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[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Version numbering, requirements
 So, there's a proposal for XML "1.1". Why is it 1.1? Back years ago, I was given a rule of thumb for version numbers on unix-alike machines, typically for open-source software. It has three parts: major version, minor version, patch. patch: for releases that fix bugs, without adding features or changing anything currently in use (except stuff that's broken because of the bug, or that works around the bug in a way that the patch breaks). minor: for addition of features that do not change the semantics of existing code. major: for changes that break existing code. By this metric, then, we've already had XML 1.0.1 (XML 1.0 + Namespaces), and XML 1.0.2 (XML 1.0 second edition + Namespaces). Or perhaps + Namespaces should be regarded as 1.1. Applied to XML, any change that adds to the set of well-formed documents is probably a feature addition. Any change that makes previously well-formed documents ill-formed is breaking existing code, so it's a major version. The Blueberry proposal, and alternates suggested here, then, both seem to represent XML 2.0. XML 1.0 well-formed documents may not be well-formed for Blueberry. I think that's unacceptable, personally. Not that my opinion ought to carry much weight. But it seems to me that the time is not yet for 2.0 (and when 2.0 is undertaken, then it ought to roll in at least Namespaces and possibly Infoset, and roll DTD out into a separate specification). If the goal is to add functionality with minimal impact, such that it can justifiably be called XML 1.1, then all XML 1.0 well-formed documents must also be XML 1.1 well-formed. 1.1 must define a true superset of 1.0. If it's done that way, too, then the folks that *need* the functionality of 1.1 can adopt, while other folks carry on with 1.0 parsers and processors (which 1.1 parsers and processors will be able to read). That allows gradual adoption: first the folks who need the languages or capabilities, then the folks that need to interoperate with those folks, then the folks interoperating with the first set of interoperators. If "1.1" is actually 2.0, a breaking change, then W3C is likely to splinter its constituency, just at the moment of greatest adoption of XML. It makes it dramatically harder for the folks who want to interoperate, who have to have two sets of tools, because the two dialects aren't interoperable. It also makes it less likely that the folks who are satisfied with XML 1.0 semantics will ever upgrade, since they've got something meeting their needs, and have to pay the cost of changing newly ill-formed documents if they switch to 1.1. I do think that XML is going to have to solve the problem of supporting additional languages and scripts, 'cause the original solution wasn't robust and can't extend without redefinition. The problem of newline definition is trickier, and it's possible that adding *that* feature is such a fundamental change that a version proposing it ought to be labelled 2.0. On the other hand, claiming that current line-end semantics allow any text editor to work is demonstrably false (if you don't believe me, I'll send you files created on a Mac, Linux, and Windows ... open a Mac file on Linux, and it's all one line, with ^M where the line-ends should be, while a Windows file has the line-end plus ^M; open a Linux or Mac file on Windows, in a simple-minded text editor, and the result is equally unpleasant; Mac text editors generally handle the situation most gracefully, but may also show random trash, depending on the editor). So adding another "common conversion utility" (NEL->whatever platform semantics you happen to be using) doesn't seem that heavy a burden (and requires not much more than a Unicode-enabled sed script or perl one-liner). But I wonder if W3C uses the same rule of thumb, or if the adoption of "1.1" as a label is merely supposed to indicate "changes coming!" without offering a useful metric of the extent of the changes. I think that if "1.1" makes 1.0 well-formed documents ill-formed, that this will be a disaster for the W3C and for the XML community. Amy! -- Amelia A. Lewis alicorn@m... amyzing@t... "Oh, [expletive deleted]! You did it just like I told you to!" (The manager's lament) 
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