EClean - An Embedded Functional Language

C++ template metaprogramming is often regarded as a functional language, however, nowadays metaprogram libraries are not implemented in functional programming style. In this paper we discuss a compile-time graph-rewriting engine based on the properties of the functional language Clean. The most important property imported from the functional paradigm is the lazy evaluation strategy. With the help of the engine it is possible to embed lazy functional-style code into C++ programs, and transform it into template metaprograms. We present the implemented lazy evaluation strategy by examples including also infinite lists.