custom-enumerable-collect-concat.rb

require 'forwardable'

class RecordRelation
  extend Forwardable
  include Enumerable

  attr_reader :records
  def_delegators :@records, :each

  def initialize(records_array)
    @records = records_array
  end
end

class Bar
end

class Foo
  def bars
    RecordRelation.new(5.times.map { Bar.new })
  end
end

foos = [Foo.new, Foo.new]

puts foos.collect_concat(&:bars).inspect
# Gives
# [
#   #<RecordRelation:0x00007fe3218e1ed8 @record_class=Bar, @records=[#<Bar:0x00007fe3218e2388>, #<Bar:0x00007fe3218e2338>, #<Bar:0x00007fe3218e2298>, #<Bar:0x00007fe3218e2180>, #<Bar:0x00007fe3218e2018>]>,
#   #<RecordRelation:0x00007fe3218e1640 @record_class=Bar, @records=[#<Bar:0x00007fe3218e1c58>, #<Bar:0x00007fe3218e1960>, #<Bar:0x00007fe3218e1938>, #<Bar:0x00007fe3218e1848>, #<Bar:0x00007fe3218e1758>]>
# ]
#
# but I want
# <#RecordRelation:0x000000000DEADBEEF @record_class=Bar,
#   @records=[
#     #<Bar:0x00007fe3218e2388>,
#     #<Bar:0x00007fe3218e2338>,
#     #<Bar:0x00007fe3218e2298>,
#     #<Bar:0x00007fe3218e2180>,
#     #<Bar:0x00007fe3218e2018>,
#     #<Bar:0x00007fe3218e1c58>,
#     #<Bar:0x00007fe3218e1960>,
#     #<Bar:0x00007fe3218e1938>,
#     #<Bar:0x00007fe3218e1848>,
#     #<Bar:0x00007fe3218e1758>
#   ]
# >
#
# or just
# [
#   #<Bar:0x00007fe3218e2388>, 
#   #<Bar:0x00007fe3218e2338>,
#   #<Bar:0x00007fe3218e2298>,
#   #<Bar:0x00007fe3218e2180>,
#   #<Bar:0x00007fe3218e2018>,
#   #<Bar:0x00007fe3218e1c58>,
#   #<Bar:0x00007fe3218e1960>,
#   #<Bar:0x00007fe3218e1938>,
#   #<Bar:0x00007fe3218e1848>,
#   #<Bar:0x00007fe3218e1758>
# ]