Description:

Isearch is software for indexing and searching text documents. It
supports full text and field based search, relevance ranked results,
Boolean queries, and heterogeneous databases. Isearch can parse many
kinds of documents "out of the box," including HTML, mail folders,
list digests, SGML-style tagged data, and USMARC. It can be extended
to support other formats by creating descendant classes in C++ that
define the document structure. It is pretty easy to customize in this
way, provided that you know some C++ (and you will need to ftp the
source code). A CGI interface is also included for web based
searching.