Re: Prefixed notation for non tagged types

[Robert Eachus <rieachus@comcast.net>]

On Tuesday, December 19, 2017 at 6:05:01 PM UTC-5, Randy Brukardt wrote:

> Assuming that you want it to work for private types, the only choices are 
> "all types" or "tagged types", because any type can complete a normal 
> private type, and having something available for a private type that is not 
> available for the full type leads directly to madness.

Go directly to madness.  Do not pass Go.  Do not collect $200.  ;-)

Seriously, the visibility rules were hard fought way back in the early eighties.  There were lots of 'nice' features thrown out because the corners either resulted in the "wrong" function being called, or two definitions hiding each other.  The only one I know of that we missed was:

   function Foo return Integer is begin return 3;  end;
   function Foo (X: in Integer := 4) return Integer is begin return X; end;
   ...
   Y: Integer := Foo; -- ambiguous

There is no way to call the first Foo, or for that matter call the second Foo with a default argument!  Of course, the real "fix" is just don't do that. (The case where one Foo is directly visible and the other is use-visible has a rule that favors the directly visible declaration. Again madness avoidance, adding a use clause will not change the meaning of the code within the scope of the program.  If it means that there are now two use-visible homographs, the use clause can make the code illegal, but the fix is obvious.)