Experiments with the Call-by-Value Partial Evaluator

Author

María Alpuente, Moreno Falaschi, and Germán Vidal

Abstract

This paper summarizes our experience gained using the INDY system, a narrowing-driven partial evaluator for functional logic programs which combines in a useful and effective way the propagation of partial data structures, by means of logical variables and unification, with better opportunities for optimization thanks the functional dimension. INDY allows the user to select either a call-by-value (innermost, eager) or a call-by-name (outside-in, lazy) narrowing strategy to construct local narrowing trees. The trees are stopped according to an unfolding rule which is another parameter of the implementation, and then resultants are extracted from the root-to leaf paths of the tree. A short description of the system is given and some experimental results are presented for the call-by-value (innermost) evaluation strategy. The experiments show in practice that INDY can give significant performance improvements and is quite effective on several interesting transformation problems.