loops - Rails: fields_for with index?

Question

Is there a method (or way to pull off similar functionality) to do a fields_for_with_index?

Example:

<% f.fields_for_with_index :questions do |builder, index| %>  
  <%= render 'some_form', :f => builder, :i => index %>
<% end %>

That partial being rendered needs to know what the current index is in the fields_for loop.

Answer 1

The answer is quite simple as the solution is provided within Rails. You can use f.options params. So, inside your rendered _some_form.html.erb,

Index can be accessed by:

<%= f.options[:child_index] %>

You don't need to do anything else.

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Update: It seems that my answer wasn't clear enough...

Original HTML File:

<!-- Main ERB File -->
<% f.fields_for :questions do |builder| %>  
  <%= render 'some_form', :f => builder %>
<% end %>

Rendered Sub-Form:

<!-- _some_form.html.erb -->
<%= f.options[:child_index] %>