XML.orgXML.org
FOCUS AREAS |XML-DEV |XML.org DAILY NEWSLINK |REGISTRY |RESOURCES |ABOUT
OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.

 


Help: OASIS Mailing Lists Help | MarkMail Help

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index]
Re: [xml-dev] What class of grammars is an XPath?

> Ah, you have interpreted the question quite differently from me (and perhaps
> correctly?) I thought it was looking at XPath as a grammar in which the
> sentences being described are document instances. You are talking about the
> grammar in which XPath expressions are the sentences.

Exactly.


Actually, Rick is asking also about a sublanguage:

>>> I think the same question could be
>>> asked, rephrased, as "what is the smallest class of formal grammars that
>>> every Xpath (evaluating to boolean) belongs to?"

The rules for boolean expression include the rules for any XPath
expression, so the answer remains exactly the same.


-- 
Cheers,
Dimitre Novatchev
---------------------------------------
Truly great madness cannot be achieved without significant intelligence.
---------------------------------------
To invent, you need a good imagination and a pile of junk
-------------------------------------
Never fight an inanimate object
-------------------------------------
You've achieved success in your field when you don't know whether what
you're doing is work or play
-------------------------------------
Facts do not cease to exist because they are ignored.



On Thu, Jan 27, 2011 at 6:19 AM, Michael Kay <mike@saxonica.com> wrote:
> On 27/01/2011 13:26, Dimitre Novatchev wrote:
>>>
>>> Anyway, it is an interesting question. I think the same question could be
>>> asked, rephrased, as "what is the smallest class of formal grammars that
>>> every Xpath (evaluating to boolean) belongs to?"
>>
>> It isn't a regular expression -- XPath expressions may have an
>> unlimited nestedness.
>>
>> It is definitely a context-free (CF) grammar and even more
>> specifically, it is an LR(1) grammar.
>>
>> Three years ago I defined the full XPath 2.0 grammar (with one
>> exception
>
> Ah, you have interpreted the question quite differently from me (and perhaps
> correctly?) I thought it was looking at XPath as a grammar in which the
> sentences being described are document instances. You are talking about the
> grammar in which XPath expressions are the sentences.
>
> Michael Kay
> Saxonica
>
> _______________________________________________________________________
>
> XML-DEV is a publicly archived, unmoderated list hosted by OASIS
> to support XML implementation and development. To minimize
> spam in the archives, you must subscribe before posting.
>
> [Un]Subscribe/change address: http://www.oasis-open.org/mlmanage/
> Or unsubscribe: xml-dev-unsubscribe@lists.xml.org
> subscribe: xml-dev-subscribe@lists.xml.org
> List archive: http://lists.xml.org/archives/xml-dev/
> List Guidelines: http://www.oasis-open.org/maillists/guidelines.php
>
>


[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index]


News | XML in Industry | Calendar | XML Registry
Marketplace | Resources | MyXML.org | Sponsors | Privacy Statement

Copyright 1993-2007 XML.org. This site is hosted by OASIS