Re: IDREF

Marcus Carr (mrc@allette.com.au)
Mon, 23 Mar 1998 08:26:36 +1000

Rick Jelliffe wrote:

> Many people recommend that an attribute should only be called
> "ID" if it is an ID attribute. So in the following, x1 is good and
> x2 is naughty:
>
> <!ATTLIST x1 ID ID #REQURIED>
> <!ATTLIST x2 ID CDATA #REQURIED>
>
> I think it is good practice anyway: dont name an attribute
> using an XML keyword if that is not the type you want.

True, but the requirements of the attribute may not be known until processing
time. You may use a parameter entity in the declaration subset and assign the
value based on whether the parser will have access to the rest of the dataset or
whether this is a subset that would result on the generation of useless and
unwanted errors, ie:

<!ATTLIST x1 ID %IDorCDATA; #REQURIED>

in the DTD, and then, depending on the doctype element, generate either:

<!DOCTYPE WholeDataSet PUBLIC "-//My//DTD for example//EN" [
<!ATTLIST IDorCDATA "ID">]>

or:

<!DOCTYPE DataSetFrag PUBLIC "-//My//DTD for example//EN" [
<!ATTLIST IDorCDATA "CDATA">]>

at the head of the instance.

--
Regards


Marcus Carr                  email:  mrc@allette.com.au
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