Exp_CPS ==> App Id Exp_Value^*
    | If Exp_Value Exp_CPS Exp_CPS
    | Let Id Exp_Letable Exp_CPS
Exp_Value ==> Literal | Identifier 
Exp_Letable ==> Literal
    | Abs Id^* Exp_CPS
    | Exp_Value Op Exp_Value
Übung: Übersetze
(0 - (b * b)) + (4 * (a * c))