The XTATIC Experience

XTATIC is a lightweight extension of C# with native support for statically typed XML processing. It features XML trees as built-in values, a refined type system based on regular types in the style of XDUCE, and "tree grep"-style regular patterns for traversing and manipulating XML. Previous papers on XTATIC have reported results on a number of specific technical issues: basic theoretical properties of an idealized core language, novel compilation algorithms for regular pattern matching, and efficient runtime support for XML processing in the style encouraged by XTATIC. The aim of the present paper is to discuss XTATIC—less formally and more holistically—from the perspective of language design. We survey the most significant issues we faced in the design process and evaluate the choices we have made in addressing them.