In Software for Infrastructure, Bjarne Stroustrup shows a way to use templates to make the C++ compiler aware of the unit of a value (e.g. kilograms, seconds, etc.), such that it can check consistent use and prevent disasters like the well known error at NASA in 1999 caused by mixing incompatible units. In this article, I show how to extend this idea to support any number of base units and linearly related units (e.g. centimetres, metres and inches) by teaching the compiler how to do arithmetic on units.
Recently, gcc added support rvalue references for
*this. (Clang has supported it for quite a while now.) In this post, I show how to use this feature, and how it means we can finally define accessors and a few other things like