Metaobject Protocols for Julia

Abstract

Metaobject Protocols enable programmers to extend programming languages without the need to understand the lower level details of their implementation. However, designing these protocols comes with two challenges: allow programmers to limit their concerns to higher level concepts and minimize performance penalties in programs. In this work, we propose metaobject protocol for the programming language Julia. Julia’s object system is very limited, when compared to languages following the Object-Oriented paradigm. However, Julia’s compilation approach allows for a considerable degree of code optimization through the exploration of runtime type information. Through the usage of Julia’s run-time optimizations, we propose a metaobject protocol that combines user-extensibility with limited performance penalties. This paper focuses on the development of a multiple inheritance method dispatch and method combination mechanisms with zero runtime overhead.