New function: endp.

This improves compatibility with other Lisp dialects
in a small way.

* eval.c (eval_init): Register endp intrinsic.

* lib.c (endp): New function.

* lib.h (endp): Declared.

* txr.1: Documented endp.

1 files changed, 10 insertions, 0 deletions

diff --git a/lib.c b/lib.c
index 1ca1790c..6576049c 100644
--- a/lib.c
+++ b/lib.c
@@ -2758,6 +2758,16 @@ val listp(val obj)
   return if2(obj == nil || consp(obj), t);
 }
 
+val endp(val obj)
+{
+  if (obj == nil)
+    return t;
+  if (consp(obj))
+    return nil;
+  uw_throwf(error_s, lit("endp: list improperly terminated by ~s"),
+            obj, nao);
+}
+
 val proper_list_p(val obj)
 {
   while (consp(obj))