Compile-time meta-programming allows programs to be constructed by the user at compile-time. Although LISP derived languages have long had such facilities, few modern languages are capable of compile-time meta-programming, and of those that do many of the most powerful are statically typed functional languages. In this paper I present the dynamically typed object orientated language Converge which allows compile-time meta-programming in the spirit of Template Haskell. Converge demonstrates that integrating powerful, safe compile-time meta-programming features into a dynamic language requires few restrictions to the flexible development style facilitated by the paradigm. In this paper I detail Converge’s compile-time meta-programming facilities, much of which is adapted from Template Haskell, contain several features new to the paradigm. Finally I explain how such a facility might be integrated into similar languages. 1.

Compile-time meta-programming allows programs to be constructed by the user at compile-time. Few modern languages are capable of compile-time meta-programming, and of those that do, many of the most powerful are statically typed functional languages. In this paper I present the dynamically typed, object orientated language Converge which allows compile-time meta-programming in the spirit of Template Haskell. Converge demonstrates that integrating powerful, safe compiletime meta-programming features into a dynamic language requires few restrictions to the flexible development style facilitated by the paradigm.

The benefits of modularization are well known. However, modules are not standard in Scheme. This paper accompanies an invited talk at the Scheme Workshop 2002 on the current state of modules for Scheme. Implementation is not addressed, only linguistic features are covered.

1.1 Why customize a language?................................ 1 1.1.1 Creating domain-specific languages........................ 2 1.1.2 Reusing code in a new context.......................... 3