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"!
            $
}

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

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

Association SymbolAttribute (Symbol, Attribute) {
    name = "SymbolAttribute"
}

Association Link (Symbol, Symbol) {
    name = "Link"
}