`for-all`

Location: lib, 20 Lines

; Scheme 9 from Empty Space, Function Library ; By Nils M Holm, 2009 ; Placed in the Public Domain ; ; (for-all procedure list ...) ==> object ; ; Test whether all members of a sequence of N lists have a given ; property. The property is expressed using an N-ary predicate P, ; which is given in the procedure argument. P is applied to a list ; consisting of the first member of each given list. If P returns ; truth, it is applied to a list consisting of the second member of ; each given list, etc. If P returns falsity for any set of members, ; FOR-ALL returns #F. If only one set of members is left to check, ; FOR-ALL returns the value of P applied to this final set. ; When the LISTs are empty, FOR-ALL returns #T. ; ; Example: (for-all < '(1 7) '(2 8) '(3 9)) ==> #t ; ; because (< 1 2 3) and (< 7 8 9) (define(for-all p . a*) (letrec((car-of (lambda(a) (map car a))) (cdr-of (lambda(a) (map cdr a))) (any-null (lambda(a) (memq'() a))) (for-all* (lambda(a*) (cond((any-null a*) #t) ((any-null (cdr-of a*)) (apply p (car-of a*))) (else(and(apply p (car-of a*)) (for-all* (cdr-of a*)))))))) (for-all* a*)))