Function composition in Ruby

composition.rb

class Lambda < Proc

  def initialize(&block)
    @block = block
  end

  def >> (g)
    Lambda.new {|*args| g[*self[*args]]}
  end

  def method_missing(name, *args, &block)
    @block.send name, *args, &block
  end

end

def λ (&block)
  Lambda.new &block
end

double = λ {|x| x*2}
addOne = λ {|x| x+1}

puts double.(5)
puts addOne[double[5]]
puts (double >> addOne)[5]