From: John Barnette <jbarnette@...>
Date: 2009-06-18T01:28:24+09:00
Subject: Re: private method - Fixnum (NoMethodError)

Hi,

On Wed, Jun 17, 2009 at 9:13 AM, salai<sayakyi@gmail.com> wrote:
> I can't find the error in my code. Can you explain me "private method
> -  Fixnum (NoMethodError)"?
>
> def subtotal(qty = 1)
>        return nil if self.to_f <= 0 || qty.to_f <= 0
>        self.to_f * qty.to_f
> end
>
> apple = 11
>
> puts apple.subtotal(2)

You've defined the 'subtotal' method in the global scope, which is
equivalent to defining a private instance method on Object. Private
methods can't be called with a receiver. If you really want to do this
(this method seems bizarre to me), you'll want to reopen one or more
of the numeric classes and define your method there, e.g.,

class Fixnum
  def subtotal qty = 1
    return nil if to_f <= 0 || qty.to_f <= 0
    to_f * qty.to_f
  end
end

apple = 11

puts apple.subtotal(2)
# 22.0


~ j.