Work

Implementing Set-Theoretic Types

Year: 2026

Type: article

Abstract: Set-theoretic types provide a rich type algebra that supports unrestricted unions, intersections, and negations, together with a decidable type constraint-solving algorithm known as tallying. These types are particularly well suited for typing dynamic languages, where functions often exhibit both generic and overloaded behavior. However, the complexity of their implementation has hindered their widespread adoption. In this paper, we introduce a modular representation for set-theoretic types and revisit the algorithms for subtyping and tallying. We compare our approach with the historical CDuce implementation and evaluate the performance impact of some optimizations and design choices.

Source: Proceedings of the ACM on Programming Languages

DOI: 10.1145/3839466

Authors: Mickaël Laurent, Kim Nguyễn

Institutions: Charles University, Université Paris-Saclay, Laboratoire Méthodes Formelles

Language: English

Topic: Logic, programming, and type systems

Subfield: Artificial Intelligence

Field: Computer Science

Domain: Physical Sciences

Open Access status: diamond

Funder: Agence Nationale de la Recherche

Award: Improving Software Systems Security Evaluation