Question

I’ve been trying to study up on PHP lately, and I find myself getting hung up on traits. I understand the concept of horizontal code reuse and not wanting to necessarily inherit from an abstract class. What I don’t understand is: What is the crucial difference between using traits versus interfaces?

I’ve tried searching for a decent blog post or article explaining when to use one or the other, but the examples I’ve found so far seem so similar as to be identical.

Answer 1

An interface defines a set of methods that the implementing class must implement.

When a trait is use‘d the implementations of the methods come along too–which doesn’t happen in an Interface.

That is the biggest difference.

From the Horizontal Reuse for PHP RFC:

Traits is a mechanism for code reuse in single inheritance languages such as PHP. A Trait is intended to reduce some limitations of single inheritance by enabling a developer to reuse sets of methods freely in several independent classes living in different class hierarchies.