tisp

commit a713cee597378d2a201c9c7a9d705bf5cbb312a7
parent 66a687024fcce8d66d22484b37235fcaa9db4de4
Author: Ed van Bruggen <edvb@uw.edu>
Date:   Fri,  3 Jan 2020 19:29:23 -0800

Add compose function

Diffstat:
test.c
 | 
4
++++
tibs/lib.tsp
 | 
6
++++++

2 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/test.c b/test.c
@@ -274,6 +274,10 @@ char *tests[][2] = {
 	{ "(filter positive? '(1 2 -4 5 -9 10))",                   "(1 2 5 10)"        },
 	{ "(filter odd? '(8 6 17 9 82 34 27))",                     "(17 9 27)"         },
 	{ "(filter integer? '(1/2 3.e-2 9/3 3.2 0.0 8 17))",        "(3 8 17)"          },
+	{ "((compose - sqrt) 9)",                                   "-3"                },
+	{ "((compose / sqrt sqr) 18)",                              "1/18"              },
+	{ "((compose - sqrt cube) 4)",                              "-8"                },
+	{ "((compose -) 5/3)",                                      "-5/3"              },
 
 	{ "list mod",                                 NULL                        },
 	{ "(reverse '(1 2 3 4 5))",                   "(5 4 3 2 1)"               },
diff --git a/tibs/lib.tsp b/tibs/lib.tsp
@@ -180,6 +180,12 @@
     ((proc (car lst)) (cons (car lst) (filter proc (cdr lst))))
     (else (filter proc (cdr lst)))))
 
+(define (compose . procs)
+  (if procs
+    (lambda (x)
+      ((car procs) ((apply compose (cdr procs)) x)))
+    (lambda (x) x)))
+
 (define (reverse l)
   (recur f ((in l) (out nil))
          (if (pair? in)