A clever way / tool to modify xslts?

[kepler]

I'm working on putting a test data process together, but our test data is specified in .xslt files. I was thinking of writing a tool that just takes a bunch of inputs to create the nodes in the appropriate format, but since xslt is so standardised I was wondering if there's a more intelligent way to do it? I.e. a tool that parses the file, learns the appropriate available attributes and allows you to add/modify/copy nodes.

Example:
Queries can have many quotes and quotes can have many segments

        <xsl:when test="/jac:node='7375' /jac:time_qualified = 'false' and /jac:start='2014-04-01T00:00:00'" >
           <quote currency="GBP" taxpx="250.75" totaltaxpx="250.75">
              <segment dep_time="2014-04-01T09:40:00" leg="o"/>
              <segment dep_time="2014-04-08T13:50:00" leg="i"/>
           </quote>								
        </xsl:when>

Any ideas, or is this a custom job? :/