[tei-council] dating attributes

[Lou Burnard]

INASMUCHAS

- we currently have variously proposed attributes @notBefore @notAfter 
@to @from and @value
- these attributes all have a datatype of data.temporal which being 
expanded turns out to match simple w3c-conformant dates, or various ISO 
formats, or one we dreamed up all on our own, and thus provide headaches 
for simple minded validation software
- and moreover all normalized values are understood  (in a way they were 
not previously) to represent values in a single calendar system which is 
not necessarily that convenient

NOW BE IT HEREBY PROPOSED:

1. all elements the content of which describes either a point or a span 
in time should carry the same set of attributes, and constitute members 
of the att.datable class
2, the members of the att.datable class shall be @notBefore, @notAfter, 
@normw3c @norm, and @exact
3. @notBefore and @notAfter have the same significance as at present. 
Their datatype is data.temporal.user (see below)
4. @normw3c contains a normalized representation of a nodern calendar 
date in W3C format, like the current @value. Its datatype is 
data.temporal.w3c
5. @norm contains a normalized representation of a date in any 
user-chosen calendar according to a defined format. Its datatype is 
data.temporal.user, and the calendar is specified somewhere (not sure 
where) in the header.
6. @exact indicates which ends of the date range indicate by @notBefore 
and @notAfter can be considered exact: it has three possible values 
"from" "to" "both". So for example 'notbefore="x" exact="from"' is 
equivalent to "from='x'"

So far so good, but the devil is assuredly in the detail.

Comments?

My first thought was that actually I'd rather have ISOnorm than normw3c 
but that may not be an option.