Perl::Lexer is a lexer library for Perl5. It supports full spec perl5 code. Why? We can create some language related tools on Perl5 lexer library. Why is it good? It uses Perl5 code for lexical analyzing. It means the lexical analyzing rules are just compatible with Perl5 code. Why is it bad? It calls perl5's internal APIs. Related things Compiler::Lexer is written from scratch. PPI is great perl5