Experimenting with various lisps lately (clojure especially) i have wondered if there are any s expression based representations of (subsets) of c, so you could use lisp/closure to write macros and then convert the s-expression c tree to pure c.

I am not asking for a to-c-compilers of lisp/scheme/clojure but more of using lisps to transform a c syntax tree.

Little background to why i am asking this question: i find myself to really enjoy certain clojure macros like the threading macros -> doto etc. And i feel that they would be great in a non FP environment as well.