PHP: yes, it's possible

Let's see if that's possible, then we'll see when to use it.

Is is possible?

Can enumerations implement interfaces?

Yes.

Source: enumeration PHP

Is it possible to "Multi catch" in PHP?

Yes.

Instead of doing that:

try {
} catch(MyException $e) {
} catch(AnotherException $e) {
}

Do that:

try {
} catch(MyException | AnotherException $e) {
}

Source: PHP - exceptions

Can an interface extend another interface?

Yes.

Unlike with classes, you can even have multiple inheritance:

interface A
{
  public function foo();
}

interface B
{
  public function bar();
}

interface C extends A, B
{
  public function baz();
}

Source: object interfaces

Do you need it?

Does your enum need an interface?

It's usually a good practice, as you can type check for that interface quite conveniently:

interface Colorful {
  public function color(): string;
}

enum Suit implements Colorful {
  case Hearts;
  case Diamonds;
  case Clubs;
  case Spades;

  public function color(): string {
    return match($this) {
      Suit::Hearts, Suit::Diamonds => 'Red',
      Suit::Clubs, Suit::Spades => 'Black',
    };
  }
}

function paint(Colorful $c) { ... }

paint(Suit::Clubs);

Source: RFC - enumerations

Do you need Multi catch blocks?

It depends.

This syntax works:

try {
} catch(MyException | AnotherException $e) {
   echo $e->getMessage();
}

However, ensure your exceptions implement the same methods.

In contrast, using several catch blocks can be handy to catch different classes of exceptions.

Although, if you need to group your exceptions, avoid the following:

try {
} catch(AnException | AnotherException2 | AnotherException3 | AnotherException4 | AnotherException5 | AnotherException6 | AnotherException7 | AnotherException8 | AnotherException9 $e) {
   echo $e->getMessage();
}

While it's valid, it can give the false impression of clean code. Having too much exceptions is not a good [de]sign.

Inheritance with interfaces

I must admit I rarely use that one, but it's good to know:

interface Writable
{
    public function write();
}

interface Document extends Writable
{
    public function edit();
}

Do you need it?

It depends. If your interface contains too much methods, it probably means you are breaking the Interface Segregation Principle.

Comments

[CodeWithCaen]

A great question to ask is not just if we could, but if we should. However, in order to make an informed decision whether or not we should use something, we need to know all the facts. And for this reason, this article is fantastic. Thank you for sharing it!

[Nacho Colomina Torregrosa]

That's great ! In case of exceptions, we can create an interface that a set of exceptions implement and use such interface in the catch block.

[spO0q]

good point!