On Friday, 20 June 2014 at 18:15:49 UTC, Nick Sabalausky wrote:
I'm on the fence:
Pro: Upgrade paths and backwards compatibility are great,
especially for Phobos.
Con: If any semantics are changed (default ref/value passing is
the only one that comes to mind), then maybe it would mask
potential upgrade issues. Breakage would force users to notice
the change and (hopefully) deal with it appropriately.
I don't personally see it as a big deal either way, though.
Sorry for taking so long to follow up on this, it's been a busy
period ...
Anyway, here's my thinking behind the opCall idea. One of the
major shifts of the move to classes is that, suddenly, all of
these entities have to be explicitly allocated. That means that
there's some measure of responsibility on the library to offer a
sane default style of allocation, as appropriate for the expected
use-cases and performance requirements.
Now, apart from the random number generators, all of the
remaining library functionality already has helper functions
which can handle this. Currently they just "new" stuff, but
there's no reason this can't be adapted as needed, possibly with
the option for some kind of templating around different
allocation strategies.
However, RNGs themselves don't have any corresponding helper
functions, and manually writing them out would fast become
annoying (imagine having to create, say, xorshift, xorshift32,
xorshift64, ... etc. as helper functions to create Xorshift,
Xorshift32, Xorshift64, etc., instances).
opCall provides a natural way of implementing such construction
helper functions that is likely very general purpose, and
encouraging it as the default use-case has a further benefit of
encouraging the user to always seed their RNGs, if opCall has a
form like this:
static typeof(this) opCall(Seed)(Seed seed)
{
return new typeof(this)(seed);
}
It _could_ be done as a temporary measure, deprecated from the
start, to allow drop-in replacement but encourage appropriate
adaptation. But it could also be a way to serve the user with
sensible default allocation strategies that minimize the
potential performance impacts of the switch to classes.
