Introduce dedicated LanguageIdentifierDisplayNameOptions struct

components/experimental/src/displaynames/mod.rs

@@ -66,4 +66,5 @@ pub use displaynames::DisplayNamesPreferences;
 pub use options::DisplayNamesOptions;
 pub use options::Fallback;
 pub use options::LanguageDisplay;
+pub use options::LanguageIdentifierDisplayNameOptions;
 pub use options::Style;

components/experimental/src/displaynames/options.rs

@@ -35,6 +35,14 @@ pub struct DisplayNamesOptions {
     pub language_display: LanguageDisplay,
 }
 
+/// A bag of options defining how a language identifier display name will be formatted.
+#[derive(Copy, Debug, Eq, PartialEq, Clone, Default)]
+#[non_exhaustive]
+pub struct LanguageIdentifierDisplayNameOptions {
+    /// The language display kind, defaults to "dialect".
+    pub language_display: Option<LanguageDisplay>,
+}
+
 /// An enum for formatting style.
 #[allow(missing_docs)] // The variants are self explanatory.
 #[non_exhaustive]

components/experimental/src/displaynames/single/language.rs

@@ -6,7 +6,9 @@ use crate::displaynames::provider::*;
 use crate::displaynames::single::{
     RegionDisplayNameOwned, ScriptDisplayNameOwned, VariantDisplayNameOwned,
 };
-use crate::displaynames::{DisplayNamesOptions, DisplayNamesPreferences, LanguageDisplay};
+use crate::displaynames::{
+    DisplayNamesPreferences, LanguageDisplay, LanguageIdentifierDisplayNameOptions,
+};
 use alloc::vec::Vec;
 use icu_pattern::DoublePlaceholderPattern;
 use icu_provider::DataPayloadOr;
@@ -19,13 +21,13 @@ use tinystr::TinyAsciiStr;
 ///
 /// ```
 /// use icu::experimental::displaynames::{
-///     DisplayNamesPreferences, DisplayNamesOptions, single::LanguageIdentifierDisplayNameOwned,
+///     DisplayNamesPreferences, LanguageIdentifierDisplayNameOptions, single::LanguageIdentifierDisplayNameOwned,
 /// };
 /// use icu::locale::{locale, langid};
 /// use writeable::assert_writeable_eq;
 ///
 /// let prefs = DisplayNamesPreferences::from(locale!("en"));
-/// let options = DisplayNamesOptions::default();
+/// let options = LanguageIdentifierDisplayNameOptions::default();
 /// let display_name = LanguageIdentifierDisplayNameOwned::try_new(
 ///     prefs,
 ///     langid!("fr-CA"),
@@ -39,7 +41,7 @@ use tinystr::TinyAsciiStr;
 #[derive(Debug)]
 pub struct LanguageIdentifierDisplayNameOwned {
     formatting_locale: DataLocale,
-    options: DisplayNamesOptions,
+    options: LanguageIdentifierDisplayNameOptions,
     language_payload: DataPayload<LocaleNamesLanguageMediumV1>,
     script_payload: DataPayloadOr<LocaleNamesScriptMediumV1, ()>,
     region_payload: DataPayloadOr<LocaleNamesRegionMediumV1, ()>,
@@ -50,7 +52,7 @@ pub struct LanguageIdentifierDisplayNameOwned {
 
 impl LanguageIdentifierDisplayNameOwned {
     icu_provider::gen_buffer_data_constructors!(
-        (prefs: DisplayNamesPreferences, subject: icu_locale::LanguageIdentifier, options: DisplayNamesOptions) -> result: Result<Self, DataError>,
+        (prefs: DisplayNamesPreferences, subject: icu_locale::LanguageIdentifier, options: LanguageIdentifierDisplayNameOptions) -> result: Result<Self, DataError>,
         /// Loads the language display name for a given language identifier and locale using compiled data.
         functions: [
             try_new,
@@ -65,7 +67,7 @@ impl LanguageIdentifierDisplayNameOwned {
         provider: &D,
         prefs: DisplayNamesPreferences,
         mut subject: icu_locale::LanguageIdentifier,
-        options: DisplayNamesOptions,
+        options: LanguageIdentifierDisplayNameOptions,
     ) -> Result<Self, DataError>
     where
         D: DataProvider<LocaleNamesLanguageMediumV1>
@@ -91,7 +93,7 @@ impl LanguageIdentifierDisplayNameOwned {
         let mut language_payload = None;
 
         // Only try dialect if requested (which is the default)
-        if options.language_display == LanguageDisplay::Dialect {
+        if options.language_display.unwrap_or_default() == LanguageDisplay::Dialect {
             for (language, script, region) in [
                 (subject.language, Some(subject.script), Some(subject.region)),
                 (subject.language, Some(subject.script), None),

components/experimental/tests/displaynames/tests.rs

@@ -2,7 +2,9 @@
 // called LICENSE at the top level of the ICU4X source tree
 // (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
 
-use icu_experimental::displaynames::{DisplayNamesOptions, multi::LocaleDisplayNamesFormatter};
+use icu_experimental::displaynames::{
+    DisplayNamesOptions, LanguageIdentifierDisplayNameOptions, multi::LocaleDisplayNamesFormatter,
+};
 use icu_locale_core::Locale;
 use icu_locale_core::locale;
 use std::borrow::Cow;
@@ -174,8 +176,12 @@ fn test_concatenate() {
         // Test the newer LanguageIdentifierDisplayName
         use icu_experimental::displaynames::single::LanguageIdentifierDisplayNameOwned;
         let lang_id = cas.input_1.id.clone();
-        let result =
-            LanguageIdentifierDisplayNameOwned::try_new(locale.clone().into(), lang_id, options);
+        let single_options = LanguageIdentifierDisplayNameOptions::default();
+        let result = LanguageIdentifierDisplayNameOwned::try_new(
+            locale.clone().into(),
+            lang_id,
+            single_options,
+        );
         match result {
             Ok(single_display_name) => {
                 assert_eq!(cas.single_should_err, false, "{cas:?}");