Context-sensitive grammars are more general than context-free grammars, in the sense that there are languages that can be described by CSG but not by context-free grammars. Context-sensitive grammars are less general (in the same sense)
than unrestricted grammars
.
What is the difference of context free language from context-free grammar?
A valid (accepted) sentence in the language must follow particular rules, the grammar. A context-free language is a language generated by a context-free grammar. They are
more
general (and include) regular languages. The same context-free language might be generated by multiple context-free grammars.
How do you know if a grammar is context sensitive?
A grammar is context-free if
left
-hand sides of all productions contain exactly one non-terminal symbol. By definition, if one exists, then the language is context-free. An equivalent construct would be a pushdown automaton. It’s the same as DFA, but with a stack available.
What does context-free grammar mean?
In formal language theory, a context-free grammar (CFG) is a
formal grammar whose production rules are of the form
.
with a single nonterminal symbol, and a string of terminals and/or nonterminals ( can be empty)
.
Is complement of CSL is CSL?
Context-sensitive Language: The language that can be defined by context-sensitive grammar is called CSL. Properties of CSL are : Union, intersection and concatenation of two context-sensitive languages is context-sensitive. Complement of a context-
sensitive
language is context-sensitive.
What is context sensitive grammar and also write the application of context-free grammar in real life?
Context-free grammars are used in compilers and in particular for parsing,
taking a string-based program and figuring out what it means
. Typically, CFGs are used to define the high-level structure of a programming language. Figuring out how a particular string was derived tells us about its structure and meaning.
Which is a context-free grammar together with attributes and rules?
An attribute grammar
is a context-free grammar with the addition of attributes and attribute evaluation rules called semantic functions. Thus, an attribute grammar can specify both semantics and syntax while BNF specifies only the syntax.
Which of the following are context free language?
Every regular language is context free. |
m, l, k, n >= 1 }
is context free, as it is regular too. Given an expression such that it is possible to obtain a center or mid point in the strings, so we can carry out comparison of left and right sub-parts using stack.
What is the meaning of context-sensitive?
A context-sensitive word, phrase or sentence is
one which can receive different semantic values (interpretations) when used in different contexts
. In particular, a declarative sentence is context sensitive if it can express different propositions when said in different contexts.
How do you know if context free grammar is regular?
In a right-regular grammar,
every production’s right-hand side has at most one non-terminal
, and that non-terminal is the last symbol in the right-hand side. A left-regular grammar is the same except that all the non-terminals are at the beginning of their respective right-hand sides.
Why context-sensitive grammar is Noncontracting?
A grammar is essentially noncontracting
if there may be one exception
, namely, a rule S → ε where S is the start symbol and ε the empty string, and furthermore, S never occurs in the right-hand side of any rule. … If each rule even properly increases the length, the grammar is called a growing context-sensitive grammar.
Is the corresponding automata for context-sensitive language?
An example of a context-sensitive language accepted by a linear-bounded automaton is
the copy language xcx
. The family of recursively enumerable languages includes the context-sensitive languages, which in turn includes the context-free, which finally includes the regular, or finite-state, languages.
Is a Nb N context-free?
A language is a context-free language (CFL) if all of its strings are generated by a context-free grammar. Example 1: L
1
= {
a
n
b
n
| n is a positive integer
} is a context-free language.
Which model is accepted context-sensitive grammar?
| Grammar Type Grammar Accepted Automaton | Type 0 Unrestricted grammar Turing Machine | Type 1 Context-sensitive grammar Linear-bounded automaton | Type 2 Context-free grammar Pushdown automaton | Type 3 Regular grammar Finite state automaton |
|---|
Are ambiguous grammar context-free yes or no?
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.
How do you find language context free grammar?
A language is context-free if it is generated by
a CFG
. For compactness, we write S → 0S1 | ε where the vertical bar means or. Let P be language of palindromes with alpha- bet {a,b}. One can determine a CFG for P by finding a recursive decomposition.
What is the difference between regular language and context free language?
A language is said to be a regular language if it is generated by a regular grammar. Regular grammar is either right or left linear, whereas context free grammar is basically any combination of terminals and non-terminals. A language is said to be context-free if it is generated by a context-
free grammar
.
What is context free in research?
: of, relating to, or
being a grammar
or language based on rules that describe a change in a string without reference to elements not in the string also : being such a rule.
Which of the following is not a context free language?
Explanation: As the language seems to be finite, a dfa can be constructed for the same, thus is regular. 4. Which of the following is not context free? Explanation: {
a*b*c*} and (c)
are regular languages while option (a) is not context free language.
Which of the following allows you to use context-sensitive help?
Context-sensitive help can be implemented using
tooltips
, which either provide a terse description of a GUI widget or display a complete topic from the help file. Other commonly used ways to access context-sensitive help start by clicking a button. One way uses a per widget button that displays the help immediately.
(operating system)
A menu which appears in response to a user action (typically a mouse click) and whose contents are determined by which application window was clicked or has the input focus
.
Is CFL and CFG same?
In formal language theory, a context-free language (CFL) is
a language generated by a context-free grammar (CFG)
. Context-free languages have many applications in programming languages, in particular, most arithmetic expressions are generated by context-free grammars.
What are the 4 components of a CFG context-free grammar as a 4 tuple?
In general a context-free grammar G is a 4-tuple (
V,Σ, R, S
) where V is a set of variables, Σ is an alphabet of terminal symbols, R is a set of rules, and S is a start symbol. The elements of V − Σ are called nonterminals and are analogous to parts of speech.
Is CSL closed under substitution?
CSL are closed under all except 2 things
1)HOMOMORPHISM 2)SUBSTITUTION…..
Is every CSL is recursive?
Every Context sensitive language is recursive
.
Is every context-free language is a context sensitive language?
Every context-
free language is context-sensitive
. Membership of a string in a language defined by an arbitrary context-sensitive grammar, or by an arbitrary deterministic context-sensitive grammar, is a PSPACE-complete problem.
What are the 3 types of grammar?
- prescriptive.
- descriptive.
- transformational-generative.
Is English a context sensitive language?
The question whether English is a context-free language has for some time been regarded as an open one. … Since context-free languages are closed under intersection with regular sets, that L ∩ English is not a context-free language proves that
English is not a
context-free language either.
What is sensitive language?
By sensitive language we mean
words that you need to be careful about using because their use may, intentionally or not, insult or offend some people
. The Usage notes that deal with sensitive language fall into two groups: Words that may cause offence.
