On Wednesday, 10 April 2013 at 13:51:59 UTC, deadalnix wrote:
It is certainly more complex on the compiler implementation
side. But the ends result can be much better, and any program
would benefit from it.
Plus, do you know that depending on the ABI, some pass by value
are already transformed as pass by ref ? This is already in
place in some cases, and have been proven to work well.
Back to the DIP, it fail to define how and where lvalue are
implicitely created, what are their lifetime, etc . . .
Finally, ref and scope would benefit much more from the
introduction of lifetime into D than hacking around.
DIP36 was intentionally tweaked in such way so that compiler is
free to do any implementation and swap pass by values with pass
by ref if needed - until it preserves the semantics guarantees.
Introduction of lifetime is very beneficial but not really
relevant to _this_ DIP. If lifetime is well defined, idea of
making struct literal lvalues may be discussed, but that is a
different story.
I don't care about how complex compiler implementation is but
behavior needs to be predictable by programmer, no observable
magic. Scope happens to have exactly the semantics needed to make
stuff work right here and right now, with no relation to possible
improvements of ref and rvalue/lvalue system.
