node

type Argument struct {
	Variadic    bool // if ... before variable
	IsReference bool // if & before variable
	Expr        Node // Exression
}

type Identifier struct {
	Value string
}

type Node interface {
	walker.Walker
	Attributes() map[string]interface{} // Attributes returns node attributes as map
}

type Nullable struct {
	Expr Node
}

type Parameter struct {
	ByRef        bool
	Variadic     bool
	VariableType Node
	Variable     Node
	DefaultValue Node
}