Type-based specialization of XML transformations

It is often convenient to write a function and apply it to a specific input. However, a program developed in this way may be inefficient to evaluate and difficult to analyze due to its generality. In this paper, we propose a technique of new specialization for a class of XML transformations, in which no output of a function can be decomposed or traversed. Our specialization is type-based in the sense that it uses the structures of input types; types are described by regular hedge grammars and subtyping is defined settheoretically. The specialization always terminates, resulting in a program where every function is fully specialized and only accepts its rigid input. We present several interesting applications of our new specialization, especially for injectivity analysis