LibUnicode: Generate a list of available calendars

Author: https://github.com/trflynn89
Commit: https://github.com/SerenityOS/serenity/commit/ebd33e580b1
Pull-request: https://github.com/SerenityOS/serenity/pull/12223
Reviewed-by: https://github.com/linusg ✅

Meta/Lagom/Tools/CodeGenerators/LibUnicode/GenerateUnicodeDateTimeFormat.cpp

@@ -1863,6 +1863,8 @@ struct DayPeriodData {
 };
 )~~~");
 
+    generate_available_values(generator, "get_available_calendars"sv, locale_data.calendars, locale_data.calendar_aliases);
+
     locale_data.unique_formats.generate(generator, "CalendarFormatImpl"sv, "s_calendar_formats"sv, 10);
     locale_data.unique_symbol_lists.generate(generator, s_string_index_type, "s_symbol_lists"sv);
     locale_data.unique_calendar_symbols.generate(generator, "CalendarSymbols"sv, "s_calendar_symbols"sv, 10);

Meta/Lagom/Tools/CodeGenerators/LibUnicode/GeneratorUtil.h

@@ -488,3 +488,31 @@ static constexpr Array<Span<@type@ const>, @size@> @name@ { {
 } };
 )~~~");
 }
+
+template<typename T>
+void generate_available_values(SourceGenerator& generator, StringView name, Vector<T> const& values, Vector<Alias> const& aliases = {})
+{
+    generator.set("name", name);
+    generator.set("size", String::number(values.size()));
+
+    generator.append(R"~~~(
+Span<StringView const> @name@()
+{
+    static constexpr Array<StringView, @size@> values { {)~~~");
+
+    bool first = true;
+    for (auto const& value : values) {
+        generator.append(first ? " " : ", ");
+        first = false;
+
+        if (auto it = aliases.find_if([&](auto const& alias) { return alias.name == value; }); it != aliases.end())
+            generator.append(String::formatted("\"{}\"sv", it->alias));
+        else
+            generator.append(String::formatted("\"{}\"sv", value));
+    }
+
+    generator.append(R"~~~( } };
+    return values.span();
+}
+)~~~");
+}

Userland/Libraries/LibUnicode/DateTimeFormat.cpp

@@ -93,6 +93,7 @@ StringView calendar_pattern_style_to_string(CalendarPatternStyle style)
 
 Optional<Calendar> __attribute__((weak)) calendar_from_string(StringView) { return {}; }
 Optional<HourCycleRegion> __attribute__((weak)) hour_cycle_region_from_string(StringView) { return {}; }
+Span<StringView const> __attribute__((weak)) get_available_calendars() { return {}; }
 Vector<HourCycle> __attribute__((weak)) get_regional_hour_cycles(StringView) { return {}; }
 
 // https://unicode.org/reports/tr35/tr35-dates.html#Date_Field_Symbol_Table

Userland/Libraries/LibUnicode/DateTimeFormat.h

@@ -189,6 +189,8 @@ StringView calendar_pattern_style_to_string(CalendarPatternStyle style);
 Optional<Calendar> calendar_from_string(StringView calendar);
 Optional<HourCycleRegion> hour_cycle_region_from_string(StringView hour_cycle_region);
 
+Span<StringView const> get_available_calendars();
+
 Vector<HourCycle> get_regional_hour_cycles(StringView region);
 Vector<Unicode::HourCycle> get_locale_hour_cycles(StringView locale);
 Optional<Unicode::HourCycle> get_default_regional_hour_cycle(StringView locale);