A Pragmatic Approach to Declaring Specialization Scenarios

Abstract. Partial evaluation is a program transformation that automatically specializes a program with respect to invariants. Despite successful application in areas such as graphics, operating systems, and software engineering, partial evaluators have yet to achieve widespread use. One reason is the diÆculty of adequately describing specialization opportunities. Indeed, underspecialization or overspecialization often occurs, without any direct feedback as to the source of the problem. We have developed a high-level, module-based language allowing the program developer to guide the choice of both the code to specialize and the invariants to exploit during the specialization process. To ease the use of partial evaluation, the syntax of this language is similar to the declaration syntax of the target language of the partial evaluator. To provide feedback, declarations are checked during the analyses performed by partial evaluation. The language has been successfully used by a variety of users, including students having no previous experience with partial evaluation. 1