A Metamodel for SDL-2000 in the Context of Metamodelling ULF

Today the syntax of many languages is defined by using context-free grammars. These syntax definitions suffer from a major drawback: grammars do not allow the definition of abstract, reusable concept definitions. Especially in families of related languages, where multiple languages often share the same concepts, this limitation leads to unnecessary reproduction of concept definitions and a missing shared base for these related languages. Metamodels can contain inheritance hierarchies of concepts; thus multiple specifications can reuse and refine existing shared concept definitions. Therefore we propose a method to develop metamodels from existing syntax definitions. We explain our method by applying it to SDL-2000. The method starts with a mapping from BNF grammars into simple preliminary metamodels. Then, by supplying a relation between elements of these simple metamodels and abstract concepts, these metamodels are automatically transformed into metamodels that use existing descriptions of abstract concepts and thus allow a shared basis of common abstract concepts definitions.