Actually why even specify metaprogram as C like source code? It must be convenience. But there is little practical use, like a good program always models a lot of different representations of more or less the same things, just recombined and processed a little differently. Why would we want to deal with semantics of C types for example, if we can model a much clearer and better constrained universe of types used in e.g. a de/serialization framework? Even only pointers are quite special, and often only of very immediate use, but there is no point in e.g. persisting them to disk or sending them over the network.