I recently read a post by Phillip Larkson where the C preprocessor was used to implement a four-bit adder entirely at compile time. This got me wondering whether I could implement the same concept using C++ template metaprogramming. It seemed theoretically possible as all the components can be calculated at runtime, but I wanted to avoid making use of the preprocessor for anything but supplying the original values to be added. The goal was to compile something on the command line like:
