We extend the language from Sect. 4.2 with boolean operators. We add the following productions to Grammar 4.1: Exp → not Exp Exp → Exp and Exp When evaluating not e, we first evaluate e to a value v...

We extend the language from Sect. 4.2 with boolean operators. We

add the following productions to Grammar 4.1:

Exp → not Exp

Exp → Exp and Exp

When evaluating not e, we first evaluate e to a value v that is checked to be a

boolean. If it is, we return ¬ v, where ¬ is logical negation.

When evaluating e1 and e2, we first evaluate e1 and e2 to values v1 and v2 that

are both checked to be booleans. If they are, we return v1 ∧ v2, where ∧ is logical

conjunction.

Extend the interpretation function in Fig. 4.2 to handle these new constructions

as described above.