On Thu, 09 Jun 2011 13:33:28 -0400, Jonathan M Davis <jmdavisp...@gmx.com>
wrote:
On 09.06.2011 16:33, Steven Schveighoffer wrote:
> Hm... this involves cast(Duration)x? That seems like a dangerous thing
> for a common operation, no?
There's nothing dangerous about it. It's an overloaded opCast, not a
built-in
cast. Now, there was some talk of figuring out how to set it up so that
you
could define in your type how to use the to function to convert instead,
and
that would be better (though I have no idea what the situation with that
is or
what's involved in that), but an overloaded opCast is the same as a
normal
function except for its calling syntax, so it's perfectly safe.
What I mean is, whenever you use the blunt instrument 'cast' anything can
happen. This code:
cast(x)y;
can do a lot of damage, depending on what x and y are. IIRC, you recently
said that one should avoid use casting if you can help it :)
It doesn't matter if the underlying cast is safe, the keyword cast means
"do whatever I say". It doesn't mean "do whatever I say but only if it's
an opCast operation". One slight misstep, and the compiler will silently
obey instead of giving you an error. We've been told numerous times "if
you want to find all the places where your code bypasses the type system,
search for the word cast".
My point is, why can't this function simply be a function (like
toDuration()). You can also define opCast to do the same thing, but I
think the ability to avoid typing that dreaded keyword should be available.
-Steve
