pattern.scm

(use util.match)

(define-syntax %def
  (syntax-rules (->)
    ((_ (a ...) (b ...) -> x r ...)
     (%def (a ... ((b ...) x)) () r ...))
    ((_ (a ...) (b ...) x r ...)
     (%def (a ...) (b ... x) r ...))
    ((_ (a ...) ())
     (match-lambda* a ...))
    ((_ (a ...) (b ...))
     (match-lambda* a ... (else b ...)))))

(define-syntax def
  (syntax-rules ()
    ((_ n x ...)
     (define n
        (%def () () x ...)))))

(def fact
  0 -> 1
  n -> (* n (fact (- n 1)))
  )

(fact 5)