Simulation path generation handles empty vars=().

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@5399 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/simulator/GenerateSimulationPath.java

@@ -179,10 +179,12 @@ public class GenerateSimulationPath
 					s = s.substring(0, s.length() - 1);
 					done = true;
 				}
+				if (s.length() > 0) {
 					j = varList.getIndex(s);
 					if (j == -1)
 						throw new PrismException("Unknown variable \"" + s + "\" in \"vars=(...)\" list");
 					simVars.add(j);
+				}
 				while (i < n && !done) {
 					s = ss[++i];
 					if (s.indexOf(')') > -1) {