From: Robert Klemme <shortcutter@...>
Date: 2008-04-12T17:10:18+09:00
Subject: Re: how to create random object to a particular ruby object ?

On 12.04.2008 07:50, Joel VanderWerf wrote:
> Martin DeMello wrote:
>> On Fri, Apr 11, 2008 at 2:17 AM, Pokkai Dokkai <bad_good_lion@yahoo.com> wrote:
>>> how to create random object  to a particular ruby object ?
>>>
>>>  for example i want like this
>>>
>>>  rand(Fixnum)   --> 345 (randomly)
>>>  rand(Float)    --> 3877.5545(randomly)
>>>  rand(String)   --> "sfskgksf" (randomly)
>>>  rand(boolean)  --> 0(randomly)
>> The cleanest way is to add the class method make_random to all your
>> classes. For example
> 
> Here is the dirtiest, wrongest, ugliest way to do it:
> 
> module ObjectSpace
>    def self.random_object(klass)
>      n = each_object(klass){}
>      i = rand(n)
>      each_object klass do |obj|
>        if i == 0
>          return obj
>        else
>          i -= 1
>        end
>      end
>      return nil
>    end
> end
> 
> p ObjectSpace.random_object(String)
> p ObjectSpace.random_object(Float)

This does not work well for Strings because you get only instances that 
do exist already when the method is called.  That way you a) have no 
clear definition of what you get (length, contained chars...) and b) you 
either need to dup or freeze the return value.  Both have their 
problems: #freeze has side effects and #dup does not work for all classes.

Kind regards

	robert