]> Thanks, Matthieu and Jake, this is exactly what I had in mind. At the end, Camlp4 was the right solution to my simple problem, as I suspected from the beginning. Camlp4 is an extremely powerful tool and it's a pity it couldn't be used by everyone for lack of documentation. What is really needed, in my opinion, is a description of *what* one can do with Camlp4 without being an expert. For example a list of all syntax extension available out of the box might spread the use of Camlp4 among common programmers. Searching in the source code I can see things named: Camlp4ExceptionTracer, Camlp4FoldGenerator, Camlp4MetaGenerator, and so on. The names sounds great but... what is it? The source code is cryptic to every "regular" OCaml programmer like me. The same considerations apply to all the (many!) libraries available and related to Camlp4. What is needed to spread the use of this tool are some... recipes, like those available for ocamlbuild in its wiki pages. -- Paolo ~ ~ :wq