From: Leslie Viljoen <leslieviljoen@...>
Date: 2008-05-30T00:56:47+09:00
Subject: Re: Surprising Extend

On Thu, May 29, 2008 at 5:45 PM, David Masover <ninja@slaphack.com> wrote:
> On Thursday 29 May 2008 10:36:27 Leslie Viljoen wrote:
>> >
>> > Can you show some real code and real error messages?  Normally there
>> > should not be an issue with your first approach.
>> ----In StringExt.rb:
>>
>> module StringExt
>>       def to_hex
>>               unpack("C*").map{|b| b.to_s(16)}.join(" ")
>>       end
>> end
>>
>> ----In use.rb:
>>
>> require 'StringExt'
>>
>> String.extend StringExt
>> s = "anystringwilldo"
>> puts s.to_hex
>
> I'm not sure, but considering that you can extend individual instances, that
> method has probably become a class method for String? As in, String.to_hex?
>
> But your _first_ approach should work. In StringExt.rb:
>
> class String
>  def to_hex
>    unpack("C*").map{|b| b.to_s(16)}.join(" ")
>  end
> end
>
> In use.rb:
>
> require 'StringExt'
> s = 'anystringwilldo'
> puts s.to_hex
>
> For me, running use.rb outputs
>
> 61 6e 79 73 74 72 69 6e 67 77 69 6c 6c 64 6f
>
> tested in both Ruby 1.8 and Ruby 1.9.

Oh ok. And then I can use 'extend' when I want to extend an instance.
Thanks!

Les