undo DvBool.

Author: codemzs

src/Microsoft.ML.Core/Data/ColumnType.cs

@@ -624,17 +624,6 @@ public static BoolType Instance
             }
         }
 
-        private static volatile BoolType _ninstance;
-        public static BoolType NInstance
-        {
-            get
-            {
-                if (_ninstance == null)
-                    Interlocked.CompareExchange(ref _ninstance, new BoolType(DataKind.NBL, "NBool"), null);
-                return _ninstance;
-            }
-        }
-
         private readonly string _name;
 
         private BoolType(DataKind kind, string name)

src/Microsoft.ML.Core/Data/DataKind.cs

@@ -50,10 +50,7 @@ public enum DataKind : byte
         NI1 = 17,
         NI2 = 18,
         NI4 = 19,
-        NI8 = 20,
-#pragma warning disable MSML_GeneralName
-        NBL = 21,
-#pragma warning restore MSML_GeneralName
+        NI8 = 20
     }
 
     /// <summary>
@@ -62,7 +59,7 @@ public enum DataKind : byte
     public static class DataKindExtensions
     {
         public const DataKind KindMin = DataKind.I1;
-        public const DataKind KindLim = DataKind.NBL + 1;
+        public const DataKind KindLim = DataKind.NI8 + 1;
         public const int KindCount = KindLim - KindMin;
 
         /// <summary>
@@ -186,9 +183,7 @@ public static Type ToType(this DataKind kind)
                 case DataKind.TX:
                     return typeof(DvText);
                 case DataKind.BL:
-                    return typeof(bool);
-                case DataKind.NBL:
-                    return typeof(bool?);
+                    return typeof(DvBool);
                 case DataKind.TS:
                     return typeof(DvTimeSpan);
                 case DataKind.DT:
@@ -240,10 +235,8 @@ public static bool TryGetDataKind(this Type type, out DataKind kind)
                 kind = DataKind.R8;
             else if (type == typeof(DvText))
                 kind = DataKind.TX;
-            else if (type == typeof(bool))
+            else if (type == typeof(bool) || type == typeof(bool?))
                 kind = DataKind.BL;
-            else if (type == typeof(bool?))
-                kind = DataKind.NBL;
             else if (type == typeof(DvTimeSpan))
                 kind = DataKind.TS;
             else if (type == typeof(DvDateTime))
@@ -299,8 +292,6 @@ public static string GetString(this DataKind kind)
                     return "R8";
                 case DataKind.BL:
                     return "BL";
-                case DataKind.NBL:
-                    return "NBL";
                 case DataKind.TX:
                     return "TX";
                 case DataKind.TS: