In cxx-basic, "split" is written with ast but inconsistant with the new one. You can rewrite it with concrete syntax as an exercise. Remember that this filter is not so simple as it can be believed (e.g., "T T, S;" is not equivalent to "T T; T S;", see the ISO/IEC std). Have a good work. -- Valentin David valentin(a)lrde.epita.fr