title: split a string on a separator
body: <p>I have a string like <code>first part;second part</code>. I want to split it on the <code>;</code> and return the second part. Everything works fine with:</p>
  
  <pre><code>start = mystring:find(';')
  result = mystring:sub(start)
  </code></pre>
  
  <p>But I was hoping to do it on one line:</p>
  
  <pre><code>result = mystring:sub(mystring:find(';'))
  </code></pre>
  
  <p>It doesn't throws an error but it is not returning the expected result. Not a big issue as it works fine on two lines of code but understanding why it's not working on the oneliner will help me to better understand how lua works.</p>