[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Scheme-reports] ANN: first draft of R7RS small language available
Alex, here is a better example.
If I understand you correctly, you are advocating accommodating implementations
in which the following very reasonable program /wouldn't/ work.
((_ exp1 ((cons y z) exp2))
(let* ((x exp1) (y (car x)) (z (cdr x))) exp2))))))
(import (base) (match))
(match (cons 1 2)
((cons x y) (write x) (write y)))
This would /not/ work in the implementations you advocate accommodating becasue
when BASE is imported into the program a new binding for CONS would be created.
I know you don't like arguments from authority and again, I am not a big
authority, but believe me, I have gone through all the iterations you mention in
trying ot imlement modules, so I know that Kohlbecker doesn't work for modules,
and "naive copy imported bindings on import" just doesn't work in a
language with macros. I know becasue I implemented it and it was just broken in
so many ways. And you know what, it is not even simpler than a correct
implementation using ER and handling the environments correctly.
Scheme-reports mailing list