gistfile1.rb

def triangle(a, b, c)
  Triangle.new(a, b, c).type
end

class Triangle
  def initialize(a, b, c)
    @sides = *a, b, c
  end

  attr_reader :sides

  def type
    if equilateral?
      :equilateral
    elsif isosceles?
      :isosceles
    else
      :scalene
    end
  end

  def equilateral?
    sides.uniq.length == 1
  end

  def isosceles?
    sides.uniq.length == 2
  end

  def scalene?
    !equilateral? and !isosceles?
  end
end