{"id":10877705,"date":"2022-03-25T14:11:21","date_gmt":"2022-03-25T14:11:21","guid":{"rendered":"https:\/\/wpml.org\/?p=10877705"},"modified":"2023-05-25T08:18:12","modified_gmt":"2023-05-25T08:18:12","slug":"why-we-made-the-switch-to-functional-programming-for-wpml","status":"publish","type":"post","link":"https:\/\/wpml.org\/de\/announcements\/2022\/03\/why-we-made-the-switch-to-functional-programming-for-wpml\/","title":{"rendered":"Why We Made the Switch to Functional Programming for WPML"},"content":{"rendered":"\n

Functional programming is a hot topic amongst developers nowadays, and not without reason. Version 4.5 of WPML<\/a> was a large-scale project which introduced the option of automatically translating your website. For us, it was also the right moment to make the switch to functional programming. Here’s what we learned in the process.<\/p>\n\n\n\n

What is Functional Programming?<\/h2>\n\n\n\n

You\u2019ve probably heard that functional programming makes your code more readable and is easier to test. But to fully grasp functional programming, it\u2019s important to understand the related concepts of it.<\/p>\n\n\n\n

To start with, functional programming is a programming paradigm where the emphasis is on using functions to construct software and composing functions together to build more complex functions. Functional programming makes the code more declarative in nature. You express what you want rather than having a sequence of statements which update the program state.<\/p>\n\n\n\n

It\u2019s important to take note of the functions it uses – specifically pure functions. Pure functions receive data and return data, but don\u2019t have any other side effects. This makes the functions very easy to test because if you give the same parameters, you get the same result. <\/p>\n\n\n\n

Simply put, in functional programming the output depends on the input.<\/p>\n\n\n\n

Why Functional Programming?<\/h2>\n\n\n\n

WPML is a large and complex project. Up until recently, we\u2019ve used object-oriented programming (OOP) to try to manage this complexity. One of the main challenges is writing test code (Unit tests) for all of our projects. When writing testable code, we need to ensure any changes we make don\u2019t break existing code.<\/p>\n\n\n\n

Unit testing OOP code can only take you so far. Code dependencies need to be mocked so classes can be tested independently. As a result, the tests end up being large and complex.<\/p>\n\n\n\n

The main focus of functional programming is said to be \u201cWhat to solve\u201d. In contrast, object-oriented programming takes on a \u201cHow to solve\u201d approach. With this in mind, it seemed like functional programming could help us overcome some of our challenges.<\/p>\n\n\n\n

What We Did<\/h2>\n\n\n\n

When we talk about functional programming, PHP is not the first language that comes to mind – although it does allow us to introduce a functional style. For example, hooks and filters that allow WordPress to be extended use functions to override WordPress functionality.<\/p>\n\n\n\n

Unfortunately, there\u2019s no standard library for using a more functional paradigm in PHP. We reviewed many libraries but none had exactly what we needed to write expressive code in a functional style. So instead, we decided to write our own library<\/a>. We drew inspiration from different sources, but many from Javascript libraries, which we found were more mature.<\/p>\n\n\n\n

Functional programming has a different approach than other paradigms, so switching to a functional programming paradigm is actually a big step. It requires you to change the way you think about writing code and solve problems. It takes a lot of practice to write expressive code that is clear and concise.<\/p>\n\n\n\n

Did It Work?<\/h2>\n\n\n\n

We definitely think it did. Functional programming has a number of features that work to our advantage:<\/p>\n\n\n\n