15 Aug 2006 18:54:39 -0400

Related articles |
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Efficient construction of LALR Parsing Tables yasmina.andreu@gmail.com (Yasmina) (2006-08-14) |

Re: Efficient construction of LALR Parsing Tables boldyrev+nospam@cgitftp.uiggm.nsc.ru (Ivan Boldyrev) (2006-08-15) |

Re: Efficient construction of LALR Parsing Tables yasmina.andreu@gmail.com (Yasmina) (2006-08-19) |

From: | Ivan Boldyrev <boldyrev+nospam@cgitftp.uiggm.nsc.ru> |

Newsgroups: | comp.compilers |

Date: | 15 Aug 2006 18:54:39 -0400 |

Organization: | this field is intentionally left blank |

References: | 06-08-074 |

Keywords: | LALR |

On 9567 day of my life yasmina.andreu@gmail.com wrote:

*> " Reduction by A -> e is called for on input a if and only if there is*

*> a kernel item [B -> g · Cd, b] such that C => An for some n, and a is*

*> in FIRST(ndb). The set of nonterminals A such that C => An can be*

*> precomputed for each nonterminal C."*

*>*

*> "We shift on input a if there is a kernel item [B -> g · Cd, b] where*

*> C => ax in a derivation in which the last step does not use an*

*> e-production. The set of such a's can also be precomputed for each C"*

*>*

*> I don't know how to precompute the set of nonterminals A and the set of*

*> terminals a. I think that the only way to precompute this sets is*

*> derive the grammar, but this isn't efficient.*

Hint: the calculation is similar to calculation of FIRST and FOLLOW sets.

--

Ivan Boldyrev

.signature is under construction.

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