Sender

class Enumerator
  alias :e :each
end

# -----------------------------------------------------------------------------

# hash of send-array containing args
c = {
  op: [:puts, :self], #     OutPut  => puts str
  uc: [:self, :upcase], #   UpCase  => str.upcase
  en: [:self, :to_enum], #  Enum    => ar.to_enum
}

c.instance_exec {
  def →(cmd, *args)
    (self[cmd][0] == :self) ?
      args[0].send(self[cmd][1]) :
      send(self[cmd][0], *args)
  end
}

# -----------------------------------------------------------------------------

# hash of procs
» = {
  puc: proc {|str| c.→(:op, c.→(:uc, str)) },  #  puts UPCASE
  en: proc {|ar| c.→(:en, ar) }, #                return Enumerator
}

».instance_exec {
  def method_missing(key, *args)
    self.key?(key) ? self[key][*args] : super
  end
}

# -----------------------------------------------------------------------------

# example call
».en([*1..5]).e { ».puc("hej: #{it}") }

# => output
# HEJ: 1
# HEJ: 2
# HEJ: 3
# HEJ: 4
# HEJ: 5