Well, one way is source filters - however I'd strongly recommend against them! They can break Perl code in really strange and unexplained ways (just one example being the Switch module, e.g. Perl Code Changes Behavior if Two Subroutine definitions are swapped). If you still want to take a peek, the module Data::Dumper::Simple uses a source filter. As you can tell your pprint idea is one that has been thought about often - unfortunately with no really good answers, partly because of the reasons I named in my update.