MDriven has been extended and you now have ScriptEval that does things like this:
https://wiki.mdriven.net/index.php?title=Documentation:OCLOperators_scripteval
let info=self.ScriptEvalCheck(false,Double, self.SomeString) in
(
vSomeStringResult:=(info='ok').casetruefalse(self.ScriptEval(false,Double, self.SomeString).asstring,info)
)