2 Oct 2005 02:50:07 -0400

Related articles |
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Parsing fully context-free grammars lowell@coasttocoastresearch.com (Lowell Thomas) (2005-09-17) |

Re: Parsing fully context-free grammars haberg@math.su.se (2005-09-18) |

Re: Parsing fully context-free grammars lowell@coasttocoastresearch.com (Lowell Thomas) (2005-09-22) |

Re: Parsing fully context-free grammars haberg@math.su.se (2005-09-23) |

Re: Parsing fully context-free grammars paul@parsetec.com (Paul Mann) (2005-10-02) |

Re: Parsing fully context-free grammars haberg@math.su.se (2005-10-02) |

Re: Parsing fully context-free grammars drikosv@otenet.gr (Evangelos Drikos) (2005-10-03) |

Re: Parsing fully context-free grammars paul@parsetec.com (Paul Mann) (2005-10-04) |

Re: Parsing fully context-free grammars hannah@schlund.de (2005-10-06) |

Re: Parsing fully context-free grammars drikosv@otenet.gr (Evangelos Drikos) (2005-10-07) |

Re: Parsing fully context-free grammars lowell@coasttocoastresearch.com (lowell@coasttocoastresearch.com) (2005-10-20) |

From: | haberg@math.su.se (Hans Aberg) |

Newsgroups: | comp.compilers |

Date: | 2 Oct 2005 02:50:07 -0400 |

Organization: | Mathematics |

References: | 05-09-090 05-09-117 |

Keywords: | parse |

Posted-Date: | 02 Oct 2005 02:50:07 EDT |

haberg@math.su.se (Hans Aberg) wrote:

*> When writing a compiler, one needs to have the parse tree built according*

*> to the grammar specification, due to the stuff put into the actions of the*

*> rules.*

Actually, a situation where it is convenient using a different parse than

of the language grammar, is when one has a large number of operator

precedences (like in Prolog) which cannot be conveniently parsed via a

parser generated by a Yacc style static grammar parser generator. In the

parse, one puts the operators and values on a stack or compute the

semantic value as parenthesizes and operator precedences so require.

In article 05-09-067, "Lowell Thomas"

<lowell@coasttocoastresearch.com> wrote:

*> It seems to me that this could be generalized to say, in effect, that*

*> any tree from the forest can be emulated by any other. Does anyone*

*> know of a contradiction to this?*

So there are indeed situations where this is useful and used. But I do not

know of any general exploration of the topic.

--

Hans Aberg

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