tree: node set functions and syntactic places.

* lisplib.c (defset_set_entries): Autoload entries for left,
right and key.

* share/txr/stdlib/defset.tl (left, right, key): New
simple-form defsets.

* tree.c (set_left, set_right, set_key): New functions.
(tree_init): Register intrinsics set-left, set-right and
set-key.

* tree.h (set_left, set_right, set_key): Declared.

* txr.1: key, left and right classified as accessors.
Documented set-key, set-left and set-right.

1 files changed, 3 insertions, 0 deletions

diff --git a/tree.h b/tree.h
index 0f056429..528bae7b 100644
--- a/tree.h
+++ b/tree.h
@@ -34,6 +34,9 @@ val tnodep(val obj);
 val left(val node);
 val right(val node);
 val key(val node);
+val set_left(val node, val nleft);
+val set_right(val node, val nright);
+val set_key(val node, val nkey);
 val copy_tnode(val node);
 val tree(val keys, val key_fn, val less_fn, val equal_fn);
 val treep(val obj);