Parse, Analyze and Manipulate Perl (without perl)

The purpose of PPI is not to parse Perl *Code*, but to parse Perl
*Documents*. By treating the problem this way, we are able to parse a
single file containing Perl source code "isolated" from any other
resources, such as libraries upon which the code may depend, and without
needing to run an instance of perl alongside or inside the parser.

Authors:
    Adam Kennedy <adamk@cpan.org>