Re: overloading predefined operators

["Jeffrey R.Carter" <spam.jrcarter.not@spam.acm.org.not>]

On 2022-06-24 10:10, L. B. wrote:
> 
> type my_float is new float;
> 
> function "=" (left, right : in my_float) return boolean is begin
>   ....
> end "="
> 
> a, b : my_float;
> 
> a := 0.01
> b := 0.009;
> 
> -- For some reasons I still need access to the overloaded original "=" function:
> if a = b then -- shall use the original "="
>   null;
> end if;
> 
> What can I do ?

With a derived type like this, you can convert back to the parent type:

if Float (A) = Float (B) then

With a completely new type, you can only name one of the operations "=". You 
have to decide which one you want to call "=", and which one you want to call 
something else, like Equal. So, for

type Real is digits 7;

you can either call your new operation Equal

function Equal (Left : in Real; Right : in Real) return Boolean;

which leave "=" for the predefined operation, or you can rename the predefined 
operation to Equal as Kazakov has described

function Equal (Left : in Real; Right : in Real) return Boolean renames "=";
function "=" (Left : in Real; Right : in Real) return Boolean;

-- 
Jeff Carter
"[I]t is foolish to polish a program beyond the
point of diminishing returns, but most programmers
do too little revision; they are satisfied too
early."
Elements of Programming Style
189