Write an attribute grammar whose BNF basis is that of Example 3.6 in Section 3.4.5 but whose language rules are as follows: Data types cannot be mixed in expressions, but assignment statements need not have the same types on both sides of the assignment operator.

Data from Example 3.6:

Transcribed Image Text:

1. Syntax rule: Semantic rule: .expected_type .actual_type 2. Syntax rule: → [2] + [3] Semantic rule: .actual_type - → = <еxpr> if ([2].actual_type = int) and ([3].actual_type = int) then int else real end if Predicate: .actual_type %33D .expected_type 3. Syntax rule: Semantic rule: .actual_type .actual_type Predicate: → <ехpr>.actual_tyре %3D3D <ехpr>.expected_type → A | BIC 4. Syntax rule: Semantic rule: .actual_type look-up (.string)