Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.forth > #20627

Re: Quotations revisited

Show all headers | View raw

Michael L Gassanenko wrote:

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

Call the quotation.

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

Hm, this asks for some kind of vector.  Use a deferred word for allocation, 
or use some construct like <heap [:{ a b } ... ;] heap> to redirect 
dictionary allocation temporarily to a heap object (or the other way round - 
heap allocation to here).

However, I'm not convinced that we want closures as persistent objects - we 
already have create does> for that.  The only reason to use closures instead 
of Create DOES> for persistent stuff is that they may be more comfortable to 
write.

> 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".
> 
> So we get something like:
> : foo
>    ...
>    {{ a b }} HERE SWAP ALLOT [DOES> DUP a SWAP b + ;]
>    ...
> ;

Yes, that's sort of how you would do it.

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

Back to comp.lang.forth | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

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

csiph-web