From: Gregory Brown <gregory.t.brown@...>
Date: 2008-08-08T12:01:30+09:00
Subject: [ruby-core:18187] Re: New array methods cycle, choice, shuffle (plus bug in cycle)

On Thu, Aug 7, 2008 at 10:54 PM, Charles Oliver Nutter
<charles.nutter@sun.com> wrote:
> Florian Frank wrote:

>> Because nobody has mentioned this yet: I know, that rails defines a method
>> with that name in Array, but I think it is a bad idea. It breaks existing
>> and future code, that expects Array#rand to be Kernel#rand and have the same
>> signature and semantics of it, while being in context of  an Array instance.
>> It makes it much more difficult to get any random number out of ruby in this
>> context, even if you are aware of Array#rand.
>
> Kernel#rand is not callable as a method:
>
> ruby -e "[1,2,3].rand"
> -e:1: private method `rand' called for [1, 2, 3]:Array (NoMethodError)
>
> So this argument would only affect methods calling rand from within instance
> methods on Array or subclasses of it. I think the danger of overwriting
> Kernel#rand in a way that would break user code is pretty low.

I don't think it's terribly unlikely that someone will have a subclass
like this:

class Array
  def rand
    "o hai"
  end
end

class Foo < Array
  def bar
    rand(20)
  end
end

puts Foo.new.bar


But since I pretty much loathe the idea of subclassing core classes, I
don't mind breaking them :)

-greg

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