proper-time?Location: lib, 20 Lines
; Scheme 9 from Empty Space, Function Library ; By Nils M Holm, 2009 ; Placed in the Public Domain ; ; (proper-time? time-list) ==> boolean ; ; Return #T if the given TIME-LIST is a proper TIME-LIST as defined ; by the UNIX-TIME->TIME procedure. Otherwise return #F. ; ; Example: (proper-time? '(3 1970 1 1 0 0 0)) ==> #t (load-from-library "leap-yearp.scm") (load-from-library "for-all.scm") (define (proper-time? t) (let ((days/mon (vector 31 28 31 30 31 30 31 31 30 31 30 31))) (if (and (list? t) (= (length t) 7) (number? (cadr t)) (leap-year? (cadr t))) (vector-set! days/mon 1 29)) (and (list? t) (= (length t) 7) (for-all number? t) (<= 0 (list-ref t 0) 6) (<= 1 (list-ref t 2) 12) (<= 1 (list-ref t 3) (vector-ref days/mon (- (list-ref t 2) 1))) (<= 0 (list-ref t 4) 23) (<= 0 (list-ref t 5) 59) (<= 0 (list-ref t 6) 59))))