Re: user-defined type conversion

[Dmitry A. Kazakov <mailbox@dmitry-kazakov.de>]

On Sun, 19 May 2002 21:12:56 GMT, Jeffrey Carter <jrcarter@acm.org>
wrote:

>Russ wrote:
>> 
>> "David C. Hoos, Sr." <david.c.hoos.sr@ada95.com> wrote in message news:<mailman.1021805103.320.comp.lang.ada@ada.eu.org>...
>> > No, because a type conversion has the same syntax as a function, so
>> > there's no way to "read the programmer's mind," as to what he intended.
>> 
>> Type conversion IS a function!
>
>Are you sure? Given
>
>type Real is new Float;
>
>F : Float;
>R : Real;
>
>a statement such as
>
>R := Real (F);
>
>probably has no code generated for the type conversion. No function
>call, no inline expansion, nothing.

So what? A function that does nothing is still a function. More
interesting is the following:

   procedure Increment (X : in out Float);
   I : Integer := 1;
begin
   Increment  (Float (I));

Here Float is a pair of functions: To_Float and From_Float and
Increment  (Float (..)) is a composition:

To_Float o Increment o From_Float

---
Regards,
Dmitry Kazakov
www.dmitry-kazakov.de