05. Schema Proposal:
The META spec should come along with a formal schema definition. (SlavenRezic) Comments: * There are at least two schema languages available for this task, both with a Perl implementation: Kwalify and Data::Rx. For the old META 1.3 spec an attempt to define a Kwalify schema [http://cpansearch.perl.org/src/SREZIC/Kwalify-1.20/t/testdata/META-spec-1.3.yml] exists. As you can see from the embedded comments, some parts of the current META spec are not clear enough. * Note that Kwalify does not define a "any of" type (but Rx does). This type would be necessary if definitions like "author may be a scalar or a list" would be allowed. I am willing to implement any-of as a non-standard extension to Kwalify. But maybe the META definition should be as simple as possible?