New function: tailp.

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

* lib.c (tailp): New function.

* lib.h (tailp): Declared.

* txr.1: Documented.

1 files changed, 10 insertions, 0 deletions

diff --git a/lib.c b/lib.c
index 374b038a..ebcd1670 100644
--- a/lib.c
+++ b/lib.c
@@ -1682,6 +1682,16 @@ val ldiff_old(val list1, val list2)
   return make_like(out, list_orig);
 }
 
+val tailp(val obj, val list)
+{
+  while (obj != list) {
+    if (atom(list))
+      return nil;
+    list = cdr(list);
+  }
+  return t;
+}
+
 val memq(val obj, val list)
 {
   val list_orig = list;