That is more about functional programming than laziness, but maybe I am splitting hairs. OpenGL, for example, implements the matrix stack functionality, and the

That is more about functional programming than laziness, but maybe I am splitting hairs. OpenGL, for example, implements the matrix stack functionality, and then it only works for one class. A lot of work then to get ky everywhere you need it. Clojure is doing a lot of work with fusion and sequences to transfer laziness from arrays up to the other objects that consume them, but it is harder as you go farther away.