* src/fns.c (Fnreverse): Allow vectors and bool vectors.

* doc/lispref/lists.texi (Building Cons Cells and Lists): Remove
description of `nreverse' and generalize it...
* doc/lispref/sequences.texi (Sequences): ...for sequences here.
* tests/automated/fns-tests.el (fns-tests-nreverse)
(fns-tests-nreverse-bool-vector): New tests.

1 files changed, 45 insertions, 15 deletions

diff --git a/src/fns.c b/src/fns.c
index 8f9734cd7cc..1694f1c798d 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -1697,25 +1697,55 @@ changing the value of a sequence `foo'.  */)
 }
 
 DEFUN ("nreverse", Fnreverse, Snreverse, 1, 1, 0,
-       doc: /* Reverse LIST by modifying cdr pointers.
-Return the reversed list.  Expects a properly nil-terminated list.  */)
-  (Lisp_Object list)
+       doc: /* Reverse order of items in a list or vector SEQ.
+If SEQ is a list, it should be nil-terminated, and reversed
+by modifying cdr pointers.  Return the reversed SEQ.
+
+Note that unlike `reverse', this function doesn't work with strings.
+It is strongly encouraged to treat them as immutable.  */)
+  (Lisp_Object seq)
 {
-  register Lisp_Object prev, tail, next;
+  if (NILP (seq))
+    return seq;
+  else if (CONSP (seq))
+    {
+      Lisp_Object prev, tail, next;
 
-  if (NILP (list)) return list;
-  prev = Qnil;
-  tail = list;
-  while (!NILP (tail))
+      for (prev = Qnil, tail = seq; !NILP (tail); tail = next)
+	{
+	  QUIT;
+	  CHECK_LIST_CONS (tail, tail);
+	  next = XCDR (tail);
+	  Fsetcdr (tail, prev);
+	  prev = tail;
+	}
+      seq = prev;
+    }
+  else if (VECTORP (seq))
     {
-      QUIT;
-      CHECK_LIST_CONS (tail, tail);
-      next = XCDR (tail);
-      Fsetcdr (tail, prev);
-      prev = tail;
-      tail = next;
+      ptrdiff_t i, size = ASIZE (seq);
+
+      for (i = 0; i < size / 2; i++)
+	{
+	  Lisp_Object tem = AREF (seq, i);
+	  ASET (seq, i, AREF (seq, size - i - 1));
+	  ASET (seq, size - i - 1, tem);
+	}
     }
-  return prev;
+  else if (BOOL_VECTOR_P (seq))
+    {
+      ptrdiff_t i, size = bool_vector_size (seq);
+
+      for (i = 0; i < size / 2; i++)
+	{
+	  bool tem = bool_vector_bitref (seq, i);
+	  bool_vector_set (seq, i, bool_vector_bitref (seq, size - i - 1));
+	  bool_vector_set (seq, size - i - 1, tem);
+	}
+    }
+  else
+    wrong_type_argument (Qarrayp, seq);
+  return seq;
 }
 
 DEFUN ("reverse", Freverse, Sreverse, 1, 1, 0,