From: Chad Perrin <code@...>
Date: 2012-02-03T12:11:57+09:00
Subject: Re: problem with method

On Fri, Feb 03, 2012 at 11:55:13AM +0900, luk malcik wrote:
> Why method pole= doesn't work??
> 
> Kolo = Struct.new (:x,:y,:r)
> Kwadrat = Struct.new (:x,:y,:a)
> Prostokat = Struct.new (:x,:y,:a,:b)
> 
> module Domieszka
>    attr_accessor :x, :y
> 
>    def moveto(x,y)
>       @x = x
>       @y = y
>    end
> end
> 
> class Kolo
>    include Domieszka
>    def pole=
>    @r = r
>    pole = r * Math.PI
>    return pole
>    end
> end

I'm not entirely sure what you're trying to do.  Does this accomplish
what you want?

    class Kolo
      include Domieszka

      def pole=(r)
        @r = r
        r * Math::PI
      end
    end

Note that PI is a constant within Math's namespace, and not a method.
The period is used as a method call operator; the double-colon is a
namespace separator, used to access constants within the module's
namespace.

Also note that the pole= definition needs to have an argument defined for
it if you want to use that argument -- which I think is what you were
trying to do with that "r".

-- 
Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ]