[plcs-dex] SEDS against Message

["Barker, Sean (UK)" <sean.barker@baesystems.com>]

Resend with attachment

Please register the attached SEDS on Message, to allow explicit
selection of the message content items. I will also add this to the
issues register for the module.

Sean Barker
0117 302 8184


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Section 1. GENERAL INFORMATION (completed by SEDS Coordinator):
SEDS Report Issue Number: 
Date Submitted: 
Status and date: 
SEDS Team Leader: 
SEDS Team Members: 

Section 2. ENHANCEMENT AND DISCREPANCY INFORMATION (completed by author of SEDS Report):
Author: S. Barker (sean.barker@baesystems.com)
Submitted by: UK
Part/Clause Affected by the Issue: ISO/IS 10303-1270 ARM
Other Parts Affected by the Issue: 
Problem Description:
The use of message always requires the use of the escape mechanism to reference items, whereas, in some cases an AP may wish to restrict the usage to particular entities.

Suggest:
The entity Content_item should be subtyped (oneof) to Content_item_selected and Content_item_reference
Content_item would become an abstract type, and the current attributes migrated to Onservation_item_reference
Content_item_selected would have a single attribute pointing to an extensible select.

Additional Notes:
An AP could chose to define the set of things an observation is restricted to by a rule allowing only the Content_item_select subtype and extending the associated select.

Section 3. RESPONSE INFORMATION (completed by SEDS Team Leader):
Accepted/Rejected (date): 
If Accepted, Resolution: 

If Rejected, Reason:
Solution:
Comments:

Section 4. FOLLOW-UP INFORMATION (completed by WG Convener):
Class: 
Priority: 
Impact of Change: 
Further Action Required: 
Action Required by SEDS Coordinator/WG Conveners/QC/SC4: