tisp

commit 0f4cf7164be8002ed2cea767c54d13737f55da83
parent 7c9bf31bcfecfc1ff89adfa2c9d681319c998a12
Author: Ed van Bruggen <edvb@uw.edu>
Date:   Thu, 14 Nov 2019 16:43:20 -0800

Add count list function

Diffstat:
test.c
 | 
5
+++++
tibs/lib.tsp
 | 
5
+++++

2 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/test.c b/test.c
@@ -255,6 +255,11 @@ char *tests[][2] = {
 	{ "(nth (list 3 5/2 .332 -2) 2)",           "0.332" },
 	{ "(nth '(a b c) 0)",                       "a"     },
 	{ "(nth (list 'foo 'bar 'zar 'baz) 3)",     "baz"   },
+	{ "(count 3 '(1 2 3 4))",                   "1"     },
+	{ "(count 1/2 (list 1/2 1/3 2/4 8 9.0))",   "2"     },
+	{ "(count 'a '(b c a a f h a b c a))",      "4"     },
+	{ "(count 3.2 nil)",                        "0"     },
+	{ "(count \"Bobandy\" '(1/2 1/4 \"Jim\"))", "0"     },
 
 	{ "apply",                     NULL          },
 	{ "(apply list '(1 2 3))",     "(1 2 3)"     },
diff --git a/tibs/lib.tsp b/tibs/lib.tsp
@@ -119,6 +119,11 @@
       (car lst)
       (nth (cdr lst) (- i 1)))))
 
+(define (count x lst)
+  (cond ((nil? lst) 0)
+        ((= x (car lst)) (+ 1 (count x (cdr lst))))
+        (else (count x (cdr lst)))))
+
 (define (apply proc args)
   (eval (map (lambda (x) ; prevent args from being evaluated twice
                (list 'quote x))