A Unifying Approach to Goal-Directed Evaluation

Olivier Danvy, Bernd Grobauer, Morten Rhiger


Goal-directed evaluation, as embodied in Icon and Snobol, is built on the notions of backtracking and of generating successive results, and therefore it has always been something of a challenge to specify and implement. In this article, we address this challenge using computational monads and partial evaluation.

We consider a subset of Icon and we specify it with a monadic semantics and a list monad. We then consider a spectrum of monads that also fit the bill, and we relate them to each other. For example, we derive a continuation monad as a Church encoding of the list monad. The resulting semantics coincides with Gudeman's continuation semantics of Icon.

We then compile Icon programs by specializing their interpreter (i.e., by using the first Futamura projection), using type-directed partial evaluation. Through various back ends, including a run-time code generator, we generate ML code, C code, and OCaml byte code. Binding-time analysis and partial evaluation of the continuation-based interpreter automatically give rise to C programs that coincide with the result of Proebsting's optimized compiler.

Full Text:


DOI: http://dx.doi.org/10.7146/brics.v8i29.21689
This website uses cookies to allow us to see how the site is used. The cookies cannot identify you or any content at your own computer.

ISSN: 0909-0878 

Hosted by the Royal Danish Library and Aarhus University Library