* The WG should choose an existing specification language (or maybe it is useful to mix two ones).
* We prefer that the specification language does not look like the implementation language (to avoid putting too much implementation in the specification).
* The specification language should not restrict the implementation language.
* There should be a way to use it legally.
* It should be easy to learn, so good documentation is required.
* We prefer that there exist tools for the specification language to check the specification and to check if the implementation fulfills the specification.
* The specification language should support modularity (encapsulation).
* It should be able to express definitions, rules and assumptions.