def compare_source_offsets(a, b)
      diff = a[0] - b[0]
      diff = a[1] - b[1] if diff == 0

      if diff < 0
        -1
      elsif diff > 0
        1
      else
        0
      end
    end
def compare_source_offsets(a, b)
      diff = a[0] - b[0]
      diff = a[1] - b[1] if diff == 0

      if diff < 0
        -1
      elsif diff > 0
        1
      else
        0
      end
    end
Public: Compare two source map offsets.

 Compatible with Array#sort.

 a - Array [line, column]
 b - Array [line, column]

 Returns -1 if a < b, 0 if a == b and 1 if a > b.