[SpecGL Draft] D1: Indicate which subdivisions are mandatory

(remember: this only applies, if the GP: subdivide the technology is done)

Comments?


Principle: Indicate which subdivisions are mandatory for conformance

What does this mean?
Regardless of the subdivision technique (i.e., profile, level or module), 
state whether one or more of the subdivisions is required for 
conformance.  Address the conditions or constraints on their usage, 
including: Can an implementation conform without implementing one of the 
subdivisions?  Does the subdivision apply to specific classes of products 
and not others?  Are there combinations of the subdivided technology that 
always go together and can not be implemented alone?

Why care?
Subdividing the technology affects and can complicated conformance with all 
the various combination of choices it provides  (a Chinese menu syndrome  1 
from column A, 2 from column B and desert is included).  Thinking about the 
various possibilities helps to structure the conformance model, allotting 
how the subdivision will affect various classes of products.  Implementers 
as well as users need to know what is mandatory, optional, prohibited or 
conditional with respect to choosing what to implement and be conformant.

Related

Techniques
Consider the following conditions:
·       atomicity of the subdivisions
·       any mandatory subdivisions
·       dependencies among subdivisions: e.g., modules that require and 
build on functionally related modules, modules that require modules from 
other functional areas
·       constraints against combined occurrence of particular pairs of modules
·       other conditions or constraints beyond these.

Examples:
Content can be required to conform to one of the subdivisions (e.g., 
profiles)  or it may be conformant to the specification independently of a 
subdivision.  The question arises for a producer (of content): is it 
conforming if it generates content that is otherwise valid but does not 
conform to the subdivision.

SMIL 2.0 has a SMILO 2.0 Language Profile for user agents but also provides 
a SMIL 2.0 Basic Profile for wireless and embedded devices. The SMIL 2.0 
language Profile requires that a user agent implement the BasicAnimation 
module but not the SplineAnimation Module.  The SMIL 2.0 Basic Profile on 
the other hand does not require implementation of any of the animation 
modules.