Embrace the from template?

[Jonathan M Davis]

On Friday, August 24, 2018 7:03:37 PM MDT Jonathan Marler via Digitalmars-d 
wrote:
> > What uses does this actually have, I only see one example from
> > the article and it is an oversimplistic example that
> > effectively translates to either phobos being used or not being
> > used. All the extra bloat this template would add to the
> > already bloated if constraints is not welcome at all. The
> > potential small benefit this might add isn't worth the
> > unreadable mess it will turn code into.
>
> I can't help but laugh when you say "all the extra bloat this
> template would add..." :)  Sorry, I don't mean to insult but that
> really gave me a laugh.
>
> I hate to be blunt, but its clear from your response that you
> failed to grok the original post, which makes anything else I say
> pointless.  So I'm going to slowly back away from this
> one...step...step..step....*stp*....*s*...*

It actually does add more template instantiations - and therefore arguably
more bloat. It's just that because it more tightly ties importing to the use
of the symbol, it reduces how many symbols you import unnecessarily, which
can therefore reduce the bloat. So, if the symbol is used everywhere anyway,
then from just adds bloat, whereas if it really is used in a more restricted
way, then it reduces compilation times.

The reason that I personally hate from's guts is because of how verbose it
is. I'd _much_ rather see lazy importing be added like Walter likes to bring
up from time to time. It should get us the reduction in compile times
without all of the verbosity. As such, I would hate to see from in a place
like object.d (or honestly, anywhere in druntime or Phobos), because then it
might be used in Phobos all over the place, and I simply don't want to have
to deal with it. It's bad enough that we're using scoped and local imports
all over the place. They do help with tying imports to what uses them (and
in the case of templated code can actually result in imports only happening
when they need to), but it's so painfully verbose. I'd much rather not see
the situation get that much worse by from being considered best practice
instead of just fixing the compiler so that it's more efficient at importing
and thus avoiding all of that extra verbosity in the code.

- Jonathan M Davis