[JENA-270] Support dynamic function invocation in ARQ

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: ARQ 2.9.2
• Fix Version/s: ARQ 2.9.2
• Component/s: ARQ
• Labels: call dynamic functions sparql
• Assignee: Rob Vesse
• Reporter: Rob Vesse
• Created: 22/Jun/12 20:33
• Updated: 26/Jun/12 13:52
• Resolved: 26/Jun/12 13:51

Description

Per my suggestion to the SPARQL Working Group I am proposing a new built in CALL() which can be used in SPARQL queries for dynamic function invocation.

CALL with no argument returns null
CALL with some arguments evaluates the first argument, sees if the result is a URI (if not errors) and if so tries to generate a function from it and invoke it with the arguments to that invocation being the remaining arguments to CALL

I have implemented a prototype implementation of this in the ARQ language which I have committed to Trunk, others with more knowledge of expression and function evaluation in ARQ may have suggestions on how to improve the implementation