- From: Williams, Stuart <skw@hp.com>
- Date: Wed, 16 Jul 2003 16:09:41 +0100
- To: "Ian B. Jacobs (ij@w3.org)" <ij@w3.org>
- Cc: "'www-tag@w3.org'" <www-tag@w3.org>
Ian, Below are the remaining comments on the June 27th draft that I said send seperately yesterday. I've seperated them into Technical, Editorial and Typos (in that order) and each follows through in document order. There are quiet a few that I've labelled Technical... some may be editorial on with further explaination. Regards Stuart -- Technical ---------- -- Section 2: "All important resources SHOULD be identified by a URI." Is this saying that they should be identifiable by URI. Taking the car/brand example from the discussion with Roy. One could argue that the car/brand is (indirectly) identifiable by the use of a URI (as Roy showed in the interpretation of a 'sentence' - a usage of a URI in some context). However, in the example no URI was actually assigned to the brand or model of car. The URI was assigned to a web-page. So... are we saying that every important resource should be assigned a URI (conceptually being labelled with at least one - and implicitly that all labels are different so that a given label is affixed to at most one resource). Or are we saying that "All important resource should be identifiable - through some referencing function - by URI." I think that this is an identity/identification distinction. I also think it relates to the questions that Pat Hayes is asking us [a]. [a] http://lists.w3.org/Archives/Public/www-tag/2003Jul/0129.html -- 2.2 URI Scheme: Re thee list of URI scheme names... the relevant RFCs all speak of the schemes URI's being used to 'designate' particular sorts of resource. Seems that we have a number of words used in various works that feel like synonymous but probably have subtle differences in nuance.: "designate", "identify", "denote". Do URI identify, denote, and/or designate? -- 2.2 URI Scheme: "We note in passing that even more expensive than... is introducing a new identification mechansim for the Web." Hmmm.... don't know whether to suggest removing this (because of the "In passing..." prefix), or seek an example... and as I sit to think about it, IRI's as a new identification system for the Web come to mind - and it may indeed prove to be a very expensive thing to introduce. -- 2.4. Fragment Identifiers "Although the generic URI syntax allows any URI to end with a fragment identifier, some URI schemes do not specify the use of fragment identifiers. For instance, fragment identifier semantics are not specified for MAILTO URIs." Tricky... but aren't the 'semantics' of fragment identifiers bound to media-types rather than URI schemes. Are there any URI schemes give an account of fragment identifier 'semantics'. I wouldn't expect to find any. Equally, I'm not aware of any URI schemes that prohibit the use of frag ids in references made using that scheme. -- 2.4.1. Fragment identifiers and content negotiation "This URI makes sense for the SVG representation, since SVG defines fragment identifier semantics. However, the URI does not make sense for the PNG and JPEG/JFIF representations; those specifications do not define fragment identifier semantics." Would like tighter language that 'makes sense' and 'does not make sense'. No suggestions... sorry. -- 2.5. Dereferencing a URI "Such operations are defined by the formats and protocols that make use of URIs." It's not at all clear to me how formats contribute to the *definition* of 'such operations'. -- 2.5.1 Retrieving a Representation "As stated above, the authority responsible for a URI determines what the URI identifies and which representations are used for interaction with the resource." I think this should be "...which representation media-types are used...." -- 2.6 URI Persistence "Similarly, one should not use the same URI to refer to a person and to that person's mailbox." This impinges on the discussion in the metadataInURI threads re Mark Baker using "mailto:distobj@acm.org" to identify himself in person. Roy spoke of "referring functions" and context in [b] (and thread). [b] http://lists.w3.org/Archives/Public/www-tag/2003Jul/0102.html -- 2.8.3. Consistency of fragment identifier semantics among different media types "There has been some discussion but no agreement that new access protocols should provide a means to convert fragment identifiers according to media type." I am not aware of any such dicussion inside or outside the TAG, can you provide a reference. Secondly, I have no idea what it means to "convert fragment identifiers according to media type." -- 3 Representations "A representation is data that represents or describes the state of a resource." Are 'represents' and 'describes' being used as synonyms? If so... pick one. If not, are they covering some uncertainty or confusion about what it is that a representation represents? Again I think this intersects with Pat Hayes questions [a]. [a] http://lists.w3.org/Archives/Public/www-tag/2003Jul/0129.html -- 3.2.1. Desirable Characteristics of Format Specifications "Attention to Programmer Needs ... In particular, the specification SHOULD be in part formal and mathematical, rather than relying exclusively on narrative." Advice I think we should take to heart ourselves... -- 3.2.2.2. Final-form v. Reusable "In general XML-based data formats are more re-usable and repurposable than the alternatives, although the example of XSL-FO shows that this is not an absolute." This feels like a gratuitous side swipe at XSL-FO. Needs to either be explicit about the 'complaint' or struck from the document. -- 3.2.4. Embedding Hyperlinks in Representations "Representation formats based on XML SHOULD use at least the XPointer Framework and XPointer element() Schemes for their fragment identifier syntax." Roy has expressed some reservations about Xpointer based fragment identifier syntax. I don't think that the TAG has really discussed it or formed an opinion. But there is at least one voice on the TAG that object to this statement - this is relevant to abstractComponentRefs-37. [c] http://lists.w3.org/Archives/Public/www-tag/2003Jul/0013.html [d] http://lists.w3.org/Archives/Public/www-xml-linking-comments/2002OctDec/0039 .html -- Editorial: ---------- Section 2: Identification and Resources. "Web Architecture start with Uniform Resource Identifiers (URI) defined by..." I would prefer: "Uuniveral Resource Identifier (URI) defined by... are central to Web Architetcture." -- Section 2: Identification and Resources. "When a representation of one resource refers to another resource with a URI, a link is formed between the two resources." This suggests that a respresentation (of the first resource) is necessary in order for a link to be formed. Suggest: "When one resource refers to another resource with a URI, a link is formed between the two resources." Even that seems overly constraining on how links are formed. Also, give the discussion with Roy there is some question over quite what the link is between... a link/reference to a brand of car or to a web-page (or both, one indirectly via the other). -- Section 2: "The value of the Web grow exponentially as a function of the number of linked resources (the "network effect")." I can take or leave this... feels like a bit of marketing polemic. -- 2.4.1. Fragment identifiers and content negotiation "This URI makes sense for the SVG representation, since SVG defines fragment identifier semantics. However, the URI does not make sense for the PNG and JPEG/JFIF representations; those specifications do not define fragment identifier semantics." Would like tighter language that 'makes sense' and 'does not make sense'. No suggestions... sorry. -- Section 2.6 URI Persistence "...or the work itself in an abstract sense (for example, using RDF),..." Don't understand the need of the parenthesised aside. Suggested it be deleted. -- 3. Representations " 1. Electronic data expressed in one or more formats (e.g., XHTML, CSS, PNG, XLink, RDF/XML, and SMIL animation) used separately or in combination. 2.Metadata about the representation, such as the Internet Media Type (defined in RFC 2046 [RFC2046]). The Internet Media Type is the key to the correct interpretation of a resource representation, and governs the handling of fragment identifiers. When transferred by a Web protocol, a representation often includes metadata about both the representation and the message bearing the representation (for example, some HTTP headers). Web agents use representations to modify as well as read resource state." Seems to be struggling for a term for the non-metadata part of a representation. "Content" and "Content Metadata" come to mind, but they are not ideal. Also, the last bit is wrong wrt to our discussion at our Feb F2F... a representation does NOT contain message metadata. I think Roy has made this point already. Finally suggest s/read/retrieve/ in the final sentence quoted above. -- 3.2.3. Presentation, Content, and Interaction I was unable to make sense of this section as is. However more, possible a replacement, is expected. -- Typos ----- 2.5.1 Retrieving a Representation: List item 6 s/but/by/ 3 Representations: list item 5 s/result/resulting/ 3.2.2.1. Binary v. Textual: 2nd paragraph s/so represented are include/so represented include/
Received on Wednesday, 16 July 2003 11:10:31 UTC