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, 24 insertions, 0 deletions

diff --git a/tree.c b/tree.c
index 43330c06..70e43158 100644
--- a/tree.c
+++ b/tree.c
@@ -119,6 +119,27 @@ val key(val node)
   return node->tn.key;
 }
 
+val set_left(val node, val nleft)
+{
+  type_check(lit("set-left"), node, TNOD);
+  node->tn.left = nleft;
+  return node;
+}
+
+val set_right(val node, val nright)
+{
+  type_check(lit("set-right"), node, TNOD);
+  node->tn.right = nright;
+  return node;
+}
+
+val set_key(val node, val nkey)
+{
+  type_check(lit("set-key"), node, TNOD);
+  node->tn.key = nkey;
+  return node;
+}
+
 val copy_tnode(val node)
 {
   val obj = (type_check(lit("copy-tnode"), node, TNOD), make_obj());
@@ -684,6 +705,9 @@ void tree_init(void)
   reg_fun(intern(lit("left"), user_package), func_n1(left));
   reg_fun(intern(lit("right"), user_package), func_n1(right));
   reg_fun(intern(lit("key"), user_package), func_n1(key));
+  reg_fun(intern(lit("set-left"), user_package), func_n2(set_left));
+  reg_fun(intern(lit("set-right"), user_package), func_n2(set_right));
+  reg_fun(intern(lit("set-key"), user_package), func_n2(set_key));
   reg_fun(intern(lit("copy-tnode"), user_package), func_n1(copy_tnode));
   reg_fun(tree_s, func_n4o(tree, 0));
   reg_fun(tree_construct_s, func_n2(tree_construct));