Add text prompt support

src/Spectre.Console/Extensions/AnsiConsoleExtensions.Input.cs

@@ -0,0 +1,49 @@
+using System;
+
+namespace Spectre.Console
+{
+    /// <summary>
+    /// Contains extension methods for <see cref="IAnsiConsole"/>.
+    /// </summary>
+    public static partial class AnsiConsoleExtensions
+    {
+        internal static string ReadLine(this IAnsiConsole console, Style? style, bool secret)
+        {
+            if (console is null)
+            {
+                throw new ArgumentNullException(nameof(console));
+            }
+
+            style ??= Style.Plain;
+
+            var result = string.Empty;
+            while (true)
+            {
+                var key = console.Input.ReadKey(true);
+
+                if (key.Key == ConsoleKey.Enter)
+                {
+                    return result;
+                }
+
+                if (key.Key == ConsoleKey.Backspace)
+                {
+                    if (result.Length > 0)
+                    {
+                        result = result.Substring(0, result.Length - 1);
+                        console.Write("\b \b");
+                    }
+
+                    continue;
+                }
+
+                result += key.KeyChar.ToString();
+
+                if (!char.IsControl(key.KeyChar))
+                {
+                    console.Write(secret ? "*" : key.KeyChar.ToString(), style);
+                }
+            }
+        }
+    }
+}