More datetime polish (#5690)

#1317

components/datetime/src/format/neo.rs

@@ -7,7 +7,6 @@ use super::{
     GetNameForDayPeriodError, GetNameForMonthError, GetNameForWeekdayError, GetSymbolForEraError,
     MonthPlaceholderValue,
 };
-use crate::calendar::CldrCalendar;
 use crate::external_loaders::*;
 use crate::fields::{self, Field, FieldLength, FieldSymbol};
 use crate::helpers::size_test;
@@ -22,6 +21,7 @@ use crate::neo_skeleton::NeoDateTimeSkeleton;
 use crate::pattern::PatternItem;
 use crate::provider::neo::*;
 use crate::provider::time_zones::tz;
+use crate::scaffold::*;
 use crate::time_zone::ResolvedNeoTimeZoneSkeleton;
 use crate::time_zone::TimeZoneDataPayloadsBorrowed;
 use core::fmt;

components/datetime/src/lib.rs

@@ -89,7 +89,6 @@
 
 extern crate alloc;
 
-mod calendar;
 mod error;
 mod external_loaders;
 pub mod fields;
@@ -108,15 +107,14 @@ pub mod options;
 pub mod pattern;
 pub mod provider;
 pub(crate) mod raw;
+pub mod scaffold;
 #[doc(hidden)]
 #[allow(clippy::exhaustive_structs, clippy::exhaustive_enums)] // private-ish module
 #[cfg(feature = "datagen")]
 pub mod skeleton;
 mod time_zone;
 mod tz_registry;
 
-pub use calendar::CldrCalendar;
-pub use calendar::InternalCldrCalendar;
 pub use error::MismatchedCalendarError;
 pub use format::datetime::DateTimeWriteError;
 pub use format::neo::{FormattedDateTimePattern, LoadError, SingleLoadError, TypedDateTimeNames};

components/datetime/src/neo.rs

@@ -4,7 +4,6 @@
 
 //! High-level entrypoints for Neo DateTime Formatter
 
-use crate::calendar::AnyCalendarProvider;
 use crate::external_loaders::*;
 use crate::format::datetime::try_write_pattern_items;
 use crate::format::datetime::DateTimeWriteError;
@@ -13,7 +12,7 @@ use crate::input::ExtractedInput;
 use crate::neo_marker::DateInputMarkers;
 use crate::neo_marker::HasConstComponents;
 use crate::neo_marker::{
-    AllInputMarkers, CalMarkers, ConvertCalendar, DateDataMarkers, DateTimeMarkers, GetField,
+    AllInputMarkers, ConvertCalendar, DateDataMarkers, DateTimeMarkers, GetField,
     IsAnyCalendarKind, IsInCalendar, IsRuntimeComponents, TimeMarkers, TypedDateDataMarkers,
     ZoneMarkers,
 };
@@ -23,7 +22,7 @@ use crate::options::preferences::HourCycle;
 use crate::provider::neo::*;
 use crate::provider::ErasedPackedPatterns;
 use crate::raw::neo::*;
-use crate::CldrCalendar;
+use crate::scaffold::*;
 use crate::MismatchedCalendarError;
 use core::fmt;
 use core::marker::PhantomData;

components/datetime/src/neo_marker.rs

@@ -341,7 +341,7 @@ use crate::{
     format::neo::*,
     neo_skeleton::*,
     provider::{neo::*, time_zones::tz, *},
-    CldrCalendar,
+    scaffold::*,
 };
 use icu_calendar::{
     any_calendar::IntoAnyCalendar,
@@ -356,18 +356,6 @@ use icu_timezone::{
     CustomTimeZone, CustomZonedDateTime, MetazoneId, TimeZoneBcp47Id, UtcOffset, ZoneVariant,
 };
 
-// TODO: Figure out where to export these traits
-#[doc(inline)]
-pub use crate::calendar::CalMarkers;
-#[doc(inline)]
-pub use crate::calendar::FullDataCalMarkers;
-#[doc(inline)]
-pub use crate::calendar::NoDataCalMarkers;
-
-pub(crate) mod private {
-    pub trait Sealed {}
-}
-
 /// A type that can be converted into a specific calendar system.
 pub trait ConvertCalendar {
     /// The converted type. This can be the same as the receiver type.
@@ -993,7 +981,7 @@ pub trait HasConstZoneComponent {
 
 /// A trait associating types for date formatting in any calendar
 /// (input types only).
-pub trait DateInputMarkers: private::Sealed {
+pub trait DateInputMarkers: UnstableSealed {
     /// Marker for resolving the year input field.
     type YearInput: Into<Option<YearInfo>>;
     /// Marker for resolving the month input field.
@@ -1008,7 +996,7 @@ pub trait DateInputMarkers: private::Sealed {
 
 /// A trait associating types for date formatting in a specific calendar
 /// (data markers only).
-pub trait TypedDateDataMarkers<C>: private::Sealed {
+pub trait TypedDateDataMarkers<C>: UnstableSealed {
     /// Marker for loading date skeleton patterns.
     type DateSkeletonPatternsV1Marker: DataMarker<DataStruct = PackedPatternsV1<'static>>;
     /// Marker for loading year names.
@@ -1021,7 +1009,7 @@ pub trait TypedDateDataMarkers<C>: private::Sealed {
 
 /// A trait associating types for date formatting in any calendar
 /// (data markers only).
-pub trait DateDataMarkers: private::Sealed {
+pub trait DateDataMarkers: UnstableSealed {
     /// Cross-calendar data markers for date skeleta.
     type Skel: CalMarkers<ErasedPackedPatterns>;
     /// Cross-calendar data markers for year names.
@@ -1034,7 +1022,7 @@ pub trait DateDataMarkers: private::Sealed {
 
 /// A trait associating types for time formatting
 /// (input types and data markers).
-pub trait TimeMarkers: private::Sealed {
+pub trait TimeMarkers: UnstableSealed {
     /// Marker for resolving the day-of-month input field.
     type HourInput: Into<Option<IsoHour>>;
     /// Marker for resolving the day-of-week input field.
@@ -1051,7 +1039,7 @@ pub trait TimeMarkers: private::Sealed {
 
 /// A trait associating types for time zone formatting
 /// (input types and data markers).
-pub trait ZoneMarkers: private::Sealed {
+pub trait ZoneMarkers: UnstableSealed {
     /// Marker for resolving the time zone offset input field.
     type TimeZoneOffsetInput: Into<Option<UtcOffset>>;
     /// Marker for resolving the time zone id input field.
@@ -1076,7 +1064,7 @@ pub trait ZoneMarkers: private::Sealed {
 
 /// A trait associating constants and types implementing various other traits
 /// required for datetime formatting.
-pub trait DateTimeMarkers: private::Sealed + DateTimeNamesMarker {
+pub trait DateTimeMarkers: UnstableSealed + DateTimeNamesMarker {
     /// Associated types for date formatting.
     ///
     /// Should implement [`DateDataMarkers`], [`TypedDateDataMarkers`], and [`DateInputMarkers`].
@@ -1150,7 +1138,7 @@ where
 #[allow(clippy::exhaustive_enums)] // empty marker enum
 pub enum NeoNeverMarker {}
 
-impl private::Sealed for NeoNeverMarker {}
+impl UnstableSealed for NeoNeverMarker {}
 
 impl DateInputMarkers for NeoNeverMarker {
     type YearInput = NeverField;
@@ -1215,7 +1203,7 @@ pub struct DateTimeCombo<D, T, Z> {
     pub fractional_second_digits: Option<FractionalSecondDigits>,
 }
 
-impl<D, T, Z> private::Sealed for DateTimeCombo<D, T, Z> {}
+impl<D, T, Z> UnstableSealed for DateTimeCombo<D, T, Z> {}
 
 impl<D, T, Z> DateTimeCombo<D, T, Z> {
     /// Creates a date/time/zone skeleton with the given formatting length.
@@ -1833,7 +1821,7 @@ macro_rules! impl_date_or_calendar_period_marker {
             $(alignment: $option_alignment_yes,)?
             $(year_style: $year_yes,)?
         );
-        impl private::Sealed for $type {}
+        impl UnstableSealed for $type {}
         impl DateTimeNamesMarker for $type {
             type YearNames = datetime_marker_helper!(@names/year, $($years_yes)?);
             type MonthNames = datetime_marker_helper!(@names/month, $($months_yes)?);
@@ -2057,7 +2045,7 @@ macro_rules! impl_time_marker {
             alignment: yes,
             $(fractional_second_digits: $nanosecond_yes,)?
         );
-        impl private::Sealed for $type {}
+        impl UnstableSealed for $type {}
         impl DateTimeNamesMarker for $type {
             type YearNames = datetime_marker_helper!(@names/year,);
             type MonthNames = datetime_marker_helper!(@names/month,);
@@ -2202,7 +2190,7 @@ macro_rules! impl_zone_marker {
             $type,
             sample_length: $sample_length,
         );
-        impl private::Sealed for $type {}
+        impl UnstableSealed for $type {}
         impl DateTimeNamesMarker for $type {
             type YearNames = datetime_marker_helper!(@names/year,);
             type MonthNames = datetime_marker_helper!(@names/month,);
@@ -2742,15 +2730,15 @@ impl_zoneddatetime_marker!(
 );
 
 /// Trait for components that can be formatted at runtime.
-pub trait IsRuntimeComponents: private::Sealed + GetField<NeoComponents> {}
+pub trait IsRuntimeComponents: UnstableSealed + GetField<NeoComponents> {}
 
 impl GetField<NeoComponents> for NeoDateSkeleton {
     fn get_field(&self) -> NeoComponents {
         self.components.into()
     }
 }
 
-impl private::Sealed for NeoDateSkeleton {}
+impl UnstableSealed for NeoDateSkeleton {}
 
 impl IsRuntimeComponents for NeoDateSkeleton {}
 
@@ -2805,7 +2793,7 @@ impl_get_field!(NeoDateSkeleton, length, yes);
 impl_get_field!(NeoDateSkeleton, alignment, yes);
 impl_get_field!(NeoDateSkeleton, year_style, yes);
 
-impl private::Sealed for NeoCalendarPeriodSkeleton {}
+impl UnstableSealed for NeoCalendarPeriodSkeleton {}
 
 impl GetField<NeoComponents> for NeoCalendarPeriodSkeleton {
     fn get_field(&self) -> NeoComponents {
@@ -2866,7 +2854,7 @@ impl_get_field!(NeoCalendarPeriodSkeleton, length, yes);
 impl_get_field!(NeoCalendarPeriodSkeleton, alignment, yes);
 impl_get_field!(NeoCalendarPeriodSkeleton, year_style, yes);
 
-impl private::Sealed for NeoTimeSkeleton {}
+impl UnstableSealed for NeoTimeSkeleton {}
 
 impl GetField<NeoComponents> for NeoTimeSkeleton {
     fn get_field(&self) -> NeoComponents {
@@ -2914,7 +2902,7 @@ impl_get_field!(NeoTimeSkeleton, length, yes);
 impl_get_field!(NeoTimeSkeleton, alignment, yes);
 impl_get_field!(NeoTimeSkeleton, fractional_second_digits, yes);
 
-impl private::Sealed for NeoTimeZoneSkeleton {}
+impl UnstableSealed for NeoTimeZoneSkeleton {}
 
 impl GetField<NeoComponents> for NeoTimeZoneSkeleton {
     fn get_field(&self) -> NeoComponents {
@@ -2964,7 +2952,7 @@ impl DateTimeMarkers for NeoTimeZoneSkeleton {
 impl_get_field!(NeoTimeZoneSkeleton, never);
 impl_get_field!(NeoTimeZoneSkeleton, length, yes);
 
-impl private::Sealed for NeoDateTimeSkeleton {}
+impl UnstableSealed for NeoDateTimeSkeleton {}
 
 impl GetField<NeoComponents> for NeoDateTimeSkeleton {
     fn get_field(&self) -> NeoComponents {
@@ -3004,7 +2992,7 @@ impl_get_field!(NeoDateTimeSkeleton, alignment, yes);
 impl_get_field!(NeoDateTimeSkeleton, year_style, yes);
 impl_get_field!(NeoDateTimeSkeleton, fractional_second_digits, yes);
 
-impl private::Sealed for NeoSkeleton {}
+impl UnstableSealed for NeoSkeleton {}
 
 impl GetField<NeoComponents> for NeoSkeleton {
     fn get_field(&self) -> NeoComponents {

components/datetime/src/calendar.rs → components/datetime/src/scaffold/calendar.rs

@@ -2,6 +2,8 @@
 // called LICENSE at the top level of the ICU4X source tree
 // (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
 
+//! Scaffolding traits and impls for calendars.
+
 use icu_calendar::any_calendar::AnyCalendarKind;
 use icu_calendar::chinese::Chinese;
 use icu_calendar::roc::Roc;
@@ -14,22 +16,10 @@ use icu_calendar::{
 use icu_provider::prelude::*;
 
 use crate::provider::{neo::*, *};
+use crate::scaffold::UnstableSealed;
 use core::marker::PhantomData;
 use icu_provider::marker::NeverMarker;
 
-/// Internal-ish trait for sealing `CldrCalendar`.
-///
-/// The `CldrCalendar` trait is sealed except when the `"experimental"` Cargo
-/// feature is enabled. If implementing `CldrCalendar`, you must also
-/// implement `UnstableCldrCalendar` and acknowledge the stability policy.
-///
-/// <div class="stab unstable">
-/// 🚧 This trait is considered unstable; it may change at any time, in breaking or non-breaking ways,
-/// including in SemVer minor releases. Do not implement this trait in userland.
-/// </div>
-// TODO(#4338): Decide what to do with this when we retire this crate's "experimental" feature.
-pub trait InternalCldrCalendar {}
-
 /// A calendar that can be found in CLDR
 ///
 /// New implementors of this trait will likely also wish to modify `get_era_code_map()`
@@ -39,7 +29,7 @@ pub trait InternalCldrCalendar {}
 /// 🚧 This trait is considered unstable; it may change at any time, in breaking or non-breaking ways,
 /// including in SemVer minor releases. Do not implement this trait in userland.
 /// </div>
-pub trait CldrCalendar: InternalCldrCalendar {
+pub trait CldrCalendar: UnstableSealed {
     /// The data marker for loading year symbols for this calendar.
     type YearNamesV1Marker: DataMarker<DataStruct = YearNamesV1<'static>>;
 
@@ -155,35 +145,31 @@ impl CldrCalendar for Roc {
     type SkeletaV1Marker = RocDateNeoSkeletonPatternsV1Marker;
 }
 
-impl InternalCldrCalendar for () {}
-impl InternalCldrCalendar for Buddhist {}
-impl InternalCldrCalendar for Chinese {}
-impl InternalCldrCalendar for Coptic {}
-impl InternalCldrCalendar for Dangi {}
-impl InternalCldrCalendar for Ethiopian {}
-impl InternalCldrCalendar for Gregorian {}
-impl InternalCldrCalendar for Hebrew {}
-impl InternalCldrCalendar for Indian {}
-impl InternalCldrCalendar for IslamicCivil {}
-impl InternalCldrCalendar for IslamicObservational {}
-impl InternalCldrCalendar for IslamicTabular {}
-impl InternalCldrCalendar for IslamicUmmAlQura {}
-impl InternalCldrCalendar for Japanese {}
-impl InternalCldrCalendar for JapaneseExtended {}
-impl InternalCldrCalendar for Persian {}
-impl InternalCldrCalendar for Roc {}
-
-mod private {
-    pub trait Sealed {}
-}
+impl UnstableSealed for () {}
+impl UnstableSealed for Buddhist {}
+impl UnstableSealed for Chinese {}
+impl UnstableSealed for Coptic {}
+impl UnstableSealed for Dangi {}
+impl UnstableSealed for Ethiopian {}
+impl UnstableSealed for Gregorian {}
+impl UnstableSealed for Hebrew {}
+impl UnstableSealed for Indian {}
+impl UnstableSealed for IslamicCivil {}
+impl UnstableSealed for IslamicObservational {}
+impl UnstableSealed for IslamicTabular {}
+impl UnstableSealed for IslamicUmmAlQura {}
+impl UnstableSealed for Japanese {}
+impl UnstableSealed for JapaneseExtended {}
+impl UnstableSealed for Persian {}
+impl UnstableSealed for Roc {}
 
 /// A collection of marker types associated with all calendars.
 ///
 /// This is used to group together the calendar-specific marker types that produce a common
 /// [`DynamicDataMarker`]. For example, this trait can be implemented for [`YearNamesV1Marker`].
 ///
 /// This trait serves as a building block for a cross-calendar [`BoundDataProvider`].
-pub trait CalMarkers<M>: private::Sealed
+pub trait CalMarkers<M>: UnstableSealed
 where
     M: DynamicDataMarker,
 {
@@ -228,14 +214,14 @@ where
 #[allow(clippy::exhaustive_enums)] // empty enum
 pub enum FullDataCalMarkers {}
 
-impl private::Sealed for FullDataCalMarkers {}
+impl UnstableSealed for FullDataCalMarkers {}
 
 /// Implementation of [`CalMarkers`] that includes data for no calendars.
 #[derive(Debug)]
 #[allow(clippy::exhaustive_enums)] // empty enum
 pub enum NoDataCalMarkers {}
 
-impl private::Sealed for NoDataCalMarkers {}
+impl UnstableSealed for NoDataCalMarkers {}
 
 impl<M> CalMarkers<M> for NoDataCalMarkers
 where

components/datetime/src/scaffold/mod.rs

@@ -0,0 +1,25 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+//! Scaffolding traits and types for the datetime crate.
+//!
+//! Items in this module are mostly for trait bounds. Most users should not need to reference
+//! these items in userland code.
+
+mod calendar;
+
+pub(crate) use calendar::AnyCalendarProvider;
+pub use calendar::CalMarkers;
+pub use calendar::CldrCalendar;
+pub use calendar::FullDataCalMarkers;
+pub use calendar::NoDataCalMarkers;
+
+/// Trait marking other traits that are considered unstable and should not generally be
+/// implemented outside of the datetime crate.
+///
+/// <div class="stab unstable">
+/// 🚧 This trait is considered unstable; it may change at any time, in breaking or non-breaking ways,
+/// including in SemVer minor releases. Do not implement this trait in userland.
+/// </div>
+pub trait UnstableSealed {}