Si on savait depuis longtemps qui est pire que le C++, on ne le savait pas formellement : http://perlmonks.org/?node_id=663393 Perl Cannot Be Parsed: A Formal Proof In the man page for PPI, Adam Kennedy conjectures that perl is unparseable, and suggests how to prove it. Below I carry out a rigorous version of the proof, which should put the matter beyond doubt.