Re: Sacla loop: a new loop implementation

[Sam S. <sd...@gn...>]

> * Bruno Haible <oe...@py...t> [2004-10-05 19:59:42 +0200]:
>
> Sam wrote:
>> * destructuring on the result of multiple-value-list form is transformed
>>   to a multiple-value-setq form, reducing the amout of consing.
>>   e.g. (macroexpand '(loop for (a b c) = (multiple-value-list (foo))))
>>        => (BLOCK NIL
>>             (LET ((A NIL) (B NIL) (C NIL))
>>               (MACROLET ((LOOP-FINISH NIL '(GO #:LOOP-EPILOGUE-7002)))
>>                 (TAGBODY
>>                    #:LOOP-BODY-7001
>>                    (MULTIPLE-VALUE-SETQ (A B C) (FOO))
>>                    (GO #:LOOP-BODY-7001)
>>                    #:LOOP-EPILOGUE-7002))))
>>
>> CLISP is _much_ worse:
>> ...
>>
>> 1. conses in MULTIPLE-VALUE-LIST
>
> yes, it would be good to optimize this. I've added it in the TODO.
> (For now, it's very low priority.)

:-(

>> 2. has the MULTIPLE-VALUE-LIST code in 2 places
>
> I had tried to coalesce most of the bindings in such a way that forms
> only occur once. But the many specific rules about the LOOP macro in
> ANSI CL don't give much freedom. Cf. requires-stepbefore /
> depends-preceding / later-depend.

how about outsourcing loop to sacla?
if their implementation is complete & GPL, it might save us some effort.

-- 
Sam Steingold (http://www.podval.org/~sds) running w2k
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