GATE Overflow Test Series | Compiler Design | Test 1 | Question: 8

Question

Which of the following statements regarding $LR(0)$ parser is/are FALSE? (Mark all the appropriate choices)

• A. A $LR(0)$ configurating set cannot have multiple reduce items
• B. A $LR(0)$ configurating set cannot have both shift as well as reduce items
• C. If a reduce item is present in a $LR(0)$ configurating set it cannot have any other item
• D. An $LR(0)$ parser can parse any regular grammar

Comments

why option d is true @gatecse

LR(0) cannot parse all regular languages. We cannot have a LR(0) for a*.

https://gateoverflow.in/1251/gate2007-53

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@ val_pro20 I think you may misread the question.

In question, they ask the FALSE statements and option D is false. That’s why D is answer. 

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what is the meaning of the word “configuration set”?  Is it means the parsing table because if it does then option B, C and D are FALSE….

Please correct me...

Answer 1

Options A,B,C are TRUE.

No grammar with empty production can be LR(0). But empty rules are allowed in regular grammar as the only condition for a grammar to be regular is to be either left linear or right linear. So, not all regular grammars are $LR(0)$ and hence not all regular grammars can be parsed by an $LR(0)$ parser.

So, correct option D.

Comments

Can the reason “Regular grammar can be ambiguous and hence LR(0) cannot parse all regular grammar” be valid?

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Yes

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@Sachin Mittal 1 sir 

A configuration set can have reduce item and still can have other items also such as goto item..

hence option c should be true also..