On 09.05.22 23:24, Ben Jones wrote:
enum x;
enum y = 5;
struct Wrap(alias T) {
static if(isType!T){
T value; //When t == x this doesn't work because `x` is opaque
and has no default initializer
}
}
[...]
x is a "type" as far as isType is concerned (which makes sense to me),
but I don't think you can ever declare a variable of that type since
there's no way to initialize it... Is there a trait that can tell if you
can initialize a variable of a certain type? The best I can think of is
__traits(compiles, "T x;"), but it seems like it should be possible to
do better?
`x` is a type, period.
You can use void initialization to declare values of types that don't
have an `init` value: `x value = void;`
As for an alternative to the brute force `__traits(compiles, ...)`, you
can check if `T.init` is a thing:
static if (is(typeof(T.init))) { T value; }
I'm not sure if that's really better, though.
By the way, what is your `Wrap` supposed to do with `x`? Treating it
like `y` will likely fail, too, because `x` is not a value.
