From fbe0c77a06a711bd746261406e47c16c55e660a8 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Thu, 26 Jan 2012 16:20:10 -0800
Subject: * lib.c (listref, listref_l): Negative indices must have semantics
 consistent with vecref and ranges.

---
 lib.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'lib.c')

diff --git a/lib.c b/lib.c
index 29049969..3dd57738 100644
--- a/lib.c
+++ b/lib.c
@@ -310,7 +310,7 @@ val sixth(val cons)
 val listref(val list, val ind)
 {
   if (lt(ind, zero))
-    return nil;
+    ind = plus(ind, length_list(list));
   for (; gt(ind, zero); ind = minus(ind, one))
     list = cdr(list);
   return car(list);
@@ -321,6 +321,9 @@ val *listref_l(val list, val ind)
   val olist = list;
   val oind = ind;
 
+  if (lt(ind, zero))
+    ind = plus(ind, length_list(list));
+
   for (; gt(ind, zero) && list; ind = minus(ind, one))
     list = cdr(list);
   if (consp(list))
-- 
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