Re: U : Unbounded_String := "bla bla bla"; (was: Is the Writing...)

["Alexandre E. Kopilovitch" <aek@vib.usr.pu.ru>]

"(see below)" <yaldnifb@blueyonder.co.uk> wrote:

> > type Flex is private;
> > for Flex'Literal_Conversion use To_Flex;
> ...
> > My concern is quite opposite: I'd like have a control for blocking such
> > overloadings (thus denying an opportunity for multiple literal types for a
> > given type),
>
>   for Flex'Literal_Conversion use <>;  -- ??

Well, I don't see this form as informative, but I must confess that here I'm
guilty myself, because this part of my concern was probably a sort of 
self-inflicted FUD. But

> > including those that may emerge within a derivation of a new type;
>
>   for Flex'Class'Literal_Conversion use <>;  -- ??

this part of the concern is real, and idea about 'Class seems interesting and
perhaps good enough. I think that the angle brackets are actually not needed
here, we can simply write:

  for Flex'Class'Literal_Conversion use To_Flex;

and this will mean that for all types belonging to Flex'Class two restrictions
are in effect:

1) To_Flex functions declared in other packages cannot be used for conversions
of literals;

2) Literal_Conversion attribute cannot be (re)defined in other packages.

So, there will be a clear difference between
   
  for Flex'Literal_Conversion use To_Flex;

and

  for Flex'Class'Literal_Conversion use To_Flex;



Alexander Kopilovitch                      aek@vib.usr.pu.ru
Saint-Petersburg
Russia