In GNU/Denemo we have some scheme which has been working in guile 1.8
but which fails (if I have tested correctly) in guile 2.0
Apparently the code originated at:
http://www.ccs.neu.edu/home/dorai/t-y-scheme/t-y-scheme-Z-H-11.html#node_sec_9.2
I wonder if someone could comment on why it should fail? (I am running
Debian stable myself so don't have direct access to guile 2.x so my
testing is limited). - Richard Shann
(define-macro defstruct
(lambda (s . ff)
(let ((s-s (symbol->string s)) (n (length ff)))
(let* ((n+1 (+ n 1))
(vv (make-vector n+1)))
(let loop ((i 1) (ff ff))
(if (<= i n)
(let ((f (car ff)))
(vector-set! vv i
(if (pair? f) (cadr f) '(if #f #f)))
(loop (+ i 1) (cdr ff)))))
(let ((ff (map (lambda (f) (if (pair? f) (car f) f))
ff)))
`(begin
(define ,(string->symbol
(string-append "make-" s-s))
(lambda fvfv
(let ((st (make-vector ,n+1)) (ff ',ff))
(vector-set! st 0 ',s)
,@(let loop ((i 1) (r '()))
(if (>= i n+1) r
(loop (+ i 1)
(cons `(vector-set! st ,i
,(vector-ref vv i))
r))))
(let loop ((fvfv fvfv))
(if (not (null? fvfv))
(begin
(vector-set! st
(+ (list-position (car fvfv) ff)
1)
(cadr fvfv))
(loop (cddr fvfv)))))
st)))
,@(let loop ((i 1) (procs '()))
(if (>= i n+1) procs
(loop (+ i 1)
(let ((f (symbol->string
(list-ref ff (- i 1)))))
(cons
`(define ,(string->symbol
(string-append
s-s "." f))
(lambda (x) (vector-ref x ,i)))
(cons
`(define ,(string->symbol
(string-append
"set!" s-s "." f))
(lambda (x v)
(vector-set! x ,i v)))
procs))))))
(define ,(string->symbol (string-append s-s "?"))
(lambda (x)
(and (vector? x)
(eqv? (vector-ref x 0) ',s))))))))))
