Groups > comp.lang.forth > #11937

Re: Distinguishing DOES>

From	JennyB <jennybrien@googlemail.com>
Newsgroups	comp.lang.forth
Subject	Re: Distinguishing DOES>
Date	2012-05-05 07:19 -0700
Organization	http://groups.google.com
Message-ID	<8512970.374.1336227597535.JavaMail.geo-discussion-forums@vbez20> (permalink)
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On Saturday, 5 May 2012 11:16:51 UTC+1, Doug Hoffman  wrote:

> Actually, I notice the following when using SEE in Carbon MacForth, 
> suggesting that only implementation-specific information is needed and 
> that a prototype for comparison is not needed to determine the defining 
> word.  Not sure if all Forths can do this:
> 
> : human create does> ;
> human bob
> 
> see bob
> 
> Name                 Token  Type  Flags     ^Code   Size     ^Data
> BOB                  9B7FC  Does>  -N-      4067FC    10    101DC0C
>    DOES> word,  Created by HUMAN
>    vocabulary: FORTH   source file: 'untitled'
> 004067FC: 95AEFFFC       stwu      r13/TOS, $-4(r14/DSP)
> 00406800: 39B3DC0C       addi      r13/TOS, r19/DBP, -9204      BOB
> 00406804: 3DAD0002       addis     r13/TOS, r13/TOS, 2
> 00406808: 4E800020       blr
> 
I suspect that the decompiler simply searches back from the code address referenced by DOES> to find the closest definition. What does it do with:

  : Foo DOES> ;
  : Human CREATE Foo ;
  Human Bob

?

What started me thinking about this was Gforth's INTERPRET/COMPILE , where ' POSTPONE and friends are then redefined to return the appropriate behaviour for interpret/compile words. In that case (where any imaginable word may be tested) there is no 100% portable solution, because you are limited to comparing data space and you can conceivably come across a definition with the same data.

LIKE? seems fairly simple for any particular Forth, but this is the best I have managed for CHILD?

: ACTOR  \ 'does ++
  CREATE ,   DOES> DUP CELL+ SWAP @ EXECUTE ;

: DEFINER \ 'builds 'does ++
  CREATE 2,  DOES> 2@ CHILD EXECUTE ;

' nop ' nop DEFINER urdefiner
' nop ACTOR uractor

: CHILD?   \ xt1 xt2 -- true if xt1 defined by xt2
  2DUP ['] urdefiner like? 
  SWAP ['] uractor like? AND 
  0= IF FALSE EXIT THEN

  >BODY @ SWAP >BODY @ = ;

Thread

Distinguishing DOES> JennyB <jennybrien@googlemail.com> - 2012-05-03 08:59 -0700
  Re: Distinguishing DOES> Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-05-03 17:23 -0700
    Re: Distinguishing DOES> Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2012-05-04 10:47 +0100
      Re: Distinguishing DOES> Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-05-04 05:12 -0500
        Re: Distinguishing DOES> anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-05-04 11:33 +0000
          Re: Distinguishing DOES> Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-05-04 08:11 -0500
            Re: Distinguishing DOES> anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-05-04 16:18 +0000
              Re: Distinguishing DOES> Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-05-05 02:02 -0500
                Re: Distinguishing DOES> anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-05-05 14:16 +0000
                Re: Distinguishing DOES> Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-05-06 02:53 -0500
                Re: Distinguishing DOES> anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-05-05 14:25 +0000
                Re: Distinguishing DOES> BruceMcF <agila61@netscape.net> - 2012-05-05 08:07 -0700
                Re: Distinguishing DOES> Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-05-08 06:23 -0700
                Re: Distinguishing DOES> Bernd Paysan <bernd.paysan@gmx.de> - 2012-05-09 00:25 +0200
                Re: Distinguishing DOES> Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-05-09 01:26 -0700
                Re: Distinguishing DOES> Mark Wills <markrobertwills@yahoo.co.uk> - 2012-05-09 03:18 -0700
                Re: Distinguishing DOES> Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-05-09 05:29 -0500
                Re: Distinguishing DOES> "Elizabeth D. Rather" <erather@forth.com> - 2012-05-09 07:11 -1000
                Re: Distinguishing DOES> Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2012-05-09 22:48 +0100
                Re: Distinguishing DOES> Bernd Paysan <bernd.paysan@gmx.de> - 2012-05-09 23:22 +0200
                Re: Distinguishing DOES> Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2012-05-09 23:43 +0100
                Re: Distinguishing DOES> Bernd Paysan <bernd.paysan@gmx.de> - 2012-05-10 00:49 +0200
                Re: Distinguishing DOES> Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2012-05-10 11:33 +0100
                Re: Distinguishing DOES> Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-05-10 10:02 +0000
                Re: Distinguishing DOES> Bernd Paysan <bernd.paysan@gmx.de> - 2012-05-10 15:13 +0200
                Re: Distinguishing DOES> Mark Wills <markrobertwills@yahoo.co.uk> - 2012-05-10 05:07 -0700
                Re: Distinguishing DOES> Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-05-10 22:57 -0700
  Re: Distinguishing DOES> Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-05-04 12:37 +0000
  Re: Distinguishing DOES> Doug Hoffman <glidedog@gmail.com> - 2012-05-04 10:14 -0400
    Re: Distinguishing DOES> humptydumpty <ouatubi@gmail.com> - 2012-05-04 20:27 +0000
      Re: Distinguishing DOES> Doug Hoffman <glidedog@gmail.com> - 2012-05-05 06:16 -0400
        Re: Distinguishing DOES> JennyB <jennybrien@googlemail.com> - 2012-05-05 07:19 -0700
          Re: Distinguishing DOES> anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-05-05 14:55 +0000
            Re: Distinguishing DOES> JennyB <jennybrien@googlemail.com> - 2012-05-07 07:24 -0700
          Re: Distinguishing DOES> Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-05-06 11:04 +0000
          Re: Distinguishing DOES> Doug Hoffman <glidedog@gmail.com> - 2012-05-06 07:47 -0400
        Re: Distinguishing DOES> ward@megawolf.com - 2012-05-08 04:39 -0700
          Re: Distinguishing DOES> Doug Hoffman <glidedog@gmail.com> - 2012-05-08 07:50 -0400
  Re: Distinguishing DOES> Hans Bezemer <the.beez.speaks@gmail.com> - 2012-05-05 14:24 +0200
    Re: Distinguishing DOES> Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-05-06 11:09 +0000

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