Debug core modules

Hi, is there a way to debug core modules like IO::Socket::INET? Thanks, Massimo

Could you give me some explanatio​ns about regex?

I've written this code: use v6; my $file =3D open us_foreign_assistance.xml; for $file.lines - $line { extract($line); } sub extract($line) { if $line ~~ m/ \ (\w+) \ / { say $/[0]; } } The xml file contains: ?xml version=3D1.0 encoding=3DUTF-8 standalone=3Dyes?