class Range

:nodoc:

def as_json(options = nil) # :nodoc:

:nodoc: 
def as_json(options = nil) # :nodoc:
  to_s
end

def overlaps?(other)

(1..5).overlaps?(7..9) # => false
(1..5).overlaps?(4..6) # => true
Compare two ranges and see if they overlap each other 
def overlaps?(other)
  other.begin == self.begin || cover?(other.begin) || other.cover?(self.begin)
end

def sum(identity = nil)

we have a range of numeric values.
Optimize range sum to use arithmetic progression if a block is not given and
:nodoc: 
def sum(identity = nil)
  if block_given? || !(first.is_a?(Integer) && last.is_a?(Integer))
    super
  else
    actual_last = exclude_end? ? (last - 1) : last
    if actual_last >= first
      sum = identity || 0
      sum + (actual_last - first + 1) * (actual_last + first) / 2
    else
      identity || 0
    end
  end
end