Add compose-n.

2020-12-18 11:43:17 +01:00 · 2020-12-18 11:43:17 +01:00 · 40eeb1745b
parent 8db577d0ff
commit 40eeb1745b
1 changed files with 9 additions and 0 deletions
--- a/typed-compose.rkt
+++ b/typed-compose.rkt
@ -22,3 +22,12 @@

 (module+ test
  (require typed/rackunit))
+
+(: compose-n (All (a) (-> (-> a a) * (-> a a))))
+(define (compose-n . funcs)
+  (λ (x)
+    (for/foldr ([x x]) ([f funcs])
+      (f x))))
+
+(module+ test
+  (check-equal? ((compose-n add1 add1 add1) 3) 6))