What's the cleanest way to add a class attribute to an html element in a view in rails

Question

I'm writing some Rails code for a partial view, and I want it to only show a comment field if somebody is already logged onto a site here.

If the page is viewed by someone who isn't a member of the site yet, the shared/comment_not_logged_in fragment should be passed in.

However, I'm totally stumped as to why I can't run the same check to decide if the page should add the class attribute "missing_your_voice" to the enclosing div element here:

   <li class="user_submission_form bubble comment_form <% "missing_your_voice" if not current_user %>">

      <% if current_user %>      
        <%= image_tag(current_user.avatar(:comment), :class => "profile_pic") %>
        <% form_for [parent, Comment.new] do |f| %>
        <%= render "comments/form", :f => f %>
        <% end %>
      <% else %>
        <%= render :partial => 'shared/comment_not_logged_in' %>
      <% end %>

  </li>

The same idiom, "missing_your_voice" if not current_user returns the string in irb, and also in the console debugger.

What am I doing wrong here?

Answer 1

You forgot an =. Replace <% by <%=, so that you get:

<%= "missing_your_voice" if not current_user %>

Remember that <% ... %> will only run Ruby code, but not display anything. Using <%= ... %> will run the code and display the result of the expression.

Answer 2

As molf already pointed out, there's a missing = on your view.
It should be <%=.

Other than that, be sure to make your controller method available to your view by calling helper_method in your controller.

Take a look on the documentation if needed.