Parsing and Syntax directed translation

Question 11

Consider the grammar with non-terminals N = {S,C,S1 },terminals T={a,b,i,t,e}, with S as the start symbol, and the following set of rules:

S --> iCtSS1|a
S1 --> eS|ϵ
C --> b

The grammar is NOT LL(1) because:

• it is left recursive

• it is right recursive

• it is ambiguous

• It is not context-free.

Question 12

Consider the following two statements:

P: Every regular grammar is LL(1)
Q: Every regular set has a LR(1) grammar

Which of the following is TRUE?

• Both P and Q are true
• P is true and Q is false
• P is false and Q is true
• Both P and Q are false

Question 13

Consider the following grammar.

S -> S * E
S -> E
E -> F + E
E -> F
F -> id

Consider the following LR(0) items corresponding to the grammar above.

(i) S -> S * .E
(ii) E -> F. + E
(iii) E -> F + .E 

Given the items above, which two of them will appear in the same set in the canonical sets-of-items for the grammar?

• (i) and (ii)
• (ii) and (iii)
• (i) and (iii)
• None of the above

Question 14

A canonical set of items is given below

S --> L. > R
Q --> R.

On input symbol < the set has

• a shift-reduce conflict and a reduce-reduce conflict.
• a shift-reduce conflict but not a reduce-reduce conflict.
• a reduce-reduce conflict but not a shift-reduce conflict.
• neither a shift-reduce nor a reduce-reduce conflict.

Question 15

Consider the grammar defined by the following production rules, with two operators ∗ and +

    S --> T * P 
    T --> U | T * U
    P --> Q + P | Q
    Q --> Id
    U --> Id

Which one of the following is TRUE?

• + is left associative, while ∗ is right associative
• + is right associative, while ∗ is left associative
• Both + and ∗ are right associative
• Both + and ∗ are left associative

Question 16

Consider the following grammar:

S → FR
R → S | ε
F → id

In the predictive parser table, M, of the grammar the entries M[S, id] and M[R, $] respectively.

• {S → FR} and {R → ε }
• {S → FR} and { }
• {S → FR} and {R → *S}
• {F → id} and {R → ε}

Question 17

Consider the following translation scheme. S → ER R → *E{print("*");}R | ε E → F + E {print("+");} | F F → (S) | id {print(id.value);} Here id is a token that represents an integer and id.value represents the corresponding integer value. For an input \'2 * 3 + 4\', this translation scheme prints

• 2 * 3 + 4
• 2 * +3 4
• 2 3 * 4 +
• 2 3 4+*

Question 18

The grammar A → AA | (A) | ε is not suitable for predictive-parsing because the grammar is

• ambiguous

• left-recursive

• right-recursive

• an operator-grammar

Question 19

Consider the grammar

E → E + n | E × n | n 

For a sentence n + n × n, the handles in the right-sentential form of the reduction are

• n, E + n and E + n × n
• n, E + n and E + E × n
• n, n + n and n + n × n
• n, E + n and E × n

Question 20

Consider the grammar

S → (S) | a

Let the number of states in SLR(1), LR(1) and LALR(1) parsers for the grammar be n1, n2 and n3 respectively. The following relationship holds good

• n1 < n2 < n3
• n1 = n3 < n2
• n1 = n2 = n3
• n1 ≥ n3 ≥ n2