title: Variables in content_tag blocks
body: <p>I've been looking for this and can't seem to find a solution:</p>
  
  <p>I have a content_tag block with a lot of logic in a helper (probably not great, but it is what it is). There's a variable in there that needs to increment. However, the code like this</p>
  
  <p>num = num + 1</p>
  
  <p>Actually ends up outputting num + 1 instead of incrementing it. Is there a way to temporarily evaluate that expression instead of outputting it in the buffer?</p>
  
  <p>Thanks</p>