Add calendar control

Closes #101

src/Spectre.Console/Extensions/HasCultureExtensions.cs

@@ -0,0 +1,73 @@
+using System;
+using System.Globalization;
+
+namespace Spectre.Console
+{
+    /// <summary>
+    /// Contains extension methods for <see cref="IHasCulture"/>.
+    /// </summary>
+    public static class HasCultureExtensions
+    {
+        /// <summary>
+        /// Sets the culture.
+        /// </summary>
+        /// <typeparam name="T">An object type with a culture.</typeparam>
+        /// <param name="obj">The object to set the culture for.</param>
+        /// <param name="culture">The culture to set.</param>
+        /// <returns>The same instance so that multiple calls can be chained.</returns>
+        public static T SetCulture<T>(this T obj, CultureInfo culture)
+            where T : class, IHasCulture
+        {
+            if (obj is null)
+            {
+                throw new ArgumentNullException(nameof(obj));
+            }
+
+            if (culture is null)
+            {
+                throw new ArgumentNullException(nameof(culture));
+            }
+
+            obj.Culture = culture;
+            return obj;
+        }
+
+        /// <summary>
+        /// Sets the culture.
+        /// </summary>
+        /// <typeparam name="T">An object type with a culture.</typeparam>
+        /// <param name="obj">The object to set the culture for.</param>
+        /// <param name="name">The culture to set.</param>
+        /// <returns>The same instance so that multiple calls can be chained.</returns>
+        public static T SetCulture<T>(this T obj, string name)
+            where T : class, IHasCulture
+        {
+            if (obj is null)
+            {
+                throw new ArgumentNullException(nameof(obj));
+            }
+
+            obj.Culture = CultureInfo.GetCultureInfo(name);
+            return obj;
+        }
+
+        /// <summary>
+        /// Sets the culture.
+        /// </summary>
+        /// <typeparam name="T">An object type with a culture.</typeparam>
+        /// <param name="obj">The object to set the culture for.</param>
+        /// <param name="name">The culture to set.</param>
+        /// <returns>The same instance so that multiple calls can be chained.</returns>
+        public static T SetCulture<T>(this T obj, int name)
+            where T : class, IHasCulture
+        {
+            if (obj is null)
+            {
+                throw new ArgumentNullException(nameof(obj));
+            }
+
+            obj.Culture = CultureInfo.GetCultureInfo(name);
+            return obj;
+        }
+    }
+}