Re: New array methods cycle, choice, shuffle (plus bug in cycle)

Martin Duerst wrote:
> At 07:11 07/09/07, David Flanagan wrote:
>> Four new methods have been added to Array the Ruby 1.9 trunk.  I've got a couple of questions and comments and one bug report:
>>
>> cycle is an iterator that is like calling each on the array within an infinite loop. Matz: have you considered generalizing this to be a method of Enumerable?
> 
> This would be great, but probably won't work, because Enumerable
> (or something else) would have to store all the elements cicled
> through, because that's not necessarily done by the class that
> includes Enumerable.

Here's a trivial implementation that only works for Enumerables that 
have an empty? method:

module Enumerable
   def cycle &b
     each &b until empty?
   end
end

And here's a version that tests for emptiness itself:

module Enumerable
   def cycle
     loop do
       empty = true
       each do |x|
         empty = false
         yield x
       end
       break if empty
     end
   end
end

	David