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, 1 insertions, 0 deletions

diff --git a/lisplib.c b/lisplib.c
index 43c9e5d1..62b41b3b 100644
--- a/lisplib.c
+++ b/lisplib.c
@@ -792,6 +792,7 @@ static val defset_set_entries(val dlt, val fun)
 {
   val name[] = {
     lit("defset"), lit("sub-list"), lit("sub-vec"), lit("sub-str"),
+    lit("left"), lit("right"), lit("key"),
     nil
   };
   set_dlt_entries(dlt, name, fun);