module ActiveSupport::CompareWithRange

def ===(value)

The given range must be fully bounded, with both start and end.

(5..9) === (11) # => false
('a'..'f') === ('c') # => true
The native Range#=== behavior is untouched.

(1..5) === (2..6) # => false
(1..5) === (1...6) # => true
(1..5) === (2..3) # => true
(1..5) === (1..5) # => true
Extends the default Range#=== to support range comparisons. 
def ===(value)
  if value.is_a?(::Range)
    is_backwards_op = value.exclude_end? ? :>= : :>
    return false if value.begin && value.end && value.begin.public_send(is_backwards_op, value.end)
    # 1...10 includes 1..9 but it does not include 1..10.
    # 1..10 includes 1...11 but it does not include 1...12.
    operator = exclude_end? && !value.exclude_end? ? :< : :<=
    value_max = !exclude_end? && value.exclude_end? ? value.max : value.last
    super(value.first) && (self.end.nil? || value_max.public_send(operator, last))
  else
    super
  end
end