簡単にやるならこんな感じかな
(use gauche.sequence) (use util.list)
(define-class <test> () (%slots))
(define-method initialize ((self <test>) initargs)
(next-method)
(slot-set! self '%slots (map (lambda (x) (cons (string->symbol (keyword->string (car x))) (cadr x))) (slices initargs 2))))
(define-method ref ((self <test>) slot) (assq-ref (slot-ref self '%slots) slot))
(define-method (setter ref) ((self <test>) slot val) (assq-set! (slot-ref self '%slots) slot val))
ほんとうのスロットのようにふるまわせたいならMOP使わないとだめかも。