From: Intransition <transfire@...>
Date: 2010-10-13T22:59:28+09:00
Subject: Re: Options in a class



On Oct 13, 9:41 am, Paul Bergstrom <p...@palbergstrom.com> wrote:
> I have some problems understanding the basics of classes and modules in
> Ruby – and arg and options. How do you create a e g class that can take
> some options, but leave them out if not needed? This is what I'm
> familiar with now, sending along an arg to the method in a module.
>
> module Abc
> def self.test(arg)
> puts arg
> end
> end
>
> In this occasion I have to pass along a an arg, or nil, or there will an
> error. But how do I design my module so I can pass options, or leave
> them out if wanted? Like:
>
> Abc.test(:color => 'red') or Abc.test()

Simply:

  class Abc
    def initialize(opts={})
      @color = opts[:color]
    end
  end

But I usually do:

  class Abc
    attr_accessor :color
    def initialize(opts={})
      opts.each do |k,v|
        send("#{k}=", v)
      end
    end
  end

Also, if you want args and opts,

    def initialize(*args)
      opts = (Hash === args.last ? args.pop : {})
      ...