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Re: Quotations revisited

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>>>>> "Michael" == Michael L Gassanenko <m_l_g3@yahoo.com> writes:

> 1. We need to decide what RECURSE means for quotations: call the
> quotation or call the enclosing named definition?

Maybe just declare use of RECURSE as an ambiguous condition?

> 2. Closures (about which we sort of agreed to speak only
> theoretically), resemble CREATE-DOES> definitions in the same way as
> quotations resemble colon definitions.  Quotations may reside in ROM;
> closures will need some RAM.

This idea is brilliant.  I didn't think Forth could capture the notion
of quotations, given its low-level nature, but your approach would
nicely match Forth concepts.

I don't think that quotations' data necessarily need to reside in RAM.
There are scenarios where you just want to have constant data
(e.g. compiled via CREATE an , ) associated with a closure.

> 2.1. Closures assume run-time creation of execution tokens.

Doesn't this creation of execution tokens create a memory leak?  

> 2.2. As to where the memory for data is allocated, I think, the best
> answer is: let the user choose, it may be ALLOCATE or HERE SWAP ALLOT
> .

> 2.3. To create a closure, we will need to: allocate an area of memory
> with some room for the "code field"; fill the "data field" with the
> data; bind the closure with the desired behavior (writing to the "code
> field"); create an xt for that "code field".

In GCC this would be called a "trampoline", i.e. something like

: make-trampoline ( xt1 a-addr -- xt2 )
  :NONAME POSTPONE LITERAL COMPILE, POSTPONE ;

created for every execution token.  But how to track that memory?  We'd
have to provide a new word for freeing the trampoline.

FORGET-[DOES>;]  ( xt -- )  

which cannot be implemented in ANS Forth for a definition of
make-trampoline relying on :NONAME .

cheers,

David
-- 
GnuPG public key: http://dvdkhlng.users.sourceforge.net/dk.gpg
Fingerprint: B17A DC95 D293 657B 4205  D016 7DEF 5323 C174 7D40

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Re: Quotations revisited Michael L Gassanenko <m_l_g3@yahoo.com> - 2013-03-13 01:54 -0700
  Re: Quotations revisited Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-03-13 04:21 -0500
    Re: Quotations revisited Michael L Gassanenko <m_l_g3@yahoo.com> - 2013-03-13 03:36 -0700
      Re: Quotations revisited Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-03-13 07:14 -0500
    Re: Quotations revisited anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-03-13 11:55 +0000
      Re: Quotations revisited Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-03-13 07:20 -0500
        Re: Quotations revisited anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-03-13 14:36 +0000
      Re: Quotations revisited albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-03-13 13:01 +0000
        Re: Quotations revisited anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-03-13 14:21 +0000
  Re: Quotations revisited David Kuehling <dvdkhlng@gmx.de> - 2013-03-13 10:33 +0100
    Re: Quotations revisited Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-03-13 04:41 -0500
      Re: Quotations revisited David Kuehling <dvdkhlng@gmx.de> - 2013-03-13 11:44 +0100
  Re: Quotations revisited Lars Brinkhoff <lars.spam@nocrew.org> - 2013-03-13 11:23 +0100
  Re: Quotations revisited Bernd Paysan <bernd.paysan@gmx.de> - 2013-03-13 12:52 +0100
    Re: Quotations revisited Lars Brinkhoff <lars.spam@nocrew.org> - 2013-03-14 09:47 +0100
      Re: Quotations revisited Sieur de Bienville <morrimichael@gmail.com> - 2013-03-14 10:45 -0700
        Re: Quotations revisited Lars Brinkhoff <lars.spam@nocrew.org> - 2013-03-14 19:41 +0100
          Re: Quotations revisited Sieur de Bienville <morrimichael@gmail.com> - 2013-03-14 12:58 -0700
    Re: Quotations revisited Michael L Gassanenko <m_l_g3@yahoo.com> - 2013-03-14 23:09 -0700

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