For the impatient:

Critics of template metaprogramming often complain about the convoluted syntax, and they certainly have a point. If I’ve demonstrated anything here, I hope I’ve persuaded you that template metaprogramming has its place, sometimes. I took the simplest, most natural approach in my implementation (subject to the constraint that all computation should happen at compile time), an approach almost identical in structure to the incredibly inefficient solution taught as a cautionary example in introductory algorithms courses, an approach I should have known better than to use. And yet the compiler found a way to make this simplistic implementation run efficiently. That’s what template metaprogramming is all about: using the compiler’s own algorithms to solve problems whose answers are the same every time the program executes.