I see in this discussion: http://ruby.11.x6.nabble.com/ruby-dev-38392-Enumerable-gather-each-td3534746.html that
Enumerable#slice_before was named as such, having in mind the possibility of
Enumerable#slice_after being implemented in the future. I feel the former convenient, but believe the latter should be as well, and am wondering why the latter was not implemented at the same time. I request it to be implemented.