delegates and interfaces

In trying to explain some functional concepts in C# to an OO programmer, it became apparent that there is a quite clear correspondance between an interface and a delegate (function pointer).

The following is a list of comparisons:

1. An interface provides a level of indirection/abstraction for a class - a delegate provides a level of indirection/abstraction for a function
2. An interface provides signatures for a bunch of functions/properties - a delegate provides signatures for a function
3. both can be passed as variables
4. An interface will only work with an object, whereas a delegate can work with static and instance methods
5. Finally, delegates can be "invoked" or called asynchronously
6. An interface quite clearly relates to a class
7. An class can only implement an interface once, but can have many functions, which match a delegate

In many cases a delegate can provide simpler implementation than an interface, especially when the function is stateless and can therefore be made static therefore reducing side-effects. Its food for thought anyway!