Re: very specific question on Ada syntax

[Robert Dewar <robert_dewar@my-deja.com>]

In article <877l3ck7nb.fsf@deneb.enyo.de>,
  Florian Weimer <fw@deneb.enyo.de> wrote:
> Robert Dewar <robert_dewar@my-deja.com> writes:
>
> > Yes, you can imagine a world in which 16 bit characters are
> > used uniformly, but that world is not today's world (I am
> > talking about common usage in Japan, Korea and China -- all
> > of which tend to use different representation methods, all
> > common ones of which are supported by GNAT.
>
> BTW, Unicode is now a 21.something bit character set, and the
> Wide_Character type is no longer appropriate for representing
Unicode
> (UCS-4) characters.  Will Ada be adapted accordingly?

I think in practice that the 16-bit subset of Unicode, the BMP
page of 10646, will be much more widely used in practice than
the full 21-bit set, and it was a quite deliberate decision
in the design of Ada to restrict Wide_Chararacter to the BMP.

Of course there is certainly nothing to stop the addition of
a Wide_Wide_Character type to the language, and at the very
least it would be worth an ARG ruling permitting this usage.

Actually our experience is that very few people are even using
the BMP in most Ada applications. There was certainly a
requirement to support it in Ada 95 (it in fact was a deal that
had been made in passing the ISO Ada 85 standard, where it was
noted that the standard was deficient with respect to character
set support, and it was agred that this would be addressed
in the next revision of the language).

Of course if Ada gets used more in international commerce,
perhaps making use of the IS annex, then the provision of
Wide_Character is important.

So far, the most significant program I know of using
Wide_Character and Wide_String is the ASIS definition
itself, where it is used to represent source texts.



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