what do I need to know to understand camlp4

[ben kuin <benkuin@gmail.com>]

hi
I'm a Ocaml n00b (without any degree). Therefore I have a faible for
everything that makes Ocamls syntax more algol/imperative like [1]. An
example would be an extension like 'newref'
(http://bitbucket.org/johannes/newref/wiki/Home), which turns:

    print_int !i       into       print_int $i    (* newref *)

so I fiercely try to also perlify the declaration that turns

     let i = ref 3     into        let $i = 3     (* my idea ... *)

but camlp4 makes my head spin. The syntax is very difficult and in a
lot of camlp4 documentation there is AST modification involved, which
is a subject I don't get although I made several attempts. And simple
program transformation with camlp4 (using concrete syntax) is nowhere
documented.

Could someone give any idea how I can begin to understand how to write
simple camlp4 extensions?

thanks
ben

[1] please don't kill me