PHP/interface

About

In PHP, an interface is a set of public method-functions which can be required in either of two circumstances:

• in the declaration of a class
  • This works almost identically to declaring the interface's methods as abstract functions in a trait or parent class.
• the type of a function argument or return value
  • Advantages over declaring the object as a class:
    • narrows down (more closely specifies) the function's expectations of a passed or returned object
    • does not tie the object to a specific class hierarchy

Predefined

• instanceof works with both classes and interfaces
  • official
• interface_exists() returns TRUE if the interface has been declared in code that has executed.
  • official

Links

• official: interfaces
• 2018-01-13 PHP Interfaces Explained