MaudeTypedLog: A Typed Interpreter for Prolog in Maude

2026-07-22

AI Summary

Prolog lacks a mainstream static type system, making it difficult to detect type errors prior to execution. To address this limitation, this work presents the first implementation of an operational semantics based on Typed SLD-resolution in Maude, yielding an interpreter named MaudeTypedLog. This interpreter integrates a typed unification algorithm to dynamically identify type errors in both Prolog programs and queries during execution. By doing so, the study not only fills a gap in Maude’s support for typed logic programming but also provides Prolog with an effective runtime mechanism for type safety, thereby enhancing program reliability without requiring static type annotations.

Abstract

Prolog is traditionally thought of as an untyped logic programming language, although there are queries that result in a type error. Several attempts of statically introducing a type discipline in Prolog have been made but they have not been widely adopted. We use Maude to implement a typed unification algorithm and use it as the basis for an interpreter for Prolog called MaudeTypedLog. This interpreter follows the Typed SLD-resolution operational semantics for logic programming, that makes it possible to detect type errors in both programs and queries dynamically.

Problem

• Prolog
• type error
• typed logic programming
• dynamic type checking
• unification

Innovation

• typed unification
• Maude
• Prolog
• Typed SLD-resolution
• dynamic type checking