Domain specific languages (DSLs) are mini-languages which are increasingly seen as being a valuable tool for software developers and non-developers alike. DSLs must currently be created in an ad-hoc fashion, often leading to high development costs and implementations of variable quality. In this paper I show how expressive DSLs can be hygienically embedded in the Converge programming language using its compile-time meta-programming facility, the concept of DSL blocks, and specialised error reporting techniques. By making use of pre-existing facilities, and following a simple methodology, DSL implementation costs can be significantly reduced whilst leading to higher quality DSL implementations.

Abstract. Powerful, safe macro systems allow programs to be programatically constructed by the user at compile-time. Such systems have traditionally been largely confined to LISP-like languages and their successors. In this paper we describe and compare two modern, dynamically typed languages Converge and Metalua, which both have macro-like systems. We show how, in different ways, they build upon traditional macro systems to explore new ways of constructing programs. 1

Model transformations are recognised as a vital aspect of Model Driven Development, but current approaches cover only a small part of the possible spectrum. In this paper I present the MT model transformation which shows how a QVT-like language can be extended with novel pattern matching constructs, how tracing information can be automatically constructed and visualized, and how the transformed model is pruned of extraneous elements. As MT is implemented as a DSL within the Converge language, this paper also demonstrates how a general purpose language can be embedded in a model transformation language, and how DSL development can aid experimentation and exploration of new parts of the model transformation spectrum. 1.

The design of the Icon programming language’s expression evaluation system, which can perform limited backtracking, was unique amongst imperative programming languages when created. In this paper I explain and critique the original Icon design and show how a similar system can be integrated into a modern dynamically typed language. Finally I detail my experiences of this system and offer suggestions for the lessons to be learned from it.

Working with Mitch Wand has been a rare privilege. I am grateful for all he has taught me and for the opportunity to work for a man I admire. A great deal of my education took place in the extraordinary Programming Research Laboratory on the third floor of West Village H. In particular, I find it hard to imagine ever finishing this work without the perspective, insight,

Abstract. A meta-program is a program that generates or manipulates another program; in homogeneous meta-programming, a program may generate new parts of, or manipulate, itself. Meta-programming has been used extensively since macros were introduced to Lisp, yet we have little idea how formally to reason about metaprograms. This paper provides the first program logics for homogeneous metaprogramming – using a variant of MiniML □ e by Davies and Pfenning as underlying meta-programming language. We show the applicability of our approach by reasoning about example meta-programs from the literature. We also demonstrate that our logics are relatively complete in the sense of Cook, enable the inductive derivation of characteristic formulae, and exactly capture the observational properties induced by the operational semantics. 1

Abstract. Domain Specific Languages (DSLs) are small languages designed for use in a specific domain. DSLs typically evolve quite radically throughout their lifetime, but current DSL implementation approaches are often clumsy in the face of such evolution. In this paper I present a case study of an DSL evolving in its syntax, semantics, and robustness, implemented in the Converge language. This shows how real-world DSL implementations can evolve along with changing requirements. 1