GATE CSE 2017 | Set 2 | Question: 6

Question

Which of the following statements about parser is/are CORRECT?

1. $\text{Canonical LR}$ is more powerful than $\text{SLR}$
2. $\text{SLR}$ is more powerful than $\text{LALR}$
3. $\text{SLR}$ is more powerful than $\text{Canonical LR}$

• A. I only
• B. II only
• C. III only
• D. II and III only

Comments

previous year question.

https://gateoverflow.in/1663/gate1998_1-26

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Repeated $\mathbf{thrice}$ in GATE.

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I would like to mention one more fact :

 If number of states LR(0) = n1,

  number of states SLR = n2,

  number of states LALR = n3,

  number of states CLR = n4 then,

  n1 = n2 = n3 <= n4

Answer 1

For a parser more power means it can parse more strings. So, here only the first statement is correct.

Correct Answer: $A$

Answer 2

Correct Answer: $A $

• $\text{LALR}$ is more powerful than $\text{SLR}$ because $\text{SLR}$ has more restrictive reduction rules.
• $\text{Canonical LR}$ means $\text{LR(1).}$ It is more powerful than $\text{SLR.}$

Reference: http://stackoverflow.com/questions/2676144/what-is-the-difference-between-lr-slr-and-lalr-parsers

Answer 3

$CLR(1)>LALR(1)>SLR(1)>LR(0)>LL(1)$

Answer 4

CLR is the most powerful among all LR(k) parsers.

Answer 5

A)Only 1

CLR is more powerful than SLR

CLR>LALR>SLR

Answer 6

CLR > LALR > SLR

CLR is more powerful than LALR

LALR is more powerful than SLR

Only option (A) is correct....