Re: [Jscheme-user] apply/2 vs apply/n (absent): apply takes only 2 arguments

[Timothy H. <tim...@ma...>]

On Tuesday, June 18, 2002, at 03:57 AM, Hoehle, Joerg-Cyril wrote:

> Hi,
>
> apply in Jscheme takes exactly 2 arguments.
>> apply
> {jsint.Primitive apply[2]}
>
> In R4RS terms:
>   essential procedure: apply proc args
>   procedure: apply proc arg1 ... args
> , this means that only the essential part if implemented in Jscheme.
>
> R5RS' apply takes n arguments and doesn't make a distinction anymore.=20=

> Having only apply/2 is a nightmare for recursive procedures with=20
> variable number of arguments.
>
> BTW, the documentation at
> http://jscheme.sourceforge.net/jscheme/doc/R4RSprimitives.html
> is inconsistent. It says
> (apply f arguments ) ...
> (map F L) ...
> Yet map takes n arguments (in both R4RS and R5RS and) in Jscheme.
>
>
> While it is a trivial exercise to write an apply/n based on the =
apply/2,

You can load in a file newapply.scm that redefines apply:

(set! apply
   (let ((ap apply))
     (letrec ((list*(lambda (R) (if (null? (rest R)) (first R) (cons=20
(first R) (list* (rest R)))))))
        (lambda (f . R)
         (ap f (list* R))))))


>  it is not so w.r.t. compiler optimization and inlining.
For the future this may be an issue. For the moment, the Jscheme=20
compiler does not
make use of much optimization or inlining.

> Will the home-grown apply/n compile to as efficient code/bytecode as=20=

> apply/2?
For now yes, but in the future no.
>
> BTW, Common Lisp has list* which is quite useful for a straightforward=20=

> apply/n->apply/2.

You have a point, perhaps we should add list* and apply/n to Jscheme...
---Tim---

>
> Regards,
> 	J=F6rg H=F6hle.
> Using Jscheme 5.0 04/05/2002 on MS-Woes-2000
>
> =
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