As a by-product of its new MarkLogic content storage database, O’Reilly has just launched an XQuery driven search engine that allows you to search for code within the context of all of their books. Check out their Code Search.

Under the covers, the code search greps the XML (DocBook) source of all O’Reilly books and considers any programlisting longer then three lines, source code. Code that shows up in results is displayed with a few contextual sentences from the paragraph above where it occurred in the book. All source code includes formated line-numbers that don’t get pulled into your clipboard as you cut and paste.

This should be the tip of an iceberg of features that are possible with XQuery and MarkLogic. Keep your eye on labs.oreilly.com for a first look as more of these tools emerge.