Reversible Language Extensions and their Application in Debugging

TL;DR

This paper introduces a reversible language extension technique for Prolog that preserves source-level information through symbolic annotations, enhancing debugging and program analysis capabilities.

Contribution

It proposes an augmented approach to language extensions that allows reversing code transformations, improving debugging and analysis in Prolog programs.

Findings

Enables source-level debugging of extended Prolog programs

Supports various language extensions like functional notation and DCGs

Improves debugging experience with minimal modifications to existing tools

Abstract

A range of methodologies and techniques are available to guide the design and implementation of language extensions and domain-specific languages. A simple yet powerful technique is based on source-to-source transformations interleaved across the compilation passes of a base language. Despite being a successful approach, it has the main drawback that the input source code is lost in the process. When considering the whole workflow of program development (warning and error reporting, debugging, or even program analysis), program translations are no more powerful than a glorified macro language. In this paper, we propose an augmented approach to language extensions for Prolog, where symbolic annotations are included in the target program. These annotations allow selectively reversing the translated code. We illustrate the approach by showing that coupling it with minimal extensions to a generic Prolog debugger allows us to provide users with a familiar, source-level view during the debugging of programs which use a variety of language extensions, such as functional notation, DCGs, or CLP{Q,R}.