From: Tim Vaughan <tgvaughan@gmail.com>
Date: Sun, 6 Nov 2016 08:53:01 +0000 (+1300)
Subject: Added (length)
X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=commitdiff_plain;h=069f0a8c965a6b7277f5ba8a3f939c69d787838e;p=scheme.forth.jl.git

Added (length)
---

diff --git a/scheme-library.scm b/scheme-library.scm
index f95ed65..484f500 100644
--- a/scheme-library.scm
+++ b/scheme-library.scm
@@ -13,6 +13,14 @@
 (define (cddr l) (cdr (cdr l)))
 (define (cadar l) (car (cdr (car l))))
 
+; Return number of items in list
+(define (length l)
+  (define (iter a count)
+    (if (null? a)
+      count
+      (iter (cdr a) (+ count 1))))
+  (iter l 0))
+
 ; Join two lists together
 (define (join l1 l2)
   (if (null? l1)