Ace Test Series 2018: Compiler Design - Parsing

Question

Consider the following context-free grammar
S → SS + | SS*| a

It is

a)LL(1)

b)LR(0)

c)Both

d)none

Comments

Its unambiguous grammer i'm sure of that.

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i think this is left recursive grammar so the option should be d that is none

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The Grammar is unambiguous.....we dont get different parse trees for above derivations......

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Grammer is LR(0) no RR and SR moves! and It's  unambiguous too.

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ambiguous grammar is one that has either two leftmost derivations or two rigthtmost derivations for the same string

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construct 2 different tree for same string then ?!

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Given grammar is left recursive doesn't implies it is an ambiguous grammar. A grammar is ambiguous if it is left recursive and right recursive. The given grammar is not right recursive as there exist a terminal in the end of every production.

https://gateoverflow.in/84491/ambiguity

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https://gateoverflow.in/197547/ace-grand-test-2-compiler-design

Answer 1

Its a LR(0) grammer so answer is B. No RR or SR conflicts.

Wrong answer was given in ace test series. This grammer is unambiguous because only one parse tree is possible for any string generated by it.

Having more than one expansion have nothing to do with ambiguity.

Comments

I am gettong sr conflict

Answer 2

• Given grammar is left recursive . And if a grammar is left recursive then it never be LL(1).

• Given grammar is LR(0) HENCE SLR also . So option b is true .

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