ArgumentError in #new, Subclassing Enumerator

问题

I'm subclassing Enumerator like this:

class CuadraticPrimeGenerator < Enumerator
  def initialize(a=1,b=49)
    super do |y|
      x = 1
      loop do 
        y << x**2 + a*x + b
        x += 1
      end
    end
  end
end

However...

> CuadraticPrimeGenerator.new(1,49)
0027.rb:41:in `initialize': 49 is not a symbol (TypeError)
    from 0027.rb:41:in `initialize'
    from 0027.rb:48:in `new'
    from 0027.rb:48:in `<main>'

Thoughts?

回答1:

What about:

class CuadraticPrimeGenerator < Enumerator
  def initialize(a=1,b=49)
    super() do |y|
      count, x = 0, 1
      loop { y.yield(x**2 + a*x + b) }
    end
  end
end

来源：https://stackoverflow.com/questions/16016995/argumenterror-in-new-subclassing-enumerator