# 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.