Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

XML Handling

AutoIndex is rather simplistic in its handling of XML:

When indexing a document, all block content at the paragraph level gets collapsed into a single string for matching against the regular expressions representing each index term. In other words, for the most part, you can assume that you're indexing plain text when writing regular expressions.
Named XML entities for &, ", ', < or > are converted to their corresponding characters before indexing a section of text. However, decimal or hex escape sequences are not currently converted.
Index terms are assumed to be plain text (whether they originate from the script file or from scanning source files) and the characters &, ", < and > will be escaped to & " < and > respectively.