tree: introduce copy-tnode.

* lib.c (copy): Handle TNOD casee via copy_tnode.

* tree.c (copy_tnode): New function.
(tree_init): copy-tnode intrinsic registered.

* tree.h (copy_tnode): Declared.

* txr.1: copy function documented as handling tnode type via
copy-tnode. That function is documented.

4 files changed, 30 insertions, 0 deletions

diff --git a/lib.c b/lib.c
index ea7f7495..81f3d06d 100644
--- a/lib.c
+++ b/lib.c
@@ -10072,6 +10072,8 @@ val copy(val seq)
     return copy_buf(seq);
   case FUN:
     return copy_fun(seq);
+  case TNOD:
+    return copy_tnode(seq);
   case COBJ:
     if (seq->co.cls == hash_s)
       return copy_hash(seq);
diff --git a/tree.c b/tree.c
index 22cac379..43330c06 100644
--- a/tree.c
+++ b/tree.c
@@ -119,6 +119,13 @@ val key(val node)
   return node->tn.key;
 }
 
+val copy_tnode(val node)
+{
+  val obj = (type_check(lit("copy-tnode"), node, TNOD), make_obj());
+  obj->tn = node->tn;
+  return obj;
+}
+
 static ucnum tn_size(val node)
 {
   return 1 + if3(node->tn.right, tn_size(node->tn.right), 0) +
@@ -677,6 +684,7 @@ 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("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));
   reg_fun(intern(lit("treep"), user_package), func_n1(treep));
diff --git a/tree.h b/tree.h
index 94270b4b..0f056429 100644
--- a/tree.h
+++ b/tree.h
@@ -34,6 +34,7 @@ val tnodep(val obj);
 val left(val node);
 val right(val node);
 val key(val node);
+val copy_tnode(val node);
 val tree(val keys, val key_fn, val less_fn, val equal_fn);
 val treep(val obj);
 val tree_insert_node(val tree, val node);
diff --git a/txr.1 b/txr.1
index ad97ed52..5bc31393 100644
--- a/txr.1
+++ b/txr.1
@@ -28073,6 +28073,8 @@ the type of the argument, as follows:
 .meti (copy-carray << object )
 .coIP random-state
 .meti (make-random-state << object )
+.coIP tnode
+.meti (copy-tnode << object )
 .RE
 
 .IP
@@ -45230,6 +45232,23 @@ functions retrieve the corresponding fields of the
 object, which must be of type
 .codn tnode .
 
+.coNP Function @ copy-tnode
+.synb
+.mets (copy-tnode << node )
+.syne
+.desc
+The
+.code copy-tnode
+function creates a new
+.code tnode
+objects, whose
+.codn key ,
+.code left
+and
+.code right
+fields are copied from
+.codn node .
+
 .coNP Function @ tree
 .synb
 .mets (tree >> [ elems >> [ keyfun >> [ lessfun <> [ equalfun ]]]])