1; SketchyLISP Library 2; Copyright (C) 2005,2006,2007 Nils M Holm. All rights reserved. 3; See the file LICENSE of the SketchyLISP distribution 4; for conditions of use. 5 6; ---name--- 7; natural? 8 9; ---conformance--- 10; SketchyLISP Core 11 12; ---purpose--- 13; Test whether a number is a natural number or zero. 14 15; ---args--- 16 17; ---keywords--- 18; NATURAL? function, numbers, digit, predicate, natural 19 20; ---see-also--- 21; digits, natural, integer? 22 23; ---example--- 24; (natural? 567) => #t 25 26(define naturalp #t) 27 28(require "digits.scm") 29(require "non-negativep.scm") ; non-negative? 30 31; ---code--- 32(define natural? non-negative?) 33