Re: [xml-dev] RELAX question re: required value

[John Cowan <johnwcowan@gmail.com>]

On Wed, Jan 22, 2014 at 11:30 AM, Michael Sokolov <msokolov@safaribooksonline.com> wrote:

I have a schema that allows a bunch of different elements to be interleaved in any order; one of them is <collection>;  I want to require that a collection with value "all" be present, as well as allowing any number of other collections, in any order, using RELAX -- is that possible? 

 

No, it isn't.  It would have to be element collection {"all"} & element collection {text}, and it is forbidden to have the same element name on both sides of &.  This is one of the few arbitrary restrictions in RNG.  Even that formulation, if it were legal, would allow more than one "all" collection, since there is no way to say "everything but 'all'" in RNG.

However, this is a perfect application for an embedded Schematron rule asserting that count(collection[text() = "all"] = 1.  Jing supports embedded Schematron 1.5 rules quite nicely.

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