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Groups > comp.lang.forth > #39516

Field name overloading (was: ColorForth - another dead end?)

From anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups comp.lang.forth
Subject Field name overloading (was: ColorForth - another dead end?)
Date 2015-06-02 09:47 +0000
Organization Institut fuer Computersprachen, Technische Universitaet Wien
Message-ID <2015Jun2.114719@mips.complang.tuwien.ac.at> (permalink)
References (5 earlier) <mkbvcb$en0$1@dont-email.me> <ebfc8bdf-0f90-49b7-8469-b52bcae527e3@googlegroups.com> <77c3499b-2f89-41ec-b477-f529b7c2345b@googlegroups.com> <2015Jun1.152134@mips.complang.tuwien.ac.at> <c097cfc0-7763-469b-b2ac-8cb9489da270@googlegroups.com>

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humptydumpty <ouatubi@gmail.com> writes:
>in '+field' version 'see 2testY' shows:
>: 2testY  
>  Ob Y ? ;
>
>in my struct version 'see 2testY' shows:
>: 2testY  
>  Ob 8 + ? ;

And SEE Y shows

: Y  
  8 + ; ok

The behaviour is the same, but admittedly the run-time is slower on
Forth systems that don't inline automatically.

>and also show independence of 'Base' content.

Yes, I took a closer look at your STRUCT and the usage patterns, and
found that you have integrated a workaround for the BASE problem.  An
alternative would be to use a number prefix to make the string BASE
independent.

What is still missing is a workaround that guarantees that the right
"+" will be found.  Counterexample for the current implementation:

struct POS
  cell field X
  cell field Y
end-struct

: + cr ." funny +" cr ;

CREATE Ob POS SIZEOF allot
Ob POS Y .s

After fixing this the result is certainly an interesting solution to
the field (and method?) name overloading resulution problem in the
context of the current standard (you would need to get rid of some
Gforthisms, but that should be possible). The interesting part is in
STRUCT and would work also with the +FIELD I defined (but, as seen
above, there is a difference in inlining).

That problem has led to defining words for STATE-smart words in Bernd
Paysan's OOF and AFAIK other programs.  Other proposed solutions to
the problem go outside the standard: preludes and the dot-parser (the
latter implemented with recognizers).  I think it's cleaner than a
STATE-smart approach.

What you cannot do with it directly is ticking and postponing POS Y,
but you can define

: pos-y POS Y ;

and tick or postpone that.  However, why not just define POS-Y without
overloading right from the start?  Always writing POS Y instead of
POS-Y is not an advantage.

One possible advantage is in the context of inheritance: If you have a
class A with field X and class B and C inherit field X from A, you
don't want to refer to the field with A-X (because that would make
reorganizing the class hierarchy hard); referring to the field with
A X or B X or C X would be possible with a variation of your
technique, and would restrict class reorganizations only as necessary.

- 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 2015: http://www.mpeforth.com/euroforth2015/euroforth2015.htm

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ColorForth - another dead end? borota@gmail.com - 2015-05-24 12:22 -0700
  Re: ColorForth - another dead end? hughaguilar96@gmail.com - 2015-05-24 14:00 -0700
    Re: ColorForth - another dead end? borota@gmail.com - 2015-05-24 16:18 -0700
      Re: ColorForth - another dead end? hughaguilar96@gmail.com - 2015-05-24 16:45 -0700
      Re: ColorForth - another dead end? "Elizabeth D. Rather" <erather@forth.com> - 2015-05-24 14:50 -1000
        Re: ColorForth - another dead end? hughaguilar96@gmail.com - 2015-05-24 18:12 -0700
          Re: ColorForth - another dead end? onewhohopes@gmail.com - 2015-05-28 13:00 -0700
            Re: ColorForth - another dead end? hughaguilar96@gmail.com - 2015-05-28 18:55 -0700
            Re: ColorForth - another dead end? Howerd <howerdo@yahoo.co.uk> - 2015-05-29 00:49 -0700
              Re: ColorForth - another dead end? Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-05-29 07:56 -0700
                Re: ColorForth - another dead end? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-29 15:04 +0000
                Re: ColorForth - another dead end? Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-05-29 10:03 -0700
                Re: ColorForth - another dead end? Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-05-29 10:15 -0700
                Re: ColorForth - another dead end? hughaguilar96@gmail.com - 2015-05-29 19:28 -0700
                Re: ColorForth - another dead end? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-30 12:34 +0000
                Re: ColorForth - another dead end? hughaguilar96@gmail.com - 2015-05-29 19:19 -0700
                Re: ColorForth - another dead end? Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-05-29 22:30 -0700
                Re: ColorForth - another dead end? "Rod Pemberton" <fork@lllljunkqwer.cpm> - 2015-05-30 00:14 -0400
                Re: ColorForth - another dead end? Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-05-29 22:22 -0700
                Re: ColorForth - another dead end? "Alex McDonald" <blog@rivadpm.com> - 2015-05-30 09:27 +0100
                Re: ColorForth - another dead end? Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-05-30 02:05 -0700
                Re: ColorForth - another dead end? "Alex McDonald" <blog@rivadpm.com> - 2015-05-30 10:21 +0100
                Re: ColorForth - another dead end? Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-05-30 04:08 -0700
                Re: ColorForth - another dead end? hughaguilar96@gmail.com - 2015-05-30 07:43 -0700
                Re: ColorForth - another dead end? Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-05-30 09:42 -0700
                Re: ColorForth - another dead end? hughaguilar96@gmail.com - 2015-05-30 10:25 -0700
                Re: ColorForth - another dead end? Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-05-30 22:36 -0700
                Re: ColorForth - another dead end? hughaguilar96@gmail.com - 2015-05-31 16:38 -0700
                Re: ColorForth - another dead end? "Alex McDonald" <blog@rivadpm.com> - 2015-05-31 09:11 +0100
                Re: ColorForth - another dead end? humptydumpty <ouatubi@gmail.com> - 2015-05-31 11:31 -0700
                Re: ColorForth - another dead end? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-06-01 13:21 +0000
                Re: ColorForth - another dead end? humptydumpty <ouatubi@gmail.com> - 2015-06-01 08:18 -0700
                Re: ColorForth - another dead end? humptydumpty <ouatubi@gmail.com> - 2015-06-01 09:07 -0700
                Re: ColorForth - another dead end? humptydumpty <ouatubi@gmail.com> - 2015-06-01 23:31 -0700
                Field name overloading (was: ColorForth - another dead end?) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-06-02 09:47 +0000
                Re: Field name overloading (was: ColorForth - another dead end?) humptydumpty <ouatubi@gmail.com> - 2015-06-02 13:07 -0700
                Re: ColorForth - another dead end? humptydumpty <ouatubi@gmail.com> - 2015-06-01 08:20 -0700
                Re: ColorForth - another dead end? "Rod Pemberton" <fork@lllljunkqwer.cpm> - 2015-05-30 15:34 -0400
                Re: ColorForth - another dead end? hughaguilar96@gmail.com - 2015-05-29 22:55 -0700
                Re: ColorForth - another dead end? Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-05-30 00:54 -0700
              Re: ColorForth - another dead end? stephen@mpeforth.com (Stephen Pelc) - 2015-05-30 17:20 +0000
                Re: ColorForth - another dead end? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-05-31 15:17 +0000
        Re: ColorForth - another dead end? Hannu Vuolasaho <vuokkosetae@gmail.com> - 2015-05-25 10:06 +0300
        Re: ColorForth - another dead end? Jason Damisch <jasondamisch@yahoo.com> - 2015-05-25 11:11 -0700
          Re: ColorForth - another dead end? rickman <gnuarm@gmail.com> - 2015-05-25 14:22 -0400
            Re: ColorForth - another dead end? "Elizabeth D. Rather" <erather@forth.com> - 2015-05-25 14:57 -1000
              Re: ColorForth - another dead end? borota@gmail.com - 2015-05-25 20:42 -0700
              Re: ColorForth - another dead end? hughaguilar96@gmail.com - 2015-05-29 19:46 -0700
                Re: ColorForth - another dead end? "Rod Pemberton" <fork@lllljunkqwer.cpm> - 2015-05-30 00:03 -0400
  Re: ColorForth - another dead end? Howerd <howerdo@yahoo.co.uk> - 2015-05-24 21:51 -0700
    Re: ColorForth - another dead end? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-05-25 11:17 +0000
  Re: ColorForth - another dead end? Mark Wills <markwills1970@gmail.com> - 2015-05-25 01:50 -0700
    Re: ColorForth - another dead end? Howerd <howerdo@yahoo.co.uk> - 2015-05-25 02:11 -0700
  Re: ColorForth - another dead end? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-25 14:11 +0000

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