Question

Consider the productions $A\to PQ\text{and}A\to XY.$ Each of the five non-terminals A, P, Q, X and Y has two attributes: s is a synthesized attribute, and i is an inherited attribute. Consider the following rules.
Rule 1: P.i = A.i + 2, Q.i = P.i + A.i and A.s = P.s + Q.s
Rule 2: X.i = A.i + Y.s and Y.i = X.s + A.i

Which one of the following is TRUE?

• A. Both Rule 1 and Rule 2 are L-attributed.
• B. Only Rule 2 is L-attributed.
• C. Neither Rule 1 nor Rule 2 is L-attributed.
• D. Only Rule 1 is L-attributed.

Answer 1

The correct option is D Only Rule 1 is L-attributed.

Rule 1: It is L-attributed by definition.
Rule 2: It is not L-attributed because this expresion (X.i = A.i + Y.s) fails to satisfy the definition of L-attributed.