(j3.2006) Abstract type question

[Bill Long]

With reference to the current CD (though similar issues are in f03),  
[49:C406] says that you cannot have a declaration of 
TYPE(<abstract-type>).  This is what I expect, and seems to be a 
fundamental distinction of abstractness.

However, you can have a polymorphic entity declared with an abstract 
type, as in CLASS(T) where T is an abstract type.  In fact, [124:C627] 
specifically anticipates that you can have an <allocate-object> of 
abstract type.

Questions:

1) The first sentence of para 5 of 4.3.1.3 CLASS (page 50) says "A 
polymorphic allocatable object may be allocated to be of any type with 
which it is type compatible."  Does this include the base abstract type 
used in the declaration?  If so, it would seem to contradict the idea of 
not having objects whose dynamic type is abstract. And the sentence in 
para 4, "A polymorphic entity that is not a unlimited polymorphic entity 
is type compatible with entities of the same declared type or any of its 
extensions."  seems to suggest you can have type compatibility with your 
own declared abstract type.

2) In the list of constraints following the syntax for the ALLOCATE 
statement, I do not see a constraint that says "If <type-spec> appears, 
it shall not specify an abstract type".   Should that be the case? Or is 
this covered somewhere else?

I think I know what the answer is supposed to be here, but I'm looking 
for the words. I suspect I just missed something, but clarification 
would be appreciated.

Cheers,
Bill

-- 
Bill Long                                   longb at cray.com
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