Interface Compilation : Steps toward Compiling Program Interfaces

Interfaces | the collection of procedures and data structures that deene a library, a subsystem, a module | are syntactically poor programming languages. They have state (deened both by the interface's data structures and internally), operations on this state (deened by the interface's procedures), and semantics associated with these operations. Given a way to incorporate interface semantics into compilation, interfaces can be compiled in the same manner as traditional languages such as ANSI C or FORTRAN. This paper makes two contributions. First, it proposes and explores the metaphor of interface compilation , and provides the beginnings of a programming methodology for exploiting it. Second, it presents Magik, a system built to support interface compilation. Using Magik, software developers can build optimizers and checkers for their interface languages, and have these extensions incorporated into compilation, with a corresponding gain in eeciency and safety. This organization contrasts with traditional compilation, which relegates programmers to the role of passive consumers, rather than active exploiters of a compiler's transformational abilities.