diff options
| -rw-r--r-- | tree.c | 11 | ||||
| -rw-r--r-- | txr.1 | 33 |
2 files changed, 39 insertions, 5 deletions
@@ -423,13 +423,19 @@ static val tree_lookup(val tree, val key) return if2(node, node->tn.key); } -static val tree_delete(val tree, val key) +static val tree_delete_node(val tree, val key) { - val self = lit("tree-delete"); + val self = lit("tree-delete-node"); struct tree *tr = coerce(struct tree *, cobj_handle(self, tree, tree_s)); return tr_delete(tr, key); } +static val tree_delete(val tree, val key) +{ + val node = tree_delete_node(tree, key); + return if2(node, node->tn.key); +} + static val tree_root(val tree) { val self = lit("tree-root"); @@ -678,6 +684,7 @@ void tree_init(void) reg_fun(intern(lit("tree-insert"), user_package), func_n2(tree_insert)); reg_fun(intern(lit("tree-lookup-node"), user_package), func_n2(tree_lookup_node)); reg_fun(intern(lit("tree-lookup"), user_package), func_n2(tree_lookup)); + reg_fun(intern(lit("tree-delete-node"), user_package), func_n2(tree_delete_node)); reg_fun(intern(lit("tree-delete"), user_package), func_n2(tree_delete)); reg_fun(intern(lit("tree-root"), user_package), func_n1(tree_root)); reg_fun(intern(lit("tree-begin"), user_package), func_n1(tree_begin)); @@ -45463,13 +45463,13 @@ A possible implementation is this: (key node))) .brev -.coNP Function @ tree-delete +.coNP Function @ tree-delete-node .synb -.mets (tree-delete < tree << key ) +.mets (tree-delete-node < tree << key ) .syne .desc The -.code tree-delete +.code tree-delete-node function searches .meta tree for an element which matches @@ -45493,6 +45493,33 @@ Otherwise, if a matching element is not found, then .code nil is returned. +.coNP Function @ tree-delete +.synb +.mets (tree-delete < tree << key ) +.syne +.desc +The +.code tree-delete +function tries to removes from +.meta tree +the element which matches +.metn key . + +If successful, it returns that element, otherwise it returns +.codn nil . + +Note: the semantics of the +.code tree-delete +function can be understood in terms of +.codn tree-delete-node . +A possible implementation is this: + +.verb + (defun tree-delete (tree key) + (iflet ((node (tree-delete-node tree key))) + (key node))) +.brev + .coNP Function @ tree-root .synb .mets (tree-root < tree ) |