From 1d15785f23c0c44ce469ec9817fae9fd2eaab4ed Mon Sep 17 00:00:00 2001
From: Alex Shinn <ashinn@users.noreply.github.com>
Date: Sun, 27 Nov 2011 21:55:32 +0900
Subject: [PATCH] making gcd and lcm n-ary

---
 lib/init-7.scm | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/lib/init-7.scm b/lib/init-7.scm
index f95332ad..a25245d5 100644
--- a/lib/init-7.scm
+++ b/lib/init-7.scm
@@ -978,14 +978,26 @@
         (if (<= res 0) res (+ res b))
         (if (>= res 0) res (+ res b)))))
 
-(define (gcd a b)
+(define (gcd2 a b)
   (if (= b 0)
       (abs a)
       (gcd b (remainder a b))))
 
-(define (lcm a b)
+(define (gcd . args)
+  (if (null? args)
+      0
+      (let lp ((x (car args)) (ls (cdr args)))
+        (if (null? ls) x (lp (gcd2 x (car ls)) (cdr ls))))))
+
+(define (lcm2 a b)
   (abs (quotient (* a b) (gcd a b))))
 
+(define (lcm . args)
+  (if (null? args)
+      1
+      (let lp ((x (car args)) (ls (cdr args)))
+        (if (null? ls) x (lp (lcm2 x (car ls)) (cdr ls))))))
+
 (define (max x . rest)
   (let lp ((hi x) (ls rest))
     (if (null? ls)