XML Schemas and the Enumeration Facet
I have some questions about using the enumeration facet along with other facets which I hope someone can explain. The enumeration facet is defined as "constrain[ing] the value space of the datatype to the specified list" which I take to mean intuitively that the "instances" of data which are to be checked against the datatype with the enumeration must be in the list. An enumeration could be as follows: <datatype name="example" source="string"> <enumeration value="first value"> <enumeration value="another"> <enumeration value="third"> </datatype> This would mean that any elements corresponding to the example datatype must be either "first value", "another" or "third". So <example>third</example> is OK, but <example>ABC</example> is wrong. (Assuming example is of type example, of course :) HOWEVER, suppose that instead: <datatype name="example" source="string"> <enumeration value="first value"> <enumeration value="another"> <enumeration value="third"> <maxlength value="7"> </datatype> This would be OK, except that "first value" has a length of eleven, meaning that it does not fit in the datatype where the maximum length is seven. However, it is specified to belong by enumeration. Which takes precendence? The first to appear? The last? Can enumeration be used to add values which would otherwise be illegal? And what happens when enumeration is used with other facets? Apparently this is legal. And if a user-defined datatype specifies facets over a datatype with enumerated values, what happens if the new facets render some of the enumerated values invalid? (Or what if it enumerates values which are illegal by the underlying datatype it's generated over?) Finally, a quick question about the float/double datatype. Should the default exponent *really* be one? Shouldn't it be zero? According to the spec, if Exx is not specified, it defaults to one. Isn't 1E1 = 10? So wouldn't that multiply all values by ten compared to what the author most likely intended? (If I wrote <float>3.14159</float>, wouldn't it be read as 31.4159?) Just curious if this is a typo, or if I'm misunderstanding something, or if it is intended the way I understand it. Thanks for any help on these questions. xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1 To unsubscribe, mailto:majordomo@i... the following message; unsubscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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