We use this at our startup. We have a Haskell math library where every vector/matrix/rotation knows the spaces they deal with (World, Camera, etc), and using th

We use this at our startup. We have a Haskell math library where every vector/matrix/rotation knows the spaces they deal with (World, Camera, etc), and using them with incorrect spaces is a type error. This is enormously useful because in 3D computer vision/graphics almost everything is 3 or 4-dimensional, so it's very easy to use them the wrong way. When you read C++ computer vision code a datatype often has a Matrix3 or worse yet a double[] in it and you have no idea what coordinate system (or even matrix order) it represents. With this, it's all self-documenting and difficult to get wrong.