PHP: Can I Use Fields In Interfaces?

Question

In PHP, can I specify an interface to have fields, or are PHP interfaces limited to functions?

<?php interface IFoo {     public $field;     public function DoSomething();     public function DoSomethingElse(); } ?> 

If not, I realize I can expose a getter as a function in the interface:

public GetField(); 

Answer 1

You cannot specify members. You have to indicate their presence through getters and setters, just like you did. However, you can specify constants:

interface IFoo {     const foo = 'bar';         public function DoSomething(); } 

See http://www.php.net/manual/en/language.oop5.interfaces.php

Answer 2

Late answer, but to get the functionality wanted here, you might want to consider an abstract class containing your fields. The abstract class would look like this:

abstract class Foo {     public $member; } 

While you could still have the interface:

interface IFoo {     public function someFunction(); } 

Then you have your child class like this:

class bar extends Foo implements IFoo {     public function __construct($memberValue = "")     {         // Set the value of the member from the abstract class         $this->member = $memberValue;     }      public function someFunction()     {         // Echo the member from the abstract class         echo $this->member;     } } 

There's an alternative solution for those still curious and interested. :)