title: Return value of std.regex.regex?
body: <p>I'm trying to write a function that takes an input string, a regex (made by <code>std.regex.regex</code> from a rawstring) and an error message string, and attempt to match something from the input string using the regex, displaying the error message if there are no matches. I came up with the following signature so far:</p>
  
  <pre><code>string check_for_match (string input, Regex r, string error_message)
  </code></pre>
  
  <p>However, this doesn't seem to work, as the compiler complains, saying:</p>
  
  <pre><code>struct std.regex.Regex(Char) is used as a type
  </code></pre>
  
  <p>So what should I use instead?</p>