GO Classes Test Series 2024 | Mock GATE | Test 14 | Question: 26

Question

Which attributes in the following grammar are synthesized?

• A. A.a
• B. B.b
• C. B.x
• D. C.c

Comments

B-Cannot be the answer it's visible the B.b is taking it's values from a which is part of its left ancestor

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@Sachin Mittal 1 sir please look in to this

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Definition provided in Ullman:

A synthesized attribute for a nonterminal A at a parse-tree node N is defined by a semantic rule associated with the production at N. Note that the production must have A as its head. A synthesized attribute at node N is defined only in terms of attribute values at the children of N and at N itself.

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@Sachin Mittal 1 sir, .As a child's attributes can only be dependent on inherited attributes of the parent, B.b can not be synthesized, as C.c is taking values from B.b so B.b can not be synthesized, this can also be a reason?
 

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yes obviously if option D is not the answer then B also should not be the one.

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https://www.youtube.com/live/CFoJsU6nvq4?si=vAk95XKOwKBGf8b-&t=3243

check solution

Answer 1

Why "c" can't be an answer?

Comments

because C.c is synthesizing by its left siblings and again it synthesizes to its parent C.x which is correct synthesized. here C.x is answer not C.c