Comment by colonwqbang

Compilers follow the "as if" principle, they don't have to literally follow the formal rules given by the standard. They could implement #embed by doing as you say, pretty printing out numbers and then parsing them back in again. But that would be an extremely roundabout way to do it, so I doubt anyone will actually do it that way. Unless you're running the compiler in some kind of debugging mode like GCC's -E.