# Re: Next and Previous Articles **URL:** \ **Category:** Radiant CMS\ **Created:** [September 6, 2006, 9:26pm UTC](https://www.ruby-forum.com/t/re-next-and-previous-articles/67794 "2006-09-06T21:26:55Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![df-sean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f07891/32.png) [@df-sean](https://www.ruby-forum.com/u/df-sean)\ **Post date:** [September 6, 2006, 9:26pm UTC](https://www.ruby-forum.com/t/re-next-and-previous-articles/67794/1 "2006-09-06T21:26:55Z")
Keith B. wrote: > Not as elegant as John’s, but for some reason current.siblings > returns an empty array. FWIW, the problem wasn’t that current.siblings was returning null. Rather, the problem was that current.siblings returns a list that doesn’t include the current page [1], so siblings.index(current) was returning null. Calling “self\_and\_siblings” instead of “siblings” works fine. Here’s the corrected version: class Behavior::Base define\_tags do ``` tag "next" do |tag| current = tag.locals.page by = tag.attr['by'] || 'title' siblings = current.self_and_siblings.sort_by { |page| ``` page.attributes[by] } index = siblings.index(current) next\_page = siblings[index + 1] if next\_page tag.locals.page = next\_page tag.expand end end ``` tag "previous" do |tag| current = tag.locals.page by = tag.attr['by'] || 'title' siblings = current.self_and_siblings.sort_by { |page| ``` page.attributes[by] } index = siblings.index(current) previous = siblings[index - 1] if previous tag.locals.page = previous tag.expand end end end end - Sean [1] [Peak Obsession](http://ar.rubyonrails.com/classes/ActiveRecord/Acts/Tree/) ClassMethods.html ---
**Author:** ![df-sean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f07891/32.png) [@df-sean](https://www.ruby-forum.com/u/df-sean)\ **Post date:** [September 11, 2006, 10:03pm UTC](https://www.ruby-forum.com/t/re-next-and-previous-articles/67794/2 "2006-09-11T22:03:04Z")
On 06/09/06, Sean S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Here’s the corrected version: If I want to use these behaviours, how do I go about that? 🙂 – Regards, Dave ---
**Author:** ![df-sean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f07891/32.png) [@df-sean](https://www.ruby-forum.com/u/df-sean)\ **Post date:** [September 11, 2006, 10:43pm UTC](https://www.ruby-forum.com/t/re-next-and-previous-articles/67794/3 "2006-09-11T22:43:10Z")
> If I want to use these behaviours, how do I go about that? 🙂 Oh, and if you were also wondering how you would actually use the tags once you’ve got the behavior installed, here’s an example: \\\ \\\ - Sean ---
**Author:** ![df-sean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f07891/32.png) [@df-sean](https://www.ruby-forum.com/u/df-sean)\ **Post date:** [September 11, 2006, 10:39pm UTC](https://www.ruby-forum.com/t/re-next-and-previous-articles/67794/4 "2006-09-11T22:39:08Z")
> If I want to use these behaviours, how do I go about that? 🙂 Create a file named “00\_next\_previous\_behavior.rb”, paste in the code, and save it to your radiant/app/behaviors directory. Then restart the app. HTH, - Sean ---
**Author:** ![df-sean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f07891/32.png) [@df-sean](https://www.ruby-forum.com/u/df-sean)\ **Post date:** [September 12, 2006, 1:46pm UTC](https://www.ruby-forum.com/t/re-next-and-previous-articles/67794/5 "2006-09-12T13:46:45Z")
On 11/09/06, Sean S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: Hi Sean, Thanks for the quick response! 🙂 > > If I want to use these behaviours, how do I go about that? 🙂 > > Create a file named “00\_next\_previous\_behavior.rb”, paste in the > code, and save it to your radiant/app/behaviors directory. Then > restart the app. There was no radiant/app directory so I’ve created it and its behaviors child. I now get these errors: undefined tag `previous' undefined tag `next’ Could this work if it was packaged as a plugin? – Regards, Dave ---
**Author:** ![df-sean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f07891/32.png) [@df-sean](https://www.ruby-forum.com/u/df-sean)\ **Post date:** [September 12, 2006, 3:08pm UTC](https://www.ruby-forum.com/t/re-next-and-previous-articles/67794/6 "2006-09-12T15:08:57Z")
On 12/09/06, Sean S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > There was no radiant/app directory so I’ve created it and its > > behaviors child. I now get these errors: > > Sorry, Dave, I should have been more clear. In your Radiant > installation (wherever that is), find the app directory, in which > there should be a behaviors directory. For example, if you installed > radiant in /home/dave/foo/radiant-0.5.2, you should put the > 00\_next\_previous\_behavior.rb in /home/dave/foo/radiant-0.5.2/app/ > behaviors/. Ah, another issue caused by using the gem installation then. I’ll look into using the SVN version I think 🙂 Thanks again! – Regards, Dave ---
**Author:** ![df-sean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f07891/32.png) [@df-sean](https://www.ruby-forum.com/u/df-sean)\ **Post date:** [September 12, 2006, 2:40pm UTC](https://www.ruby-forum.com/t/re-next-and-previous-articles/67794/7 "2006-09-12T14:40:54Z")
> There was no radiant/app directory so I’ve created it and its > behaviors child. I now get these errors: Sorry, Dave, I should have been more clear. In your Radiant installation (wherever that is), find the app directory, in which there should be a behaviors directory. For example, if you installed radiant in /home/dave/foo/radiant-0.5.2, you should put the 00\_next\_previous\_behavior.rb in /home/dave/foo/radiant-0.5.2/app/ behaviors/. HTH, - Sean