ikarus/scheme/ikarus.apply.ss

41 lines
1.1 KiB
Scheme

(library (ikarus apply)
(export apply)
(import
(except (ikarus) apply)
(ikarus system $pairs)
(ikarus system $stack))
(define apply
(let ()
(define (err f ls)
(if (procedure? f)
(error 'apply "not a list")
(error 'apply "~s is not a procedure" f)))
(define (fixandgo f a0 a1 ls p d)
(cond
[(null? ($cdr d))
(let ([last ($car d)])
($set-cdr! p last)
(if (and (procedure? f) (list? last))
($$apply f a0 a1 ls)
(err f last)))]
[else (fixandgo f a0 a1 ls d ($cdr d))]))
(define apply
(case-lambda
[(f ls)
(if (and (procedure? f) (list? ls))
($$apply f ls)
(err f ls))]
[(f a0 ls)
(if (and (procedure? f) (list? ls))
($$apply f a0 ls)
(err f ls))]
[(f a0 a1 ls)
(if (and (procedure? f) (list? ls))
($$apply f a0 a1 ls)
(err f ls))]
[(f a0 a1 . ls)
(fixandgo f a0 a1 ls ls ($cdr ls))]))
apply)))