Re: Reformulation of "STATE @ IF"

From	"Rod Pemberton" <do_not_have@notemailnot.cmm>
Newsgroups	comp.lang.forth
Subject	Re: Reformulation of "STATE @ IF"
Date	2012-04-25 01:44 -0400
Organization	Aioe.org NNTP Server
Message-ID	<jn82vk$h2d$1@speranza.aioe.org> (permalink)
References	<4f958ae9$0$7610$9b4e6d93@newsspool1.arcor-online.net>

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"A. K." <akk@nospam.org> wrote in message
news:4f958ae9$0$7610$9b4e6d93@newsspool1.arcor-online.net...
> I know the ambiguities of state-smart words. However I am wondering
> whether there is some common practice (or even an alternative optimum?)
> of how to replace the construct by other means, eg dual wordlists and or
> dual execution tokens, and with another practical syntax.
>

Ok, I reread the thread, but I'm not following ...  None of the replies seem
to have anything to do with your initial question, AIUI.

Wasn't this ("Reformulation of 'STATE @ IF'") already solved with ' (tick)?

Tick was state-smart in fig-Forth, but was then made state-dumb for later
forths.  It was split into ' (tick) and ['] .  Other state-smart words were
also broken into or implemented as an interpret version and a "compile-time"
version.  The compile-time versions use brackets around the name [ ] .
Later on, they merged COMPILE and [COMPILE] into state-aware POSTPONE .

> F. ex. F83 contains:
>
> : IS   (S cfa --- )
>    STATE @ IF  COMPILE (IS)  ELSE  ' >IS !  THEN ; IMMEDIATE
>
> (the meanings of >IS and (IS) are of no great importance now)
>
> How would one reformulate this?  Perhaps similar to CREATE ... DOES>? Eg:
> : IS
>    executes> ' >is ! compiles> compile (is) ; IMMEDIATE
>

Given the [] notation for compile-time versions of words.  I'd split IS into
IS and [IS] .  That will eliminate the STATE @ IF ... ELSE ... THEN
construct.  E.g.,

: IS ' >IS ! ;

: [IS] COMPILE (IS) ;  IMMEDIATE


> But which subpart would then be affected by IMMEDIATE?
> Etc etc.... ?????
>

I think that's answered both with the definition above and with the
explanation that follows.

The whole word IS as you posted it is IMMEDIATE.  The first section of the
IF, i.e., IF-ELSE, due to STATE @ is the compile-time portion.  The
IMMEDIATE is needed so that the compile-time IF-ELSE section is executed
immediately during compilation, i.e., during a colon-definition.  That is
the section which will have COMPILEs or [COMPILE]s or POSTPONEs.  For ANS,
POSTPONE replaces COMPILE and [COMPILE] .  You can convert back, if needed.
COMPILE for non-immediates and [COMPILE] for immediates.  The other IF
section, i.e., ELSE-THEN, is for interpretive mode.


From the c.l.f. archives, IS typically is implemented either with the same
definition as TO, which is usually inline, i.e., without >IS or (IS) .

: IS ' >BODY STATE @ IF POSTPONE LITERAL POSTPONE ! ELSE ! THEN ; IMMEDIATE

: IS ' >BODY STATE @ IF [COMPILE] LITERAL COMPILE ! ELSE ! THEN ; IMMEDIATE

As you can see, ' >BODY !   is the key definition.  Sometimes you'll see IS
or TO written with ' and >BODY moved into the IF sections.  Since your F83
definition doesn't have ' and >BODY, that must've been done for them.


IS can also be implemented in terms of TO which was standardized:

: IS POSTPONE TO ; IMMEDIATE

I saw an old discussion in c.l.f. that claimed "POSTPONE TO" is not valid
for ANS Forth.


Rod Pemberton

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Thread

Reformulation of "STATE @ IF" "A. K." <akk@nospam.org> - 2012-04-23 19:01 +0200
  Re: Reformulation of "STATE @ IF" anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-04-23 17:18 +0000
    Re: Reformulation of "STATE @ IF" "A. K." <akk@nospam.org> - 2012-04-23 19:56 +0200
      Re: Reformulation of "STATE @ IF" "A. K." <akk@nospam.org> - 2012-04-23 20:20 +0200
      Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-04-23 14:42 -0700
        Re: Reformulation of "STATE @ IF" "A. K." <akk@nospam.org> - 2012-04-24 07:57 +0200
          Re: Reformulation of "STATE @ IF" "Elizabeth D. Rather" <erather@forth.com> - 2012-04-23 22:06 -1000
            Re: Reformulation of "STATE @ IF" Hans Bezemer <the.beez.speaks@gmail.com> - 2012-04-26 08:42 +0200
              Re: Reformulation of "STATE @ IF" Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-04-26 03:55 -0500
          Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-04-24 07:55 -0700
          Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-04-24 08:00 -0700
        Re: Reformulation of "STATE @ IF" awegel@arcor.de (Alex Wegel) - 2012-04-25 14:32 +0200
      Re: Reformulation of "STATE @ IF" anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-04-24 10:26 +0000
        Re: Reformulation of "STATE @ IF" "A. K." <akk@nospam.org> - 2012-04-24 19:38 +0200
          Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-04-24 11:25 -0700
            Re: Reformulation of "STATE @ IF" "A. K." <akk@nospam.org> - 2012-04-24 22:10 +0200
              Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-04-24 16:02 -0700
              Re: Reformulation of "STATE @ IF" "Elizabeth D. Rather" <erather@forth.com> - 2012-04-24 13:54 -1000
                Re: Reformulation of "STATE @ IF" "A. K." <akk@nospam.org> - 2012-04-25 06:58 +0200
                Re: Reformulation of "STATE @ IF" "Elizabeth D. Rather" <erather@forth.com> - 2012-04-24 21:01 -1000
                Re: Reformulation of "STATE @ IF" "Elizabeth D. Rather" <erather@forth.com> - 2012-04-24 21:40 -1000
                Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-04-25 05:56 -0700
        Re: Reformulation of "STATE @ IF" Alex McDonald <blog@rivadpm.com> - 2012-04-24 12:11 -0700
        Re: Reformulation of "STATE @ IF" Coos Haak <chforth@hccnet.nl> - 2012-04-24 22:40 +0200
          Re: Reformulation of "STATE @ IF" anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-04-25 13:03 +0000
            Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-04-25 08:37 -0700
              Re: Reformulation of "STATE @ IF" anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-04-26 16:17 +0000
  Re: Reformulation of "STATE @ IF" "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-04-25 01:44 -0400
    Re: Reformulation of "STATE @ IF" "A. K." <akk@nospam.org> - 2012-04-25 08:33 +0200
      Re: Reformulation of "STATE @ IF" Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-04-25 04:09 -0500
        Re: Reformulation of "STATE @ IF" stephenXXX@mpeforth.com (Stephen Pelc) - 2012-04-25 13:15 +0000
          Re: Reformulation of "STATE @ IF" Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-04-25 10:52 -0500
            Re: Reformulation of "STATE @ IF" stephenXXX@mpeforth.com (Stephen Pelc) - 2012-04-25 17:50 +0000
              Re: Reformulation of "STATE @ IF" Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-04-26 04:06 -0500
                Re: Reformulation of "STATE @ IF" Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-04-27 11:37 +0000
            Re: Reformulation of "STATE @ IF" "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-04-25 15:28 -0400
              Re: Reformulation of "STATE @ IF" "Elizabeth D. Rather" <erather@forth.com> - 2012-04-25 10:02 -1000
              Re: Reformulation of "STATE @ IF" Mark Wills <markrobertwills@yahoo.co.uk> - 2012-04-26 01:30 -0700
                Re: Reformulation of "STATE @ IF" Coos Haak <chforth@hccnet.nl> - 2012-04-26 16:48 +0200
                Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-04-26 09:27 -0700
                Re: Reformulation of "STATE @ IF" "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-04-26 16:42 -0400
                Re: Reformulation of "STATE @ IF" Coos Haak <chforth@hccnet.nl> - 2012-04-27 00:46 +0200
                Re: Reformulation of "STATE @ IF" "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-04-27 05:32 -0400
                Re: Reformulation of "STATE @ IF" Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-04-27 05:35 -0500
                Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-04-27 04:00 -0700
                Re: Reformulation of "STATE @ IF" "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-04-27 20:38 -0400
                Re: Reformulation of "STATE @ IF" awegel@arcor.de (Alex Wegel) - 2012-04-28 03:02 +0200
                Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-04-27 18:12 -0700
                Re: Reformulation of "STATE @ IF" anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-04-30 12:45 +0000
                Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-04-30 07:56 -0700
                Re: Reformulation of "STATE @ IF" anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-04-30 16:17 +0000
                Re: Reformulation of "STATE @ IF" "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-05-02 15:51 -0400
                Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-05-02 13:15 -0700
                Re: Reformulation of "STATE @ IF" Mark Wills <markrobertwills@yahoo.co.uk> - 2012-05-02 12:59 -0700
                Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-05-02 13:54 -0700
                Re: Reformulation of "STATE @ IF" Mark Wills <markrobertwills@yahoo.co.uk> - 2012-05-02 14:25 -0700
              Re: Reformulation of "STATE @ IF" Mark Wills <markrobertwills@yahoo.co.uk> - 2012-04-26 01:43 -0700
                Re: Reformulation of "STATE @ IF" Mark Wills <markrobertwills@yahoo.co.uk> - 2012-04-26 02:18 -0700
                Re: Reformulation of "STATE @ IF" Coos Haak <chforth@hccnet.nl> - 2012-04-26 16:54 +0200
                Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-04-26 10:46 -0700
                Re: Reformulation of "STATE @ IF" Mark Wills <markrobertwills@yahoo.co.uk> - 2012-04-26 12:21 -0700
                Re: Reformulation of "STATE @ IF" "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-04-26 18:31 -0400
                Re: Reformulation of "STATE @ IF" "Elizabeth D. Rather" <erather@forth.com> - 2012-04-26 14:32 -1000
                Re: Reformulation of "STATE @ IF" BruceMcF <agila61@netscape.net> - 2012-04-27 01:50 -0700
                Re: Reformulation of "STATE @ IF" anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-04-27 09:10 +0000
                Re: Reformulation of "STATE @ IF" "Elizabeth D. Rather" <erather@forth.com> - 2012-04-27 09:47 -1000
                Re: Reformulation of "STATE @ IF" "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-04-27 05:33 -0400
                Re: Reformulation of "STATE @ IF" "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-04-27 15:06 -0400
                Re: Reformulation of "STATE @ IF" JennyB <jennybrien@googlemail.com> - 2012-04-27 02:54 -0700
                Re: Reformulation of "STATE @ IF" stephenXXX@mpeforth.com (Stephen Pelc) - 2012-04-27 11:30 +0000
                Re: Reformulation of "STATE @ IF" Mark Wills <markrobertwills@yahoo.co.uk> - 2012-04-26 12:18 -0700
                Re: Reformulation of "STATE @ IF" Coos Haak <chforth@hccnet.nl> - 2012-04-26 22:21 +0200
              Re: Reformulation of "STATE @ IF" Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-04-26 04:27 -0500
    Re: Reformulation of "STATE @ IF" Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-04-25 04:08 -0500
      Re: Reformulation of "STATE @ IF" "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-04-25 15:29 -0400
        Re: Reformulation of "STATE @ IF" "Elizabeth D. Rather" <erather@forth.com> - 2012-04-25 10:27 -1000
        Re: Reformulation of "STATE @ IF" Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-04-26 04:31 -0500
        Re: Reformulation of "STATE @ IF" anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-04-26 16:35 +0000
          Re: Reformulation of "STATE @ IF" Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-04-27 11:58 +0000

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