On Thursday, 19 July 2018 at 19:18:43 UTC, jmh530 wrote:
However, it seems like hasUDA doesn't seem to produce the
result I would have expected here. I tried using getAttributes,
but that didn't work either.
Am I missing something, or should I submit an enhancement
request?
UDAs apply to symbols. When you pass something to a function, the
symbol does not go with the value, and thus that UDA goes away.
It's similar to assigning to a different variable:
import std.traits : hasUDA;
@("foo")
Foo foo1;
Foo foo2 = foo1;
assert(!hasUDA!(foo2, "foo"));
Since UDAs are compile-time constructs, they really can't follow
values around in that way. Consider:
void main(string[] args) {
@("foo")
Foo foo1;
@("bar")
Foo foo2;
Foo foo3 = (args.length % 2) ? foo1 : foo2;
assert(hasUDA!(foo3, "foo")); // Would you expect this to
pass or fail?
}
Timoses first checkUDA function is exactly what I would suggest
you use.
--
Simen
