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Re: Offline compilation of Forth

From anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups comp.lang.forth
Subject Re: Offline compilation of Forth
Date 2013-01-29 08:55 +0000
Organization Institut fuer Computersprachen, Technische Universitaet Wien
Message-ID <2013Jan29.095507@mips.complang.tuwien.ac.at> (permalink)
References <ke5otq$92o$1@oravannahka.helsinki.fi>

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Lauri Alanko <la@iki.fi> writes:
>Forth is often used in embedded systems. I'm not very familiar with
>them, but I'd expect resources to be so scarce that cross-compilation to
>the target's native code would be the preferred implementation
>technique: interpretation would waste cycles on an already slow
>microcontroller, and there wouldn't be enough memory for a native
>non-cross-compiler, JIT or otherwise.

Simple native-code compilers can be quite small.  Maybe Bernd Paysan
can provide numbers for bigForth.  It just copies a bit of native code
for every word that is compiled, and then performs some peephole
optimization; and the table for peephole optimization is not that big,
either, AFAIK.

>However, standard Forth is specified as an interpreted language, where
>execution semantics and compilation semantics can be interleaved, each
>affecting the other. For instance:
>
>variable counter
>0 counter !
>: inc counter @ dup 1+ counter ! ;
>inc .
>: foo inc postpone literal ; immediate
>: bar foo . ;
>inc .
>bar
>bye
>
>With such a tight interdependency between compilation and execution,
>it's hard to see how standard Forth could be efficiently compiled
>statically in the general case.

I assume that with "statically" you mean that there is a hard line
between compilation and run-time.  Forth cross compilers have that,
and yes, if you use a typical cross compiler, you cannot draw the line
before the last colon definition in the example above.  So yes, cross
compilers generally do not work on all standard Forth programs.

Such code does not appear to be that common, and maybe the limitations
of cross-compilers are a contributing factor.

The other alternative is to have some kind of code generator in the
target, even if it produces threaded code.  I don't think that a
different code generation strategy has been used for Forth, but the
GNU Java implementation used native code (GCC-based) for "static code"
(before the line) and a bytecode interpreter (GIJ) for "dynamic code"
(after the line).

>So how do offline native Forth compilers tackle the problem? Do they
>also require use of non-standard features in order to provide efficient
>compilation, or is there some other solution?

Cross-compilers just don't support the features that would require too
much memory to implement.

- 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/

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Thread

Offline compilation of Forth Lauri Alanko <la@iki.fi> - 2013-01-28 11:54 +0000
  Re: Offline compilation of Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-01-28 17:19 +0000
    Re: Offline compilation of Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-01-28 22:08 +0100
    Re: Offline compilation of Forth "Peter Knaggs" <pjk@bcs.org.uk> - 2013-02-03 10:50 +0000
      Re: Offline compilation of Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-03 12:11 +0000
        Re: Offline compilation of Forth "A. K." <akk@nospam.org> - 2013-02-03 14:59 +0100
          Re: Offline compilation of Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-03 15:14 +0100
            Re: Offline compilation of Forth Hannu Vuolasaho <hannu.vuolasaho@nospam.tut.fi.invalid> - 2013-02-03 15:25 +0000
          Re: Offline compilation of Forth Gary Bergstrom <g.bergstrom@ieee.org> - 2013-02-05 08:13 -0800
      Re: Offline compilation of Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-04 16:23 +0000
  Re: Offline compilation of Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-01-28 12:26 -1000
  Re: Offline compilation of Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-01-29 08:55 +0000
    Re: Offline compilation of Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-01-29 17:49 +0100
      Re: Offline compilation of Forth Paul Rubin <no.email@nospam.invalid> - 2013-01-30 00:42 -0800
        Re: Offline compilation of Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-01-30 11:58 +0000
        Re: Offline compilation of Forth Mark Wills <forthfreak@gmail.com> - 2013-01-30 23:16 -0800
          Re: Offline compilation of Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-01-31 13:29 +0000
            Re: Offline compilation of Forth "Ed" <invalid@nospam.com> - 2013-02-03 12:49 +1100
              Re: Offline compilation of Forth "Clyde W. Phillips Jr." <cwpjr02@gmail.com> - 2013-02-14 20:37 -0800
      Re: Offline compilation of Forth mhx@iae.nl (Marcel Hendrix) - 2013-02-03 21:15 +0200
        Re: Offline compilation of Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-04 02:04 +0100
      Re: Offline compilation of Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-04 13:22 +0000
        Re: Offline compilation of Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-04 20:07 +0100
          Re: Offline compilation of Forth mhx@iae.nl (Marcel Hendrix) - 2013-02-04 23:07 +0200
            Re: Offline compilation of Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-05 18:33 +0100
              Re: Offline compilation of Forth mhx@iae.nl (Marcel Hendrix) - 2013-02-06 22:53 +0200
                Re: Offline compilation of Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-07 00:30 +0100
    Re: Offline compilation of Forth Paul Rubin <no.email@nospam.invalid> - 2013-01-30 00:36 -0800
  Re: Offline compilation of Forth Lauri Alanko <la@iki.fi> - 2013-01-30 18:12 +0000
    Re: Offline compilation of Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-01-30 09:36 -1000
    Re: Offline compilation of Forth "A. K." <akk@nospam.org> - 2013-01-31 07:45 +0100
    Re: Offline compilation of Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-01-31 03:37 -0600
      Re: Offline compilation of Forth Lauri Alanko <la@iki.fi> - 2013-02-01 00:01 +0000
        Re: Offline compilation of Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-01-31 14:59 -1000
          Re: Offline compilation of Forth Lauri Alanko <la@iki.fi> - 2013-02-05 15:17 +0000
            Re: Offline compilation of Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-05 10:46 -0600
              Re: Offline compilation of Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-05 18:47 +0100
    Re: Offline compilation of Forth "Ed" <invalid@nospam.com> - 2013-01-31 21:47 +1100
      Re: Offline compilation of Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-01-31 06:12 -0600
        Re: Offline compilation of Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-01-31 13:32 +0000
        Re: Offline compilation of Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-01-31 08:27 -1000
          Re: Offline compilation of Forth "Ed" <invalid@nospam.com> - 2013-02-01 10:23 +1100
            Re: Offline compilation of Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-01-31 13:53 -1000
              Re: Offline compilation of Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-01 03:17 +0000
                Re: Offline compilation of Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-01-31 18:43 -1000
                Re: Offline compilation of Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-01 08:45 -0800
              Re: Offline compilation of Forth Mark Wills <forthfreak@gmail.com> - 2013-01-31 23:05 -0800
                Re: Offline compilation of Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-01-31 21:25 -1000
                Re: Offline compilation of Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-01 08:55 -0800
                Re: Offline compilation of Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-01 09:18 -1000
                Re: Offline compilation of Forth Mark Wills <forthfreak@gmail.com> - 2013-02-01 13:04 -0800
              Re: Offline compilation of Forth "Ed" <invalid@nospam.com> - 2013-02-03 11:20 +1100
                Re: Offline compilation of Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-03 12:20 +0000
                Re: Offline compilation of Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-03 07:22 -0800
                Re: Offline compilation of Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-03 17:54 +0000
                Re: Offline compilation of Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-03 10:17 -0800
                Re: Offline compilation of Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-03 19:33 +0000
                Re: Offline compilation of Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-03 11:53 -0800
                Re: Offline compilation of Forth Coos Haak <chforth@hccnet.nl> - 2013-02-04 00:59 +0100
                Re: Offline compilation of Forth Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2013-02-04 11:38 +0100
                Re: Offline compilation of Forth Brad Eckert <hwfwguy@gmail.com> - 2013-02-06 09:13 -0800
                Re: Offline compilation of Forth "Clyde W. Phillips Jr." <cwpjr02@gmail.com> - 2013-02-14 21:02 -0800
                Re: Offline compilation of Forth "Clyde W. Phillips Jr." <cwpjr02@gmail.com> - 2013-02-14 20:55 -0800
                Re: Offline compilation of Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-03 08:26 -1000
                Re: Offline compilation of Forth "Ed" <invalid@nospam.com> - 2013-02-05 13:04 +1100
                Re: Offline compilation of Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-05 10:33 +0000
                Re: Offline compilation of Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-05 08:56 -1000
                Re: Offline compilation of Forth "Ed" <invalid@nospam.com> - 2013-02-08 02:07 +1100
                Re: Offline compilation of Forth Roelf Toxopeus <rt4all@notthis.hetnet.nl> - 2013-02-07 19:03 +0100
                Re: Offline compilation of Forth "Ed" <invalid@nospam.com> - 2013-02-09 22:45 +1100
                Re: Offline compilation of Forth Roelf Toxopeus <rt4all@notthis.hetnet.nl> - 2013-02-09 18:56 +0100
                Re: Offline compilation of Forth Roelf Toxopeus <rt4all@notthis.hetnet.nl> - 2013-02-11 00:19 +0100
                Re: Offline compilation of Forth Alex McDonald <blog@rivadpm.com> - 2013-02-09 11:59 -0800
                Re: Offline compilation of Forth "Ed" <invalid@nospam.com> - 2013-02-13 13:13 +1100
                Re: Offline compilation of Forth Alex McDonald <blog@rivadpm.com> - 2013-02-12 19:19 -0800
                Re: Offline compilation of Forth "Clyde W. Phillips Jr." <cwpjr02@gmail.com> - 2013-02-14 21:01 -0800
      Re: Offline compilation of Forth Roberto Waltman <usenet@rwaltman.com> - 2013-02-03 16:26 -0500
        Re: Offline compilation of Forth "Ed" <invalid@nospam.com> - 2013-02-05 15:32 +1100
          Re: Offline compilation of Forth Mark Wills <forthfreak@gmail.com> - 2013-02-04 23:18 -0800

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