I've been using Devel::REPL for a while now. Like all good modules (Perl::Critic, POE, Plagger, etc), it's very extensible. Devel::REPL's design is worth studying: keep a simple core and ship all the fancy behavior as plugins. Moose amplifies the power and convenience of this design with roles, method modifiers, and general awesomeness. There are plugins to dump output with Data::Dump::Streamer, e