private function writeVariable() {
    $node = new ReferenceVariableNode();
    $this->mustMatch('&', $node);
    $node->addChild($this->variable(), 'variable');
    return $node;
  }
private function writeVariable() {
    $node = new ReferenceVariableNode();
    $this->mustMatch('&', $node);
    $node->addChild($this->variable(), 'variable');
    return $node;
  }
private function writeVariable ( ) { $ node = new ReferenceVariableNode ( ) ; $ this -> mustMatch ( '&' , $ node ) ; $ node -> addChild ( $ this -> variable ( ) , 'variable' ) ; return $ node ; }
Parse a write variable.
@return ReferenceVariableNode
Parse a write variable .