2026-07-22T14:20:42Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:18204 2024-03-06T11:01:22Z ddc:004 open_access

super-Charging Object-Oriented Programming Through Precise Typing of Open Recursion Fan, Andong Parreaux, Lionel Object-Oriented Programming the Expression Problem Open Recursion We present a new variation of object-oriented programming built around three simple and orthogonal constructs: classes for storing object state, interfaces for expressing object types, and mixins for reusing and overriding implementations. We show that the latter can be made uniquely expressive by leveraging a novel feature that we call precisely-typed open recursion. This features uses "this" and "super" annotations to express the requirements of any given partial method implementation on the types of respectively the current object and the inherited definitions. Crucially, the fact that mixins do not introduce types nor subtyping relationships means they can be composed even when the overriding and overridden methods have incomparable types. Together with advanced type inference and structural typing support provided by the MLscript programming language, we show that this enables an elegant and powerful solution to the Expression Problem. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Andong Fan and Lionel Parreaux 2023 Is Part Of LIPIcs, Volume 263, 37th European Conference on Object-Oriented Programming (ECOOP 2023) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.ECOOP.2023.11 urn:nbn:de:0030-drops-182047 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2023.11 eng https://creativecommons.org/licenses/by/4.0/legalcode