Issue 15220: OCL 2.2 7.5.4 Property-qualified association navigation has no concrete or abstract syntax (ocl2-rtf)
Source: Model Driven Solutions (Dr. Edward Willink, ed(at)willink.me.uk)
Nature: Uncategorized Issue
Severity: 
Summary: Section 7.5.4 describes an association navigation qualification to
accommodate
recursive associations.


e.g. self.employeeRanking[bosses]


in which "bosses" is a Property role name.


OCL 2.2 has no concrete syntax for this. Superficially it resembles an
AssociationClassCallExp, but that requires OclExpression values for its
qualifiers.


Prior to OCL 2.0 (and still present in many obstinate residual artefacts in
OCL 2.2),
there was an AssociationEndCallExp, whose syntax was identical to an
AssociationClassCallExp
and so it was removed and merged with AttributeCallExp as PropertyCallExp.


It would appear that a form of AssociationEndCallExp is required with
syntaxes


OclExpressionCS '.' pathNameCS[1] ('[' pathNameCS[2] ']')? isMarkedPreCS?
pathNameCS[1] ('[' pathNameCS[2] ']')? isMarkedPreCS?


in which pathNameCS[2] defines the NavigationCallExpCS.ast.navigationSource
that is currently completely undefined and very confusingly described in
Section 8.3.2:


"navigationSource The source denotes the association end Property at the end
of the object itself. This is used to
resolve ambiguities when the same Classifier is at more than one end (plays
more than one
role) in the same association. In other cases it can be derived."


Suggest:


Remove NavigationCallExp::navigationSource that currently has no semantics


Introduce QualifiedPropertyCallExp (and etc.) as a further NavigationCallExp
to support
the qualified navigation. It has two associations:


referredSourceProperty: Property (e.g. "bosses")
referredTargetProperty: Property (e.g. "employeeRanking").

Resolution: 
Revised Text: 
Actions taken:
April 22, 2010: received issue
Discussion: 

End of Annotations:=====

m: "Willink, Ed" <Ed.Willink@thalesgroup.com>
To: "'issues@omg.org'" <issues@omg.org>
Subject: OCL 2.2 7.5.4 Property-qualified association navigation has no co
 ncrete or abstract syntax
Date: Thu, 22 Apr 2010 16:06:36 +0100
X-Mailer: Internet Mail Service (5.5.2657.72)


Hi


Section 7.5.4 describes an association navigation qualification to
accommodate
recursive associations.


e.g. self.employeeRanking[bosses]


in which "bosses" is a Property role name.


OCL 2.2 has no concrete syntax for this. Superficially it resembles an
AssociationClassCallExp, but that requires OclExpression values for its
qualifiers.


Prior to OCL 2.0 (and still present in many obstinate residual artefacts in
OCL 2.2),
there was an AssociationEndCallExp, whose syntax was identical to an
AssociationClassCallExp
and so it was removed and merged with AttributeCallExp as PropertyCallExp.


It would appear that a form of AssociationEndCallExp is required with
syntaxes


OclExpressionCS '.' pathNameCS[1] ('[' pathNameCS[2] ']')? isMarkedPreCS?
pathNameCS[1] ('[' pathNameCS[2] ']')? isMarkedPreCS?


in which pathNameCS[2] defines the NavigationCallExpCS.ast.navigationSource
that is currently completely undefined and very confusingly described in
Section 8.3.2:


"navigationSource The source denotes the association end Property at the end
of the object itself. This is used to
resolve ambiguities when the same Classifier is at more than one end (plays
more than one
role) in the same association. In other cases it can be derived."


Suggest:


Remove NavigationCallExp::navigationSource that currently has no semantics


Introduce QualifiedPropertyCallExp (and etc.) as a further NavigationCallExp
to support
the qualified navigation. It has two associations:


referredSourceProperty: Property (e.g. "bosses")
referredTargetProperty: Property (e.g. "employeeRanking").



        Regards
                        
                Ed Willink


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