Re: A hole in Ada type safety

[Adam Beneschan <adam@irvine.com>]

On May 11, 10:51 pm, AdaMagica <christ-usch.gr...@t-online.de> wrote:
> Randy has already given the answer.
>
> Let me add a further remark (but note, I'm no language lawyer):
>
> You argue about the return statement. But there is no return statement
> involved in the RM with Unchecked_Conversion, it's just compiler magic
> that is being performed. (Being intrinsic, Unchecked_Conversion need
> not be implemented in Ada. In fact, I think there is no code at all,
> it just takes the bit pattern as is and reinterpretes it.)

I think the poster's argument (inasmuch as I could follow it) was that
although Unchecked_Conversion is implemented via compiler magic, it
has to be defined in such a way that it *could* be written in Ada, and
this would be a problem because you couldn't write a RETURN statement
that would make it work.  Or something like that.  The basic problem
is that there is no such rule (and never has been) that the function
has to be writeable in Ada, despite the poster's assertion that "that
goes back to the origins of Ada and has not change", so the whole
argument is based on a false premise.  The poster tried to make an
argument to prove this premise, but I'm still trying to figure out
what this argument was.  It seems to be based on reading much more
into certain language rules than is written there.

                                   -- Adam