Re: progv in scheme

[Andrew Gwozdziewycz <apgwoz@gmail.com>]

On Tue, Sep 13, 2011 at 3:09 PM, Bill Schottstaedt
<bil@ccrma.stanford.edu> wrote:
> if lambda were applicable, this would work in both cases:
>
> (define-macro (progv vars vals . body)
>  `(apply (apply lambda ,vars ',body) ,vals))
>
>> (let ((s '(one two)) (v '(1 2))) (progv s v (+ one two)))
> 3
>> (progv '(one two) '(1 2) (+ one two))
> 3
>
> (running a mystery scheme...)


Bill-

It seems as though this would work actually in many schemes that do
incremental expansion of macros as part of their eval. If eval was
written as such:

(define (eval form env)
  (cond
    ((self-evaluating? form) form)
    ((variable? form) (lookup env (car form)))
    (...
    ((macro? form env) (eval (expand-macro (car form) (cdr form)) env))
    ...))

Then it seems as though it'd work perfectly fine. I haven't been using
guile very long, but it seems as though it's doing bytecode
compilation, which makes the story a bit different.

(I could totally be wrong of course)



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