Re: Access types as parameters

[rickduley <rickduley@gmail.com>]

On Jul 18, 12:28 am, Hibou57 (Yannick Duchêne)
<yannick_duch...@yahoo.fr> wrote:
> Adam has already given a good answer, but I may say a bit the same in
> shorter words :
>
> access My_Type'Class in a function declaration, is a so called “
> anonymous type ”, and as this type is only declared locally, it cannot
> match any other types defined at wider level (beceause this would
> simply not be type conformant).
>
> access My_Type'Class does not have a so wide validity as
> My_Access_Type may have.
>
> This is conveniant and safe
>
> More words....
>
> As an hint : you may use My_Access_Type if the reference is to be
> stored into a record (as an exemple) and may use access My_Type'Class
> if you only need it locally. Looking at the function signature, you
> may then quicly see what kind of things the function may allowed it-
> self to do with the reference you gave it.
>
> If you see the function wants an “ access My_Type'Class ”, you nearly
> do not have to bother about anything, but if you see it wants a “
> My_Access_Type ” you may need to be sure there is a good collaboration
> between the caller and the callee. This is anyway, a good invitation
> to read the function documentation (if comments are provided about its
> usage).
>
> But this does not means “ access My_Type'Class ” is better beceause it
> is “ safer ” (quotes, beceause the other way is not always not safe),
> as sometime, My_Access_Type is mandatory, depending on what the
> function have to do with the reference.

Hi Yannick

Thanks for that.

I don't quite see what you mean by:

> But this does not means “ access My_Type'Class ” is better beceause it
> is “ safer ” (quotes, beceause the other way is not always not safe),
> as sometime, My_Access_Type is mandatory, depending on what the
> function have to do with the reference.

If the function is called, and the actual parameter is valid, what
difference can it make what the function does with the data?