Reflection has proved to be a powerful feature to support the design of development environments and to extend languages. However, the granularity of structural reflection stops at the method level. This is a problem since without sub-method reflection developers have to duplicate efforts, for example to introduce transparently pluggable type-checkers or fine-grained profilers. In this paper we present Persephone, an efficient implementation of a sub-method meta-object protocol (MOP) based on AST annotations and dual methods (a compiled method and its meta-object) that reconcile AST expressiveness with bytecode execution. We validate the MOP by presenting TreeNurse, a method instrumentation framework and TypePlug, an optional, pluggable type system which is based on Persephone.

Abstract. The ability to reengineer object-oriented legacy systems has become a vital matter in today’s software industry. Early adopters of the object-oriented programming paradigm are now facing the problem of transforming their objectoriented “legacy ” systems into full-fledged frameworks. To address this problem, a series of workshops has been organised to set up a forum for exchanging experiences, discussing solutions, and exploring new ideas. Typically, these workshops were organised as satellite events of major software engineering conferences, such as ECOOP [1,2,3,4,5,6,7,8,9,10,11] and ESEC/FSE [12,13,14]. During the past 10 years, participants of this workshop series have been actively contributing to the state-of-the-art on reengineering of object-oriented systems. This special 10 th anniversary edition was no exception and this report summarises the key discussions and outcome of that workshop. 1

Prof. Dr. P. Messerli This dissertation is available as a free download from