Set up locales

core/src/main/kotlin/eu/iamgio/quarkdown/document/locale/JVMLocale.kt

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+package eu.iamgio.quarkdown.document.locale
+
+/**
+ * [Locale] implementation using [java.util.Locale].
+ */
+internal class JVMLocale(private val jvmLocale: java.util.Locale) : Locale {
+    override val code: String
+        get() = jvmLocale.language
+
+    override val countryCode: String?
+        get() = jvmLocale.country.takeIf { it.isNotBlank() }
+
+    override val localizedName: String
+        get() = jvmLocale.getDisplayLanguage(jvmLocale)
+
+    override val localizedCountryName: String?
+        get() = jvmLocale.getDisplayCountry(jvmLocale).takeIf { it.isNotBlank() }
+}

core/src/main/kotlin/eu/iamgio/quarkdown/document/locale/JVMLocaleLoader.kt

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+package eu.iamgio.quarkdown.document.locale
+
+/**
+ * Loader of [JVMLocale]s.
+ */
+internal object JVMLocaleLoader : LocaleLoader {
+    override val all: Iterable<Locale>
+        get() = java.util.Locale.getAvailableLocales().map(::JVMLocale)
+
+    override fun fromTag(tag: String): Locale? =
+        java.util.Locale.forLanguageTag(tag)
+            ?.let(::JVMLocale)
+            ?.takeIf { it.code.isNotBlank() }
+}

core/src/main/kotlin/eu/iamgio/quarkdown/document/locale/Locale.kt

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+package eu.iamgio.quarkdown.document.locale
+
+/**
+ * Represents a locale, which defines the document language.
+ */
+interface Locale {
+    /**
+     * Language code of the locale.
+     * For instance, `en` for English and `it` for Italian.
+     */
+    val code: String
+
+    /**
+     * Country code of the locale.
+     */
+    val countryCode: String?
+
+    /**
+     * Name of the locale, possibly in the locale's language itself.
+     * For instance, `English` for English and `italiano` for Italian.
+     */
+    val localizedName: String
+
+    /**
+     * Name of the country of the locale, possibly in the locale's language itself.
+     * For instance, `United States` for `en-US` and `Italia` for `it`.
+     */
+    val localizedCountryName: String?
+}

core/src/main/kotlin/eu/iamgio/quarkdown/document/locale/LocaleLoader.kt

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+package eu.iamgio.quarkdown.document.locale
+
+/**
+ * Loader of [Locale]s.
+ */
+interface LocaleLoader {
+    /**
+     * All available locales.
+     */
+    val all: Iterable<Locale>
+
+    /**
+     * @param tag language code of the locale and optionally the country code, separated by a hyphen.
+     *            Example: `en`, `en-US`, `it`, `fr-CA`
+     * @return [Locale] with the given tag, or `null` if not found
+     */
+    fun fromTag(tag: String): Locale?
+}

core/src/test/kotlin/eu/iamgio/quarkdown/MiscTest.kt

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+package eu.iamgio.quarkdown
+
+import eu.iamgio.quarkdown.document.locale.JVMLocaleLoader
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import kotlin.test.Test
+import kotlin.test.assertNotNull
+import kotlin.test.assertNull
+
+/**
+ * Tests for miscellaneous classes.
+ */
+class MiscTest {
+    @Test
+    fun locale() {
+        val retriever = JVMLocaleLoader
+
+        with(retriever.fromTag("en")) {
+            assertNotNull(this)
+            assertEquals("en", code)
+            assertEquals("English", localizedName)
+            assertNull(countryCode)
+            assertNull(localizedCountryName)
+        }
+
+        with(retriever.fromTag("it")) {
+            assertNotNull(this)
+            assertEquals("it", code)
+            assertEquals("italiano", localizedName)
+            assertNull(countryCode)
+            assertNull(localizedCountryName)
+        }
+
+        with(retriever.fromTag("en-US")) {
+            assertNotNull(this)
+            assertEquals("en", code)
+            assertEquals("English", localizedName)
+            assertEquals("US", countryCode)
+            assertEquals("United States", localizedCountryName)
+        }
+
+        with(retriever.fromTag("fr-CA")) {
+            assertNotNull(this)
+            assertEquals("fr", code)
+            assertEquals("français", localizedName)
+            assertEquals("CA", countryCode)
+            assertEquals("Canada", localizedCountryName)
+        }
+
+        assertNull(retriever.fromTag("nonexistent"))
+
+        assertTrue(retriever.all.iterator().hasNext())
+    }
+}