strategy.rb

class SortAlogrithm
  def quick_sort
  #...
  puts "quick_sort"
  end
  def bubble_sort
  #...
  puts "bubble_sort"
  end
end

sa = SortAlogrithm.new
option = "quick_sort"

# Two ways to call fun in runtime with ease
sa.__send__ option.to_sym
eval("sa."+option)