Example of baked data crate with macros #2992
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It works across crate boundaries if I change the super-absolute imports like |
| @@ -77,6 +78,7 @@ lto = true | |||
| [profile.release-opt-size] | |||
| inherits = "release" | |||
| opt-level = "s" | |||
| debug = true | |||
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(reminder to remove this line)
| type DataStruct = | ||
| <icu_provider::hello_world::HelloWorldV1Marker as icu_provider::DataMarker>::Yokeable; | ||
| static KEYS: &[&str] = &["bn", "en", "en-US", "ja", "ru"]; | ||
| static BN: DataStruct = $crate::baked::core_helloworld_v1::data_core_helloworld_v1_bn!(); |
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This works, but it will be hard to generate because you're using the absolute path of where this will be included, e.g. it has to be included at $crate::baked. If we can't find a way to use relative addressing for the data file (either using mod or include), we should inline the data to step around this problem.
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The path is relative to the globaldata crate, which is under our control. We may need to tell databake-datagen what that path is, but this is totally an internal thing.
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It would be useful if the logic we add here is also usable by datagen clients, not only for this crate.
| include!("ru.data.rs"); | ||
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| #[macro_export] | ||
| macro_rules! impl_core_helloworld_v1 { |
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What's the plan for AnyProvider? Having one macro per key doesn't work, the keys should be arguments (plural) to the macro.
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I think it should "just work"
struct LocalBakedProvider;
impl_core_helloworld_v1!(LocalBakedProvider);
impl_decimal_symbols_v1!(LocalBakedProvider);
impl_any_provider!(LocalBakedProvider, [
icu_provider::hello_world::HelloWorldV1Marker,
icu_decimal::provider::SymbolsV1Marker,
]);| @@ -0,0 +1,10 @@ | |||
| #[macro_export] | |||
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Wrapping each data expression in a macro is a lot of cognitive overhead, and probably also compile time overhead.
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The cognitive overhead is being moved from the call site (people need to learn how data providers work) to an internal crate (that only us and power users will see).
| pub fn try_new(locale: &DataLocale) -> Result<Self, DataError> { | ||
| struct LocalBakedProvider; | ||
| use crate as icu_provider; | ||
| globaldata::impl_core_helloworld_v1!(LocalBakedProvider); |
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An open question is how to enable vertical fallback. An easy way, which is probably fine, is
let provider = globaldata::with_vertical_fallback!(LocalBakedProvider);and the macro has two versions: one that is a no-op, and one that is enabled with the globaldata/fallback feature that actually enables the fallback
See #2945