replace-list: negatives in index-list follow convention.

The index-list replacement isn't following the convention that
negative index values reference from the end of the target
sequence. Let's fix that.

* lib.c (replace_list): Likewise.

* txr.1: Documentation updated.

1 files changed, 2 insertions, 0 deletions

diff --git a/lib.c b/lib.c
index 385101cb..01e18b03 100644
--- a/lib.c
+++ b/lib.c
@@ -1438,6 +1438,8 @@ val replace_list(val list, val items, val from, val to)
                 self, nao);
 
     while (iter && seq_peek(&item_iter, &item) && seq_peek(&wh_iter, &wh)) {
+      if (minusp(wh))
+        wh = plus(wh, len ? len : (len = length(list)));
       if (lt(wh, idx)) {
         seq_geti(&wh_iter);
         seq_geti(&item_iter);