A Systematic Study of Functional Language Implementations

Abstract

We introduce a unified framework to describe, relate, compare, and classify functional language implementations. The compilation process is expressed as a succession of program transformations in the common framework. At each step, different transformations model fundamental choices. A benefit of this approach is to structure and decompose the implementation process. The correctness proofs can be tackled independently for each step and amount to proving program transformations in the functional world. This approach also paves the way to formal comparisons by making it possible to estimate the complexity of individual transformations or compositions of them. Our study aims at covering the whole known design space of sequential functional language implementations. In particular, we consider call-by-value, call-by-name, and call-by-need reduction strategies as well as environment- and graph-based implementations. We describe for each compilation step the diverse alternatives as program transformations. In some cases, we illustrate how to compare or relate compilation techniques, express global optimizations, or hybrid implementations. We also provide a classification of well-known abstract machines.