/usr/lib/s9fes/leap-yearp.scm is in scheme9 2010.11.13-2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | ; Scheme 9 from Empty Space, Function Library
; By Nils M Holm, 2009
; See the LICENSE file of the S9fES package for terms of use
;
; (leap-year? integer) ==> boolean
;
; Return #T if INTEGER represents a leap year and otherwise return #F.
;
; Example: (leap-year? 2000) ==> #t
; (leap-year? 2003) ==> #f
(define (leap-year? x)
(or (zero? (remainder x 400))
(and (zero? (remainder x 4))
(not (zero? (remainder x 100))))))
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