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> I'm somewhat new to Relax NG, but reading through it's primer doc it > appeared that the Order of the Elements was also strictly > governed by the > schema (in other words, you can't do this in RelaxNG either). It's not, although by default it is. To declare child elements as unordered, place them in an <interleave> element. > Which brings > the question, WHY? Why do the schema languages care about the particular > order of the XML nodes? In the case of XML Schema, nested unordered content can play havoc with determining the validity of an element instance in a content model. I might be able to give you an example if it weren't Monday... but it's true, I swear! > I can see the advantages of having this as an option > (i.e. something like <sequence order="fixed"> or something) but to make it a > requirement seems to backwards for most XML usages. There was an excellent thread on this last week. Basically, the argument goes: a) if order doesn't matter, choose one (because it doesn't matter!) b) if order does matter, declare the correct order I'm paraphrasing a), but I believe there is a circularity to the argument even when it's more intelligently phrased, which is why I hesitate to embrace it wholeheartedly. I'm coming around, though, since I can see where it sometimes make processing must faster and validation easier when there is a declared fixed order to content. And supplying fixed order is always easy for the content generator (I suppose); thus one should do so. Someone may come along momentarily to give a more literate answer. Let's hope.
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