Re: Question about "for X'Size use ..."

[Florian Weimer <fw@deneb.enyo.de>]

dewar@gnat.com (Robert Dewar) writes:

> The mention of storing the sign is a bit bogus, given that virtually
> all machines are twos complement now.

Hmm, the DSP on one of the sound cards lying around here is a
one-complement architecture, but you're right nevertheless.

> More importantly you now get complete interoperability for the type
>
>    type x is range 0 .. 255;
>    for x'size use 8;
>
> which was not the case before

But the cases in which one stream element is written are the only ones
which are specified completely.  The others still remain open.  I find
this highly undesirable.

With the current scenario, you don't even achieve cross-compiler
compatibility on the same architecture.  For example, a vendor might
have chosen to write integers generally in big-endian format,
independently of the preferred order of the architecture, to gain
cross-architecture compatibility for this compiler.

> If you think an AI is pointless, you are probably missing something.

Probably.  I'm still a bit irritated because people are dealing with
such issues and do not tackle the more eminent problem of specifying
the byte/octet order for discrete types (both in-memory representation
and stream I/O layout).