command line interface clean-up

src/Microsoft.DotNet.Cli.Utils/CommandContext.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Microsoft.DotNet.Cli.Utils
+{
+    internal static class CommandContext
+    {
+        internal static class Variables
+        {
+            private static readonly string Prefix = "DOTNET_CLI_CONTEXT_";
+            internal static readonly string Verbose = Prefix + "VERBOSE";
+            internal static readonly string AnsiPassThru = Prefix + "ANSI_PASS_THRU";
+        }
+
+        private static Lazy<bool> _verbose = new Lazy<bool>(() => GetBool(Variables.Verbose));
+        private static Lazy<bool> _ansiPassThru = new Lazy<bool>(() => GetBool(Variables.AnsiPassThru));
+
+        public static bool IsVerbose()
+        {
+            return _verbose.Value;
+        }
+
+        public static bool ShouldPassAnsiCodesThrough()
+        {
+            return _ansiPassThru.Value;
+        }
+        
+        private static bool GetBool(string name, bool defaultValue = false)
+        {
+            var str = Environment.GetEnvironmentVariable(name);
+            bool value;
+            if(string.IsNullOrEmpty(str) || !bool.TryParse(str, out value))
+            {
+                return defaultValue;
+            }
+            return value;
+        }
+    }
+}