On Wednesday, 6 November 2013 at 04:57:57 UTC, Jonathan M Davis
wrote:
On Tuesday, November 05, 2013 13:27:54 Jacob Carlborg wrote:
On 2013-11-05 12:16, Meta wrote:
> One gotcha relates to enums. Writing `enum a = [0, 1, 2]` is
> a really
> bad idea, because everywhere you use a, it constructs a new
> array at
> runtime. The [0, 1, 2] is "pasted in", and you'll have a
> bunch of
> allocations you didn't expect. This doesn't just happen with
> arrays, but
> that's the most common case. What *is* okay is using string
> enums, as
> strings are a bit special due to being immutable.
Isn't the problem rather that [0, 1, 2] allocates in the first
place,
regardless if an enum is used or not.
In most cases, array literals need to allocate, regardless of
whether they're
an enum or not. The cases where they don't need to allocate
(e.g. when
initializing a static array) shouldn't allocate, but an array
literal by
itself is a dynamic array, and pretty much has to allocate in
most cases in
order to be safe. Having an enum which is an array literal
rather than making
it an immutable constant then results in allocations that you
might not want,
but that's not really the literal's fault.
Can you work around that? Maybe something like:
enum a = immutable([0, 1, 2]);
