From: Robert Klemme <bob.news@...>
Date: 2006-01-07T01:57:59+09:00
Subject: Re: How to override Numeric class

Bojan Mihelac wrote:
> Hi all,
> I am new to Ruby and am trying to overload "+" operator on Integer
> class, without success.
>
> class TestNum < Integer
>   def +(other)
>        self.value - other
>   end
> end
>
> puts TestNum.new(5)+5; # should return 0
>
> I know that it should be simple, but.... any help appreciated.

Did you look at the error?

?> TestNum.new(5)+5
NoMethodError: undefined method `new' for TestNum:Class
        from (irb):7
        from :0

Your problem starts already with the creation...  Integer is an abstract
class and I suspect it does something to #new.

You should also look at #coerce, see
http://www.rubygarden.org/ruby?CoerceExplanation for example if you want
to implement operators properly.

Kind regards

    robert