Arrange the following parsers in increasing order of their power of handling grammars i.e. from the…
Parsing power increases as LL(0), LR(0), SLR(1), LALR(1), LR(1). LR(0) uses no lookahead, SLR adds FOLLOW sets, LALR(1) uses lookaheads from merged LR(1) states, and…
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Arrange the following parsers in increasing order of their power of handling grammars i.e. from the least powerful parser to the most powerful parser.
A. LR(0)
B. LR(1)
C. LALR(1)
D. LL(0)
E. SLR
Answer and explanation
Correct answer C
Parsing power increases as LL(0), LR(0), SLR(1), LALR(1), LR(1). LR(0) uses no lookahead, SLR adds FOLLOW sets, LALR(1) uses lookaheads from merged LR(1) states, and canonical LR(1) keeps full lookahead sets in its items, so it handles the largest class of grammars. Merging LR(1) states with the same core can introduce reduce-reduce conflicts, so LALR(1) is weaker than LR(1), not stronger.
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UGC NET Computer Science and Applications