(j3.2006) (SC22WG5.3848) [ukfortran] 09-007/UTI 151

Reinhold Bader Reinhold.Bader
Tue Jan 13 13:28:09 EST 2009


Hello,

Malcolm Cohen schrieb:
[...]
>> (2) However, I am not sure I understand that any ambiguities actually occur based on
>>       the bullet list in UTI 151.
> I think otherwise, as I tried to explain in the text of the UTI.
>>  In my opinion, "all-encompassing" pretty much is what
>>       is intended by the rule since it refers to *use association* only.
> I don't agree that the words there convey such an implication (or if 
> they do, it is a very weak one - too weak in fact).
> 
> ...
>>       For example take the case of  Bullet 1:
> ...snipped example that doesn't match what the first bullet says.
> 
>>   If I am misunderstanding the bullet list, can someone provide an example
>>       which demonstrates either an ambiguity or a situation which cannot be checked by the
>>       compiler?
>>   
> Access via a use-associated pointer that is pointer-associated with the 
> module entity.  As it says, "access via use then pointer association".  
> Is this allowed?  

Since the accessibility rules refer to an identifier and not the entity
identified (5.3.2 para 1,2), I'd answer this with yes even under the
current wording.


> I know neither whether it is allowed by the current 
> wording, nor whether it was intended to be allowed.  One might *guess* 
> that it is supposed to be allowed... but it is not clear to me.
> 
> It's also not clear to me just what this restriction is supposed to be 
> giving us - since in many cases it looks like one could wriggle around 
> it (unlike the previous version); that certainly makes it harder to 
> reason about.  Maybe the restriction shouldn't be there at all! 

In which case a rule like "host access beats use access" would be needed, at
least for this particular situation.

> Or, if 
> there is a real problem, maybe we ought not to loosen it after all!
> 
> I don't think it's impossible to get the wording right (whatever "right" 
> is),  but just saying "indirectly" is almost certainly wrong.
> 
> Cheers,


-- 
  Dr. Reinhold Bader

  Leibniz-Rechenzentrum, Abt. Hochleistungssysteme | Tel. +49 89 35831 8825
  Boltzmannstr. 1, 85748 Garching                  | Fax  +49 89 35831 9700




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