title: rails : how to conditionally assign tag in haml
body: <p>I'd like to add same content but assign a different tag in haml for the sake of SEO.
  More specifically, I want the header to be <code>&lt;h1&gt;</code> in <code>PostsController#index</code> but to be <code>&lt;p&gt;</code> on other pages so I try to use </p>
  
  <pre><code>-if current_page?(controller: 'top', action: 'index') ? %h2 , %h3
  </code></pre>
  
  <p>but it doesn't work and I think the wrong part in <code>%h2</code> <code>%h3</code> part.</p>