Re: Ada2012 : Expression functions and extended return statements

[stefan-lucks@see-the.signature]

On Fri, 6 Jan 2012, Martin wrote:

> Also, on the topic of extended return statements...
> 
> What's the rational for having to explicitly repeat the return type?
> Seems rather redundant to my eyes. I wouldn't have minded:

I guess, this is because the object actually returned may not necessarily 
be of exactly the same type of subtype as the declared return type -- like 
the ordinary return statement. See the following examples:

   function Characters(I: Integer; Filler: Character := '_') return String is
   begin
      return Result: String(1..I) := (others => Filler) do
        return;
      end return;
   end Characters; 

   type T is tagged record I: Integer; end record;
   type S is new T with record J: Natural; end record;

   function Fun(N, M: Natural) return T'Class is
   begin
      return Result: S do
        Result.I := M;
        Result.J := N;
      end return; 
   end Fun;


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