autocall.rb

module AutoCall

  def method_missing(method, *args)
    __send__(find_nearest_method(method), *args)
  end

  private

  def find_nearest_method(method)
    methods.sort_by{ |my_method|
      levenshtein_distance(my_method, method)
    }.first
  end

  # http://d.hatena.ne.jp/kenkitii/20090204/ruby_levenshtein_distance
  def levenshtein_distance(str1, str2)
    col, row = str1.size + 1, str2.size + 1
    d = row.times.inject([]){|a, i| a << [0] * col }
    col.times {|i| d[0][i] = i }
    row.times {|i| d[i][0] = i }

    str1.size.times do |i1|
      str2.size.times do |i2|
        cost = str1[i1] == str2[i2] ? 0 : 1
        x, y = i1 + 1, i2 + 1
        d[y][x] = [d[y][x-1]+1, d[y-1][x]+1, d[y-1][x-1]+cost].min
      end
    end
    d[str2.size][str1.size]
  end
end

list = [1,2,3,4]

list.instance_eval{
  extend AutoCall
}

puts list.lengtththhth          # => 4
p list.revvvvvvvvvvvvvvverse    # => [4, 3, 2, 1]