From: Robert Klemme <shortcutter@...>
Date: 2010-01-28T05:50:06+09:00
Subject: Re: Class with Multi Constrcutor ( initialize )

On 27.01.2010 16:58, Pierre Lecocq wrote:
> Hello Mido,
>
> There are several solutions to this problem.
>
> The first one is this equivalent of vaargs in C language
>
> def initialize(*args)
>    args.each do |a|
>      puts a.class.inspect
>    end
> end
>
> The second one is to pass a hash or an array in parameter.
>
> And the third is to put default values to your args:
>
> def initialize(var1='', var2=0, var3=nil)
> end
>
> Hope i helped !

A solution like this was proposed for overloading once but it does not 
seem to be widely used:

irb(main):001:0> def overload(*a)
irb(main):002:1> case a.map {|x|x.class}
irb(main):003:2> when [String]
irb(main):004:2> puts "a single string"
irb(main):005:2> when [Fixnum, String]
irb(main):006:2> puts a[1] * a[0]
irb(main):007:2> else
irb(main):008:2* raise ArgumentError, "can't %p" % a
irb(main):009:2> end
irb(main):010:1> end
=> nil
irb(main):011:0> overload "foo"
a single string
=> nil
irb(main):012:0> overload 2, "foo"
foofoo
=> nil
irb(main):013:0> overload 2
ArgumentError: can't 2
         from (irb):8:in `overload'
         from (irb):13
         from /usr/local/bin/irb19:12:in `<main>'
irb(main):014:0>

You can even shorten that to

case a.map(&:class)
...

Kind regards

	robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/