Executable specifications for language implementation

Abstract

Generating programs from specifications is an ambitious task that is solved at most for restricted application domains. General solutions which are practically satisfying as well are hard to achieve. Language implementation is a field, where tools and toolsets are available which process executable specifications and derive language implementing programs (compilers or interpreters) from them.

In this paper we will study specification principles that contribute to the success of program generation in this application domain. Examples are taken from the specification techniques of the Eli-System. The task of language implementation is decomposed into subtasks which have well understood and sufficiently general algorithmic solutions. Hence the instances of subtasks for a particular language can be specified. Certain language concepts like scope rules can be understood as a combination and variation of some basic rules. This situation allows specifications on a rather high level and reuse of precoined solutions. Domain specific expert know-how embedded in a toolset can further raise the specification level. The presentation of such specification principles in language implementation may raise discussion whether and how they can be applied to other areas as well.