On Tue, 28 May 2013 22:20:08 -0400, Jonathan M Davis <jmdavisp...@gmx.com>
wrote:
On Tuesday, May 28, 2013 20:37:12 Steven Schveighoffer wrote:
This is a different problem. Your problem is you can't apply const
selectively to the tail of the reference. It's fundamentally sound, but
D
lacks the syntax to do it.
The syntax is actually the easy part. The problem is that the type system
itself doesn't differentiate between a class and a reference to a class,
and
the whole compiler is wired that way. So, while adding a new syntax
isn't that
hard (several have been proposed before), actually implementing it is a
royal
pain (enough so that Walter gave up on it). It would definitely be nice
to have
that fixed though.
No, this is wrong. The issue is entirely syntax. And it is hard, because
*conceptually*, it's difficult to separate out the reference from the
data. It's hard to say "The part of C that isn't the reference" in a
succinct way.
Michel Fortin has created a pull request to make
const(T)ref
work, and only apply the const to the data. It's certainly doable. But
the syntax, as you can see, is ugly.
As it turns out, we need more than this, and a more critical problem to
solve is creating tail-const custom ranges (I am working on an article to
discuss and hopefully address this).
-Steve
