Alternatives to S" and TO (was: ?EXEC)

From	anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups	comp.lang.forth
Subject	Alternatives to S" and TO (was: ?EXEC)
Date	2012-06-22 15:19 +0000
Organization	Institut fuer Computersprachen, Technische Universitaet Wien
Message-ID	<2012Jun22.171947@mips.complang.tuwien.ac.at> (permalink)
References	(6 earlier) <jrog44$jsi$1@online.de> <2012Jun19.165240@mips.complang.tuwien.ac.at> <jrvvcd$853$1@online.de> <4fe445d5.175973121@192.168.0.50> <97-dnWNi04BM0HnSnZ2dnUVZ8nydnZ2d@supernews.com>

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Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>I've been thinking the opposite.  Maybe the problem with some of the
>modern techniques is that they're exposed to the programmer; they're
>too shallow.  Perhaps the right solution is to let the Forth compiler
>generate tokens (just like a very trad Forth) and then let the
>optimizing compiler run over them.

That's an implementation issue, but it's the right approach.

> Let IMMEDIATE do what it used to
>do.  Get rid of other ways of creating words that execute at compile
>time.

There is no other way in the standard.  A problem may be that the
other ways are *not* exposed to the programmer (in standard programs),
so people still resort to STATE-smartness in standard programs.

Anyway, it's not totally clear what you mean by this.

One interpretation is that we should go back to implementing S" and TO
with STATE-smart words, and to make STATE-smart words an accepted
technique, and to hell with xts, POSTPONE, code generators and other
guru stuff that's troublesome in the presence of STATE-smart words.

Another take on your statement is that we should get rid of words like
S" and TO (and not design more of the kind) which some implementations
implement with STATE-smartness, for which other implementations
provide implementations with better properties, but with repercussions
that are far more trouble than these words are worth.

Instead, we would only have normal words (like +) and IMMEDIATE words
like ( and IF (the latter maybe compile-only), but no access to STATE
and no words that have independent interpretation and compilation
semantics.

We would have to replace S" and TO with something else.  The classic
approach would be the ' ['] solution, but that's not very popular.

What is popular is the solution taken for numbers: The text
interpreter deals with them as appropriate and everyone is happy.  We
don't use NUM 123 and [NUM] 123 for numbers, we let the text
interpreter deal with them.

Probably most of the parsing words (the main driver behind STATE-smart
words) can be eliminated by having a few additions to the text
interpreter.  E.g., instead of writing ." bla" or .( bla) one could
write "bla" TYPE, and have code that works both interpretively and
compiled as intended.

There are a few parsing words where the replacement requires its own
treatment in the text interpreter, in particular TO.  Instead of 

TO v

we could write

->v

and the text interpreter would do the appropriate thing with V.

Albert van der Horst used to call this feature "denotations", but
lately I have seen him use "prefixes".

Many will cry out against this complication of the text interpreter.
Some may also find the idea bad because up to now the text interpreter
is a black box so any additions there are only done by the compiler
vendor.  However:

1) I think that this feature adds relatively little complexity to the
text interpreter, and it gets rid of a huge amount of baggage
elsewhere (STATE-smart words and the restrictions that their defenders
want to put upon us, or the complexities of the alternatives and their
ramifications).

2) One could make it possible for "mere" users to add further
prefixes/denotations (or, as Gforth calls them, recognizers) to the
text interpreter, just like it is possible to add further words now.
Of course some people will fear giving this much power to the users,
and it's certainly a feature that should be used sparingly, but that's
a management issue.

>This is probably worthy of a workshop at EuroFORTH.

Yes.

- 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 2012: http://www.euroforth.org/ef12/

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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