This is Perl module Sub::Sequence.
Sub::Sequence installation is straightforward. If your CPAN shell is set up, you should just be able to do
% cpan Sub::Sequence
Download it, unpack it, then build it as per the usual:
% perl Makefile.PL % make && make test
Then install it:
% make install
Sub::Sequence documentation is available as in POD. So you can do:
% perldoc Sub::Sequence
Sub::Sequence is hosted on github http://github.com/bayashi/Sub-Sequence
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.
Dai Okabayashi <email@example.com>