SiSU output can easily and conveniently be indexed by a number of standalone indexing tools, such as Lucene, Hyperestraier.
Because the document structure of sites created is clearly defined, and the text object citation system is available hypothetically at least, for all forms of output, it is possible to search the sql database, and either read results from that database, or map the results to the html or other output, which has richer text markup.
SiSU can populate a relational sql type database with documents at an object level, including objects numbers that are shared across different output types. Making a document corpus searchable with that degree of granularity. Basically, your match criteria is met by these documents and at these locations within each document, which can be viewed within the database directly or in various output formats.