ruby: define_method vs. def

as programming exercise, i've combined flush dash creates class, instantiates twin objects class, monkeypatches object, relies method_missing monkeypatch one.

here's deal. works intended:

class monkey

  def chatter
    puts "i am chattering monkey!"
  end

  def method_missing(m)
    puts "no #{m}, i'll one..."
    def screech
      puts "this new screech."
    end
  end
end

m1 = monkey.new
m2 = monkey.new

m1.chatter
m2.chatter

def m1.screech
  puts "aaaaaargh!"
end

m1.screech
m2.screech
m2.screech
m1.screech
m2.screech

you'll notice i have parameter method_missing. i since i anticipating define_method boldly emanate blank methods suitable name. however, doesn't work. fact, even controlling define_method stationary name so:

def method_missing(m)
  puts "no #{m}, i'll one..."
  define_method(:screech) do
    puts "this new screech."
  end
end

ends following result:

argumenterror: wrong array arguments (2 1)

method method_missing   untitled request during line 9
method method_missing   untitled request during line 9
at tip turn    untitled request during line 26
program exited.

what creates blunder summary some-more bewildering i wholly have justification method_missing...