From: Peter Vandenabeele <peter@...>
Date: 2012-02-03T06:12:09+09:00
Subject: Re: moveto(x,y) method

--20cf30334973c6a68204b801a56c
Content-Type: text/plain; charset=UTF-8

On Thu, Feb 2, 2012 at 9:56 PM, luk malcik <aport99@gmail.com> wrote:

> How can I declare moveto method if I want to change co-ordinates (x,y)
> that are actually in object. That's my code:
>
>
> module Domieszka
>

You probably want a class here, so you can make
new instances of it. I could be a module, but then
you need to include it and that is more complicated
at this learning level .

  attr_accessor :@x
>   attr_accessor :@y
>

This should be

attr_accessor :x, :y




>
>   def inspect
>       "You are in: #{@x} #{@y}"
>   end
>
>   def moveto(x,y)
>

You have 2 choices. use the instance variable or use the accessors.
I demonstrate below with the instance variables:

@x, @y = x,y



>
>   end
> end
>
>
> For example if I wrote i=sthClass.new
> i.x = 4
> i.y = 5
> I have (4,5) object, and how to change x and y in object?
>

A full demo is this:

$ irb
...
class Domieska
  attr_accessor :x, :y
  def move_to(x,y)
    @x, @y = x,y
  end
end

018:0> d = Domieska.new
=> #<Domieska:0x8c2c150>
019:0> d.move_to(10,20)
=> [10, 20]
021:0> d.instance_variable_get(:@x)
=> 10


Actually here, in the more advanced "instance_variable_get"
you need the special :@x notation.

HTH,

Peter

--20cf30334973c6a68204b801a56c--