On Sunday, 17 November 2013 at 10:56:16 UTC, Jonathan M Davis
wrote:
I think that the typical approach at this point is to just drop
purity for the
moment, but if you want you really want it, you are indeed
going to have to
implement it yourself. But we'll get there with Phobos
eventually. The primary
holdup is some compiler improvements, and we'll get them. It's
just a question
of when.
- Jonathan M Davis
Why is it that compiler improvements are the holdup? Honest
question. Is it more that the approach taken for the specific
implementation went beyond the capabilities of the compiler at
the time (like its inferencing capabilities)? Maybe purity was
not a focus at the time of writing a lot of phobos and there are
not loads of testing on it where purity was a factor. If so,
isn't an alternative implementation now an improvement over
waiting for the compiler updates. A corollary question would be
are the benefits of Voldermort types in phobos worth the purity
issues they cause?
From this article
(http://www.drdobbs.com/cpp/voldemort-types-in-d/232901591)
Walter says, regarding the pre-Voldermort version of
RandomNumberGenerator:
"I could mark it with the private attribute and modules other
than rnd won't be able to access it. But it's still there,
outside the scope of where it belongs, and other module members
can still access it, private or not (in D, private declarations
are not hidden from other declarations within the same module).
Besides, I want it to be so clean it squeaks."
Noble goal - maybe. But maybe not as noble as users' efforts to
realize benefits of purity now. Purity/const/immutable when
broken spread virally.
Thanks
Dan
