The Apply operator

The Apply operators allows you to partially apply a function:

DelFunc.DF1 add = (int a, int b) => a + b;

var addTwo = add.Apply(a: 2);

var twoPlusThree = addTwo.Invoke(b: 3);
DelFunc.DF1 is a Delegate Function. Delegate Functions is a way to support treating lambdas as functions.

In the example above, Apply returns a function that takes an integer b and returns b + 2.