Files
linguist/samples/Scheme/lambdastar.sls
2014-06-22 15:28:49 +02:00

46 lines
1.1 KiB
Scheme

(library (lambdastar)
(export (rename (lambda* lambda)))
(import (rnrs))
(define-syntax lambda*
(syntax-rules ()
((_ a* e* ...)
( lambda*-h a* (let () e* ...)))))
(define-syntax lambda*-h
(syntax-rules ()
((_ () e)
(lambda a* (if (null? a*) e (apply (e) a*))))
((_ (a a* ...) e) (posary-h (a a* ...) e))
((_ (a a* ... . rest) e)
(polyvariadic-h (a a* ... . rest) e))
((_ a* e) (lambda a* e))))
(define-syntax posary-h
(syntax-rules ()
((_ (a a* ...) e)
(letrec
((rec
(case-lambda
(() rec)
((a a* ...) e)
((a a* ... . rest)
(apply (rec a a* ...) rest))
(some (get-more rec some)))))
rec))))
(define-syntax polyvariadic-h
(syntax-rules ()
((_ (a a* ... . rest) e)
(letrec
((rec
(case-lambda
(() rec)
((a a* ... . rest) e)
(some (get-more rec some)))))
rec))))
(define get-more
(lambda (rec some)
(lambda more
(apply rec (append some more))))))