Re: RFD: Quotations V2 update

From	"Alex McDonald" <blog@rivadpm.com>
Newsgroups	comp.lang.forth
Subject	Re: RFD: Quotations V2 update
Date	2015-08-04 21:07 +0100
Organization	A noiseless patient Spider
Message-ID	<mpr5v7$nog$1@dont-email.me> (permalink)
References	<mpq2n2$85u$1@dont-email.me> <mpr5ic$lst$1@dont-email.me>

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on 04/08/2015 21:00:43, Bernd Paysan wrote:
> Alex McDonald wrote:
> 
>> There are two schools of thought.
>>
>> 1. Define [: ;] such that a standard program may not access
>> local variables of the outer definition inside the quotation.
>>
>> 2. Permit such a feature, but restrict valid execution of the
>> quotation to the lifetime of the parent's execution.
> 
> I've found more problems with 2. A lot of my quotation use (especially
> in MINOS) requires that the quotation outlives the lifetime of the
> parents.
> 
> Essentially, I create objects with actions attached (action = xt). So
> the object initialization takes one or more xts. These xts are
> quotations. If we allow access to outer locals via local frames, we,
> at the same time, would disallow this use, because the local frame
> dies when the creator of the quotation exits (unless it is a real
> closure)
> 
> Typical use comes from converting Leo Brodie's DOER MAKE examples into
> DEFER/IS/quotations examples:
> 
> Defer type  ( a # -- )
>: video   [: ( ...code for video...) ;] is type ;
>: printer [: ( ...code for printer...) ;] is type ;
> 
> This only works if the quotation outlives its surrounding definition.
> So it has to be either a real closure (with garbage collection and
> everything) if it can access outer locals, or it may not access outer
> locals.
> 
> I'm not against real closures, but would strongly advice *not* to use
> the normal locals and quotation syntax for closures.
> 

Agreed. Even though I can support (2), I would vote against it on the
grounds that it's not generalyy useful, and it's expensive to implement.

Thread

RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-04 11:05 +0100
  Re: RFD: Quotations V2 update Mark Wills <markwills1970@gmail.com> - 2015-08-04 04:09 -0700
    Re: RFD: Quotations V2 update Lars Brinkhoff <lars.spam@nocrew.org> - 2015-08-04 13:35 +0200
      Re: RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-04 13:54 +0100
        Re: RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-04 14:01 +0100
    Re: RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-04 13:38 +0100
      Re: RFD: Quotations V2 update Mark Wills <markwills1970@gmail.com> - 2015-08-04 07:37 -0700
  Re: RFD: Quotations V2 update anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-04 14:23 +0000
    Re: RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-04 16:09 +0100
      Re: RFD: Quotations V2 update anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-04 15:38 +0000
        Re: RFD: Quotations V2 update Bernd Paysan <bernd.paysan@gmx.de> - 2015-08-04 22:30 +0200
          Re: RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-04 23:09 +0100
            Re: RFD: Quotations V2 update Bernd Paysan <bernd.paysan@gmx.de> - 2015-08-05 01:45 +0200
              Re: RFD: Quotations V2 update anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-05 07:23 +0000
                Re: RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-05 09:55 +0100
          Re: RFD: Quotations V2 update Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-08-05 12:03 +0100
            Re: RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-05 13:50 +0100
              Re: RFD: Quotations V2 update anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-05 16:07 +0000
              Re: RFD: Quotations V2 update Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-08-05 20:23 +0100
  Re: RFD: Quotations V2 update Bernd Paysan <bernd.paysan@gmx.de> - 2015-08-04 22:00 +0200
    Re: RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-04 21:07 +0100
  Re: RFD: Quotations V2 update Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-08-04 21:53 +0100
    Re: RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-04 23:22 +0100
      Re: RFD: Quotations V2 update Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-08-05 12:38 +0100
        Re: RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-05 13:41 +0100
          Re: RFD: Quotations V2 update anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-05 12:46 +0000
            Re: RFD: Quotations V2 update Bernd Paysan <bernd.paysan@gmx.de> - 2015-08-06 02:12 +0200
              Re: RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-06 14:16 +0100
              Re: RFD: Quotations V2 update anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-06 13:46 +0000
    Re: RFD: Quotations V2 update anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-05 08:15 +0000
      Re: RFD: Quotations V2 update Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-08-05 20:31 +0100
        Re: RFD: Quotations V2 update peter.m.falth@gmail.com - 2015-08-05 14:41 -0700
          Re: RFD: Quotations V2 update "Elizabeth D. Rather" <erather@forth.com> - 2015-08-05 18:39 -1000
            Re: RFD: Quotations V2 update peter.m.falth@gmail.com - 2015-08-05 23:22 -0700
        Re: RFD: Quotations V2 update anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-06 13:19 +0000
          Re: RFD: Quotations V2 update Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-08-07 22:28 +0100
            Re: RFD: Quotations V2 update Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-08-07 22:34 +0100
              Re: RFD: Quotations V2 update anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-08 15:53 +0000
                Re: RFD: Quotations V2 update Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-08-11 21:16 +0100
            Re: RFD: Quotations V2 update anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-08 15:39 +0000
              Re: RFD: Quotations V2 update Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-08-10 12:55 +0100
                Re: RFD: Quotations V2 update anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-10 12:08 +0000
  Re: RFD: Quotations V2 update hughaguilar96@gmail.com - 2015-08-04 18:09 -0700
    Re: RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-05 09:22 +0100
    Re: RFD: Quotations V2 update "Alex McDonald" <blog@rivadpm.com> - 2015-08-05 09:53 +0100

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