How to include vector operators?

How to include vector operators?

[tolkamp]

In my application the package Ada.Numerics.Generic_Real_Arrays  is
included.

Code:

with Ada.Numerics.Generic_Real_Arrays;
package Vectors is new Ada.Numerics.Generic_Real_Arrays(Float);

How to include the vector operators like "+" and "-" ?

I tried the follwing:
function "+" (Left, Right : Vectors.Real_Vector) return
Vectors.Real_Vector
               renames
Ada.Numerics.Generic_Real_Arrays.Instantiations."+";

However this gives the error:
invalid prefix in selected component "Generic_Real_Arrays".

Re: How to include vector operators?

[Adam Beneschan]

On Dec 6, 1:03 pm, tolkamp <f.tolk...@gmail.com> wrote:
> In my application the package Ada.Numerics.Generic_Real_Arrays  is
> included.
>
> Code:
>
> with Ada.Numerics.Generic_Real_Arrays;
> package Vectors is new Ada.Numerics.Generic_Real_Arrays(Float);
>
> How to include the vector operators like "+" and "-" ?
>
> I tried the follwing:
> function "+" (Left, Right : Vectors.Real_Vector) return
> Vectors.Real_Vector
>                renames
> Ada.Numerics.Generic_Real_Arrays.Instantiations."+";
>
> However this gives the error:
> invalid prefix in selected component "Generic_Real_Arrays".

function "+" (Left, Right : Vectors.Real_Vector) return
Vectors.Real_Vector
   renames Vectors."+";

But you probably really want to use this, which will make all the
operators visible:

   use type Vectors.Real_Vector;

(and maybe the same for Real_Matrix).

But NOT this:

   use type Ada.Numerics.Generic_Real_Arrays.Real_Vector;

You can't access declarations in a generic package directly.  You have
to access the declarations in a generic *instance*.

                                -- Adam

Re: How to include vector operators?

[Gautier write-only]

> with Ada.Numerics.Generic_Real_Arrays;

Since it's generic, you can't use it directly. It's why you have:

> package Vectors is new Ada.Numerics.Generic_Real_Arrays(Float);
>
> How to include the vector operators like "+" and "-" ?

I guess you want to write things like (i):
  u+v
whereas now you need to write (ii)
  Vectors."+"(u,v)

To be able to write the form (i), you can put
  use Vectors;
after the above definition (package Vectors is new ...)
and you'll be happy.
______________________________________________________________
Gautier's Ada programming -- http://gautiersblog.blogspot.com/
NB: follow the above link for a working e-mail address

Re: How to include vector operators?

[tolkamp]

On 6 dec, 22:37, Adam Beneschan <a...@irvine.com> wrote:
> On Dec 6, 1:03 pm, tolkamp <f.tolk...@gmail.com> wrote:
>
>
>
>
>
> > In my application the package Ada.Numerics.Generic_Real_Arrays  is
> > included.
>
> > Code:
>
> > with Ada.Numerics.Generic_Real_Arrays;
> > package Vectors is new Ada.Numerics.Generic_Real_Arrays(Float);
>
> > How to include the vector operators like "+" and "-" ?
>
> > I tried the follwing:
> > function "+" (Left, Right : Vectors.Real_Vector) return
> > Vectors.Real_Vector
> >                renames
> > Ada.Numerics.Generic_Real_Arrays.Instantiations."+";
>
> > However this gives the error:
> > invalid prefix in selected component "Generic_Real_Arrays".
>
> function "+" (Left, Right : Vectors.Real_Vector) return
> Vectors.Real_Vector
>    renames Vectors."+";
>
> But you probably really want to use this, which will make all the
> operators visible:
>
>    use type Vectors.Real_Vector;
>
> (and maybe the same for Real_Matrix).
>
> But NOT this:
>
>    use type Ada.Numerics.Generic_Real_Arrays.Real_Vector;
>
> You can't access declarations in a generic package directly.  You have
> to access the declarations in a generic *instance*.
>
>                                 -- Adam- Tekst uit oorspronkelijk bericht niet weergeven -
>
> - Tekst uit oorspronkelijk bericht weergeven -

Thank you for your solution. Now it works correct.

Fred