goccy san released Compiler::Lexer. It is a lexical analyzer written in C++. It can analyze Perl5 code. I write a Perl::MinimumVersion::Fast based on Compiler::Lexer. Perl::MinimumVersion is built on PPI, is not so fast. And PPI is a parser. It's over kill to detect required perl5 version. Here is a benchmarking result of these two modules: Rate Perl::MinimumVersion Perl::MinimumVersion::Fast Perl