Attribute Macro icu_provider::data_struct
source ยท #[data_struct]
Expand description
The #[data_struct]
attribute should be applied to all types intended
for use in a DataStruct
.
It does the following things:
Apply #[derive(Yokeable, ZeroFrom)]
. TheZeroFrom
derive can be customized with#[zerofrom(clone)]
on non-ZeroFrom fields.
In addition, the attribute can be used to implement DataMarker
and/or KeyedDataMarker
by adding symbols with optional key strings:
use icu::locid::extensions::unicode::key;
use icu::locid_transform::fallback::*;
use icu_provider::yoke;
use icu_provider::zerofrom;
use icu_provider::KeyedDataMarker;
use std::borrow::Cow;
#[icu_provider::data_struct(
FooV1Marker,
BarV1Marker = "demo/bar@1",
marker(
BazV1Marker,
"demo/baz@1",
fallback_by = "region",
extension_key = "ca"
)
)]
pub struct FooV1<'data> {
message: Cow<'data, str>,
};
// Note: FooV1Marker implements `DataMarker` but not `KeyedDataMarker`.
// The other two implement `KeyedDataMarker`.
assert_eq!(&*BarV1Marker::KEY.path(), "demo/bar@1");
assert_eq!(
BarV1Marker::KEY.metadata().fallback_priority,
LocaleFallbackPriority::Language
);
assert_eq!(BarV1Marker::KEY.metadata().extension_key, None);
assert_eq!(&*BazV1Marker::KEY.path(), "demo/baz@1");
assert_eq!(
BazV1Marker::KEY.metadata().fallback_priority,
LocaleFallbackPriority::Region
);
assert_eq!(BazV1Marker::KEY.metadata().extension_key, Some(key!("ca")));
If the #[databake(path = ...)]
attribute is present on the data struct, this will also
implement it on the markers.