From: Robert Klemme <bob.news@...>
Date: 2005-08-16T22:46:14+09:00
Subject: Re: newbie, to_s question

EdUarDo wrote:
> Hi all, I have this class:
> 
> class Tactic
>      attr_reader :name, :cells
>      class Cell
>          attr_reader :x, :y, :position, :playerId
>          attr_writer :x, :y, :position, :playerId
>          def initialize(x, y, position)
>              @x = x
>              @y = y
>              @playerId = 0
>              @position = position
>          end
> 
>          def to_s
>              puts "(#@x, #@y): #@position, #@playerId"
>          end
>      end
> 
>      def loadDefaultTactic
> file = File.new('tactics.dat')
> # Identificador de la tactica
> @name = file.readline
> # Posiciones
> file.each(';') {
>     |line| coords = line.split(',')
>     x, y = coords[0].to_i, coords[1].to_i
>     @cells << Cell.new(x, y, getPosition(x, y))
> }
> file.close
>      end
> 
>      def initialize
>          @cells = Array.new
>          # TODO Hay que leer el fichero de datos y cargar la tactica
>      por defecto end
> 
>      def to_s
> puts "#@name"
>      end
> end
> 
> 
> I do:
> 
> tactic = Tactic.new
> tactic.loadDefaultTactic
> puts tactic
> 
> and get:
> 
> 4-4-2
> #<Tactic:0xb78db8fc>
> 
> 
> Why do I get the internal representation of Tactic?

Because your to_s method returns nil. You want this

def to_s() @name.to_s end

and not

def to_s() puts "#@name" end

> Why is not the response '4-4-2' only?

Maybe you have an error in the reading code (file.each for example).

I'd also use the block form:

File.open('tactics.dat') do |file|
  # read
end

Kind regards

    robert