Issue 10438: 11.7.1 (ocl2-rtf)
Source: NIST (Mr. Peter Denno, peter.denno(at)nist.gov)
Nature: Uncategorized Issue
Severity: 
Summary:  null "conforms to all other types." Thus I suppose null->isEmpty() and 
null->notEmpty() are defined. What do these methods evaluate to when applied 
to null? This should be discussed in this section.



Resolution: 
Revised Text: (1) In Section 11.2.3, replace sentence of OclVoid by:

"Any property call applied on null results in OclInvalid, except for the operation oclIsUndefined(). OclVoid is itself an instance of the metatype VoidType."

By

Any property call applied on null results in OclInvalid, except for the operation oclIsUndefined() and oclIsInvalid(). However, by virtue of the implicit conversion to a collection literal, an expression evaluating to null can  be used as source of collection operations (such as 'isEmpty'). If the source is the null literal, it is implicitly converted to Bag{}.
The OclVoid type is an instance of the metatype VoidType.

(2) In Section 11.7.1, after isEmpty() definifion add the following note:
Note: null->isEmpty() returns 'true', in virtue of the implicit casting from null to Bag{}.

(3) In Section 11.7.1, after notEmpty() definifion add the following note:
Note: null->notEmpty() returns 'false', in virtue of the implicit casting from null to Bag{}.
Actions taken:
November 2, 2006: received issue
October 16, 2009: closed issue
Discussion: 
Similarly as when we write self.manager->isEmpty() this is a short writing of self.manager.asSet()->isEmpty(), the meaning of null->isEmpty() could be Set{}->isEmpty(), except that the decision on what kind of literal collection it is (set, bag, ordered set, sequence). By convention for null we decide the implicit casting  is Bag{}.
Apart this syntax convention, null 
We add a note to clarify this point.

End of Annotations:=====
s is issue # 10438

11.7.1

 null "conforms to all other types." Thus I suppose null->isEmpty() and 
null->notEmpty() are defined. What do these methods evaluate to when applied 
to null? This should be discussed in this section.