From: "Mehr, Assaph (Assaph)" <assaph@...>
Date: 2004-03-19T11:47:22+09:00
Subject: Re: exiting each (was Thinking about a date-matching algorithm...)

Sam Roberts wrote:
> Similar problem with detect, etc., once the times yielded are out of
> range, I'm not interested anymore, and want to break.
>
> What to do?

You can use throw & catch:

class A
    def each
        item = firstItem
        items = []
        catch (:done) do 
            loop do
                throw :done if reachedLimit(item)
                items << item
                yield item
                item = item.succ
            end
        end
        items
    end
    
    include Enumerable
    def firstItem; 0; end
    def reachedLimit(item); item > 10; end
end

a = A.new
p a.include?(3)
p a.include?(11)
p a.each { |i| puts i }