Which one of the following statements is TRUE?
Show Hint
- The LALR(1) parser for a grammar G cannot have reduce-reduce conflict if the LR(1) parser for G does not have reduce-reduce conflict.
- Symbol table is accessed only during the lexical analysis phase.
- Data flow analysis is necessary for run-time memory management.
- LR(1) parsing is sufficient for deterministic context-free languages.
The Correct Option is D
Solution and Explanation
- Option (B) is false. The symbol table is typically accessed during both the lexical analysis and the semantic analysis phases, not just during lexical analysis. In fact, it is used throughout the compilation process, particularly during syntax and semantic analysis.
- Option (C) is false. Data flow analysis is not directly related to run-time memory management, but rather to analyzing how data is propagated throughout a program. It helps detect errors and optimize code but does not deal with memory allocation or management directly.
- Option (D) is true. LR(1) parsing is indeed sufficient for deterministic context-free languages, which are those that can be parsed deterministically using a single lookahead symbol. LR(1) parsers can handle a broader class of languages compared to LL(1) parsers. This is the correct statement.
Final Answer: (D)
Top Questions on Parsing
Consider the augmented grammar with \(\{+,* , (, ), id\}\) as the set of terminals. \[ S' \rightarrow S \] \[ S \rightarrow S + R \mid R \] \[ R \rightarrow R^{\,*} P \mid P \] \[ P \rightarrow (S) \mid id \] If \(I_0\) is the set of two LR(0) items \(\{[S' \rightarrow S.], [S \rightarrow S. + R]\}\), then \(goto(\text{closure}(I_0), +)\) contains exactly \(\underline{\hspace{1cm}}\) items.
Consider the following context-free grammar where the set of terminals is \(\{a,b,c,d,f\}\):
\[ S \rightarrow daT \mid Rf \] \[ T \rightarrow aS \mid baT \mid \epsilon \] \[ R \rightarrow caTR \mid \epsilon \] The following is a partially-filled LL(1) parsing table.
Which one of the following choices represents the correct combination for the numbered cells in the parsing table ("blank" denotes that the corresponding cell is empty)?
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\[ S_1:\ \text{Every SLR(1) grammar is unambiguous but there are certain unambiguous grammars that are not SLR(1).} \] \[ S_2:\ \text{For any context-free grammar, there is a parser that takes at most } O(n^3) \text{ time to parse a string of length } n. \] Which one of the following options is correct? Consider the following augmented grammar with terminals {#, @, <, >, a, b, c}.
$S' → S$
$S → S\#cS$
$S → SS$
$S → S@$
$S → <S>$
$S → a$
$S → b$
$S → c$Let I0 = CLOSURE({ S' → • S }). The number of items in the set GOTO(GOTO(I0, <), <) is .
Consider the following ANSI C program:
int main() { Integer x; return 0; }Which one of the following phases in a seven-phase C compiler will throw an error?
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