title: How to get demangled function name using regex
body: <p>I have list of demangled-function names like <code>_Z6__comp7StudentS_</code>
  <code>_Z4SortiSt6vectorI7StudentSaIS0_EE</code>. I read wiki and found out that it follows some sort of defined structure. _Z is mangled Symbol followed by a number and then the function name of that length.</p>
  <p>So I wanted to retrieve that function name using regex. I only come close to <code>_Z(?:\d)(?&lt;function_name&gt;[a-z_A-Z]){\1}</code>. But referring \1 won't work because its string, right? Is there a single regex pattern solution to this.</p>