Re: Re-exporting primitive operations of a private type (like "-", and 'min)

[Anonymous Coward <bogus_addy@bogus_domain.net>]

In article <ErC9f.4432$yX2.1697@newsread2.news.pas.earthlink.net>, Jeffrey R. Carter wrote:
> 
> You should be able to say (in the private part)
> 
> function Subtract (Left, Right : in Public_Distance_Type)
> return Public_Distance_Type renames "-";
> 
> type Private_Distance_Type is new Public_Distance_Type;
> -- Subtract is defined for Private_Distance_Type.
> 
> function "-" (Left, Right : in Private_Distance_Type)
> return Private_Distance_Type renames Subtract;

That would probably work as long as the definition of Subtract does a
type conversion explicitly on the Left and Right to the parent types.
But what are the advantages?  Why would I define a Subtract operation
and use a renames clause, when I can simply define a "-" operation
directly?  

The "-" operation must still be replaced, and it still has to have a
declaration in the public part.  So in your case above, there would
have to be a 

  function "-" (Left, Right : in Private_Distance_Type)
    return Private_Distance_Type; 

in the public part.