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Re: XPattern Specification

• To: Petr Cimprich <petr@g...>
• Subject: Re: XPattern Specification
• From: Alan Gutierrez <alan-xml-dev@e...>
• Date: Mon, 17 Jan 2005 10:50:17 -0500
• Cc: 'xml-dev' <xml-dev@l...>
• In-reply-to: <41EBDB33.7050104@g...>
• Mail-followup-to: Petr Cimprich <petr@g...>,'xml-dev' <xml-dev@l...>
• References: <20050116220239.GB10592@m...> <41EBAA9F.3080204@g...> <41EBC8B1.2040701@w...> <20050117144625.GA17626@m...> <41EBDB33.7050104@g...>
• User-agent: Mutt/1.4.1i

* Petr Cimprich <petr@g...> [2005-01-17 10:33]:
> Alan Gutierrez wrote:
> 
> >Thinking more in terms of pattern matching, less in terms of
> >   document traversal.
> > 
> >
> 
> I have no problem with this kind of thinking (as far as I can see myself 
> :). Any streaming processing is more declarative and there is not much 
> space for a document traversal. But still, you have to maintain some 
> amount of information to be able to decide if a pattern matches or not.

> >       <xp:capture name="foo" select="/document/reverse"/>
> >       <xp:insert-after match="/document/reverse">
> >           <reversed><xp:value-of select="util::reverse($foo)"/></reversed>
> >       </xp:insert-after>

> When you process endElement for reverse, you need to know whether its 
> parent is document in order to decide if /document/reverse matches. This 
> information necessary for matching is what I call "the context".

> Then, you could navigate through the context data with a XPattern-like 
> language (with limited axis etc.), but this is another story. So, I'm 
> also talking about matching patterns against a stream of events; but I 
> just need to know what info is available to test the pattern.

    To match that partuclar end element, with that partucular
    pattern, you only need to update a state machine as the events
    stream by. There's no need to traverse at end element. The
    pattern matches and an event handler takes over the stream.

    <foo>
      <bar>one</bar>
      <baz>
        <a><b><c>two</c></b></a>
      </baz>
      <bar>three</bar>
    </foo>

    /foo[baz/a/b/c = 'two']/bar[. = 'three']

    I can know that the above pattern matches at the end of the last
    bar, without keeping any nodes at all.

--
Alan Gutierrez - alan@e...

• Follow-Ups:
  • Re: XPattern Specification
    • From: Petr Cimprich <petr@g...>

• References:
  • XPattern Specification
    • From: Alan Gutierrez <alan-xml-dev@e...>
  • Re: XPattern Specification
    • From: Petr Cimprich <petr@g...>
  • Re: XPattern Specification
    • From: Karl Waclawek <karl@w...>
  • Re: XPattern Specification
    • From: Alan Gutierrez <alan-xml-dev@e...>
  • Re: XPattern Specification
    • From: Petr Cimprich <petr@g...>

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