[browser][non-icu] HybridGlobalization compare

docs/design/features/hybrid-globalization.md

@@ -18,3 +18,157 @@ Affected public APIs:
 - TextInfo.ToTitleCase.
 
 Case change with invariant culture uses `toUpperCase` / `toLoweCase` functions that do not guarantee a full match with the original invariant culture.
+
+**String comparison**
+
+Affected public APIs:
+- CompareInfo.Compare,
+- String.Compare,
+- String.Equals.
+
+The number of `CompareOptions` and `StringComparison` combinations is limited. Originally supported combinations can be found [here for CompareOptions](https://learn.microsoft.com/dotnet/api/system.globalization.compareoptions) and [here for StringComparison](https://learn.microsoft.com/dotnet/api/system.stringcomparison).
+
+- `IgnoreWidth` is not supported because there is no equivalent in Web API. Throws `PlatformNotSupportedException`.
+``` JS
+let high = String.fromCharCode(65281)                                       // %uff83 = ﾃ
+let low = String.fromCharCode(12486)                                        // %u30c6 = テ
+high.localeCompare(low, "ja-JP", { sensitivity: "case" })                   // -1 ; case: a ≠ b, a = á, a ≠ A; expected: 0
+
+let wide = String.fromCharCode(65345)                                       // %uFF41 = ａ
+let narrow = "a"
+wide.localeCompare(narrow, "en-US", { sensitivity: "accent" })              // 0; accent: a ≠ b, a ≠ á, a = A; expected: -1
+```
+
+For comparison where "accent" sensitivity is used, ignoring some type of character widths is applied and cannot be switched off (see: point about `IgnoreCase`).
+
+- `IgnoreKanaType`:
+
+It is always switched on for comparison with locale "ja-JP", even if this comparison option was not set explicitly.
+
+``` JS
+let hiragana = String.fromCharCode(12353)             // %u3041 = ぁ
+let katakana = String.fromCharCode(12449)             // %u30A1 = ァ
+let enCmp = hiragana.localeCompare(katakana, "en-US") // -1
+let jaCmp = hiragana.localeCompare(katakana, "ja-JP") // 0
+```
+
+For locales different than "ja-JP" it cannot be used separately (no equivalent in Web API) - throws `PlatformNotSupportedException`.
+
+- `None`:
+
+No equivalent in Web API for "ja-JP" locale. See previous point about `IgnoreKanaType`. For "ja-JP" it throws `PlatformNotSupportedException`.
+
+- `IgnoreCase`, `CurrentCultureIgnoreCase`, `InvariantCultureIgnoreCase`
+
+For `IgnoreCase | IgnoreKanaType`, argument `sensitivity: "accent"` is used.
+
+``` JS
+let hiraganaBig = `${String.fromCharCode(12353)} A`                          // %u3041 = ぁ
+let katakanaSmall = `${String.fromCharCode(12449)} a`                        // %u30A1 = ァ
+hiraganaBig.localeCompare(katakanaSmall, "en-US", { sensitivity: "accent" }) // 0;  accent: a ≠ b, a ≠ á, a = A
+```
+
+Known exceptions:
+
+| **character 1** | **character 2** | **CompareOptions** | **hybrid globalization** | **icu** |                       **comments**                      |
+|:---------------:|:---------------:|--------------------|:------------------------:|:-------:|:-------------------------------------------------------:|
+|        a        |   `\uFF41` ａ   |   IgnoreKanaType   |             0            |    -1   |            applies to all wide-narrow chars             |
+|   `\u30DC` ボ   |    `\uFF8E` ﾎ   |     IgnoreCase     |             1            |    -1   | 1 is returned in icu when we additionally ignore width  |
+|   `\u30BF` タ   |    `\uFF80` ﾀ   |     IgnoreCase     |             0            |    -1   |                                                         |
+
+
+For `IgnoreCase` alone, a comparison with default option: `sensitivity: "variant"` is used after string case unification.
+
+``` JS
+let hiraganaBig = `${String.fromCharCode(12353)} A`                          // %u3041 = ぁ
+let katakanaSmall = `${String.fromCharCode(12449)} a`                        // %u30A1 = ァ
+let unchangedLocale = "en-US"
+let unchangedStr1 = hiraganaBig.toLocaleLowerCase(unchangedLocale);
+let unchangedStr2 = katakanaSmall.toLocaleLowerCase(unchangedLocale);
+unchangedStr1.localeCompare(unchangedStr2, unchangedLocale)                  // -1;
+let changedLocale = "ja-JP"
+let changedStr1 = hiraganaBig.toLocaleLowerCase(changedLocale);
+let changedStr2 = katakanaSmall.toLocaleLowerCase(changedLocale);
+changedStr1.localeCompare(changedStr2, changedLocale)                        // 0;
+```
+
+From this reason, comparison with locale `ja-JP` `CompareOption` `IgnoreCase` and `StringComparison`: `CurrentCultureIgnoreCase` and `InvariantCultureIgnoreCase` behave like a combination `IgnoreCase | IgnoreKanaType` (see: previous point about `IgnoreKanaType`). For other locales the behavior is unchanged with the following known exceptions:
+
+|                  **character 1**                 |                       **character 2**                      | **CompareOptions**                | **hybrid globalization** | **icu** |
+|:------------------------------------------------:|:----------------------------------------------------------:|-----------------------------------|:------------------------:|:-------:|
+| `\uFF9E`  (HALFWIDTH KATAKANA VOICED SOUND MARK) | `\u3099`   (COMBINING KATAKANA-HIRAGANA VOICED SOUND MARK) | None / IgnoreCase / IgnoreSymbols |             1            |    0    |
+
+- `IgnoreNonSpace`
+
+`IgnoreNonSpace` cannot be used separately without `IgnoreKanaType`. Argument `sensitivity: "case"` is used for comparison and it ignores both types of characters. Option `IgnoreNonSpace` alone throws `PlatformNotSupportedException`.
+
+``` JS
+let hiraganaAccent = `${String.fromCharCode(12353)} á`                           // %u3041 = ぁ
+let katakanaNoAccent = `${String.fromCharCode(12449)} a`                         // %u30A1 = ァ
+hiraganaAccent.localeCompare(katakanaNoAccent, "en-US", { sensitivity: "case" }) // 0; case:  a ≠ b, a = á, a ≠ A
+```
+
+- `IgnoreNonSpace | IgnoreCase`
+Combination of `IgnoreNonSpace` and `IgnoreCase` cannot be used without `IgnoreKanaType`. Argument `sensitivity: "base"` is used for comparison and it ignores three types of characters. Combination `IgnoreNonSpace | IgnoreCase` alone throws `PlatformNotSupportedException`.
+
+``` JS
+let hiraganaBigAccent = `${String.fromCharCode(12353)} A á`                              // %u3041 = ぁ
+let katakanaSmallNoAccent = `${String.fromCharCode(12449)} a a`                          // %u30A1 = ァ
+hiraganaBigAccent.localeCompare(katakanaSmallNoAccent, "en-US", { sensitivity: "base" }) // 0; base: a ≠ b, a = á, a = A
+```
+
+- `IgnoreSymbols`
+
+The subset of ignored symbols is limited to the symbols ignored by `string1.localeCompare(string2, locale, { ignorePunctuation: true })`. E.g. currency symbols, & are not ignored
+
+``` JS
+let hiraganaAccent = `${String.fromCharCode(12353)} á`                     // %u3041 = ぁ
+let katakanaNoAccent = `${String.fromCharCode(12449)} a`                   // %u30A1 = ァ
+hiraganaBig.localeCompare(katakanaSmall, "en-US", { sensitivity: "base" }) // 0; base: a ≠ b, a = á, a = A
+```
+
+- List of all `CompareOptions` combinations always throwing `PlatformNotSupportedException`:
+
+`IgnoreCase`,
+
+`IgnoreNonSpace`,
+
+`IgnoreNonSpace | IgnoreCase`,
+
+`IgnoreSymbols | IgnoreCase`,
+
+`IgnoreSymbols | IgnoreNonSpace`,
+
+`IgnoreSymbols | IgnoreNonSpace | IgnoreCase`,
+
+`IgnoreWidth`,
+
+`IgnoreWidth | IgnoreCase`,
+
+`IgnoreWidth | IgnoreNonSpace`,
+
+`IgnoreWidth | IgnoreNonSpace | IgnoreCase`,
+
+`IgnoreWidth | IgnoreSymbols`
+
+`IgnoreWidth | IgnoreSymbols | IgnoreCase`
+
+`IgnoreWidth | IgnoreSymbols | IgnoreNonSpace`
+
+`IgnoreWidth | IgnoreSymbols | IgnoreNonSpace | IgnoreCase`
+
+`IgnoreKanaType | IgnoreWidth`
+
+`IgnoreKanaType | IgnoreWidth | IgnoreCase`
+
+`IgnoreKanaType | IgnoreWidth | IgnoreNonSpace`
+
+`IgnoreKanaType | IgnoreWidth | IgnoreNonSpace | IgnoreCase`
+
+`IgnoreKanaType | IgnoreWidth | IgnoreSymbols`
+
+`IgnoreKanaType | IgnoreWidth | IgnoreSymbols | IgnoreCase`
+
+`IgnoreKanaType | IgnoreWidth | IgnoreSymbols | IgnoreNonSpace`
+
+`IgnoreKanaType | IgnoreWidth | IgnoreSymbols | IgnoreNonSpace | IgnoreCase`

src/libraries/Common/tests/TestUtilities/System/PlatformDetection.cs

@@ -348,10 +348,14 @@ public static string GetDistroVersionString()
         private static readonly Lazy<bool> m_isInvariant = new Lazy<bool>(()
             => (bool?)Type.GetType("System.Globalization.GlobalizationMode")?.GetProperty("Invariant", BindingFlags.NonPublic | BindingFlags.Static)?.GetValue(null) == true);
 
+        private static readonly Lazy<bool> m_isHybrid = new Lazy<bool>(()
+            => (bool?)Type.GetType("System.Globalization.GlobalizationMode")?.GetProperty("Hybrid", BindingFlags.NonPublic | BindingFlags.Static)?.GetValue(null) == true);
+
         private static readonly Lazy<Version> m_icuVersion = new Lazy<Version>(GetICUVersion);
         public static Version ICUVersion => m_icuVersion.Value;
 
         public static bool IsInvariantGlobalization => m_isInvariant.Value;
+        public static bool IsHybridGlobalization => m_isHybrid.Value;
         public static bool IsNotInvariantGlobalization => !IsInvariantGlobalization;
         public static bool IsIcuGlobalization => ICUVersion > new Version(0, 0, 0, 0);
         public static bool IsNlsGlobalization => IsNotInvariantGlobalization && !IsIcuGlobalization;