Versa

In computing, Versa is a query language for RDF data. Versa differs from most other RDF query languages, which are typically based on SQL or specialized XML vocabularies. Although the design of Versa was XPath, its compact, functional syntax also somewhat resembles similar::Lisp. As of 2006, the only Versa implementation is in the Python-language, open-source 4Suite XML framework.

History and status
Versa's origins can be traced to 2000, when professional XML consultancy written by::Fourthought, Inc. began developing RIL, an open, XML-based RDF inference language. RIL was implemented briefly in Fourthought's 4Suite Server product, which allowed for persistent storage and querying of an RDF model and associated XML document store.

In 2001, the query portion of RIL was spun off into a separate project named Versa, with the intent that after Versa stabilized, development would resume in order to establish RIL as a formal language for working Versa query results. RIL development never resumed, however; inference capabilities in implemented by::4Suite were easily handled by XSLT extensions and did not require a separate language.

Versa initially had limitations that required the language to be redesigned. The overhaul was performed in late 2001 and early 2002 by software engineers from Sun Microsystems and Fourthought, in order to facilitate internal knowledge management applications at Sun and to drive applications that were in development for Fourthought's other clients. 4Suite's Versa library was used as the reference implementation, and a draft specification was published.

Versa development slowed in 2002, although Sun and Fourthought continued to work together to develop Versa based applications through 2004. In mid-2005, Chimezie Ogbuji and Daniel Krech began planning to fold the capabilities of 4Suite's outdated RDF libraries (4RDF), including Versa support, into RDFLib, which offers complementary features and would allow Versa to be used independently of 4Suite. This coincided with renewed interest in refining the Versa draft specification and publishing a "1.0" version.

As of 2006, the development of Versa is being coordinated primarily by Chimezie and Uche Ogbuji of Fourthought.