# Method Parser.XML.Tree.AbstractSimpleNode()->walk_preorder()

Method walk_preorder

  `int walk_preorder(function(AbstractSimpleNode, mixed ... :int|void) callback, mixed ... args)`

Description

  Traverse the node subtree in preorder, root node first, then subtrees from left to right, calling the callback function for every node. If the callback function returns STOP_WALK the traverse is promptly aborted and STOP_WALK is returned.