C-Ast is a GNU Guile library for generating C code. There are some examples in the example directory, but briefly, it lets you turn s-expresions like:
(for ((= i 0) (< i limit) (+= i 1))
(call printf "i = %d\n" i))
Into C source code:
for (i = 0; i < limit; i += 1) {
printf("i = %d\n", i);
}
...which can then be fed through a C compiler.
This is interesting because it allows use of scheme to easily manipulate C programs -- many the same benefits of a proper lisp-style macro system can be used to write low-level code.
The intention is for this to be a building block for building other tools.
C-Ast is still in a very early stage of development -- you can write hello world, but it's missing a lot of important features and some documentation, and probably isn't packaged the way a guile library should be -- I'm still very new to the language.
To run the test suite, you will need an implementation of srfi-64. The one I use is: https://gitorious.org/srfi-64-port.