Add CultureInfo.GetParents() and CultureInfo.GetSelfAndParents() extensions

PowerKit.Tests/CultureInfoExtensionsTests.cs

@@ -0,0 +1,46 @@
+using System.Globalization;
+using FluentAssertions;
+using PowerKit.Extensions;
+using Xunit;
+
+namespace PowerKit.Tests;
+
+public class CultureInfoExtensionsTests
+{
+    [Fact]
+    public void GetParents_Test()
+    {
+        // Act & assert
+        new CultureInfo("en-US")
+            .GetParents()
+            .Should()
+            .Equal(new CultureInfo("en"), CultureInfo.InvariantCulture);
+
+        new CultureInfo("en")
+            .GetParents()
+            .Should()
+            .Equal(CultureInfo.InvariantCulture);
+
+        CultureInfo.InvariantCulture.GetParents().Should().BeEmpty();
+    }
+
+    [Fact]
+    public void GetSelfAndParents_Test()
+    {
+        // Act & assert
+        new CultureInfo("en-US")
+            .GetSelfAndParents()
+            .Should()
+            .Equal(new CultureInfo("en-US"), new CultureInfo("en"), CultureInfo.InvariantCulture);
+
+        new CultureInfo("en")
+            .GetSelfAndParents()
+            .Should()
+            .Equal(new CultureInfo("en"), CultureInfo.InvariantCulture);
+
+        CultureInfo.InvariantCulture
+            .GetSelfAndParents()
+            .Should()
+            .Equal(CultureInfo.InvariantCulture);
+    }
+}

PowerKit/Extensions/CultureInfoExtensions.cs

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+using System.Collections.Generic;
+using System.Globalization;
+
+namespace PowerKit.Extensions;
+
+internal static class CultureInfoExtensions
+{
+    extension(CultureInfo culture)
+    {
+        /// <summary>
+        /// Enumerates the parent cultures of the current culture, from the immediate parent up to
+        /// <see cref="CultureInfo.InvariantCulture" />.
+        /// </summary>
+        public IEnumerable<CultureInfo> GetParents()
+        {
+            var current = culture;
+            while (!current.Equals(current.Parent))
+            {
+                current = current.Parent;
+                yield return current;
+            }
+        }
+
+        /// <summary>
+        /// Enumerates the current culture and its parent cultures, from the current culture up to
+        /// <see cref="CultureInfo.InvariantCulture" />.
+        /// </summary>
+        public IEnumerable<CultureInfo> GetSelfAndParents()
+        {
+            yield return culture;
+            foreach (var parent in culture.GetParents())
+            {
+                yield return parent;
+            }
+        }
+    }
+}