Towards an automatic translation algorithm from Prolog to the Andorra Kernel Language

Abstract

The Andorra family of languages (which includes the Andorra Kernel Language -AKL) offers the advantage of supporting simultaneously the programming styles of Prolog and committed choice languages. However, Prolog programs cannot be executed directly on the AKL. This is due to a number of factors, from more or less trivial syntactic differences to more involved issues such as the treatment of cut and making the exploitation of certain types of parallelism possible. These differences can be bridged, however, through program analysis and transformation. This paper provides basic guidelines for constructing an automatic compiler of Prolog programs into AKL. First we revisit the Andorra Kernel Language flow of control and then introduce t he basic translation paradigms for dealing with each type of transformation needed. Finally, we present a basic translation algorithm. The translation process benefits from an abstract interpretation-based global analysis of the program. We also put special attention on a style of translation which attempts to achieve independent and-parallel execution where possible, since this type of parallel execution preserves through the translation the user-perceived "complexity" of the originai Prolog program. This process is simplified in part by making use of some compile-time analysis technology developed in the context of the &-Prolog compiler.