update case-lambda impl

This commit is contained in:
Yuichi Nishiwaki 2014-07-16 14:47:25 +09:00
parent 6ee4d49a96
commit bdcb83296e
1 changed files with 21 additions and 36 deletions

View File

@ -1425,42 +1425,27 @@
(define-syntax case-lambda
(syntax-rules ()
((case-lambda
(?a1 ?e1 ...)
?clause1 ...)
((case-lambda (params body0 ...) ...)
(lambda args
(let ((l (length args)))
(case-lambda "CLAUSE" args l
(?a1 ?e1 ...)
?clause1 ...))))
((case-lambda "CLAUSE" ?args ?l
((?a1 ...) ?e1 ...)
?clause1 ...)
(if (= ?l (length '(?a1 ...)))
(apply (lambda (?a1 ...) ?e1 ...) ?args)
(case-lambda "CLAUSE" ?args ?l
?clause1 ...)))
((case-lambda "CLAUSE" ?args ?l
((?a1 . ?ar) ?e1 ...)
?clause1 ...)
(case-lambda "IMPROPER" ?args ?l 1 (?a1 . ?ar) (?ar ?e1 ...)
?clause1 ...))
((case-lambda "CLAUSE" ?args ?l
(?a1 ?e1 ...)
?clause1 ...)
(let ((?a1 ?args))
?e1 ...))
((case-lambda "CLAUSE" ?args ?l)
(error "Wrong number of arguments to CASE-LAMBDA."))
((case-lambda "IMPROPER" ?args ?l ?k ?al ((?a1 . ?ar) ?e1 ...)
?clause1 ...)
(case-lambda "IMPROPER" ?args ?l (+ ?k 1) ?al (?ar ?e1 ...)
?clause1 ...))
((case-lambda "IMPROPER" ?args ?l ?k ?al (?ar ?e1 ...)
?clause1 ...)
(if (>= ?l ?k)
(apply (lambda ?al ?e1 ...) ?args)
(case-lambda "CLAUSE" ?args ?l
?clause1 ...)))))
(let ((len (length args)))
(letrec-syntax
((cl (syntax-rules ::: ()
((cl)
(error "no matching clause"))
((cl ((p :::) . body) . rest)
(if (= len (length '(p :::)))
(apply (lambda (p :::)
. body)
args)
(cl . rest)))
((cl ((p ::: . tail) . body)
. rest)
(if (>= len (length '(p :::)))
(apply
(lambda (p ::: . tail)
. body)
args)
(cl . rest))))))
(cl (params body0 ...) ...)))))))
(export case-lambda))