title: RegEx: Word immediately before the last opened parenthesis
body: <p>I have a little knowledge about RegEx, but at the moment, it is far above of my abilities.</p>
  
  <p>I'm needing help to find the text before the last open-parenthesis that doesn't have a matching close-parenthesis.</p>
  
  <p>(It is for CallTip of a open source software in development.)</p>
  
  <p>Below some examples:</p>
  
  <pre><code>--------------------------
  Text               I need
  --------------------------
  aaa(                  aaa
  aaa(x)                ''
  aaa(bbb(              bbb
  aaa(y=bbb(            bbb
  aaa(y=bbb()           aaa
  aaa(y &lt;- bbb()        aaa
  aaa(bbb(x)            aaa
  aaa(bbb(ccc(          ccc
  aaa(bbb(x), ccc(      ccc
  aaa(bbb(x), ccc()     aaa
  aaa(bbb(x), ccc())    ''
  --------------------------
  </code></pre>
  
  <p>Is it possible to write a RegEx (PCRE) for these situations?</p>
  
  <p>The best I got was <code>\([^\(]+$</code> but, it is not good and it is the opposite of what I need.</p>
  
  <p>Anyone can help please?</p>