Re: Any students looking for an interesting project?

Here's an XSLT project that I think would be ideal for a bright student:

Given a stylesheet S, and a representative selection of input documents D, create a trimmed-down stylesheet S' that is equivalent to S when applied to any document in D, by eliminating all template rules that don't match anything in D (as well as other components like named templates and functions that become unreachable after this process).

It's a practical problem: the docbook stylesheets, for example, are far too large to run in Saxon-CE, but if trimmed down to contain only the rules needed for a particular docbook profile, might well be a tiny fraction of the size. Using trimmed-down stylesheets could also give performance benefits in many batch publishing workflows.

The only tricky part of the problem, I think, is dealing with any cases of template rules that are there to match nodes in temporary trees rather than nodes in a source document. One might be able to determine the set of element names used in temporary trees by static analysis, or to determine that xsl:apply-templates is never applied to a temporary tree, or perhaps to gather extra information by actually running S against D and monitoring what happens.

Michael Kay
Saxonica