ERB conditionally includes <% end%> tag

I wonder how to conditionally include the "end" tag

I have many "partial forms" like this

_form_part_x.html.erb (But this is not what I want to do)

<%= form_for(@model) do |f| %>
  <%= f.some_tag(...) %>
<% end %>

      

        
        
        
      

    

In many views, I just need to render one of these guys.

Now the problem is that I want to have another big view for my model, where I am doing all these partial (form_part_1, form_part_2, etc.). In my case, I am using bootstrap tabs and each tab is partial, which in turn will cause multiple partial form_part_x

to create specific fields.

BUT I don't want to have multiple form tags in my HTML, just one big form, so everything is saved at the same time. So before mine, render tabX

I write the code to create the HTML tag and I close it after all the tabs are displayed.

simple_view.html.erb

<%= render 'form_part_x' %> 

      

        
        
        
      

    

big_view.html.erb

<%= form_for(something) do |f| %>
  <%= render 'tab1', f:f %>
  <%= render 'tab2', f:f %>
    ...
  <%= render 'tab5', f:f %>
<% end %>

      

        
        
        
      

    

_tab1.html.erb

<%= render 'form_part_10', f:f %>
<%= render 'form_part_23', f:f %>

      

        
        
        
      

    

_form_part_x.html.erb (This can be adapted to what I am doing. If I knew how to add <% end%> inside the <% if%> block

So, basically, I thought I could set up my partial elements to conditionally include <%= form_for(@model) do |f| %>

:

<%
# These lines help determine whether an HTML `form` tag should be generated or not
f ||= false
if not f then
  existing_form = false
else
  existing_form = true
%>

<% if not existing_form %>
  # If the partial is called without sending a local f, we want to create the HTML `form` tag
  <%= form_for(something) do |f| %>
<% end %>

  <%= f.text_field(:some_field) %>
  <p>Many more stuff</p>

<% if not existing_form %>
  # If the partial is called without sending a local f, we want to CLOSE the newly created HTML `form` tag
  <!-- I need to add an <% end %> here !
<% end %>