Cppo is an equivalent of the C preprocessor targeted at the OCaml language
and its variants.

The main purpose of cppo is to provide a lightweight tool for simple macro
substitution (#define) and file inclusion (#include) for the occasional case
when this is useful in OCaml. Processing specific sections of files by
calling external programs is also possible via #ext directives.

The implementation of cppo relies on the standard library of OCaml and on
the standard parsing tools Ocamllex and Ocamlyacc, which contribute to the
robustness of cppo across OCaml versions.