Data-Walk

Data::Walk is for data, what File::Find is for file systems. You can use it for traversing arbitrarily complex Perl data structures.

Its closest relatives on CPAN are currently Data::Traverse and Data::Walker. Data::Traverse is very similar but can only handle unblessed references and has less options. Data::Walker offers an interactive approach for traversing data structures.

Data::Dumper also offers some callbacks when traversing the structures, but not the ones that I needed. That was motivation enough for writing Data::Walk.