title: Limit regex scope to match items only in a section of code
body: <p>This is a general regex question.</p>
  
  <p>Suppose I have the following code:</p>
  
  <pre><code>function (item1, item2, item3) {
      var item4 = null
      var item5 = null
  }
  </code></pre>
  
  <p>I know that's javascript, but I don't want a javascript-specific answer: I'm curious about a pure regex answer.</p>
  
  <p>Suppose I want to write regex that matches any word that starts with "item", but I <em>only</em> want matches that are between parenthesis.</p>
  
  <p>So my question: is there a way to write a regex query that matches everything that starts with <code>item</code> but is also between parens? Like a way to limit my regex scope to just things within parens?</p>
  
  <p>UPDATE: Just so people know, I am asking because I am working on language support for Atom (the text editor), which (to my knowledge) supports only pure regex to match patterns to add language styling. Because of this, I'm stuck with pure regex, even though I am parsing JS.</p>