[vertex-four]

One language that does support syntax extensions from macros is the Metalua extensions to Lua. There's a bunch of special syntax allowing you to hook into the parser and modify it while it parses a file.

[alco]

There's also Racket[1] and Rust[2].

[1]: http://queue.acm.org/detail.cfm?id=2068896 [2]: http://static.rust-lang.org/doc/0.10/guide-macros.html