Received: (from majordomo@localhost) by mail.proper.com (8.8.8/8.8.5) id HAA19616 for ietf-xml-mime-bks; Wed, 2 Jun 1999 07:32:38 -0700 (PDT) Received: from hesketh.net (wasabi-eth0-1.hesketh.net [216.27.10.31]) by mail.proper.com (8.8.8/8.8.5) with ESMTP id HAA19611 for ; Wed, 2 Jun 1999 07:32:33 -0700 (PDT) Received: from thinkpad (slip129-37-221-72.ny.us.ibm.net [129.37.221.72]) by hesketh.net (8.9.3/8.9.3) with SMTP id KAA27217 for ; Wed, 2 Jun 1999 10:33:43 -0400 Message-Id: <199906021433.KAA27217@hesketh.net> X-Sender: simonstl@pop.hesketh.net X-Mailer: QUALCOMM Windows Eudora Pro Version 4.0.1 Date: Wed, 02 Jun 1999 10:36:56 -0400 To: ietf-xml-mime@imc.org From: "Simon St.Laurent" Subject: Re: Media types, fragment identifiers, and XPointer In-Reply-To: <199905280157.AA00636@archlute.apsdc.ksp.fujixerox.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-ietf-xml-mime@imc.org Precedence: bulk List-Archive: List-Unsubscribe: At 10:57 AM 5/28/99 +0900, MURATA Makoto wrote: >It appears that media types, fragment identifiers, and XPointer are >actually related. This is an important question that operates on several levels. Fragment identifiers (and supporting linking mechanisms) are a 'generic' tool that can be used with any XML document. On the other hand, not all applications using XML will support fragment identifier processing. XLink (ancient but current draft, 3/98) suggests that regular #xxx identifiers be processed on the client, and gives a query syntax for getting the fragment from the server, but this infrastructure seems inadequate. >XPointer is intended to be used as a fragment identifier. > > "The locator for a resource is typically provided by means of a > Uniform Resource Identifier, or URI. XPointers can be used as fragment > identifiers in conjunction with the URI structure to specify a more precise > sub-resource." > >I personally have expected that XPointer is usable for every XML document >no matter what the media type is. But I am apparently wrong. Do we need >a top-level media type "xml" or some convention such as "image/xml.vml" >so that XPointer can be used for any XML document? Or, are "text/xml" and >"application/xml" enough? XPointer should be usable for every document that is a well-formed XML document, whatever the media type. However, software is going to need to know that the document is indeed XML to know how to interpret the XPointer... XPointer is an excellent example of a generic XML tool that works with any XML document in a wide variety of of different situations. There's still the issue of who does what processing. I'm not thrilled with the XLink proposals for syntax suggesting how that should be setup - I'd rather see some negotiation between client and server determining whether the bandwidth-saving approach of server fragment retrieval is appropriate or the server-processing-saving approach of shipping the whole file to the client and letting it do the work is appropriate. I'd like to see something more sophisticated than putting it right in the URL, though that may raise other issues back at the XLink/XPointer corral. MURATA Makoto then asked two good questions: >Q1. Do we need XPointers for every XML instance? > >I personally think that this is too much. For example, I do not think we have >use XPointers for RDF, which is in the XML syntax. I think you'll actually see lots of use of XPointers with RDF. Dublin Core metadata is a prime example where I can see an application only wanting to grab part of the information (say author and copyright info) without needing the entire file. It's easy to make arguments for just about any XML instance, though the admittedness blurriness between XPointer and a 'real query language' certainly helps. In general, though, I'd say XPointer fragment identifiers can be useful with _any_ XML instance. >Q2. Do we need XPointers only for human-readable documents that are rendered > by some browsers? > >I am not sure if the answer is Yes. How do XLL experts in this ML feel? A number of the people who've been calling for XPointer and XLink plan to use them in applications where human-readability is not an issue. If you use an XML document to describe an object structure (nested objects and properties as elements and attributes, or some variation), you can use XLink to connect multiple object sets, for instance, and XPointer to retrieve particular pieces from the set. XLink and XPointer may also see use in some general modeling cases - it seems like the WG is trying to make sure this remains possible even though the 'focus' is hypertext. I'd say XLink and XPointer can go anywhere XML can go, human-readable or not, browser or custom application. Simon St.Laurent XML: A Primer / Building XML Applications Inside XML DTDs: Scientific and Technical (July) Sharing Bandwidth / Cookies http://www.simonstl.com Received: (from majordomo@localhost) by mail.proper.com (8.8.8/8.8.5) id HAA09124 for ietf-xml-mime-bks; Tue, 1 Jun 1999 07:52:06 -0700 (PDT) Received: from locke.ccil.org (root@[192.190.237.102]) by mail.proper.com (8.8.8/8.8.5) with ESMTP id HAA09120 for ; Tue, 1 Jun 1999 07:52:04 -0700 (PDT) Received: from locke.ccil.org (cowan@ns1.ccil.org [192.190.237.102]) by locke.ccil.org (8.8.5/8.8.5) with ESMTP id LAA03524 for ; Tue, 1 Jun 1999 11:10:14 -0400 (EDT) Message-ID: <3753F3C8.659CA3F0@locke.ccil.org> Date: Tue, 01 Jun 1999 10:52:56 -0400 From: John Cowan Organization: Lojban Peripheral X-Mailer: Mozilla 4.06 [en] (WinNT; U) MIME-Version: 1.0 To: ietf-xml-mime@imc.org Subject: Re: Media types, fragment identifiers, and XPointer References: <199906010652.AA00659@archlute.apsdc.ksp.fujixerox.co.jp> <3753CABD.513330B4@w3.org> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-ietf-xml-mime@imc.org Precedence: bulk List-Archive: List-Unsubscribe: Chris Lilley wrote: > It is arguable that a later, refined syntax for RDF should use XPointer, > for compatibility with other XML applications. As currently defined, RDF uses bare ID values, which is a degenerate form of XPointer that the (current) XLink WD blesses. -- John Cowan http://www.ccil.org/~cowan cowan@ccil.org You tollerday donsk? N. You tolkatiff scowegian? Nn. You spigotty anglease? Nnn. You phonio saxo? Nnnn. Clear all so! 'Tis a Jute.... (Finnegans Wake 16.5) Received: (from majordomo@localhost) by mail.proper.com (8.8.8/8.8.5) id FAA04804 for ietf-xml-mime-bks; Tue, 1 Jun 1999 05:05:05 -0700 (PDT) Received: from tux.w3.org (root@tux.w3.org [18.29.0.27]) by mail.proper.com (8.8.8/8.8.5) with ESMTP id FAA04800 for ; Tue, 1 Jun 1999 05:05:04 -0700 (PDT) Received: from w3.org (root@localhost [127.0.0.1]) by tux.w3.org (8.8.7/8.8.7) with ESMTP id IAA12638; Tue, 1 Jun 1999 08:06:09 -0400 Message-ID: <3753CABD.513330B4@w3.org> Date: Tue, 01 Jun 1999 13:57:49 +0200 From: Chris Lilley X-Mailer: Mozilla 4.6 [en] (WinNT; I) X-Accept-Language: en MIME-Version: 1.0 To: MURATA Makoto CC: ietf-xml-mime@imc.org Subject: Re: Media types, fragment identifiers, and XPointer References: <199906010652.AA00659@archlute.apsdc.ksp.fujixerox.co.jp> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-ietf-xml-mime@imc.org Precedence: bulk List-Archive: List-Unsubscribe: MURATA Makoto wrote: > Q1. Do we need XPointers for every XML instance? They should be available, even if that capability is not used by a particular instance. Other instances may point to that instance, and will use XPointer to do so. A particular xml document type might not use XPointer itself, internally, but other people linking to parts of that document might well expect XPointers which *they* make to that document type, to work. > I personally think that this is too much. For example, I do not think we have > use XPointers for RDF, which is in the XML syntax. It is arguable that a later, refined syntax for RDF should use XPointer, for compatibility with other XML applications. > > Q2. Do we need XPointers only for human-readable documents that are rendered > by some browsers? > > I am not sure if the answer is Yes. How do XLL experts in this ML feel? SVG (which is human viewable, though non-viewing applicationsa re also possible) uses XPointer and XLink for such things as referencing graphical symbols, which are to be re-used, or for pointing to runs of text which are to be presented graphically (for example, as text on a curved path). -- Chris