Re: What about code blocks (not Forth blocks)?

From	Bernd Paysan <bernd.paysan@gmx.de>
Newsgroups	comp.lang.forth
Subject	Re: What about code blocks (not Forth blocks)?
Date	2013-12-23 19:31 +0100
Organization	1&1 Internet AG
Message-ID	<l99vit$kq7$1@online.de> (permalink)
References	(2 earlier) <4535bd12-7ebd-42fa-8dde-6eeb8d1d740a@googlegroups.com> <2013Dec20.134114@mips.complang.tuwien.ac.at> <2013Dec20.184631@mips.complang.tuwien.ac.at> <90b90b42-84d0-4150-bd25-3215c0c7baec@googlegroups.com> <2013Dec23.110715@mips.complang.tuwien.ac.at>

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Anton Ertl wrote:

> Alexander Skobelev <al.skobelev@gmail.com> writes:
>>I'm voting not for the full fledged quotations, that are almost like the
>>usual Forth words just without a name.  I'd prefer to have a local
>>quotations =96 that are not the words but rather syllables. They are parts
>>of a word definition that are happy to get their own XT. So they can not
>>have their own local variables and are not valid outside the scope of
>>the definition body. But being a part of definition they can access the
>>its locals.
> 
> Having their own locals costs nothing at run-time and is not too
> expensive to implement (true, it does not buy much, either).
> 
> Accessing outer locals does cost extra, even if the quotation cannot
> be passed out.  Consider:
> 
> : foo {: xt :} xt execute ;
> 
> : bar {: a b :} [: a b + ;] foo ;
> 
> : flip {: xt :} xt foo ;
> 
> : flop {: c :} [: c ;] flip ;
> 
> We need frame pointers and static links (or a display) for this to
> work in general, which locals up to now don't need.

Actually no, there's an impelentation method through a trampoline, which is 
relatively easy to do:

For each quotation that works as nested function (accesses outer locals), 
you create a local buffer which contains the CFA of a wrapper function and 
the pointer to the outer local scope and the static part of the quotation.  
The wrapper function's DOES> part is just

DOES> 2@ execute ;

and the quotation xt itself is equal to

:noname {: display :} ... ;

whereas all references to the outer locals use "display" as base.

IIRC, GCC uses such a "trampoline" technique for nested functions:

http://gcc.gnu.org/onlinedocs/gccint/Trampolines.html

> Maybe we will find that feature useful enough that we want to require
> it eventually, but I don't see that yet.  For a first proposal, the
> chances of succes are probably best if it does not propose
> standardizing locals in quotations at all.

Yes.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/

Thread

What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-17 23:56 -0800
  Re: What about code blocks (not Forth blocks)? mhx@iae.nl - 2013-12-18 01:14 -0800
    Re: What about code blocks (not Forth blocks)? Mark Wills <markrobertwills@yahoo.co.uk> - 2013-12-18 01:34 -0800
    Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 02:33 -0800
      Re: What about code blocks (not Forth blocks)? Coos Haak <chforth@hccnet.nl> - 2013-12-18 14:36 +0100
        Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 06:24 -0800
          Re: What about code blocks (not Forth blocks)? Coos Haak <chforth@hccnet.nl> - 2013-12-19 02:54 +0100
            Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 22:12 -0800
      Re: What about code blocks (not Forth blocks)? mhx@iae.nl - 2013-12-18 05:43 -0800
  Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-12-18 11:21 +0000
    Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 04:31 -0800
      Re: What about code blocks (not Forth blocks)? Ilya Tarasov <ilya74.tarasov@gmail.com> - 2013-12-18 04:49 -0800
        Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 05:12 -0800
  Re: What about code blocks (not Forth blocks)? "Elizabeth D. Rather" <erather@forth.com> - 2013-12-18 08:26 -1000
    Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-18 11:03 -0800
      Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 11:21 -0800
    Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 11:19 -0800
      Re: What about code blocks (not Forth blocks)? "Elizabeth D. Rather" <erather@forth.com> - 2013-12-18 10:08 -1000
        Re: What about code blocks (not Forth blocks)? Bernd Paysan <bernd.paysan@gmx.de> - 2013-12-18 21:58 +0100
          Re: What about code blocks (not Forth blocks)? "Ed" <invalid@invalid.com> - 2013-12-19 14:15 +1100
            Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-19 13:32 +0000
              Re: What about code blocks (not Forth blocks)? "Ed" <invalid@invalid.com> - 2013-12-20 21:07 +1100
                Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-20 12:35 +0000
                Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-20 13:02 +0000
                Re: What about code blocks (not Forth blocks)? "Ed" <invalid@invalid.com> - 2013-12-22 14:19 +1100
                Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-22 10:15 +0000
                Re: What about code blocks (not Forth blocks)? "Ed" <invalid@invalid.com> - 2013-12-24 12:30 +1100
                Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-12-24 16:48 +0000
                Re: What about code blocks (not Forth blocks)? "Ed" <invalid@invalid.com> - 2013-12-28 11:08 +1100
                Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-12-28 11:40 +0000
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-26 18:03 +0000
                Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-26 10:34 -0800
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-27 15:53 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-28 17:26 +0000
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-28 17:53 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-28 18:21 +0000
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-29 14:49 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-29 20:45 +0000
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-30 17:08 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-30 20:00 +0000
                Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-12-28 18:04 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-28 18:47 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-28 19:12 +0000
                Re: What about code blocks (not Forth blocks)? "Ed" <invalid@invalid.com> - 2013-12-28 11:09 +1100
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-28 13:45 +0000
          Re: What about code blocks (not Forth blocks)? Elizabeth D Rather <erather@forth.com> - 2013-12-18 19:04 -1000
            Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-19 09:25 +0000
            Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-19 05:00 -0800
        Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 23:41 -0800
        Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-19 01:00 -0800
        Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-19 02:47 -0800
          Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-19 11:23 +0000
            Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-19 03:52 -0800
  Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-19 15:58 +0000
    Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-19 10:05 -0800
      Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-19 20:07 +0000
        Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-19 12:33 -0800
          Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-19 20:33 +0000
            Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-12-19 20:52 +0000
            Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-19 18:52 -0800
          Re: What about code blocks (not Forth blocks)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-12-28 12:52 -0600
            Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-28 11:47 -0800
              Re: What about code blocks (not Forth blocks)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-12-29 07:39 -0600
                Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-29 08:11 -0800
            Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-29 15:25 +0000
              Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-29 08:15 -0800
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-29 16:03 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-29 20:54 +0000
                Re: What about code blocks (not Forth blocks)? mhx@iae.nl - 2013-12-29 13:38 -0800
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-30 17:04 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-30 20:05 +0000
                Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-30 16:49 -0800
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-01-02 17:27 +0000
              Re: What about code blocks (not Forth blocks)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-12-29 16:40 -0600
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-30 16:51 +0000
                Re: What about code blocks (not Forth blocks)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-12-30 11:15 -0600
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-30 17:37 +0000
                Re: What about code blocks (not Forth blocks)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-12-30 12:07 -0600
        Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-20 13:50 +0000
      Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2013-12-19 21:49 -0800
        Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-20 08:56 +0000
          Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-04-03 19:13 -0700
        Re: What about code blocks (not Forth blocks)? "WJ" <w_a_x_man@yahoo.com> - 2014-03-11 05:35 +0000
          Re: What about code blocks (not Forth blocks)? Bernd Paysan <bernd.paysan@gmx.de> - 2014-03-11 12:59 +0100
            Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-03-11 23:44 -0700
              Re: What about code blocks (not Forth blocks)? Julian Fondren <ayrnieu@gmail.com> - 2014-03-12 11:48 -0700
                Re: What about code blocks (not Forth blocks)? Bernd Paysan <bernd.paysan@gmx.de> - 2014-03-12 20:21 +0100
                Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-03-12 23:35 -0700
                Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2014-03-14 14:25 +0000
                Re: What about code blocks (not Forth blocks)? Bernd Paysan <bernd.paysan@gmx.de> - 2014-03-14 16:36 +0100
                Re: What about code blocks (not Forth blocks)? mhx@iae.nl - 2014-03-14 11:27 -0700
                Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-03-16 17:38 -0700
                Re: What about code blocks (not Forth blocks)? "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-03-17 03:35 -0400
                Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2014-03-17 20:36 -0700
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-03-18 13:13 +0000
                Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-03-18 14:28 +0000
                Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2014-03-18 10:10 -0700
                Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2014-03-25 12:54 -0700
                Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-03-25 23:09 -0700
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-03-26 13:49 +0000
                Re: What about code blocks (not Forth blocks)? Bernd Paysan <bernd.paysan@gmx.de> - 2014-03-26 22:07 +0100
                Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-03-20 22:11 -0700
                Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-03-28 22:18 -0700
                Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2014-03-29 10:57 +0000
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-03-13 16:42 +0000
          Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-03-11 12:51 +0000
            Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2014-03-11 14:54 +0000
    Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-19 21:36 -0800
      Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-20 16:56 +0000
    Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-19 23:24 -0800
      Re: What about code blocks (not Forth blocks)? mhx@iae.nl - 2013-12-20 02:05 -0800
      Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-20 12:41 +0000
        Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-20 17:46 +0000
          Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-21 08:11 -0800
            Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-23 10:07 +0000
              Re: What about code blocks (not Forth blocks)? Bernd Paysan <bernd.paysan@gmx.de> - 2013-12-23 19:31 +0100
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-26 17:45 +0000

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