Helper для построения деревьев

Helper:

def tree_ul(acts_as_tree_set, init=true, &block)
if acts_as_tree_set.size > 0
ret = ‘<ul>’
acts_as_tree_set.collect do |item|
next if item.parent_id && init
ret += ‘<li>’
ret += yield item
ret += tree_ul(item.children, false, &block) if item.children.size > 0
ret += ‘</li>’
end
ret += ‘</ul>’
end
end

Представление:

‘edit’, :id => item } %>