                               Set::Relation
---------------------------------------------------------------------------

Following is a summary of things that still need doing.

* Add these 20 relational operators: wrap, cmpl_wrap, unwrap, group,
cmpl_group, ungroup, summary, join_with_group, rank, limit, substitution,
static_substitution, substitution_in_restriction,
static_substitution_in_restriction, substitution_in_semijoin,
static_substitution_in_semijoin, outer_join_with_group,
outer_join_with_undefs, outer_join_with_static_extension,
outer_join_with_extension.

* Add code examples, tutorial, cookbook, FAQ, etc.

* Make the test suite actually run the code, not just compile it; maybe
start off with running same code examples in documentation, tutorial, etc.

* Consider adding public operators such as for comparing headings eg for
disjointness etc, mirroring some set operators, perhaps to help users
implement more operators?

* Consider adding disjoint insertion, union operators (same as normal but
fails on a duplicate).

* Consider adding support for explicit keys / unique key constraints on
Set::Relation objects.

* Consider adding more mutator methods.

* Improve performance.

* Port this to Perl 6 again; meanwhile, a much older initial version
pre-dating this Perl 5 rewrite already exists FYI.

* Whatever else needs doing, such as, fixing bugs.
