context-free-grammar Questions
9
Solved
I'm studying for a finite automata & grammars test and I'm stuck with this question:
Construct a grammar that generates L:
L = {a^n b^m c^m+n|n>=0, m>=0}
I believe my productions shoul...
Geaghan asked 20/6, 2009 at 15:48
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I'm getting back into language design/specification (via BNF/EBNF grammars) after 20+ years of leaving the topic alone (since my CS undergrad degree).
I only vaguely recall the various related term...
Tamworth asked 14/12, 2022 at 23:40
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Are there any tools to convert ANTLR grammar syntax to and from other BNF syntaxes? There are several forms Backus-Naur Form (BNF, EBNF, ABNF, W3C-BNF, XBNF...) with specification, e.g. see t...
Perturb asked 1/2, 2011 at 22:52
3
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From this wikipedia page:
The fundamental difference between
context-free grammars and parsing
expression grammars is that the PEG's
choice operator is ordered. If the
first alternative succ...
Collimator asked 31/3, 2011 at 13:59
2
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According to the ECMAScript spec:
There are several situations where the identification of lexical input
elements is sensitive to the syntactic grammar context that is
consuming the input elements...
Applicable asked 16/11, 2021 at 2:25
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I am reading Rebol Wikipedia page.
"Parse expressions are written in the parse dialect, which, like the do dialect, is an expression-oriented sublanguage of the data exchange dialect. Unlike ...
Rase asked 12/9, 2019 at 14:13
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I'm working on a non-English parser with Unicode characters. For that, I decided to use NLTK.
But it requires a predefined context-free grammar as below:
S -> NP VP
VP -> V NP | V NP PP
...
Hermelindahermeneutic asked 17/7, 2013 at 9:6
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This might be related to me not understanding the Keyword Extraction feature, which from the docs seems to be about avoiding an issue where no space exists between a keyword and the following expre...
Garnetgarnett asked 21/3, 2021 at 14:36
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Or, to be a little more precise: which programming languages are defined by a context-free grammar?
From what I gather C++ is not context-free due to things like macros and templates. My gut tells...
Millhon asked 22/5, 2009 at 15:31
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NLTK (Natural Language Toolkit) lets you parse a FCFG grammar using nltk.FCFG.fromstring([grammar string here]). Where is the FCFG grammar format specification*? I googled it to death, but all I co...
Scrubber asked 12/3, 2016 at 21:10
3
Does anyone have a good tool for drawing parse trees arising from a context-free grammar? There is this question, but it dealt specifically with finite automata instead of parse trees. I've b...
Barbarian asked 11/2, 2011 at 18:16
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When looking through C's BNF grammar, I thought it was weird that the production rule for a declaration looked like this (according to https://cs.wmich.edu/~gupta/teaching/cs4850/sumII06/The%20synt...
Beanstalk asked 4/4, 2020 at 9:50
2
I am currently going over CFG and saw the answer and I am not sure how they got it. How did they get it to convert into Regular Expression from CFG here?
S -> aS|bX|a
X -> aX|bY|a
Y -> aY...
Demythologize asked 10/4, 2014 at 17:1
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I often hear claims that C++ is a context-sensitive language. Take the following example:
a b(c);
Is this a variable definition or a function declaration? That depends on the meaning of the symb...
Sclerenchyma asked 29/1, 2013 at 18:5
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I understand that EBNF can be used to express Context Free Grammar, but is there any difference between the two?
I am asking because there are questions that ask to convert EBNF to CFG, but as of ...
Cheliform asked 1/2, 2014 at 0:36
4
I have the following grammar, which I'm told is LR(1) but not SLR(1):
S ::= a A | b A c | d c | b d a
A ::= d
I don't understand why this is. How would you prove this?
Wray asked 8/5, 2012 at 20:7
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How can I find if an attribute is synthesized or inherited from the productions of a grammar?
I guess for that the attribute must be predefined in the problem -- if its value depends on child or p...
Ratafia asked 11/4, 2015 at 10:35
1
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Many productions in EcmaScript are given with the following "modifiers":
[Yield, Await, In, Return]
Here are a few examples:
ArrayLiteral[Yield, Await]:
...
ElementList[Yield, Await]:
... As...
Olander asked 3/9, 2017 at 11:21
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I've watched this course by Alex Aiken and read through many other resources. But I'm struggling to find clear classification of top-down parsers.
This document doesn't provide a clear classificati...
Cathar asked 31/8, 2017 at 8:57
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According to "Recursive descent parser" on Wikipedia, recursive descent without backtracking (a.k.a. predictive parsing) is only possible for LL(k) grammars.
Elsewhere, I have read that the implem...
Autocephalous asked 21/8, 2017 at 12:2
1
I have to check if a string can be derived from a given context free that is in Chomsky normal form. I'm using C++.
There is very nice pseudocode on the Wikipedia article covering the CYK algorith...
Acquiescence asked 5/12, 2012 at 17:7
4
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A C program source code can be parsed according to the C grammar(described in CFG) and eventually turned into many ASTs. I am considering if such tool exists: it can do the reverse thing by firstly...
Schenk asked 17/12, 2010 at 5:54
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I understand both LR and LALR are bottom-up parsing algorithms, but what's the difference between the two?
What's the difference between LR(0), LALR(1), and LR(1) parsing? How can I tell if ...
Personable asked 29/10, 2013 at 16:9
2
I want to design a context free grammar for the following language:
L = { w e {(, )}* | w is balanced}
I proposed the following grammar:
S -> (S)S | E
Whereas the proposed solution in the...
Beheld asked 24/2, 2017 at 3:14
5
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I need a CFG which will generate strings other than palindromes. The solution has been provided and is as below.(Introduction to theory of computation - Sipser)
R -> XRX | S
S -> aTb | bTa
T...
Earthiness asked 27/6, 2011 at 15:23
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