XML Schema Datatype Questions

Daniel Potter dpotter at mitre.org
Thu Dec 30 16:10:54 GMT 1999

I am currently developing a type checker designed to validate data in an
instance document corresponding to an XML schema.  I have a few
questions about the datatype spec I am hoping someone can answer.

First question, what is Not A Number in respect to the float/double
datatypes?  Or, rather, what is it in relationship to a min/max range? 
If I specify that mininclusive=0 and maxinclusive=INF, then is NAN in
that range?  What about mininclusive=-3 and maxexclusive=4?  Or does NAN
need to be specified in the enumeration?  (On that note, can the
enumeration facet be used to allow values outside the range specified by
min/max to be included?  Or do enumeration values need to fall within
the range?  There is no constraint saying that enumeration and min/max
values cannot be set together, which leads me to believe that they are
combined to describe legal values.)

In other words, if I specify a range of values, does NAN ever fall in
that range?  Or does it need to be specified as a legal value through
the enumeration facet?

Also relating to float, are the characters case sensitive?  Can I use
"inf" as a value or does it need to be "INF"?  Is "6.22e22" legal?  Or
does it need to be "6.22E22"?

One last question:  For the binary datatype, what is the default
encoding?  According to the encoding facet, it must be either hex or
base64, but what happens if the user doesn't specify?  If I specify that
an element is of type binary, but leave out the encoding facet, what
encoding is then used?  As far as I can tell, there is no default value
for encoding.  I would assume hex is default because it is listed first,
but it would be nice to know for certain which encoding is truely
intended as default.

Thanks for any help.

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