A tail-recursive Ruby method to split a date range into smaller month-based date ranges.

months.rb

RubyVM::InstructionSequence.compile_option = {
  :tailcall_optimization => true,
  :trace_instruction => false
}

RubyVM::InstructionSequence.new(<<-RUBY).eval
  def acc(start_date, end_date, accu)
    if start_date >= end_date
      accu + [end_date]
    else
      acc(start_date >> 1, end_date, accu + [start_date])
    end
  end
  
  def months(start_date, end_date)
    acc(start_date, end_date, [])
  end
RUBY