For example, say you have a class RecordCollection which contains an array @records. You could provide the lookup method #record_number(), which simply calls # on the @records array, like this:
class RecordCollection extend Forwardable def_delegator :@records, :, :record_number end
Further, if you wish to provide the methods #size, #<<, and #map, all of which delegate to @records, this is how you can do it:
class RecordCollection # extend Forwardable, but we did that above def_delegators :@records, :size, :<<, :map end
Also see the example at forwardable.rb.