next and previous methods for a model

rubyonrails-talk
1

Anyone know of a plugin or gem that would create methods such as next and previous on a model to traverse among siblings? For example, @post.next and @post.prev.

2

I don't know of any, sorry.

In the past I've written two simple instance methods and two named_scopes in my models.

named_scope :next, lambda {|post, user|   { :conditions => ["created_at > ? and user_id = ?", post.created_at, user.id], :order => "created_at ASC" } }

named_scope :prev, lambda {|post, user|   { :conditions => ["created_at < ? and user_id = ?", post.created_at, user.id], :order => "created_at DESC" } }

def next(user)   Post.next(self, user).first end

def prev(user)   Post.prev(self, user).first end

3

you could try acts_as_list