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= AwesomeNestedSet

Awesome Nested Set is an implementation of the nested set pattern for ActiveRecord models. It is replacement for acts_as_nested_set and BetterNestedSet, but awesomer.

== What makes this so awesome?

This is a new implementation of nested set based off of BetterNestedSet that fixes some bugs, removes tons of duplication, adds a few useful methods, and adds STI support.

== Installation

If you are on Rails 2.1 or later:

  script/plugin install git://github.com/collectiveidea/awesome_nested_set.git

== Usage

To make use of awesome_nested_set, your model needs to have 3 fields: lft, rgt, and parent_id:

  class CreateCategories < ActiveRecord::Migration

    def self.up

      create_table :categories do |t|

        t.string :name

        t.integer :parent_id

        t.integer :lft

        t.integer :rgt

      end

    end

    def self.down

      drop_table :categories

    end

  end

Enable the nested set functionality by declaring acts_as_nested_set on your model

  class Category < ActiveRecord::Base

    acts_as_nested_set

  end

Run `rake rdoc` to generate the API docs and see CollectiveIdea::Acts::NestedSet::SingletonMethods for more info.

== View Helper

The view helper is called #nested_set_options. 

Example usage:

  <%= f.select :parent_id, nested_set_options(Category, @category) {|i| "#{'-' * i.level} #{i.name}" } %>

  <%= select_tag 'parent_id', options_for_select(nested_set_options(Category) {|i| "#{'-' * i.level} #{i.name}" } ) %>

See CollectiveIdea::Acts::NestedSet::Helper for more information about the helpers.

== References

You can learn more about nested sets at:

  http://www.dbmsmag.com/9603d06.html

  http://threebit.net/tutorials/nestedset/tutorial1.html

  http://api.rubyonrails.com/classes/ActiveRecord/Acts/NestedSet/ClassMethods.html

  http://opensource.symetrie.com/trac/better_nested_set/

Copyright (c) 2008 Collective Idea, released under the MIT license