* arith.c (expt): New function.

* eval.c (eval_init): Registering new intrinsic functions,
reduce-left, reduce-right and expt.

* lib.c (minusv): Return one instead of num(1).
(exptv, reduce_right): New functions.

* lib.h (expt, exptv, reduce_right): Declared.

* txr.1: Blank sections for new functions.

1 files changed, 18 insertions, 1 deletions

diff --git a/lib.c b/lib.c
index 01f1569a..21cfb68c 100644
--- a/lib.c
+++ b/lib.c
@@ -851,7 +851,7 @@ val minusv(val minuend, val nlist)
 val mulv(val nlist)
 {
   if (!nlist)
-    return num(1);
+    return one;
   else if (!cdr(nlist))
     return car(nlist);
   return reduce_left(func_n2(mul), cdr(nlist), car(nlist), nil);
@@ -933,6 +933,11 @@ val minv(val first, val rest)
   return reduce_left(func_n2(min2), rest, first, nil);
 }
 
+val exptv(val nlist)
+{
+  return reduce_right(func_n2(expt), nlist, one, nil);
+}
+
 val string_own(wchar_t *str)
 {
   val obj = make_obj();
@@ -2073,6 +2078,18 @@ val reduce_left(val fun, val list, val init, val key)
   return init;
 }
 
+val reduce_right(val fun, val list, val init, val key)
+{
+  if (!key)
+    key = identity_f;
+
+  if (nullp(list))
+    return init;
+  return funcall2(fun, funcall1(key, car(list)),
+                       if3(cdr(list), reduce_right(fun, cdr(list), init, key),
+                                      init));
+}
+
 static val do_curry_12_2(val fcons, val arg2)
 {
   return funcall2(car(fcons), cdr(fcons), arg2);