So I was just reading
http://stackoverflow.com/questions/1448396/how-to-use-enums-as-flags-in-c
And did a quick test:
enum STC
{
A = 0x1,
B = 0x2,
C = 0x4
}
enum FOO
{
F = 0x8,
G = 0x10
}
void main()
{
STC s = STC.A | STC.C;
STC s2 = s & STC.A;
auto s2_2 = s & STC.A;
static assert(is(typeof(s2_2) == STC));
static assert(!__traits(compiles, { if (s & FOO.F) {} })); //
fails. that one's hard to track down
static assert(!__traits(compiles, { auto s3 = s & FOO.F; })); //
fails, cause implicitly converts to int
static assert(!__traits(compiles, { STC s4 = s & FOO.F; }));
static assert(!__traits(compiles, { FOO s5 = s & FOO.F; }));
static assert(!__traits(compiles, { STC t = STC.A | FOO.F; }));
static assert(!__traits(compiles, { auto t = STC.A | FOO.F; })); //
fails
static assert(!__traits(compiles, { if (s & STC.B == 0) {} })); //
works, but error not gagged
static assert(!__traits(compiles, { if (s && STC.B) {} })); //
fails
}
Does it really make sense to allow bitwise operations on different enums?
There should at least be some way to get this straight without having to
resort to a heap of code like in C++:
http://www.artima.com/cppsource/safelabels.html
