LibUnicode: Use BCP 47 data to filter valid numbering system names

There isn't too much of an effective difference here other than that the
BCP 47 data contains some aliases we would otherwise not handle.

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

@@ -803,6 +803,7 @@ static ErrorOr<void> generate_unicode_locale_implementation(Core::Stream::Buffer
 #include <AK/Vector.h>
 #include <LibUnicode/Locale.h>
 #include <LibUnicode/NumberFormat.h>
+#include <LibUnicode/UnicodeLocale.h>
 #include <LibUnicode/UnicodeNumberFormat.h>
 
 namespace Unicode {
@@ -911,22 +912,31 @@ static constexpr Array<@type@, @size@> @name@ { {)~~~");
     generate_mapping(generator, locale_data.locales, s_number_system_index_type, "s_locale_number_systems"sv, "s_number_systems_{}", nullptr, [&](auto const& name, auto const& value) { append_map(name, s_number_system_index_type, value.number_systems); });
     generate_mapping(generator, locale_data.locales, s_unit_index_type, "s_locale_units"sv, "s_units_{}", nullptr, [&](auto const& name, auto const& value) { append_map(name, s_unit_index_type, value.units); });
 
-    auto append_from_string = [&](StringView enum_title, StringView enum_snake, auto const& values) {
-        HashValueMap<String> hashes;
-        hashes.ensure_capacity(values.size());
-
-        for (auto const& value : values)
-            hashes.set(value.hash(), format_identifier(enum_title, value));
-
-        generate_value_from_string(generator, "{}_from_string"sv, enum_title, enum_snake, move(hashes));
-    };
+    generator.append(R"~~~(
+static Optional<NumberSystem> keyword_to_number_system(KeywordNumbers keyword)
+{
+    switch (keyword) {)~~~");
 
-    append_from_string("NumberSystem"sv, "number_system"sv, locale_data.number_systems);
+    for (auto const& number_system : locale_data.number_systems) {
+        generator.set("name"sv, format_identifier({}, number_system));
+        generator.append(R"~~~(
+    case KeywordNumbers::@name@:
+        return NumberSystem::@name@;)~~~");
+    }
 
     generator.append(R"~~~(
+    default:
+        return {};
+    }
+}
+
 Optional<Span<u32 const>> get_digits_for_number_system(StringView system)
 {
-    auto number_system_value = number_system_from_string(system);
+    auto number_system_keyword = keyword_nu_from_string(system);
+    if (!number_system_keyword.has_value())
+        return {};
+
+    auto number_system_value = keyword_to_number_system(*number_system_keyword);
     if (!number_system_value.has_value())
         return {};
 
@@ -940,9 +950,13 @@ static NumberSystemData const* find_number_system(StringView locale, StringView
     if (!locale_value.has_value())
         return nullptr;
 
-    auto number_system_value = number_system_from_string(system);
+    auto number_system_keyword = keyword_nu_from_string(system);
+    if (!number_system_keyword.has_value())
+        return {};
+
+    auto number_system_value = keyword_to_number_system(*number_system_keyword);
     if (!number_system_value.has_value())
-        return nullptr;
+        return {};
 
     auto locale_index = to_underlying(*locale_value) - 1; // Subtract 1 because 0 == Locale::None.
     auto number_system_index = to_underlying(*number_system_value);

Userland/Libraries/LibUnicode/Forward.h

@@ -35,7 +35,6 @@ enum class ListPatternStyle : u8;
 enum class ListPatternType : u8;
 enum class Locale : u16;
 enum class Month : u8;
-enum class NumberSystem : u8;
 enum class NumericSymbol : u8;
 enum class Property : u8;
 enum class Script : u8;

Userland/Libraries/LibUnicode/NumberFormat.cpp

@@ -16,7 +16,6 @@
 
 namespace Unicode {
 
-Optional<NumberSystem> __attribute__((weak)) number_system_from_string(StringView) { return {}; }
 Optional<StringView> __attribute__((weak)) get_number_system_symbol(StringView, StringView, NumericSymbol) { return {}; }
 Optional<NumberGroupings> __attribute__((weak)) get_number_system_groupings(StringView, StringView) { return {}; }
 Optional<NumberFormat> __attribute__((weak)) get_standard_number_system_format(StringView, StringView, StandardNumberFormatType) { return {}; }

Userland/Libraries/LibUnicode/NumberFormat.h

@@ -66,7 +66,6 @@ enum class NumericSymbol : u8 {
     PlusSign,
 };
 
-Optional<NumberSystem> number_system_from_string(StringView system);
 Optional<StringView> get_default_number_system(StringView locale);
 
 Optional<StringView> get_number_system_symbol(StringView locale, StringView system, NumericSymbol symbol);