Parsing

Question 1
Consider the following grammar along with translation rules.
\begin{aligned} &S \rightarrow S_1 \# T & & \{S._{val}=S_{1.val}*T._{val} \} \\ &S \rightarrow T & & \{S._{val}=T._{val} \} \\ &T \rightarrow T_1 \% R & & \{T._{val}=T_{1.val} \div R._{val} \} \\ &T \rightarrow R & & \{T._{val}=R._{val} \} \\ &R \rightarrow id & & \{R._{val}=id._{val} \} \\ \end{aligned}
Here \# and \% are operators and id is a token that represents an integer and id_{.val} represents the corresponding integer value. The set of non-terminals is \{S,T,R,P \} and a subscripted non-terminal indicates an instance of the non-terminal.
Using this translation scheme, the computed value of S_{.val} for root of the parse tree for the expression 20 \# 10 \% 5 \# 8 \% 2 \% 2 is
A
20
B
65
C
160
D
80
GATE CSE 2022   Compiler Design
Question 2
Consider the augmented grammar with \{+, *, (, ), id \} as the set of terminals.
\begin{aligned}&S' \rightarrow S \\ &S \rightarrow S+R|R \\ &R \rightarrow R*P|P \\ &P \rightarrow (S)|id \end{aligned}
If I_0 is the set of two LR(0) items \{ [S' \rightarrow S.], [S \rightarrow S.+R] \}, then goto(closure(I_0 ),+) contains exactly ______ items.
A
2
B
3
C
4
D
5
GATE CSE 2022   Compiler Design
Question 3
Which one of the following statements is TRUE?
A
The LALR(1) parser for a grammar G cannot have reduce-reduce conflict if the LR(1) parser for G does not have reduce-reduce conflict.
B
Symbol table is accessed only during the lexical analysis phase.
C
Data flow analysis is necessary for run-time memory management.
D
LR(1) parsing is sufficient for deterministic context-free languages.
GATE CSE 2022   Compiler Design
Question 4
Consider the following augmented grammar with \{ \#, @, <, >, a, b, c \} as the set of terminals.

\begin{array}{l} S' \rightarrow S \\ S \rightarrow S \# cS \\ S \rightarrow SS \\ S \rightarrow S @ \\ S \rightarrow < S > \\ S \rightarrow a \\ S \rightarrow b \\ S \rightarrow c \end{array}

Let I_0 = \text{CLOSURE}(\{S' \rightarrow \bullet S\}). The number of items in the set \text{GOTO(GOTO}(I_0 \lt ), \lt ) is ___________
A
6
B
7
C
8
D
9
GATE CSE 2021 SET-2   Compiler Design
Question 5
Consider the following C code segment:

a = b + c;
e = a + 1;
d = b + c;
f = d + 1;
g = e + f;

In a compiler, this code segment is represented internally as a directed acyclic graph (DAG). The number of nodes in the DAG is _____________
A
11
B
6
C
5
D
10
GATE CSE 2021 SET-1   Compiler Design
Question 6
Consider the following statements.

S1: Every SLR(1) grammar is unambiguous but there are certain unambiguous grammars that are not SLR(1).
S2: For any context-free grammar, there is a parser that takes at most O(n^3) time to parse a string of length n.

Which one of the following options is correct?
A
S1 is true and S2 is false
B
S1 is false and S2 is true
C
S1 is true and S2 is true
D
S1 is false and S2 is false
GATE CSE 2021 SET-1   Compiler Design
Question 7
A grammar is defined as
A \rightarrow B C
B \rightarrow x \mid B x
C \rightarrow B \mid D
D \rightarrow y \mid Ey
E \rightarrow z
The non terminal alphabet of the grammar is
A
\{A, B, C, D, E\}
B
\{B, C, D, E\}
C
\{A, B, C, D, E,x,y,z\}
D
\{x,y,z\}
ISRO CSE 2020   Compiler Design
Question 8
A given grammar is called ambiguous if
A
two or more productions have the same non-terminal on the left hand side
B
a derivation tree has more than one associated sentence
C
there is a sentence with more than one derivation tree corresponding to it
D
brackets are not present in the grammar
ISRO CSE 2020   Compiler Design
Question 9
Given the grammar
s \rightarrow T^{*} S \mid T
T \rightarrow U+T \mid U
U \rightarrow a \mid b
Which of the following statements is wrong?
A
Grammar is not ambiguous
B
Priority of + over * is ensured
C
Right to left evaluation of * and + happens
D
None of these
ISRO CSE 2020   Compiler Design
Question 10
Consider the following grammar.

S\rightarrow aSB|d
B\rightarrow b

The number of reduction steps taken by a bottom-up parser while accepting the string aaadbbb is___________.
A
5
B
6
C
7
D
8
GATE CSE 2020   Compiler Design
There are 10 questions to complete.

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