This is a skeletal design, added to support the overview. It should not be treated as accepted by the core team; rather, it is a placeholder until we have more time to examine this detail. Please feel welcome to rewrite and update as appropriate.
See proposal PR 89 for context -- that proposal may replace this.
Carbon provides metaprogramming facilities that look similar to regular Carbon code. These are structured, and do not offer inclusion or arbitrary preprocessing of source text such as C and C++ do.