Safely injecting VALUES into a SPARQL query

[Martynas Jusevičius]

Hi,

What would be the simplest way to safely (i.e. using query builder or
algebra) to inject a VALUES block at the beginning of a query?

For example

SELECT *
{
  ?this ?p ?o
}

should become

SELECT *
{
  VALUES ?this <http://localhost>
  ?this ?p ?o
}

after the injection.

Thanks,

Martynas