title: Using the C Preprocessor for languages other than C
body: <p>The Wikipedia entry for the <a href="http://en.wikipedia.org/wiki/C_preprocessor" rel="nofollow noreferrer">C Preprocessor</a> states:</p>
  
  <blockquote>
    <p>The language of preprocessor
    directives is agnostic to the grammar
    of <strong>C</strong>, so the <strong>C</strong> preprocessor can also
    be used independently to process other
    types of files.</p>
  </blockquote>
  
  <p>How can this be done? Any examples or techniques?</p>
  
  <p>EDIT: Yes, I'm mostly interested in macro processing. Even though it's probably not advisable or maintainable it would still be useful to know what's possible.</p>