Availability of XML-compliant TIM

Date: Thu, 26 Mar 1998 09:39:45 -0500
From: dfp@bert.ims.bellcore.com (Don Pratt(IMS))
From: Don Pratt, Technical Team Leader
Subject: Availability of XML-compliant TIM


A tentative XML-compliant version of TIM (identified as 2.1.0) is now available at ftp://ftp.bellcore.com/pub/world/TCIF/lib/sgml and is on its way to the http sites. (The updated W3C XLink - formerly XLL - working draft, dated 1998-03-03, http://www.w3.org/TR/1998/WD-xlink, was made public this week, and, by the way, this notice stakes our claim to the first fully XML-compliant DTD.)

By prior agreement, because XLink compatibility required some new elements, this version of TIM is a "minor" (i.e., 2-digit) upgrade rather than a "maintenance" upgrade, and it must have full-committee approval, so it should not be treated as the official version. (There is also the very considerable possibility that the implementation may be faulty in some respect.) Therefore it appears on the sites as tim2_1_0.dtd, and tim2.dtd (release 2.0.4) remains there as the latest official version.

To underscore the possibility of error, I'll take this opportunity to let you know that a maintenance upgrade of the DOCID DTD is also being posted. (Tonua found two fatal typos in 4.0.2.)

Now to the details. If I have read it right - those of you whose companies employ standards-committee-level SGML/XML experts, I would appreciate any review of the implementation (follow the comments below the top of the file to see what needs review) - if I have read it right, the XLink spec allows most existing simple links, including TIM's <ref> and <urlref> elements, to be made compliant simply by defining some fixed and defaulted attributes in the DTD -- instances will not have to be changed at all (thank you!) if they contain only links internal to the current document. External links via HyTime <nameloc>s are not compliant (the XLink spec allows non-XLink links - just don't expect an XML browser to know what to do with them). Existing <urlref> external links will be compliant if the URL syntax is standard. Our sometimes-a-link elements (in fact, almost all of TIM's elements, with their optional "alerts", "altreps", and "version" attributes) can also be compliant, I believe, but they are required to have explicit attribute values when making a link (including values for the attributes "xml:link" and "xml:attributes", whose colons may cause some problems for some SGML parsers).

TIM's existing HyTime ilink, <link>, is not architecturally compatible with the XLink extended link, so a new element, <xlink>, and subelement, <locator>, were created, along with the recommended <group> and <document> elements (for defining groves of documents in which to look for out-of-line links). TIM2_1_0.DTD simply adds these to the allowable elements in <resources>, where they can coexist with HyTime <link>s.

Please do any reviewing/testing you can do before the April meeting so we can base our vote on more than my humble opinion. Thanks.