Dave Beckett's blog

Rasqal RDF Query Library 0.9.20

2010-08-22 12:33

I just released a new version of my Rasqal RDF Query Library for two main new features:

  1. Support more of the new W3C SPARQL working drafts of 1 June 2010 for SPARQL 1.1 Query and SPARQL 1.1 Update.
  2. Support building with Raptor V2 API as well as Raptor V1 API..

The main change is to start to add to Rasqal's APIs and query engine changes for the new SPARQL 1.1 working drafts. This release adds support the syntax for all the changes for Query and Update. The new draft syntax is available via the 'laqrs' query language name, until the SPARQL 1.1 syntax is finalized. The 'sparql' query language provides SPARQL 1.0 support.

On Query 1.1, the addition is primarily syntax and API support for the new syntax. There is expression execution for the new functions IF(), URI(), STRLANG(), STRDT(), BNODE(), IN() and NOT IN() which are noew usable as part of the normal expression grammar. The existing aggregate function support was extended to add the new SAMPLE() and GROUP_CONCAT() but remains syntax-only. Finally the new GROUP BY with HAVING conditions were added to the syntax and had consequent API updates but no query engine execution of them.

For Update 1.1 the full set of update operations syntax were added and they create API structures. Note, however there seem to be some ambiguities in the draft syntax especially around multiple optional tokens in a row near WITH which are particularly hard to implement in flex and bison (aka "lex and yacc").

The main non-SPARQL 1.1 related change is to allow building Rasqal with Raptor V2 APIs rather than V1. Raptor V2 is in beta so this is not a final API and is thus not the default build, it has to be enabled with --enable-raptor2 with configure. When raptor V2 is stable (2.0.0), Rasqal will require it.

The changes to Rasqal in this release, in summary, are:

  • Updated to handle more of the new syntax defined by the SPARQL 1.1 Query and SPARQL 1.1 Update W3C working drafts of 1 June 2010
  • Added execution support for new SPARQL 1.1 query built-in expressions IF(), URI(), STRLANG(), STRDT(), BNODE(), IN() and NOT IN().
  • Added an 'html' query result table format from patch by Nicholas J Humfrey
  • Added API support for group by HAVING expressions.
  • Added XSD Date comparison support.
  • Support building with Raptor V2 API if configured with --with-raptor2.
  • Many other bug fixes and improvements were made.
  • Fixed Issues: #0000352, #0000353, #0000354, #0000360, #0000374, #0000377 and #0000378

See the Rasqal 0.9.20 Release Notes for the full details of the changes.

Get it at http://download.librdf.org/source/rasqal-0.9.20.tar.gz.

PS The source code control has also moved to GIT and hosted at GitHub.