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Groups > comp.lang.forth > #11945

Re: Distinguishing DOES>

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In article <8512970.374.1336227597535.JavaMail.geo-discussion-forums@vbez20>,
JennyB  <jennybrien@googlemail.com> wrote:
>On Saturday, 5 May 2012 11:16:51 UTC+1, Doug Hoffman  wrote:
>
>> Actually, I notice the following when using SEE in Carbon MacForth,=20
>> suggesting that only implementation-specific information is needed and=20
>> that a prototype for comparison is not needed to determine the defining=
>=20
>> word.  Not sure if all Forths can do this:
>>=20
>> : human create does> ;
>> human bob
>>=20
>> see bob
>>=20
>> 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
>>=20
>I suspect that the decompiler simply searches back from the code address re=
>ferenced 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 behavio=
>ur 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?=20
>  SWAP ['] uractor like? AND=20
>  0=3D IF FALSE EXIT THEN
>
>  >BODY @ SWAP >BODY @ =3D ;

Adding type information to a structure is a trivial exercise.

The question raised here is whether we can somehow define a
portable way to use the content of the pointer that is filled
in by DOES> . After all words that are CREATEd equal have
a same pointer. Tucking the same information in the first
field is just cumbersome and error prone.

Alternatively we can ask whether the information that ANSI
demands from a standard system to store, would allow a
language extension that finds out similarity based on this
already existing information.


>=20
>=20
>
>
>


--
-- 
Albert van der Horst, UTRECHT,THE NETHERLANDS
Economic growth -- being exponential -- ultimately falters.
albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst

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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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