Which of the following statements about parser is/are CORRECT? I. Canonical LR is more powerful than SLR. II. SLR is more powerful than LALR. III. SLR is more powerful than Canonical LR.

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Official answer: A) I only

Lexical Analysis, Parsing and SDT

The relative expressive power (the set of grammars that can be parsed without conflicts) of LR parsers is:

\text{LR}(0) < \text{SLR}(1) < \text{LALR}(1) < \text{CLR}(1)

Statement I is TRUE: Canonical LR (CLR) is strictly more powerful than SLR.
Statement II is FALSE: LALR is strictly more powerful than SLR (SLR is less powerful than LALR).
Statement III is FALSE: SLR is less powerful than Canonical LR.

Thus, only statement I is correct, matching option (A).

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This Lexical Analysis, Parsing and SDT previous year question is Q6 of the GATE CSE 2017 Set 2 paper. Find more GATE CSE PYQs on Lexical Analysis, Parsing and SDT in Compiler Design, or browse all GATE CSE PYQs.

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Lexical Analysis, Parsing and SDT in GATE CSE

Lexical Analysis, Parsing and SDT has 14 GATE CSE PYQs across 12 papers from 2011 to 2025. 9 of them are 1-mark MCQs like this one, and GATE CSE 2017 Set 2 has 2.

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Independent practice explanation verified by the GateAI team. GATE is conducted by the IITs; question text follows the official paper.