Hi Gerrit, you are probably looking for the xquery:eval function [1]: xquery:eval( "db:open('" || $db || "', '" || $doc || "')" || $xpath) You can make the query string safer by bind ing variables to the evaluated expression: xquery:eval( "db:open($db, $doc)" || $xpath, map { "db" := $db, "doc" = $doc }) Hope this helps, Christian [1] http://docs.basex.org/wiki/XQuery_Module ___________________________ On Mon, Nov 11, 2013 at 12:44 PM, Imsieke, Gerrit, le-tex < gerrit.imsieke@le-tex.de> wrote:

I have a RESTXQ path/function that is supposed to retrieve a document fragment, restricted to an XPath expression that is given as a query parameter, i.e., as a string. The list of possible fragment XPaths has been calculated using path() by another function, and the user of a Web application may choose to retrieve any of the fragments.

An example for such a path would be '/Q{ http://www.tei-c.org/ns/1.0}TEI[1]/Q{http://www.tei-c.org/ns/1.0}text[1]/Q{http://www.tei-c.org/ns/1.0}front[1]/Q{http://www.tei-c.org/ns/1.0}div[3] '.

Is there a better solution than the following, whose performance is of course quite poor (around 2 seconds execution time for the given documents)? I’m thinking of something like saxon:evaluate() or the XSLT 3 instruction xsl:evaluate.

Maybe I’m just unaware of the obvious solution based upon XQuery 3 or a BaseX extension.

Gerrit

declare %rest:path("/content/fragment/{$db}/{$doc}") %rest:query-param("xpath", "{$xpath}") %rest:GET function page:get-frags( $db as xs:string, $doc as xs:string, $xpath as xs:string ) as item()* { <response> { for $doc in db:open($db, $doc) return $doc//*[path(.) eq $xpath] } </response> }; _______________________________________________ BaseX-Talk mailing list BaseX-Talk@mailman.uni-konstanz.de https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk