An attempt at monads in ruby

monad.rb

class Array
  def m_return(value)
    [value]
  end

  def m_bind(f)
    self.map(&f).flatten
  end
end

arr = [4, 5]

a = arr.m_bind(lambda { |x| [x * x] })
p a

b = a.m_bind(lambda { |x| [x + x] })
p b

# OUTPUT:
# λ ppc temp → ruby monad.rb
# [16, 25]
# [32, 50]