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Right OPTION is (a) LALR parsing

To explain: LALR parser generator is software tool that reads a BNF grammar and CREATES a LALR parser which is CAPABLE of parsing FILES written in PROGRAMMING language identified by BNF grammar.

Correct choice is (d) All of the mentioned

The EXPLANATION: All the following mentioned are top down PARSERS and begin their operation from the starting symbol.

The correct choice is (a) Root with no children is called a leaf

Easy explanation: A NODE has atmost one parent, drawn above the node, and ZERO or more children drawn below. Lines CONNECT PARENTS to children. There is one node, one root, that has no parent; this node appears to be at the TOP of the tree. Nodes with no children are called leaves. Nodes that are not leaves are called interior nodes.

The correct choice is (a) Inherent Ambiguous LANGUAGE

To EXPLAIN I would say: A context free language for which no UNAMBIGUOUS GRAMMAR EXISTS, is called Inherent ambiguous language.

The CORRECT answer is (b) LOOK ahead left to RIGHT parser

To elaborate: LALR STANDS for Look ahead left to right parsers. It has more language RECOGNITION power than LR(0) parser.

Right option is (b) Regular

The explanation is: The following FORMAT of GRAMMAR is of Regular grammar and is a part of Context FREE grammar i.e. like a specific form WHOSE FINITE automata can be generated.

Correct choice is (C) Unix

For explanation: YACC technique is a computer code for the Unix OPERATING SYSTEM. It is a LALR parser generator, generating a parser, the part of a compiler that tries to MAKE syntactic SENSE of the source code.

The CORRECT option is (d) NONE of the mentioned

To explain: B was programming language designed by Dennis Ritchie and KEN Thompson for RECURSIVE, non NUMERIC, system and language softwares. It was a typeless language, everything is a word.

Right option is (a) Statement: The recursive INFERENCE procedure determines that string w is in the language of the variable A, A being the starting variable.

To explain I WOULD say: We apply the productions of CFG to infer that certain STRINGS are in the language of a certain variable.

The correct OPTION is (B) LL parser

To EXPLAIN I would say: Bottom up PARSING is done by shift reduce parsers like LALR parsers, Operator PRECEDENCE parsers, simple precedence parsers, etc.

The correct CHOICE is (d) All of the mentioned

The explanation: More that hundred of document formats USING XML syntax have been developed, including RSS, Atom, SOAP and XHTML.

The CORRECT choice is (d) All of the MENTIONED

Easy explanation: The mentioned are the correct and proper functions of a shift reduce parsers. The parsing methods are most COMMONLY used for parsing programming LANGUAGES, etc.

Correct choice is (d) None of the mentioned

For explanation I would say: G, a CFG is said to be in Chomsky normal FORM if all its productions are in ONE of the following form:

A->BC or A->a

Correct OPTION is (b) P->0110

The EXPLANATION: The FOLLOWING is a parse tree for the PRODUCTION 0110 over {0,1}*.

Correct CHOICE is (d) All of the mentioned

The BEST explanation: Parse TREES are an alternative representation to DERIVATIONS and recursive inferences. There can be several parse trees for the same string.

Right answer is (C) Both Recursive INFERENCE and DERIVATIONS

The explanation is: Two inference approaches:

1. Recursive inference, using productions from BODY to HEAD

2. Derivations, using productions from head to body

Right choice is (d) none of the mentioned

Easiest explanation: Markup languages originated with text DOCUMENTS, but there is an INCREASING USE of mark up LANGUAGE in presentation of other types of information, INCLUDING playlists, vector graphics, user interfaces and web services.

The CORRECT CHOICE is (a) reachable

To elaborate: A symbol X is generating if there exists : X->*W for some w that belongs to T*.

Also, a symbol can never be CONTEXT free.

Right answer is (B) syntactic

For EXPLANATION: A parse tree or concrete syntactic tree is an ordered, ROOTED tree that REPRESENTS the syntactic structure of a string according to some context FREE grammar.

Right option is (b) Context free LANGUAGE

To explain I WOULD say: PUSH down AUTOMATA accepts context free language.

Right option is (d) None of the mentioned

The best I can EXPLAIN: W GRAMMAR or van Wijngaarden form is used to define POTENTIALLY infinite context free grammars in a finite number of rules. It is an example of LARGER class of affix grammars. This technique was used to define the P/L Algol 68.

Correct answer is (c) Yet Another Compiler Compiler

To explain I would say: YACC STANDS for ‘Yet another compiler compiler’ and it was developed by STEPHEN Johnson in B programming language LATER TRANSLATED to C.

Right option is (d) L is a set of 0^n1^n

Explanation: There exists no finite automata to accept the given language i.e. 0^n1^n. For other OPTIONS, it is POSSIBLE to MAKE a dfa or NFA REPRESENTING the language set.

The correct choice is (c) YACC and GNU Bison

The best I can explain: YACC is a computer CODE for UNIX operating system which generates a LALR PARSER. On the other hand GNU Bison or Bison can GENERATE LALR and GLR parsers.

The CORRECT option is (a) META

The best explanation: GENERALLY speaking, a meta language is a language USED to describe a language. XML is a metalanguage that is used to describe a markup language.

Correct CHOICE is (c) S->0B|1A|eA->0SB->1S

Explanation: We can build context FREE grammar through different approaches, recursively defining the VARIABLES and TERMINALS inorder to fulfil the CONDITIONS.

Right choice is (b) true

The explanation: It is EXACTLY the opposite case where LALR parsers USES MUTUALLY recursive functions INSTEAD of tables. It is a simplified version of CANONICAL left to right parser.

The correct answer is (a) STATEMENT: R->R|TT->ε is an ambiguous grammar

The explanation is: The production can be either itself or an empty string. Thus the empty string has more than ONE leftmost derivations, depending on how many times R->R is being USED.

The correct answer is (a) dangling else PROBLEM

The explanation is: Dangling else problem: In many LANGUAGES,the else in an if-then-else STATEMENT is optional, which RESULTS into nested conditionals being ambiguous, at least in TERMS of the CFG.

The correct option is (C) both GENERATING and reachable

The best I can EXPLAIN: For a symbol X to be useful, it has to be both reachable and generating i.e.

S->* aXb -> * w where w belongs to T*.

The correct choice is (c) Grammar

To elaborate: The entity which ACCEPTS a language is termed as AUTOMATA while the one which GENERATES it is CALLED Grammar. TOKENS are the smallest individual unit of a program.

Right CHOICE is (d) Iteration

For explanation: The closure PROPERTY of a context free GRAMMAR does not include iteration or kleene or STAR operation.

Right choice is (a) DETERMINISTIC Context FREE grammars

For explanation I WOULD say: Deterministic CFGs are ALWAYS unambiguous , and are an important subclass of unambiguous CFGs; there are non-deterministic unambiguous CFGs, however.

Correct option is (b) BOTTOM up PARSER

The EXPLANATION is: Bottom up parser STARTS from the bottom with the string and comes up to the start symbolusing a PARSE tree or a derivation tree.

Right CHOICE is (c) B programming language

To explain: STEPHEN JOHNSON wrote this parser generator in B programming language which was further MODIFIED and written in C, JAVA, Python, etc.

Correct choice is (a) can no longer be 2h-1.

For explanation: It is the parse tree theorem which states:

GIVEN: Suppose we have a parse tree for a string w, according to a CNF GRAMMAR, G=(V, T, P, S). LET H be the height of the parse tree. Now, Implication: |w|<=2h-1.

Right choice is (d) All of the mentioned

Easy explanation: The following is a THEOREM which states the CLOSURE property of context FREE languages which INCLUDES Kleene operation, Union operation and DOT operation.

Correct choice is (c) TREE

To elaborate: The tree, known as “PARSE tree” when used in a compiler, is the data structure of choice to REPRESENT the source PROGRAM.

The correct choice is (b) {a^nb^nc^md^m| n,m > 0}

To explain I WOULD say: This set is CONTEXT-free, since the UNION of TWO context-free languages is always context free.

The correct CHOICE is (b) Bottom up PARSERS

To explain I would say: The YACC takes C CODE as INPUT and produces shift reduce parsers in C,also known as Bottom up parsers which execute C snippets with the associated rule.

Correct CHOICE is (a) C

Best explanation: The advantage of using high LEVEL programming LANGUAGE LIKE C and Pascal is that they allow us to write statements that look more like English.

Right ANSWER is (a) Every CFG for L is ambiguous

Best explanation: A CFL L is SAID to be inherently ambiguous if every CFG for L is ambiguous.

Correct option is (d) All of the mentioned

The best I can EXPLAIN: The following are the NOTIONS to express CONTEXT free grammars:

a) Recursive Inferences

b) Derivations

c) Sentential form

d) Parse TREES

Right choice is (c) Context Sensitive Language

For explanation: Context Sensitive Language or Type 1 or Linearly Bounded NON deterministic Language has the production rule where the production is context DEPENDENT i.e.aAb->AGB.

Correct ANSWER is (d) None of the mentioned

The best I can EXPLAIN: L={e, 01, 0011, 000111, ……0^n1^n }. As epsilon is a part of the set, thus all the OPTIONS are correct IMPLYING none of them to be wrong.