title: How to find the first occurrence of sub-strings not ended with specified characters
body: <p>I'm gonna select the first occurrence of an only-alphabet string which is not ended by any of the characters <code>"."</code>, <code>":"</code> and <code>";"</code></p>
  
  <p>For example:</p>
  
  <pre><code>"float a bbc 10" --&gt; "float"
  "float.h" --&gt; null
  "float:: namespace" --&gt; "namesapace"
  "float;" --&gt; null
  </code></pre>
  
  <p>I came up with the regex <code>\G([A-z]+)(?![:;\.])</code> but it only ignores the character before the banned characters, while I need it to skip all string before banned characters.</p>