Sun, 13 Sep 2009 02:52:56 -0400

Related articles |
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[3 earlier articles] |

Re: parser generator terminology cfc@shell01.TheWorld.com (Chris F Clark) (2009-09-06) |

Re: parser generator terminology cfc@shell01.TheWorld.com (Chris F Clark) (2009-09-07) |

Re: parser generator terminology haberg_20080406@math.su.se (Hans Aberg) (2009-09-07) |

Re: parser generator terminology mhelvens@gmail.com (Michiel) (2009-09-07) |

Re: parser generator terminology cfc@shell01.TheWorld.com (Chris F Clark) (2009-09-07) |

Re: parser generator terminology haberg_20080406@math.su.se (Hans Aberg) (2009-09-09) |

Re: parser generator terminology cfc@shell01.TheWorld.com (Chris F Clark) (2009-09-13) |

Re: parser generator terminology haberg_20080406@math.su.se (Hans Aberg) (2009-09-14) |

Re: parser generator terminology gneuner2@comcast.net (George Neuner) (2009-09-14) |

From: | Chris F Clark <cfc@shell01.TheWorld.com> |

Newsgroups: | comp.compilers |

Date: | Sun, 13 Sep 2009 02:52:56 -0400 |

Organization: | The World Public Access UNIX, Brookline, MA |

References: | 09-09-038 09-09-039 09-09-045 09-09-048 09-09-051 |

Keywords: | parse, theory |

Posted-Date: | 13 Sep 2009 20:08:28 EDT |

Hans Aberg <haberg_20080406@math.su.se> writes:

*> Chris F Clark wrote:*

*>>> In Waite & Goos, the vocabulary V is the (disjoint) union of the sets of*

*>>> non-terminals and terminals. They first defines a general rewriting*

*>>> system, with sentences members of V*, the set of finite strings (the*

*>>> free monoid) of V.*

*> ...*

*>> While I'm not so foolish as to argue with Waite, Goos, or the Bison*

*>> maintainers, epseically when I've Seen V, VT, and VN used rather*

*>> universally as the 3 sets of all symbols, terminals, and*

*>> non-terminals, there is precedence for vocbulary as VT, given that*

*>> Terence Parr uses it in ANTLR if I recall correctly.*

*>*

*> This is not formally wrong: V can be any finite set of symbols. A*

*> language is then a subset of V*. So it is OK to define a language L as a*

*> subset of T*, in which case the set of terminals T is the vocabulary.*

*> The set of non-terminals N is only needed when one wants to define a*

*> general rewriting system from a grammar to define the language L.*

*> Different grammar specs of L may lead to different N.*

Yes, good point. However, if one is trying to be clear, one needs to

be clear as to what means by Vocabulary, V = VN U VT or just VT.

Since, if I recall correctly, the original poster, Ralph Boland, was

interested in a case where he has both terminals and non-terminals and

he wanted a name for a set of just the terminals. Well, at least

that's how I interpreted his question.

The question goes back to whether there is a good one-word name for

"the set of terminals" in a language. While I like vocabulary as a

term for describing it, I think it may be non-standard, especially in

a context where there are non-terminals of interest.

Of course, it goes the other way too, if you use vocbulary for VT,

what word do you use for VN U VT? I don't think there is a common

word thet means all the words and phrases in a language (VT are the

named "words" and VN are the named "phrases" to my mind).

-Chris

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