Strategies in PRholog

TL;DR

PRholog extends logic programming with strategic conditional transformation rules, enabling flexible, nondeterministic hedge transformations and complex strategy construction for controlled rewriting in a declarative manner.

Contribution

It introduces a novel integration of strategic rewriting into logic programming, allowing complex strategy composition and flexible term selection mechanisms.

Findings

Demonstrates how rewriting strategies are expressed in PRholog

Shows flexible control of rule application through strategies

Enables nondeterministic transformations with multiple results

Abstract

PRholog is an experimental extension of logic programming with strategic conditional transformation rules, combining Prolog with Rholog calculus. The rules perform nondeterministic transformations on hedges. Queries may have several results that can be explored on backtracking. Strategies provide a control on rule applications in a declarative way. With strategy combinators, the user can construct more complex strategies from simpler ones. Matching with four different kinds of variables provides a flexible mechanism of selecting (sub)terms during execution. We give an overview on programming with strategies in PRholog and demonstrate how rewriting strategies can be expressed.