D Programming/Interfaces

There is an article in wikipedia describing the concept of interface in common.

The corresponding D specification is found on digitalmars.

An interface is something like a promise. A class implementing an interface promises to have at least all the listed methods. A class reference can be casted to the type of an implemented interface. This is useful, if another component is only interested in a certain aspect of an object.

Interface Declaration
interface Identifier {  //interface body begins here. }  //interface body ends here.