function evaluate(RelationalExpression < ShiftExpression) {
var lref = evaluate(RelationalExpression);
var lval = GetValue(lref);
var rref = evaluate(ShiftExpression);
var rval = GetValue(rref);
var r = RelationalComparison(lval, rval); // 11.8.5
if (r === undefined) return false;
return r;
}