Recent questions tagged parsing - GATE CSE Doubts

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GATE2005-83a Video Solution
Statement for Linked Answer Questions 83a & 83b: Consider the following expression grammar. The semantic rules for expression evaluation are stated next to each grammar production. ... a reduce action It detects shift-reduce conflict, and resolves the conflict in favor of a reduce over a shift action

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GATE2013-9 Video Solution
What is the maximum number of reduce moves that can be taken by a bottom-up parser for a grammar with no epsilon and unit-production (i.e., of type $A \rightarrow \epsilon$ and $A \rightarrow a$) to parse a string with $n$ tokens? $n/2$ $n-1$ $2n-1$ $2^{n}$

asked Apr 19 in Compiler Design by admin (3.6k points) | 3 views

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GATE2003-16 Video Solution
Which of the following suffices to convert an arbitrary CFG to an LL(1) grammar? Removing left recursion alone Factoring the grammar alone Removing left recursion and factoring the grammar None of the above

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GATE2017-1-43 Video Solution
Consider the following grammar: stmt $\rightarrow$ if expr then expr else expr; stmt | $0$ expr $\rightarrow$ term relop term | term term $\rightarrow$ id | number id $\rightarrow$ a | b | c number $\rightarrow [0-9]$ where relop is a relational ... program if $e_1$ then $e_2$ else $e_3$ has $2$ control flow paths. $e_1 \rightarrow e_2$ and $e_1 \rightarrow e_3$.

asked Apr 19 in Compiler Design by admin (3.6k points) | 2 views

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GATE1999-1.17 Video Solution
Which of the following is the most powerful parsing method? LL (1) Canonical LR SLR LALR

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GATE1998-1.27 Video Solution
Type checking is normally done during lexical analysis syntax analysis syntax directed translation code optimization

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GATE2015-1-1‏3 Video Solution
Which one of the following is TRUE at any valid state in shift-reduce parsing? Viable prefixes appear only at the bottom of the stack and not inside Viable prefixes appear only at the top of the stack and not inside The stack contains only a set of viable prefixes The stack never contains viable prefixes

asked Apr 19 in Compiler Design by admin (3.6k points) | 2 views

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GATE2003-57 Video Solution
Consider the grammar shown below. $S \rightarrow C \ C$ $C \rightarrow c \ C \mid d$ This grammar is LL(1) SLR(1) but not LL(1) LALR(1) but not SLR(1) LR(I) but not LALR(1)

asked Apr 19 in Compiler Design by admin (3.6k points) | 1 view

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GATE2009-42 Video Solution
Which of the following statements are TRUE? There exist parsing algorithms for some programming languages whose complexities are less than $\Theta(n^3)$ A programming language which allows recursion can be implemented with static storage allocation. No L-attributed definition ... both source language and intermediate code level. I and II I and IV III and IV I, III and IV

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GATE2014-1-34 Video Solution
A canonical set of items is given below $S \to L .> R $ $Q \to R.$ 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.

asked Apr 19 in Compiler Design by admin (3.6k points) | 2 views

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GATE2013-40 Video Solution
Consider the following two sets of LR(1) items of an LR(1) grammar.$\begin{array}{l|l} X \rightarrow c.X, c/d &X → c.X, \$\\ X \rightarrow .cX, c/d& X → .cX, \$\\ X \rightarrow .d, c/d & X → .d, \$ ... Cannot be merged since goto on c will lead to two different sets. $1$ only $2$ only $1$ and $4$ only $\text{1, 2, 3}$ and $4$

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GATE2005-14 Video Solution
The grammar $A \rightarrow AA \mid (A) \mid \epsilon$ is not suitable for predictive-parsing because the grammar is: ambiguous left-recursive right-recursive an operator-grammar

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GATE2008-11 Video Solution
Which of the following describes a handle (as applicable to LR-parsing) appropriately? It is the position in a sentential form where the next shift or reduce operation will occur It is non-terminal whose production will be used for reduction in the ... in the next step along with a position in the sentential form where the right hand side of the production may be found

asked Apr 19 in Compiler Design by admin (3.6k points) | 1 view

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GATE2008-55 Video Solution
An LALR(1) parser for a grammar G can have shift-reduce (S-R) conflicts if and only if The SLR(1) parser for G has S-R conflicts The LR(1) parser for G has S-R conflicts The LR(0) parser for G has S-R conflicts The LALR(1) parser for G has reduce-reduce conflicts

asked Apr 19 in Compiler Design by admin (3.6k points) | 1 view

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GATE2015-3-31 Video Solution
Consider the following grammar G $S \rightarrow F \mid H$ $F \rightarrow p \mid c$ $H \rightarrow d \mid c$ Where $S$, $F$, and $H$ are non-terminal symbols, $p, d$, and $c$ are terminal symbols. Which of the following statement(s) is/ ... using grammar G S2: LR(1) can parse all strings that are generated using grammar G Only S1 Only S2 Both S1 and S2 Neither S1 and S2

asked Apr 19 in Compiler Design by admin (3.6k points) | 2 views

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GATE2005-60 Video Solution
Consider the grammar: $S \rightarrow (S) \mid a$ Let the number of states in SLR (1), LR(1) and LALR(1) parsers for the grammar be $n_1, n_2$ and $n_3$ respectively. The following relationship holds good: $n_1 < n_2 < n_3$ $n_1 = n_3 < n_2$ $n_1 = n_2 = n_3$ $n_1 \geq n_3 \geq n_2$

asked Apr 19 in Compiler Design by admin (3.6k points) | 1 view

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GATE2005-83b Video Solution
Consider the following expression grammar. The semantic rules for expression evaluation are stated next to each grammar production. ... of $+$' is higher than that of $\times$', and both operators are left associative; expression is evaluated to $9$

asked Apr 19 in Compiler Design by admin (3.6k points) | 2 views

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GATE2019-19 Video Solution
Consider the grammar given below: $S \rightarrow Aa$ $A \rightarrow BD$ $B \rightarrow b \mid \epsilon $ $D \rightarrow d \mid \epsilon $ Let $a,b,d$ and $\$ be indexed as follows:$\begin{array}{|l|l|l|l|} \hline a & b & d & \$ \\ ... $)$ , then the answer should be $3210$)

asked Apr 19 in Compiler Design by admin (3.6k points) | 2 views

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GATE2012-53 Video Solution
For the grammar below, a partial $LL(1)$ parsing table is also presented along with the grammar. Entries that need to be filled are indicated as $E1, E2,$ and $E3$. $\varepsilon$ is the empty string, \$ indicates end of input, and, $ ... $ E2 : B \rightarrow S, S \rightarrow \varepsilon$ $ E3 : B \rightarrow S$

asked Apr 19 in Compiler Design by admin (3.6k points) | 1 view

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GATE2006-7 Video Solution
Consider the following grammar $S \rightarrow S * E$ $S \rightarrow E$ $E \rightarrow F + E$ $E \rightarrow F$ $F \rightarrow id$ Consider the following LR(0) items corresponding to the grammar above $S \rightarrow S *.E$ $E \rightarrow F. + E$ ... 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

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GATE2019-3 Video Solution
Which one of the following kinds of derivation is used by LR parsers? Leftmost Leftmost in reverse Rightmost Rightmost in reverse

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GATE2003-17 Video Solution
Assume that the SLR parser for a grammar G has $n_1$ states and the LALR parser for G has $n_2$ states. The relationship between $n_1$ and $n_2$ is $n_1$ is necessarily less than $n_2$ $n_1$ is necessarily equal to $n_2$ $n_1$ is necessarily greater than $n_2$ None of the above

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GATE2000-1.19, UGCNET-Dec2013-II-30 Video Solution

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GATE1998-1.26 Video Solution
Which of the following statements is true? SLR parser is more powerful than LALR LALR parser is more powerful than Canonical LR parser Canonical LR parser is more powerful than LALR parser The parsers SLR, Canonical CR, and LALR have the same power

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GATE2016-1-45 Video Solution
The attribute of three arithmetic operators in some programming language are given below. $\begin{array}{|c|l|}\hline \textbf{OPERATOR} & \textbf{PRECEDENCE} & \textbf{ASSOCIATIVITY} & \textbf{ARITY} \\\hline \text{$ ... $2-5+1-7*3$ in this language is ________.

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GATE2018-38 Video Solution
Consider the following parse tree for the expression a#b$\$c$\$d#e#f, involving two binary operators $\$ ... has higher precedence and is right associative; # is left associative

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GATE2015-3-16 Video Solution
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? SLR, LALR Canonical LR, LALR SLR, canonical LR LALR, canonical LR

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GATE1992-02,xiv Video Solution
Choose the correct alternatives (more than one may be correct ) and write the corresponding letters only: Consider the $SLR(1)$ and $LALR (1)$ parsing tables for a context free grammar. Which of the following statement is/are true? The ... identical in both the tables. The reduce entries in the tables may be different. The error entries in tables may be different

asked Apr 19 in Compiler Design by admin (3.6k points) | 3 views

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GATE2017-1-17 Video Solution
Consider the following grammar: $P\rightarrow xQRS$ $Q\rightarrow yz\mid z$ $R\rightarrow w\mid \varepsilon$ $S\rightarrow y$ What is FOLLOW($Q$)? $\left \{ R \right \}$ $\left \{ w \right \}$ $\left \{ w,y \right \}$ $\left \{ w,\$ \right \}$

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GATE2017-2-6 Video Solution
Which of the following statements about parser is/are CORRECT? Canonical LR is more powerful than SLR SLR is more powerful than LALR SLR is more powerful than Canonical LR I only II only III only II and III only

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GATE2008-IT-79 Video Solution
$A$ 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. $S → aS \mid A$ $A → aAb \mid bAa \mid \epsilon$ For the string "$aabbaab$" how many steps are required to derive the string and how many parse trees are there? $6$ and $1$ $6$ and $2$ $7$ and $2$ $4$ and $2$

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GATE2011-27 Video Solution
Consider two binary operators $` \uparrow '$ and $‘ \downarrow ’$ with the precedence of operator $\downarrow$ being lower than that of the operator $\uparrow$. Operator $\uparrow$ is right associative while operator $\downarrow$ is left associative. Which one of the following represents the parse tree for expression $(7 \downarrow 3 \uparrow 4 \uparrow 3 \downarrow 2)$

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GATE1992-02,xiii Video Solution
Choose the correct alternatives (more than one may be correct) and write the corresponding letters only: For a context free grammar, FOLLOW(A) is the set of terminals that can appear immediately to the right of non-terminal $A$ in some " ... FOLLOW(A) and RFOLLOW(A) are always the same. All the three sets are identical. All the three sets are different.

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GATE2006-58 Video Solution
Consider the following grammar: $S\rightarrow FR$ $ R\rightarrow * S\mid \varepsilon $ $ F\rightarrow id $ In the predictive parser table, M, of the grammar the entries M[S,id] and M[R,\$] respectively are $ \left \{ S\rightarrow FR \right \} $ and $ \left \ ... $ \left \{ F\rightarrow id \right \} $ and $ \left \{ R\rightarrow \varepsilon \right \} $

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GATE2007-18 Video Solution
Which one of the following is a top-down parser? Recursive descent parser. Operator precedence parser. An LR(k) parser. An LALR(k) parser.

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GATE2012-52 Video Solution
For the grammar below, a partial $LL(1)$ parsing table is also presented along with the grammar. Entries that need to be filled are indicated as $E1, E2,$ and $E3$. $\varepsilon$ is the empty string, \$ indicates end of input, and, $ ... $ \text{FOLLOW}(A) = \{a, b\} $ $ \text{FOLLOW}(B) =\{a, b\} $

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GATE2005-IT-83b Video Solution
Consider the context-free grammar $E\rightarrow E+E$ $E\rightarrow (E *E)$ $E\rightarrow \text{id}$ where $E$ is the starting symbol, the set of terminals is $\{id, (,+,),*\}$, and the set of non-terminals is $\{E\}$. For the terminal string $id + id + id + id$, how many parse trees are possible? $5$ $4$ $3$ $2$

asked Apr 19 in Compiler Design by admin (3.6k points) | 1 view

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GATE2005-IT-83a Video Solution
Consider the context-free grammar $E \rightarrow E + E$ $E \rightarrow (E * E)$ $E \rightarrow id$ where $E$ is the starting symbol, the set of terminals is $\{id, (,+,),*\}$, and the set of nonterminals is $\{E\}$. Which of the following terminal strings has more than one parse tree ... $id + (id* (id * id))$ $(id* (id * id)) + id$ $((id * id + id) * id)$

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GATE1998-22 Video Solution
An identifier in a programming language consists of up to six letters and digits of which the first character must be a letter. Derive a regular expression for the identifier. Build an $LL(1)$ parsing table for the language defined by the $LL(1)$ ... $X \rightarrow d \text{ semi } X \mid sY$ $Y \rightarrow \text{ semi } s Y \mid \epsilon$

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GATE2002-22 Video Solution
Construct all the parse trees corresponding to $i + j * k$ for the grammar $E \rightarrow E+E$ $E \rightarrow E*E$ $E \rightarrow id$ In this grammar, what is the precedence of the two operators $*$ and $+$? If only one parse tree is desired for any string in the same language, what changes are to be made so that the resulting LALR(1) grammar is unambiguous?

asked Apr 19 in Compiler Design by admin (3.6k points) | 1 view

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