What is wrong with this recursive loop in Ruby?

Question

Ok so i have this loop

def page_children(page)
  content_tag :li do
    link_to page.url, "/#{page.url_path}/#{page.url}"
    if page.children.any?
      content_tag :ul do
        page_children(page)
      end
    end
  end
end

And I keep getting stack level too deep

I am using this gem for my tree structure and my model and haml is the following

class Page < ActiveRecord::Base  
  acts_as_tree :order => 'sort_order'
  belongs_to :parent, :class_name => "Page" 
  scope :parent_nav, lambda{ |navigation| where(:parent_id => nil, :is_home => 0, :nav => navigation).order("sort_order") }
end

My haml is the following

%ul
 - Page.parent_nav("Attend").each do |page|
 = page_children(page)

Basically i want a li for each page and if the page has children then i want another ul with an li for all the children...ext....but my loop is off somehow...any ideas on what im doing wrong

ramblex · Accepted Answer · 2012-10-21 18:03:30Z

4

You're not changing the arguments you give to page_children when you call it recursively. Perhaps something like the following (untested):

def page_children(page)
  content_tag :li do
    link_to page.url, "/#{page.url_path}/#{page.url}"
    page.children.each do |child|
      content_tag :ul do
        page_children(child)
      end
    end
  end
end

answered Oct 21, 2012 at 18:03

ramblex

3,05723 silver badges20 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

tokland Over a year ago

This needs some polishing, note that helpers return strings, they do not render by performing side-effects like a ERB view.

tokland · Accepted Answer · 2012-10-21 19:39:10Z

1

I'd write (untested):

def render_pages(pages)
  return "" if pages.empty?
  content_tag(:ul) do
    pages.map do |page| 
      content_tag(:li) do
        link = link_to(page.url, helper_to_generate_the_page_path(page))
        link + render_pages(page.children)
      end
    end.join.html_safe
  end
end

= render_pages(Page.parent_nav("Attend"))

answered Oct 21, 2012 at 19:39

tokland

68.2k13 gold badges151 silver badges174 bronze badges

Collectives™ on Stack Overflow

What is wrong with this recursive loop in Ruby?

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related