es and iterators, from Dave Abrahams
        and Jeremy Siek.</li>
    <li><a href="optional/doc/optional.html">optional</a> - Discriminated-union 
    wrapper for optional values, from Fernando Cacciola.</li>
    <li><a href="pool/doc/index.html">pool</a> - Memory pool management, from
      Steve Cleary.</li>
    <li><a href="preprocessor/doc/index.html">preprocessor</a> - Preprocessor 
    metaprogramming tools including repetition and recursion, from Vesa Karvonen 
    and Paul Mensonides.</li>
    <li>