exec( <<setRootNode( $rootNode = $tree->createNode( 'Elements', 'Elements' ) ); $rootNode->addChild( $nonMetal = $tree->createNode( 'NonMetals', 'Non-Metals' ) ); $rootNode->addChild( $nobleGasses = $tree->createNode( 'NobleGasses', 'Noble Gasses' ) ); $nonMetal->addChild( $tree->createNode( 'H', 'Hydrogen' ) ); echo $tree->fetchNodeById( 'H' )->data, "\n"; ?>