csprd02 comment - id values for unit and group

Hi all,

The specification has the following constraints for the id attribute:

" When used in <unit>:
The value MUST be unique within the parent <group> or <file> element."

"When used in <group>:
The value MUST be unique within the parent <group> or <file> element."

I strongly recommend those two constraints to be changed so <unit> ids are unique within a <file> and <group> ids are unique within
a <file>.

Allowing to have the same id for two or more units (or groups) if they belong to different groups is bound to cause problems. For
example a tool using the ids in a database would have to concatenate the ids of all parents groups to ensure it is unique: if the id
values are anything like UUIDs, the length of the resulting value can become ridiculously long very quickly.

Regards,
-yves