On Tuesday, 18 August 2015 at 16:22:20 UTC, Andrei Alexandrescu
wrote:
On 8/18/15 11:39 AM, Johannes Pfau wrote:
No, this won't improve the ASM much: Enum values start at 0
and are
consecutive. With a final switch they're also bounded. All
these points
do not apply to pointers. They don't start at 0, are not
guaranteed to
be consecutive and likely can't be used with final switch.
Because of
that a switch on pointers can never use jump tables.
I agree there's a margin here in favor of integers, but it's
getting thin. Meanwhile, pointers maintain large advantages of
principle. I suggest we pursue better use of pointers as tags
instead of adding integral-tagged unions to phobos. -- Andrei
No, enum can also be cramed inline in the code for cheap, they
can be inserted in existing structure for cheap using bits
manipulations most of the time, the compiler can check that all
cases are handled in an exhaustive manner.
It is not getting thinner.
