🚀 go-pugleaf

In <4a4hc2$1qb@oznet03.ozemail.com.au> John Max Skaller 
<maxtal@suphys.physics.su.oz.au> writes:

>mlahteen@cs.Helsinki.FI (Mia Lahteenmaki) (almost) wrote:

>>template<class T> class Ref {...}; 

>>template<class T1> class Collection {...};
>>  // primary template

>>template<class T1> class Collection<Ref<T> > {...};  
>>  // specialisation

> ---> is correct as you wrote it. 

I'm sorry, I do not agree with you here (anymore).
After the answers from David Vandevoorde and Timo Holkeri and some
rethinking I agree with them that the correct form must be 

 template<class T> class Collection<Ref<T> > {...};


In <4a4hc2$1qb@oznet03.ozemail.com.au> John Max Skaller 
<maxtal@suphys.physics.su.oz.au> continues:

>... However, I wouldn't 
>advise doing this particular specialisation!

>It isn't necessary, your "Ref<T>" class(es) should do
>all the work. You could consider a container adaptor
>instead.

>BTW: you CAN'T specialise standard library templates;
>if you do you release your compiler from any obligation
>to operate correctly. 

>-- 
>John Max Skaller               voice: 61-2-566-2189
>81 Glebe Point Rd              fax:   61-2-660-0850
>GLEBE NSW 2037                 email: maxtal@suphys.physics.oz.au
>AUSTRALIA                      email: skaller@maxtal.com.au

And right you are ! 
I should have changed the type names or explain further why I'm doing 
these odd things. 
Here comes the explanation: I am not using STL or implementing collections
from the scratch. I am using commercial library having persistent-capable
collections that only accept pointer element types. I want to build 
an interface on top of this library to allow ODMG-93 standard compatible
use. In the ODMG-93 standard compatible use, the element types user
defines may be smart pointers (Ref<T>) in which case I must change the 
element type to Ref<T>*. In addition, I must take care that the smart 
pointer instance to be stored is persistent, if the collection is meant 
to be persistent. After I add the pointer to the element type, it is not
taken care automatically.

There has been some other suggestions of using template parameters
in this case. I thank you for reminding me this option. However, I 
consider class template specialization a more intuitive and suitable 
solution in this case. A collection type that has smart pointers as 
its element type is one special type of collections. 

BTW, does anyone know a compiler which implements class template
specialization already ?

 - Mia

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Mia Lahteenmaki                      University of Helsinki 
e-mail: mia.lahteenmaki@helsinki.fi  Department of Computer Science 
Tel   : +358 0 7084 4246             P.O. Box 26
Fax   : +358 0 7084 4441             FIN-00014 UNIVERSITY OF HELSINKI
                                     FINLAND                
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