Questions tagged [lr-k]

LR(k) is a common type of parser for context-free grammars

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Is THEADS the same as FIRST?

I'm reading the paper "A Practical General Method for Constructing LR(k) Parsers" by David Pager, and it contains the following paragraph: We will first of all briefly review the LR(1) parsing and ...
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1answer
150 views

Are there automatic transformation of grammar algorithms?

From time to time you can write a grammar that creates shift/reduce conflict (for example) but after reading the grammar you notice that if you rewrite the productions the conflict will go away, ...
2
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166 views

Intuitive Explanation on Converting BNF Grammar to LR(1)

Consider the following BNF Grammar G: ...
2
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0answers
326 views

How to find conflicts in LALR parser?

I have a LR analyser and I can't find out how to know whether the grammar is or is not LALR(1). I think that I have to merge states with the same rules. So I have to merge states: $2 - 12, 3 - 13, 4 -...
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27 views

Determine if two LR(1) action/goto tables always produce the same derivation

I am experimenting with implementing minimal LR(1) algorithms/techniques, but I find it very difficult to verify the correctness of what I've implemented. Is there a fast algorithm to determine if ...
1
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0answers
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Is there a direct way to obtain the RE for the handle-finding DFA of a grammar?

LR parser for a (CFG) grammar uses a handle-find automaton (which is a DFA) to find the handles. Such automata can be constructed by computing the canonical collection of sets of LR(0)/LR(1) items. Is ...
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0answers
648 views

Are LL(1) grammars a subset of LR(0) grammars?

As far as I've understood it seems that LL1 are a subset of LR0, but studying the following grammar I end up in a contraddiction. Grammar : S -> (S) | [S] | {S} | ε This is an LL1 while it seems ...
1
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209 views

Is the Java 8 Grammar still a LALR(1) grammar?

As I found out here: http://www.eclipse.org/jdt/core/howto/generate%20parser/generateParser.html , the Java Version of 2005 (might be Java 6, I'm not sure) is a LALR(1) grammar. However, I couldn't ...
1
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24 views

How equality of item (production state) is defined in LR parser?

Whenever I read about equality I took it for granted, but few days ago I wondered if my understanding is not too shallow. Consider such example (taken from: http://david.tribble.com/text/honalee.html):...
0
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1answer
25 views

What to do following a reduce in LR(1) parsing?

I am using this standard question from Dragonbook as an example, (the first problem) . I have trouble with what happens in State 4 on LR(1) parsing. Once it is reduced by the rule C->d, now what ...
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question about LL(1) and LR(0)

If grammar is an $LL(1)$ and does not contain any null production (i.e $V \rightarrow \epsilon$) then does that grammar necessarily be an $LR(0)$ grammar? I have tried to find counterexample for ...