title: What characters are allowed in Perl identifiers?
body: <p>I'm working on regular expressions homework where one question is:</p>
  
  <blockquote>
    <p>Using language reference manuals online determine the regular expressions for integer numeric constants and identifiers for Java, Python, Perl, and C.</p>
  </blockquote>
  
  <p>I don't need help on the regular expression, I just have no idea what identifiers look like in Perl. I found pages describing valid identifiers for <a href="http://publib.boulder.ibm.com/infocenter/comphelp/v8v101/index.jsp?topic=%2Fcom.ibm.xlcpp8a.doc%2Flanguage%2Fref%2Fident.htm" rel="noreferrer">C</a>, <a href="http://docs.python.org/release/2.5.2/ref/identifiers.html" rel="noreferrer">Python</a> and <a href="http://java.sun.com/docs/books/jls/third_edition/html/lexical.html" rel="noreferrer">Java</a>, but I can't find anything about Perl.</p>
  
  <p>EDIT: To clarify, finding the documentation was meant to be easy (like doing a Google search for <a href="http://www.google.com/search?q=python+identifiers" rel="noreferrer">python identifiers</a>). I'm not taking a class in "doing Google searches".</p>