Have a look at D, its metaprogramming facilities are really something. In particular string mixins will do what you want; they will also do much more, like for

Have a look at D, its metaprogramming facilities are really something. In particular string mixins will do what you want; they will also do much more, like for instance include external files written in domain specific languages and compile them in native D code; all this is done by the compiler, using language facilities, without external tools. (These is not some theoretically cool feature; it's used in real world code, like dproto, which compiles protobuf definitions into native code, or HTML templating engines which compile templates to the equivalent of Java servlets)