Re: Puzzled by SPARK global aspect

[Anh Vo <anhvofrcaus@gmail.com>]

On Friday, June 30, 2017 at 2:29:38 PM UTC-7, digitig wrote:
> Suppose in my package specification I have
> 
>    type Quadrant_Specification_Array is 
>    array(Global.Quadrant_X_Index'Range, Global.Quadrant_Y_Index'Range) 
>    of Quadrant_Specification;
> 
> (With QuadrantSpecification being a record type) and in my package body I have:
> 
>    function N_Total_Klingons return Global.Klingon_Counter
>        with
>          Refined_Global => (Input => Quadrant_Specifications)
>    is
>       Total: Global.Klingon_Counter := 0;
>    begin
>       for X in Quadrant_Specifications'Range loop
>          for Y in Quadrant_Specifications'Range(2) loop
>             Total := Total + Quadrant_Specifications(X, Y).N_Klingons;
>          end loop;
>       end loop;
>       return Total;
>    end N_Total_Klingons;
> 
> Spark gives me an error
>   useless refinement, subprogram "N_Total_Klingons" does not depend on abstract state with visible refinement
> 
> But if I take the Refined_Global specification out I get the error
> 
>   "Quadrant_Specifications" must be listed in the Global aspect of "N_Total_Klingons"
> 
> I feel I'm losing either way - if I do specify it I'm wrong, if I don't specify it I'm wrong.
> 
> How *do* I fix this?

It is pretty hard to suggest advice since it is not a complete minimal code. In addition, I rather see the code instead of guessing. I would say your codes involve package Abstract State aspect.

Anh Vo