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RE: Moving DASL to Experimental

From: Lisa Dusseault <lisa@xythos.com>
Date: Thu, 21 Jun 2001 12:10:10 -0700
To: "Julian Reschke" <julian.reschke@gmx.de>, <w3c-dist-auth@w3.org>
I'm also interested in working on DASL some more.  Xythos has implemented
it, including the basicsearch grammar :)

Although an XPath or XMLQuery syntax would be useful, basicsearch is also
useful and should not be dropped:
 - it can easily be translated into SQL for clients or servers that already
support SQL
 - it is very simple for very simple tasks
 - it can be implemented even by servers concerned about limiting their
performance "liability", because it can do very high-level searches and
restrict what properties can be searched.  (Servers don't have to support
any features which require parsing of the body or property syntaxes.  Since
parsing can be expensive, XPath/XMLQuery impose a far greater performance
 - it's very suited for directory contents listing, filters and sorting --
common browser tasks, easily automated.  E.g. only show items created since
<date>.  Only show items created by <principal>.


> -----Original Message-----
> From: w3c-dist-auth-request@w3.org
> [mailto:w3c-dist-auth-request@w3.org]On Behalf Of Julian Reschke
> Sent: Tuesday, June 12, 2001 3:12 AM
> To: w3c-dist-auth@w3.org
> Subject: Re: Moving DASL to Experimental
> Hi,
> I'm looking for other parties that would be interested on working on DASL
> again. With the current status of the spec I have mainly two
> problems, both
> of which apply to the basicsearch grammar:
> 1) The spec is completely silent about how the grammar engine is
> supposed to
> know about data types. For instance, I would suspect that property values
> for getcontentlength are supposed to be compared as numbers, while
> getlastmodified need a date comparison.
> 2) The grammar for accessing properties is not really XML-friendly, which
> has led to inventions like "DAV:iscollection". Indeed, this so-called
> "synthetic property" only solves one special case and leaves the rest
> (lockdiscovery, attributes, deltaV computed properties) untreated. I think
> DASL needs a grammar which can do "arbitrary" queries into the attributes,
> so something with the power of XPath would need to be used.
> In addition, I'm not happy with the language in chapter 3 (discovery of
> grammars). It mixes namespace prefixes with URI schemes, which is only
> correct in the very special case of "DAV:" (being a URI scheme
> and also the
> prefix used there).
> Julian
Received on Thursday, 21 June 2001 15:12:16 UTC

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