{
// get the nodemaker for the expr-var
NodeMaker nodeMaker = nodeRelation.nodeMaker(exprVar.asVar());
if (nodeMaker instanceof TypedNodeMaker) {
TypedNodeMaker typedNodeMaker = (TypedNodeMaker) nodeMaker;
Iterator<ProjectionSpec> it = typedNodeMaker.projectionSpecs().iterator();
if (!it.hasNext()) {
logger.debug("no projection spec for " + exprVar + ", assuming constant");
Node node = typedNodeMaker.makeNode(null);
result.add(new ConstantEx(NodeValue.makeNode(node).asString(), node));
}