Proceedings of the second stratego users day

Abstract

Stratego and the underlying system S are as yet untyped. We propose a type system which covers the essence of system 5. In addition to system 5, a generic traversal primitive for folding the children of a term is considered. This primitive is essential for type-changing traversal strategies. The type system which we propose is based on certain signature-independent generic types. We also have to introduce a few constructs which enable us to rephrase untyped Stratego programs in a typeful manner.