Designed by the
Common Framework Initiative (CoFI), with the aim to subsume existing specification languages, and is implemented in four orthogonal levels: ; basic specifications : for the specification of single software modules, ; structured specifications : for the modular specification of modules, ; architectural specifications : for the prescription of the structure of
implementations, ; specification libraries : for storing specifications distributed over the
Internet. The structural,
architectural, and
algebraic specification infrastructure can be extended beyond CASL. For this purpose, it has been formalized as a
logical institution. ==Extensions==