* arith.c (gcd): Fix semantics. If either operand is

zero, return the other operand.
(lcm): New function.

* eval.c (eval_init): Retarget registration of gcd to
variable argument gcdv function. Register lcm.

* lib.c (gcdv, lcmv): New functions.

* lib.h (gcdv, lcm, lcmv): Declared.

* txr.1: Re-document gcd with coverage of lcm.

* txr.vim: Regenerated.

1 files changed, 2 insertions, 1 deletions

diff --git a/eval.c b/eval.c
index 753d0211..5a5e7baf 100644
--- a/eval.c
+++ b/eval.c
@@ -3605,7 +3605,8 @@ void eval_init(void)
   reg_fun(intern(lit("expt"), user_package), func_n0v(exptv));
   reg_fun(intern(lit("exptmod"), user_package), func_n3(exptmod));
   reg_fun(intern(lit("isqrt"), user_package), func_n1(isqrt));
-  reg_fun(intern(lit("gcd"), user_package), func_n2(gcd));
+  reg_fun(intern(lit("gcd"), user_package), func_n0v(gcdv));
+  reg_fun(intern(lit("lcm"), user_package), func_n0v(lcmv));
   reg_fun(intern(lit("floor"), user_package), func_n1(floorf));
   reg_fun(intern(lit("ceil"), user_package), func_n1(ceili));
   reg_fun(intern(lit("sin"), user_package), func_n1(sine));