class Tag extends Fooclass
{
    private var params:Array <Parameter>;
    ...
}

class Parameter
{
    public var name:String;
    public var value:String;
    ...
}

class Link extends Tag
{
    public var href:Parameter;

    public function new(href:String = "")
    {
        super();

        this.href.name = "href";
        this.href.value = href;
        this.params.push(this.href);

    }

}