The Stardog manual states that “Stardog doesn’t support variables for the service URL (SERVICE ?serviceURL)”.
Will this feature be added in the upcoming version of Stardog?
It would be a very useful feature for geospatial querying using endpoints built dynamically from the coordinates of the start point.
While that syntax is valid SPARQL, queries of that type have no defined semantics in the specification for us to implement. However, some vendors do have ad-hoc implementations for queries of this type. We have an open ticket to consider an implementation strategy for this, but it is not associated with any near-term milestone. That could change depending on customer feedback.