Notations

[Charles Reitzel]

Eliot Kimber wrote:

|At 10:25 AM 12/7/98 -0500, Charles Reitzel wrote:
|
||attribute name and value as descriptive of the element.  According to Eliot
||K., some variant of SGML allows notations to be associated with attributes.
|
|In TC2 to ISO 8879 (the Web SGML Adaptations, see
|<http://www.ornl.gov/sgml/wg8/document/1955.htm>) we added a new attribute
|value type, "DATA", that lets you associate a notation name with an
|attribute in order to define the rules that govern the interpretation of
|the attribute value. The syntax is:
|
|<!ATTLIST foo
|  OrderTime 
|     DATA Iso8601_DateTime 
|     #REQUIRED
|>

I guessed pretty close!

|Where "Iso8601_DateTime" is the name of a declaration notation. For element
|content, using NOTATION attribute is sufficient (and part of the existing
|SGML and XML specifications:
|
|<!ATTLIST OrderTime
|  notation
|    NOTATION
|    (Iso8601_DateTime) Iso8601_DateTime
|>
|
|However, I agree that being able to say this on the element type
|declaration directly would be convenient.  We didn't consider this for the
|TC because it would be too much of a change to the existing syntax.

Thanks to you and James T. for pointing this out.  But there is no special
pre-defined attribute named "notation", or am I missing something?  

Rereading the spec, yet again, I see it says (sec. 3.3.1):
"A NOTATION attribute identifies a notation, declared in the DTD with
associated system and/or public identifiers, to be used in interpreting the
element to which the attribute is attached."  

So any and all NOTATION attributes are used to interpret the element.  This
is a bit vague for my taste, but I'll take it.  Any number of NOTATION
attributes are possible, so it could be unclear which controls the format of
the element value.  E.g. one might control the element value while another
might be used to perform app specific content model validation not possible
with a DTD alone. (if X is present, then Y is required, etc.).

Regards,
Charles Reitzel
creitzel at mediaone.net


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