What is unambiguous grammar with example?
A grammar can be unambiguous, if the grammar does not contain ambiguity. This means if it does not contain more than one left most derivation (LMD) or more than one right most derivation (RMD) or more than one parse tree for the given input string, it is an unambiguous grammar.
What are the unambiguous grammar give a suitable example?
As there are two different parse tree for deriving the same string, the given grammar is ambiguous. Unambiguous grammar will be: S → AB. A → Aa | a.
Can a regular grammar be ambiguous?
if a grammar is regular then it will be Context free also [as per chomsky hierarchy] it may be or may be not ambiguous depending on grammar. But it is sure any ambiguous regular grammar can be converted into unambiguous regular grammar.
Which one grammar is unambiguous from the following?
A context-free grammar is called unambiguous grammar if there exists one and only one derivation tree or parse tree….Difference between Ambiguous and Unambiguous Grammar :
| S.NO | Ambiguous Grammar | Unambiguous Grammar |
|---|---|---|
| 5. | Ambiguous grammar generates more than one parse tree. | Unambiguous grammar generates only one parse tree. |
What is leftmost and rightmost derivation?
Leftmost derivation − A leftmost derivation is obtained by applying production to the leftmost variable in each step. Rightmost derivation − A rightmost derivation is obtained by applying production to the rightmost variable in each step.
Is every regular grammar LL 1?
Computer Science Engineering (CSE) Question And LL(1) parses only unambiguous grammar, so statement P is False. Statement Q is true is for every regular set, we can have a regular grammar which is unambiguous so it can be parse by LR parser.
What is an unambiguous expression?
: clearly expressed or understood : not ambiguous.
Are all regular language unambiguous?
Every regular language is recognized by an unambiguous context-free grammar (take a deterministic automaton which recognises it, and make a production R→tS for every edge Rt→S in the DFA, and R→ϵ for every accepting state R). On the other hand, the natural “grammar” for a regular language is its regular expression.
What is ambiguous and unambiguous grammar?
In computer science, an ambiguous grammar is a context-free grammar for which there exists a string that can have more than one leftmost derivation or parse tree, while an unambiguous grammar is a context-free grammar for which every valid string has a unique leftmost derivation or parse tree.
What is the difference between CFG and regular grammar?
8 Answers. Regular grammar is either right or left linear, whereas context free grammar is basically any combination of terminals and non-terminals. Hence you can see that regular grammar is a subset of context-free grammar.
What is Sentential form and leftmost and rightmost derivation?
A left-sentential form is a sentential form that occurs in the leftmost derivation of some sentence. A right-sentential form is a sentential form that occurs in the rightmost derivation of some sentence.