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; boolean?
8
9; ---conformance---
10; R5RS
11
12; ---purpose---
13; Check whether a datum is a truth value.
14
15; ---args---
16; X - datum
17
18; ---keywords---
19; BOOLEAN? function, boolean, truth value, true, false
20; predicate
21
22; ---see-also---
23; list?, null?
24
25; ---example---
26; (boolean? #f) => #t
27
28(define booleanp #t)
29
30; ---code---
31(define (boolean? x)
32  (or (eq? x #t)
33      (eq? x #f)))
34