module ActsAsTree::TreeWalker

Public Class Methods

extended(mod) click to toggle source

# File lib/acts_as_tree.rb, line 219
def self.extended(mod)
  mod.class_eval do
    def walk_tree(options = {}, &block)
      algorithm = options.fetch :algorithm, :dfs
      where = options.fetch :where, {}
      self.class.send("walk_tree_#{algorithm}", where, self, &block)
    end
  end
end

Public Instance Methods

walk_tree(options = {}, &block) click to toggle source

Traverse the tree and call a block with the current node and current depth-level.

options:

algorithm:
  :dfs for depth-first search (default)
  :bfs for breadth-first search
where: AR where statement to filter certain nodes

The given block sets two parameters:

first: The current node
second: The current depth-level within the tree

Example of acts_as_tree for model Page (ERB view): <% Page.walk_tree do |page, level| %>

<%= link_to "#{' '*level}#{page.name}", page_path(page) %><br />

<% end %>

There is also a #walk_tree instance method that starts walking from the node it is called on.

# File lib/acts_as_tree.rb, line 213
def walk_tree(options = {}, &block)
  algorithm = options.fetch :algorithm, :dfs
  where = options.fetch :where, {}
  send("walk_tree_#{algorithm}", where, &block)
end