan@gmx.de> - 2012-06-22 21:34 +0200
                Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-24 14:58 +0000
                Re: ?EXEC Bernd Paysan <bernd.paysan@gmx.de> - 2012-06-24 23:53 +0200
                Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-19 15:43 +0000
              Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-19 14:52 +0000
                Re: ?EXEC Bernd Paysan <bernd.paysan@gmx.de> - 2012-06-21 22:15 +0200
                Re: ?EXEC stephenXXX@mpeforth.com (Stephen Pelc) - 2012-06-22 10:32 +0000
                Re: ?EXEC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-22 05:49 -0500
                Alternatives to S" and TO (was: ?EXEC) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-22 15:19 +0000
                Re: Alternatives to S'' and TO mhx@iae.nl (Marcel Hendrix) - 2012-06-22 20:37 +0200
                Re: Alternatives to S'' and TO anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-23 14:46 +0000
                Re: Alternatives to S" and TO (was: ?EXEC) BruceMcF <agila61@netscape.net> - 2012-06-22 12:32 -0700
                Re: Alternatives to S" and TO Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-23 03:07 -0500
                Re: Alternatives to S" and TO anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-23 13:32 +0000
                Re: Alternatives to S" and TO Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-24 08:50 -0500
                Re: Alternatives to S" and TO anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-24 15:39 +0000
                Re: Alternatives to S" and TO Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-25 04:49 -0500
                Re: Alternatives to S" and TO BruceMcF <agila61@netscape.net> - 2012-06-25 07:17 -0700
                Re: Alternatives to S" and TO Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-25 10:13 -0500
                Re: Alternatives to S" and TO (was: ?EXEC) Alex McDonald <blog@rivadpm.com> - 2012-06-23 16:01 -0700
                Re: Alternatives to S" and TO (was: ?EXEC) Bernd Paysan <bernd.paysan@gmx.de> - 2012-06-24 01:59 +0200
                Re: Alternatives to S" and TO (was: ?EXEC) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-24 13:21 +0000
                Re: Alternatives to S" and TO (was: ?EXEC) Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-24 16:50 +0000
                Re: Alternatives to S" and TO (was: ?EXEC) Bernd Paysan <bernd.paysan@gmx.de> - 2012-06-27 23:30 +0200
                Re: Alternatives to S" and TO (was: ?EXEC) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-24 13:15 +0000
                Re: Alternatives to S" and TO (was: ?EXEC) Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-24 16:47 +0000
                Re: ?EXEC Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-22 20:34 +0000
                Re: ?EXEC Bernd Paysan <bernd.paysan@gmx.de> - 2012-06-22 21:46 +0200
                Re: ?EXEC "Elizabeth D. Rather" <erather@forth.com> - 2012-06-22 10:16 -1000
                Re: ?EXEC Bernd Paysan <bernd.paysan@gmx.de> - 2012-06-22 22:43 +0200
                Re: ?EXEC "Elizabeth D. Rather" <erather@forth.com> - 2012-06-22 11:18 -1000
                Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-23 13:50 +0000
      Re: ?EXEC BruceMcF <agila61@netscape.net> - 2012-06-17 10:41 -0700
  Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-17 12:52 +0000
    Re: ?EXEC "Elizabeth D. Rather" <erather@forth.com> - 2012-06-17 08:03 -1000
      Re: ?EXEC "Ed" <invalid@nospam.com> - 2012-06-18 15:06 +1000
        Re: ?EXEC "Elizabeth D. Rather" <erather@forth.com> - 2012-06-17 20:31 -1000
          Re: ?EXEC "Ed" <invalid@nospam.com> - 2012-06-21 13:07 +1000
            Re: ?EXEC Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-21 14:00 +0000
              Re: ?EXEC BruceMcF <agila61@netscape.net> - 2012-06-21 07:51 -0700
              Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-21 15:39 +0000
                Re: ?EXEC Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-21 20:28 +0000
                Re: ?EXEC "Ed" <invalid@nospam.com> - 2012-06-28 14:22 +1000
                Re: ?EXEC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-28 04:00 -0500
            Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-21 16:09 +0000
            Re: ?EXEC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-21 11:51 -0500
              Re: ?EXEC BruceMcF <agila61@netscape.net> - 2012-06-21 11:21 -0700
                Re: ?EXEC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-22 01:42 -0500
                Re: ?EXEC "Elizabeth D. Rather" <erather@forth.com> - 2012-06-21 21:47 -1000
                Re: ?EXEC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-06-22 15:10 +0000
                Re: ?EXEC Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-22 20:39 +0000
                Re: ?EXEC BruceMcF <agila61@netscape.net> - 2012-06-22 12:47 -0700
                Re: ?EXEC BruceMcF <agila61@netscape.net> - 2012-06-22 12:53 -0700
        Re: ?EXEC stephenXXX@mpeforth.com (Stephen Pelc) - 2012-06-21 08:39 +0000
          Re: ?EXEC "Ed" <invalid@nospam.com> - 2012-06-23 15:36 +1000
            Re: ?EXEC stephenXXX@mpeforth.com (Stephen Pelc) - 2012-06-23 10:58 +0000
              Re: ?EXEC "Ed" <invalid@nospam.com> - 2012-06-25 14:26 +1000
                Re: ?EXEC stephenXXX@mpeforth.com (Stephen Pelc) - 2012-06-25 08:37 +0000
      Re: ?EXEC Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-18 10:34 +0000
  Re: ?EXEC Coos Haak <chforth@hccnet.nl> - 2012-06-18 17:47 +0200
    Re: ?EXEC Coos Haak <chforth@hccnet.nl> - 2012-06-18 17:49 +0200
  Re: ?EXEC jacko <jackokring@gmail.com> - 2012-06-22 15:43 -0700

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