PHP naming conventions about abstract classes and interfaces

Question

Should an abstract class always be prefixed with Abstract and suffixed with Interface (when it's an interface)? Is there any standard naming convention, similar to PSR-0 for folder structure/namespaces, but for classes?

It seems redundant as the language has literal keywords for this very purpose.

abstract class AbstractFoo {}

interface InterfaceFoo {}

trait TraitFoo {}

Answer 1

Although there's not any convention, I think it is a good practice using Abstract prefix and Interface suffix for respective components. It helps to understand better the code at a glance, IMO.

Answer 2

The PHP-FIG project indeed suggests a naming convention via the PSR Naming Convention "ByLaw" https://www.php-fig.org/bylaws/psr-naming-conventions/

It states:

• Interfaces MUST be suffixed by Interface: e.g. Psr\Foo\BarInterface

• Abstract classes MUST be prefixed by Abstract: e.g. Psr\Foo\AbstractBar

• Traits MUST be suffixed by Trait: e.g. Psr\Foo\BarTrait

These conventions are generally followed in packages