Alphard definition language
(Named after the brightest star in Hydra) A Pascal
-like language developed by Wulf, Shaw and London of CMU
in 1974. Alphard supports data abstraction
using the 'form', which combines a specification and an implementation.
["Abstraction and Verification in Alphard: Defining and Specifying Iteration and Generators", Mary Shaw, CACM 20(8):553-563, Aug 1977].