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; if 8 9; ---conformance--- 10; R5RS 11 12; ---purpose--- 13; Conditional evaluation. 14 15; ---args--- 16; P - predicate 17; C - consequent 18; A - alternative 19 20; ---keywords--- 21; IF syntax, conditional evaluation. 22 23; ---see-also--- 24; case 25 26; ---example--- 27; (if #t 'true 'false) => true 28 29; ---model--- 30; (define-syntax if 31; (syntax-rules () 32; ((_ p c a) 33; (cond (p c) (else a))))) 34 35; ---code--- 36; This syntax transformer is part of the primitive syntax. 37