Q. Consider the following expression grammar. The seman­tic rules for expression calculation are stated next to each grammar production.

E → number E.val = number. val
| E '+' E E(1).val = E(2).val + E(3).val
| E '×' E E(1).val = E(2).val × E(3).val

Assume the conflicts in Part (a) of this question are resolved and an LALR(1) parser is generated for parsing arithmetic expressions as per the given grammar. Consider an expression 3 × 2 + 1. What precedence and associativity properties does the generated parser realize?

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Q. Which of the following grammar rules violate the requirements of an operator grammar ? P, Q, R are nonterminals, and r, s, t are terminals.

1. P → Q R
2. P → Q s R
3. P → ε
4. P → Q t R r

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Q. Consider the grammar with the following translation rules and E as the start symbol.

E → E1 # T { E.value = E1.value * T.value }
| T{ E.value = T.value }
T → T1 & F { T.value = T1.value + F.value }
| F{ T.value = F.value }
F → num { F.value = num.value }

Compute E.value for the root of the parse tree for the expression: 2 # 3 & 5 # 6 & 4.

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Q. Which of the following suffices to convert an arbitrary CFG to an LL(1) grammar?

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Q. Assume that the SLR parser for a grammar G has n1 states and the LALR parser for G has n2 states. The relationship between n1 and n2 is:

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Q. In a bottom-up evaluation of a syntax directed definition, inherited attributes can

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Q. Consider the grammar shown below S → i E t S S' | a S' → e S | ε E → b In the predictive parse table. M, of this grammar, the entries M[S', e] and M[S', $] respectively are

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Q. Consider the grammar shown below.

S → C C
C → c C | d

The grammar is

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Q. Consider the translation scheme shown below

S → T R
R → + T {print ('+');} R | ε
T → num {print (num.val);}

Here num is a token that represents an integer and num.val represents the corresponding integer value. For an input string '9 + 5 + 2', this translation scheme will print

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Q. Consider the syntax directed definition shown below.

S → id : = E {gen (id.place = E.place;);}
E → E1 + E2 {t = newtemp ( ); gen (t = El.place + E2.place;); E.place = t}
E → id {E.place = id.place;}

Here, gen is a function that generates the output code, and newtemp is a function that returns the name of a new temporary variable on every call. Assume that ti's are the temporary variable names generated by newtemp. For the statement 'X: = Y + Z', the 3-address code sequence generated by this definition is

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Q. Which of the following statements is false?

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Q. Which of the following derivations does a top-down parser use while parsing an input string? The input is assumed to be scanned in left to right order.

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Q. Given the following expression grammar:

E -> E * F | F + E | F
F -> F - F | id

which of the following is true?

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Q. Which one of the following is True at any valid state in shift-reduce parsing?

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Q. In the context of abstract-syntax-tree (AST) and control-flow-graph (CFG), which one of the following is True?

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Q. Match the following:

List-I List-II
A. Lexical analysis 1. Graph coloring
B. Parsing 2. DFA minimization
C. Register allocation 3. Post-order traversal
D. Expression evaluation 4. Production tree

Codes:
A B C D
(a) 2 3 1 4
(b) 2 1 4 3
(c) 2 4 1 3
(d) 2 3 4 1

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Q. Among simple LR (SLR), canonical LR, and look-ahead LR (LALR), which of the following pairs identify the method that is very easy to implement and the method that is the most powerful, in that order?

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Q. Consider the following grammar G.

S → F ⎪ H
F → p ⎪ c
H → d ⎪ c

Where S, F and H are non-terminal symbols, p, d and c are terminal symbols. Which of the following statement(s) is/are correct?

S1: LL(1) can parse all strings that are generated using grammar G.
S2: LR(1) can parse all strings that are generated using grammar G.

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Q. A CFG G is given with the following productions where S is the start symbol, A is a non-terminal and a and b are terminals.

S→aS∣A
A→aAb∣bAa∣ϵ

For the correct answer in Q75, how many steps are required to derive the string and how many parse trees are there?

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Q. Some code optimizations are carried out on the intermediate code because

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