Exploring the Extent of Classical Object-Oriented Constructs in Julia for Mainstream Adoption

This question delves into two common misconceptions surrounding the need for classical object-oriented (OO) constructs such as classes in the Julia programming language. Specifically, it examines whether Julia should introduce these constructs to become more mainstream. The discussion highlights the nature of Julia's existing features and the factors that truly shape a programming language's popularity.

Understanding Julia's Capabilities

The first misconception revolves around the belief that Julia lacks OO constructs and can only be made mainstream by adding them. However, Julia already possesses robust features that are sufficient to handle most programming needs. In particular, its type safety system and type composition provide a solid foundation that aligns well with Python's approach to handling encapsulated data.

As Tom says, multiple dispatch in Julia is a more powerful approach to problem-solving compared to traditional classes. This paradigm allows for high-level functions to be written in a generic manner, and methods can specialize for specific types. This is a core aspect of Julia's design and serves as a key factor in how the language is used and understood.

Key Features Supporting Julia's Growth

Julia's success lies not in adding new features, but in becoming the de facto standard for certain domains. For instance, Perl remains popular because it excels at string manipulation, and many software developers use Java and JavaScript for different reasons such as "write once run anywhere" and web page development respectively. Similar to these languages, Julia could become mainstream by becoming the de facto choice for a specific area, such as Apache Spark or MATLAB replacements.

The de facto status of a language often hinges on its practical applications and relevance. For Julia to achieve mainstream status, it needs to fill a gap that existing languages do not adequately fill. Introducing classes might not be the solution if the current set of features already satisfies a broad range of programming needs.

Why Classes Might Not Be Needed

Multiple dispatch, along with inheritance from abstract types, provides Julia with a more flexible and powerful system for organizing code. The inclusion of these features in the language is not merely a matter of hipness; they are fundamental to how Julia operates. The PhD. thesis by Jeff Bezanson outlines how to combine the simplicity and utility of dynamically typed languages for numeric computing with the performance required for high-performance computing. This is achieved through a combination of type inference and multiple dispatch.

Multiple dispatch is not a new concept; it was introduced in Common Lisp Object System (CLOS). However, in Julia, this feature is part of a comprehensive design aimed at optimizing code. The Julia standard library makes extensive use of multiple dispatch, making the language more efficient and expressive. Default data types in Julia prioritize performance over abstraction, using machine integers, packed structs, and more.

While multiple dispatch and macros are powerful, they may not suffice for all users. Some features, such as enforceable data hiding and specific interface contracts, are missing. These are necessary for a more robust OO system, but Julia is flexible enough to incorporate them as optional modules or through community-driven packages.

Conclusion: Julia's Future?

In conclusion, while Julia lacks certain classical OO constructs, it is not necessarily the roadblock to achieving mainstream adoption. The key is to establish Julia as the de facto solution for specific domains. Introducing classes might not be necessary, as the existing features offer powerful alternatives. The challenge lies in convincing the programming community to see the value in Julia's unique approach.

For those interested in understanding how to approach object-oriented programming in Julia, I have recently published a guide on OOP and approaches to polymorphism in the language. You can find it here.