Issue 7329: large overlap between structural features and variables (uml2-rtf)
Source: Missouri University of Science and Technology (Dr. Thomas Weigert, weigert(at)mst.edu)
Nature: Clarification
Severity: Minor
Summary: There is large overlap between structural features and variables. For example, examine the structural features actions and compare them to variable action. Upon study, one will discover that structural features and variables have much more in common. In fact, the following equation seems to hold: StructuralFeature = Variable + Feature That is: a variable denotes a location able to hold an instance. A structural feature is a feature of an object and denotes a location ale to hold an instance. Therefore, I suggest that StructuralFeature be made a subtype of Variable. In the infrastructure, variable would have no interpretation, other than being an abstract metaclass indicating the ability to hold a value. In the superstructure, variable is concrete as described in Activities. Not only would this allow to eliminate the duplication of actions related to accessing variables, but also, other duplications (as, e.g., with respect to their being connectable elements and the related explanations) could be avoided.

Resolution: Disposition:	Deferred to UML 2.4 RTF
Revised Text: 
Actions taken:
May 9, 2004: received issue
Discussion: 
This is indeed the case but the issue needs to be addressed in greater depth since it is at
the core of the semantics of UML, and is out of scope of an FTF. Due to lack of time, the RTF/FTF agrees that the following are problems that need fixing, but decided to defer their resolution to a future RTF working on this specification.
End of Annotations:=====

m: webmaster@omg.org 
Date: 09 May 2004 15:11:08 -0400 
To: <issues@omg.org> 
Subject: Issue/Bug Report 



--------------------------------------------------------------------------------

Name: Thomas Weigert
Company: Motorola
mailFrom: thomas.weigert@motorola.com
Notification: No
Specification: UML
Section: 11, 12
FormalNumber: ptc/03-08-02
Version: 2.0
RevisionDate: 02/08/2003
Page: several
Nature: Clarification
Severity: Minor
HTTP User Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)
Description
There is large overlap between structural features and variables. For example, examine the structural features actions and compare them to variable action. Upon study, one will discover that structural features and variables have much more in common. In fact, the following equation seems to hold: StructuralFeature = Variable + Feature That is: a variable denotes a location able to hold an instance. A structural feature is a feature of an object and denotes a location ale to hold an instance. Therefore, I suggest that StructuralFeature be made a subtype of Variable. In the infrastructure, variable would have no interpretation, other than being an abstract metaclass indicating the ability to hold a value. In the superstructure, variable is concrete as described in Activities. Not only would this allow to eliminate the duplication of actions related to accessing variables, but also, other duplications (as, e.g., with respect to their being connectable elements and the related explanations) could be avoided.


OMG Issue No: 7329
Title:		large overlap between structural features and variables
Source:
Motorola (Dr. Thomas Weigert, thomas.weigert@motorola.com)
Summary:	
There is large overlap between structural features and variables. For example, examine the structural features actions and compare them to variable action. Upon study, one will discover that structural features and variables have much more in common. In fact, the following equation seems to hold: StructuralFeature = Variable + Feature That is: a variable denotes a location able to hold an instance. A structural feature is a feature of an object and denotes a location ale to hold an instance. Therefore, I suggest that StructuralFeature be made a subtype of Variable. In the infrastructure, variable would have no interpretation, other than being an abstract metaclass indicating the ability to hold a value. In the superstructure, variable is concrete as described in Activities. Not only would this allow to eliminate the duplication of actions related to accessing variables, but also, other duplications (as, e.g., with respect to their being connectable elements and the related explanations) could be avoided.
	
Discussion:
This is indeed the case but the issue needs to be addressed in greater depth since it is at the core of the semantics of UML, and is out of scope of an FTF. 
Disposition:	Defer