LibUnicode: Substitute Unicode locale aliases during canonicalization

Unicode TR35 defines how locale subtag aliases should be emplaced when
converting a locale to canonical form. For most subtags, it is a simple
substitution. Language subtags depend on context; for example, the
language "sh" should become "sr-Latn", but if the original locale has a
script subtag already ("sh-Cyrl"), then only the language subtag of the
alias should be taken ("sr-Latn").

To facilitate this, we now make two passes when canonicalizing a locale.
In the first pass, we convert the LocaleID structure to canonical syntax
(where the conversions all happen in-place). In the second pass, we form
the canonical string based on the canonical syntax.
This commit is contained in:
Timothy Flynn 2021-08-30 15:34:31 -04:00 committed by Linus Groh
parent 9b118f1f06
commit 556374a904
Notes: sideshowbarker 2024-07-18 04:57:43 +09:00
2 changed files with 178 additions and 51 deletions

View File

@ -334,4 +334,40 @@ TEST_CASE(canonicalize_unicode_locale_id)
test("EN-Z-BBB-U-AA-T-EN-0-AAA"sv, "en-0-aaa-t-en-u-aa-z-bbb"sv);
test("en-z-bbb-u-aa-t-en-0-aaa-x-ccc"sv, "en-0-aaa-t-en-u-aa-z-bbb-x-ccc"sv);
test("EN-Z-BBB-U-AA-T-EN-0-AAA-X-CCC"sv, "en-0-aaa-t-en-u-aa-z-bbb-x-ccc"sv);
// Language subtag aliases.
test("sh"sv, "sr-Latn"sv);
test("SH"sv, "sr-Latn"sv);
test("sh-cyrl"sv, "sr-Cyrl"sv);
test("SH-CYRL"sv, "sr-Cyrl"sv);
test("cnr"sv, "sr-ME"sv);
test("CNR"sv, "sr-ME"sv);
test("cnr-ba"sv, "sr-BA"sv);
test("CNR-BA"sv, "sr-BA"sv);
// Territory subtag aliases.
test("ru-su"sv, "ru-RU"sv);
test("RU-SU"sv, "ru-RU"sv);
test("ru-810"sv, "ru-RU"sv);
test("RU-810"sv, "ru-RU"sv);
test("en-su"sv, "en-RU"sv);
test("EN-SU"sv, "en-RU"sv);
test("en-810"sv, "en-RU"sv);
test("EN-810"sv, "en-RU"sv);
// Script subtag aliases.
test("en-qaai"sv, "en-Zinh"sv);
test("EN-QAAI"sv, "en-Zinh"sv);
// Variant subtag aliases.
test("en-polytoni"sv, "en-polyton"sv);
test("EN-POLYTONI"sv, "en-polyton"sv);
// Subdivision subtag aliases.
test("en-u-sd-cn11"sv, "en-u-sd-cnbj"sv);
test("EN-U-SD-CN11"sv, "en-u-sd-cnbj"sv);
test("en-u-rg-cn12"sv, "en-u-rg-cntj"sv);
test("EN-U-RG-CN12"sv, "en-u-rg-cntj"sv);
test("en-u-aa-cn11"sv, "en-u-aa-cn11"sv);
test("EN-U-AA-CN11"sv, "en-u-aa-cn11"sv);
}

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@ -480,43 +480,94 @@ Optional<LocaleID> parse_unicode_locale_id(StringView locale)
return locale_id;
}
Optional<String> canonicalize_unicode_locale_id(LocaleID& locale_id)
static void transform_unicode_locale_id_to_canonical_syntax(LocaleID& locale_id)
{
// https://unicode.org/reports/tr35/#Canonical_Unicode_Locale_Identifiers
StringBuilder builder;
auto canonicalize_language = [](LanguageID& language_id, bool force_lowercase) {
language_id.language = language_id.language->to_lowercase();
if (language_id.script.has_value())
language_id.script = language_id.script->to_titlecase();
if (language_id.region.has_value())
language_id.region = language_id.region->to_uppercase();
for (auto& variant : language_id.variants)
variant = variant.to_lowercase();
enum class Case {
Upper,
Lower,
Title,
};
if (auto alias = resolve_language_alias(*language_id.language); alias.has_value()) {
auto language_alias = parse_unicode_language_id(*alias);
VERIFY(language_alias.has_value());
auto append_sep_and_string = [&](Optional<String> const& string, Case case_ = Case::Lower) {
if (!string.has_value())
return;
switch (case_) {
case Case::Upper:
builder.appendff("-{}", string->to_uppercase());
break;
case Case::Lower:
builder.appendff("-{}", string->to_lowercase());
break;
case Case::Title:
builder.appendff("-{}", string->to_titlecase());
break;
language_id.language = move(language_alias->language);
if (!language_id.script.has_value() && language_alias->script.has_value())
language_id.script = move(language_alias->script);
if (!language_id.region.has_value() && language_alias->region.has_value())
language_id.region = move(language_alias->region);
if (language_id.variants.is_empty() && !language_alias->variants.is_empty())
language_id.variants = move(language_alias->variants);
}
if (language_id.script.has_value()) {
if (auto alias = resolve_script_tag_alias(*language_id.script); alias.has_value())
language_id.script = move(*alias);
}
if (language_id.region.has_value()) {
if (auto alias = resolve_territory_alias(*language_id.region); alias.has_value()) {
auto aliases = alias->split_view(' ');
// FIXME: Territory subtag aliases should also consult the CLDR likelySubtags.json file.
// For now, implement the spec's recommendation of using just the first alias.
language_id.region = aliases[0].to_string();
}
}
quick_sort(language_id.variants);
for (auto& variant : language_id.variants) {
variant = variant.to_lowercase();
if (auto alias = resolve_variant_alias(variant); alias.has_value())
variant = move(*alias);
}
if (force_lowercase) {
if (language_id.script.has_value())
language_id.script = language_id.script->to_lowercase();
if (language_id.region.has_value())
language_id.region = language_id.region->to_lowercase();
}
};
if (!locale_id.language_id.language.has_value())
return {};
auto canonicalize_key_value_list = [&](auto& key, auto& values, bool remove_true_values) {
key = key.to_lowercase();
builder.append(locale_id.language_id.language->to_lowercase());
append_sep_and_string(locale_id.language_id.script, Case::Title);
append_sep_and_string(locale_id.language_id.region, Case::Upper);
auto raw_values = move(values);
quick_sort(locale_id.language_id.variants);
for (auto const& variant : locale_id.language_id.variants)
append_sep_and_string(variant);
for (auto& value : raw_values) {
value = value.to_lowercase();
// Note: The spec says to remove "true" type and tfield values but that is believed to be a bug in the spec
// because, for tvalues, that would result in invalid syntax:
// https://unicode-org.atlassian.net/browse/CLDR-14318
// This has also been noted by test262:
// https://github.com/tc39/test262/blob/18bb955771669541c56c28748603f6afdb2e25ff/test/intl402/Intl/getCanonicalLocales/transformed-ext-canonical.js
if (remove_true_values && (value == "true"sv))
continue;
if (key.is_one_of("sd"sv, "rg"sv)) {
if (auto alias = resolve_subdivision_alias(value); alias.has_value()) {
auto aliases = alias->split_view(' ');
// FIXME: Subdivision subtags do not appear in the CLDR likelySubtags.json file.
// Implement the spec's recommendation of using just the first alias for now,
// but we should determine if there's anything else needed here.
values.append(aliases[0].to_string());
continue;
}
}
values.append(move(value));
}
};
canonicalize_language(locale_id.language_id, false);
quick_sort(locale_id.extensions, [](auto const& left, auto const& right) {
auto key = [](auto const& extension) {
@ -529,51 +580,91 @@ Optional<String> canonicalize_unicode_locale_id(LocaleID& locale_id)
return key(left) < key(right);
});
auto append_key_value_list = [&](auto const& key, auto const& values, bool remove_true_values) {
append_sep_and_string(key);
for (auto const& type : values) {
// Note: The spec says to remove "true" type and tfield values but that is believed to be a bug in the spec
// because, for tvalues, that would result in invalid syntax:
// https://unicode-org.atlassian.net/browse/CLDR-14318
// This has also been noted by test262:
// https://github.com/tc39/test262/blob/18bb955771669541c56c28748603f6afdb2e25ff/test/intl402/Intl/getCanonicalLocales/transformed-ext-canonical.js
if (remove_true_values && type.equals_ignoring_case("true"sv))
continue;
append_sep_and_string(type);
}
};
for (auto& extension : locale_id.extensions) {
extension.visit(
[&](LocaleExtension& ext) {
quick_sort(ext.attributes);
quick_sort(ext.keywords, [](auto const& a, auto const& b) { return a.key < b.key; });
for (auto& attribute : ext.attributes)
attribute = attribute.to_lowercase();
for (auto& keyword : ext.keywords)
canonicalize_key_value_list(keyword.key, keyword.types, true);
},
[&](TransformedExtension& ext) {
if (ext.language.has_value())
canonicalize_language(*ext.language, true);
quick_sort(ext.fields, [](auto const& a, auto const& b) { return a.key < b.key; });
for (auto& field : ext.fields)
canonicalize_key_value_list(field.key, field.values, false);
},
[&](OtherExtension& ext) {
ext.key = static_cast<char>(to_ascii_lowercase(ext.key));
for (auto& value : ext.values)
value = value.to_lowercase();
});
}
for (auto& extension : locale_id.private_use_extensions)
extension = extension.to_lowercase();
}
Optional<String> canonicalize_unicode_locale_id(LocaleID& locale_id)
{
// https://unicode.org/reports/tr35/#Canonical_Unicode_Locale_Identifiers
StringBuilder builder;
auto append_sep_and_string = [&](Optional<String> const& string) {
if (!string.has_value())
return;
builder.appendff("-{}", *string);
};
if (!locale_id.language_id.language.has_value())
return {};
transform_unicode_locale_id_to_canonical_syntax(locale_id);
builder.append(locale_id.language_id.language->to_lowercase());
append_sep_and_string(locale_id.language_id.script);
append_sep_and_string(locale_id.language_id.region);
for (auto const& variant : locale_id.language_id.variants)
append_sep_and_string(variant);
auto append_key_value_list = [&](auto const& key, auto& values) {
append_sep_and_string(key);
for (auto& value : values)
append_sep_and_string(value);
};
for (auto const& extension : locale_id.extensions) {
extension.visit(
[&](LocaleExtension const& ext) {
builder.append("-u"sv);
for (auto const& attribute : ext.attributes)
append_sep_and_string(attribute);
for (auto const& keyword : ext.keywords)
append_key_value_list(keyword.key, keyword.types, true);
append_key_value_list(keyword.key, keyword.types);
},
[&](TransformedExtension& ext) {
quick_sort(ext.fields, [](auto const& a, auto const& b) { return a.key < b.key; });
[&](TransformedExtension const& ext) {
builder.append("-t"sv);
if (ext.language.has_value()) {
append_sep_and_string(ext.language->language);
append_sep_and_string(ext.language->script);
append_sep_and_string(ext.language->region);
quick_sort(ext.language->variants);
for (auto const& variant : ext.language->variants)
append_sep_and_string(variant);
}
for (auto const& field : ext.fields)
append_key_value_list(field.key, field.values, false);
append_key_value_list(field.key, field.values);
},
[&](OtherExtension& ext) {
[&](OtherExtension const& ext) {
builder.appendff("-{:c}", to_ascii_lowercase(ext.key));
for (auto const& value : ext.values)
append_sep_and_string(value);