From: ahoward <ahoward@...>
Date: 2003-06-12T05:15:26+09:00
Subject: Re: Multiple Initialize methods?

On Wed, 11 Jun 2003, Nick wrote:

> Hi,
>
> I need to create a class either with a param in the construction or nothing:
>
> something = Object.new
>
> or
>
> something = Object.new(val1, val2)
>
> I have created an emtpy initialize() method and one with the two params.  If
> I try to create the object with nothing (first version) then I get
> "ArgumentError: wrong number of arguments(0 for 2)".
>
> class Something
>  def initialize()
>  end
>  def initialize(xdim, ydim)
>   @xdim = xdim
>   @ydim = ydim
>  end
>
> I put the empty initialze in when things didnt work, thinking i needed at
> least a marker.
>
> Thanks for any help,

ruby does not support method overloading - you may only a single method
signature for a give name.  you can do something like:

~ > cat foo
class Klass
  def initialize(*args)
    args.size == 0 ?
      init0() :
      init1(*args[0..1])
  end
private
  def init0
    @x = 4
    @y = 2
  end
  def init1 x, y
    @x = x
    @y = y
  end
  def inspect; @x.to_s << @y.to_s; end
end

k = Klass.new
p k
k = Klass.new 4, 2
p k

class Klass
  def initialize args = {}
    @x = args[:x] || 4
    @y = args[:y] || 2
  end
end

k = Klass.new
p k
k = Klass.new :x => 4, :y => 2
p k

~ > ruby foo
42
42
42
42


-a
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