private static RuleExprAst <int> MaxTotalDebt(int debtLimit)
{
return
(from amount in Dsl.GetAmount()
from creditA in Dsl.GetValue("CreditA")
from creditB in Dsl.GetValue("CreditB")
let totalCredit = creditA + creditB
select totalCredit > debtLimit ? 0 : amount);
}