Ukrainian language features

ext/js/language/language-descriptors.js

@@ -64,6 +64,8 @@ import {addSerboCroatianDiacritics, removeSerboCroatianAccentMarks} from './sh/s
 import {albanianTransforms} from './sq/albanian-transforms.js';
 import {capitalizeFirstLetter, decapitalize, removeAlphabeticDiacritics} from './text-processors.js';
 import {tagalogTransforms} from './tl/tagalog-transforms.js';
+import {removeUkrainianDiacritics, ukrainianApostropheVariants} from './uk/ukrainian-text-preprocessors.js';
+import {ukrainianTransforms} from './uk/ukrainian-transforms.js';
 import {normalizeDiacritics} from './vi/viet-text-preprocessors.js';
 import {convertFinalLetters, convertYiddishLigatures} from './yi/yiddish-text-postprocessors.js';
 import {combineYiddishLigatures, removeYiddishDiacritics} from './yi/yiddish-text-preprocessors.js';
@@ -551,7 +553,12 @@ const languageDescriptors = [
         iso639_3: 'ukr',
         name: 'Ukrainian',
         exampleText: 'читати',
-        textPreprocessors: capitalizationPreprocessors,
+        textPreprocessors: {
+            ...capitalizationPreprocessors,
+            removeUkrainianDiacritics,
+            ukrainianApostropheVariants,
+        },
+        languageTransforms: ukrainianTransforms,
     },
     {
         iso: 'vi',

ext/js/language/uk/ukrainian-text-preprocessors.js

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2026  Yomitan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/**
+ * Ukrainian uses several visually similar characters for the apostrophe which separates a labial
+ * consonant from a following iotated vowel, as in "п'ять". Dictionaries and the text they are
+ * scanned against rarely agree on which one to use, so all of them are treated as equivalent.
+ */
+const apostropheVariantsRegExp = /['‘’ʼ`´]/g;
+
+/**
+ * Dictionary terms are indexed exactly as the dictionary spells them, so a variant has to be
+ * produced for every character an entry might realistically be stored with, not just for the one
+ * the scanned text happens to use. These three all occur as headword spellings in practice.
+ */
+const apostropheNormalizations = ['\'', '’', 'ʼ'];
+
+/** @type {import('language').TextProcessor} */
+export const removeUkrainianDiacritics = {
+    name: 'Remove diacritics',
+    description: 'Á → A, á → a',
+    process: (str) => [str, str.replace(/́/g, '')],
+};
+
+/** @type {import('language').TextProcessor} */
+export const ukrainianApostropheVariants = {
+    name: 'Search for apostrophe variants',
+    description: '’ → \', ʼ → \' and vice versa',
+    process: (str) => [
+        str,
+        ...apostropheNormalizations.map((apostrophe) => str.replace(apostropheVariantsRegExp, apostrophe)),
+    ],
+};