public function AddFunction(
        \Peg\Lib\Definitions\Element\FunctionElement $function, 
        $namespace = "\\"
    )
    {
        $this->CreateNamespace($namespace);
        
        $function->header =& $this;
        $function->namespace =& $this->namespaces[$namespace];

        $this->namespaces[$namespace]
            ->functions[$function->name] = $function
        ;
    }