Proposal for 'shared' in a TA Set

[Stephen Green <stephen.green@documentengineeringservices.com>]

I start with a premise that there is a single default intention
regarding concurrency behaviour for each of the TA parts
when it is shared across a TA Set.


target:
Several TAs in set would share the target
What if they had NOT the same target at TA level but all TAs in the
set had roughly the same target where some targets were sub-categories
of a broader target and we wnated to show this by putting the less
specific target in the 'shared' section but making some TA targets more
specific by including the more specific target in the TA within the set?
All this could be consistent, I think, with a shared target which composes
(by conjunction) with targets of any TAs at individual TA level. If a TA
target is 'A' (widget) at set level and some have a more specific 'A.a' at
TA level (medium-sized widget) then it seems that in general there is
composition with conjunction since in general 'A.a' = 'A' AND 'A.a'

variable: makes sense if it always overrides (no sense having >1 value)

prerequisite: always composes but maybe a disjunction is sometimes needed
- is there another way to do that? Disjunction seems to be a change to semantics
of a ta set though so I'd just as soon make it a default rule that it
is a conjunction

predicate: makes sense not to override. Usually expect it is overridden or
there is no TA predicate when there is a TA set with shared predicate. Maybe
composition with conjugate OK as a general rules

prescription: expect might want to be able to use an override if there is
a use case where a profile TA set overrides, say, optional TAs with
mandatory prescription. This all seems a special case so default could
be the a shared prescription is overridden by a TA one because it would
not in the normal use of a TA set/shared to change the prescription of
a contained TA.


tag: makes sense that it usually composes with conjunction

norm source: as for target

comment: as for tag

interpretation: as for comment/norm source


target: compose
var: overrides
prerequisite: compose
predicate: compose
prescription: overridden?
tag: compose
norm source: compose
comment: compose
interpretation: compose


compose: target, prerequisite, predicate, tag, norm source, comment,
interpretation
overrides: var
overridden: prescription

So it seems feasible that each part has a typical defaul control
of co-occurrance because each has a typical expection when it
is shared.

This makes me suggest we could maybe just use 'shared' with
each TA Part as a direct child and the defaults could be made rules
to determine default behaviour in case of co-occurrance/concurrency.

Then there remains a question of what to do about allowing non-default
concurrency rules but one way to do this would be to defer this to
profiles and leave the 'shared' element with an 'xs:any' for extensibility.

So I would propose removing 'composites' and 'overrides' as child
elements of 'shared' and add rules to the spec with the proviso that
these can be supplemented or overridden in a conformance profile:
They are default rules.



Best regards
---
Stephen D Green