That says to me you should be using types with strongly-typed units built in (using templates/generics etc). I wouldn't expect to able to call "Set unit" on a q

That says to me you should be using types with strongly-typed units built in (using templates/generics etc). I wouldn't expect to able to call "Set unit" on a quantity though, just a function to convert it and return the new differently typed quantity. Nor would you need "get unit" as it's known at compile time.