include "primitives.alh"

SimpleAttribute String {
    constraint = $
            String function constraint(value : Element):
                if (is_physical_string(value)):
                    return "OK"!
                else:
                    return "String has a non-string value"!
            $
}

SimpleAttribute Integer {
    constraint = $
            String function constraint(value : Element):
                if (is_physical_int(value)):
                    return "OK"!
                else:
                    return "Integer has a non-integer value"!
            $
}

SimpleAttribute Boolean {
    constraint = $
            String function constraint(value : Element):
                if (is_physical_boolean(value)):
                    return "OK"!
                else:
                    return "Boolean has a non-boolean value"!
            $
}

Class Model {
    name = "Model"
    descr : String
    is_example : Boolean
}

Class Node {
    name = "Node"
    typeID : String
}

Association Edge(Node, Node) {
    name = "Edge"
    directed : Boolean
}

Class Attribute {
    name = "Attribute"
    key : String
    value : String
}

Association NodeAttribute(Node, Attribute) {
    name = "NodeAttribute"
}