Data Types

Src/Data/Myc.Data.Types.pas

@@ -7,7 +7,7 @@ uses
     System.SysUtils;
 
 type
-    TDataKind = (dkOrdinal, dkFloat, dkText, dkTimestamp, dkRecord, dkTuple, dkArray);
+    TDataKind = (dkOrdinal, dkFloat, dkText, dkTimestamp, dkRecord, dkTuple, dkArray, dkEnum);
 
     IDataType = interface
         function GetName: String;
@@ -18,7 +18,9 @@ type
 
     IDataValue = interface
         function GetDataType: IDataType;
+        function GetAsString: string;
         property DataType: IDataType read GetDataType;
+        property AsString: string read GetAsString;
     end;
 
     IDataOrdinalValue = interface(IDataValue)
@@ -57,6 +59,21 @@ type
         function CreateValue(const AValue: TDateTime): IDataTimestampValue;
     end;
 
+    IDataEnumValue = interface(IDataValue)
+        function GetValue: Integer;
+        property Value: Integer read GetValue;
+    end;
+
+    IDataEnumType = interface(IDataType)
+        function GetIdentifier(Idx: Integer): string;
+        function GetIdentifierCount: Integer;
+        function IndexOf(const AIdentifier: string): Integer;
+        function CreateValue(const AValue: Integer): IDataEnumValue; overload;
+        function CreateValue(const AIdentifier: string): IDataEnumValue; overload;
+        property IdentifierCount: Integer read GetIdentifierCount;
+        property Identifiers[Idx: Integer]: string read GetIdentifier; default;
+    end;
+
     IDataRecordValue = interface(IDataValue)
         function GetItem(Idx: Integer): IDataValue;
         property Items[Idx: Integer]: IDataValue read GetItem; default;
@@ -127,6 +144,7 @@ type
         class function ArrayOfType(const AElementType: IDataType): IDataArrayType; static;
         class function RecordOf(const Fields: TArray<TRecordField>): IDataRecordType; overload; static;
         class function RecordOf(const Fields: array of TRecordField): IDataRecordType; overload; static;
+        class function EnumOf(const AName: string; const AIdentifiers: array of string): IDataEnumType; static;
 
         property DataType: IDataType read FDataType;
         property Name: String read GetName;
@@ -147,6 +165,7 @@ type
         function AsRecord: IDataRecordValue;
         function AsTuple: IDataTupleValue;
         function AsArray: IDataArrayValue;
+        function AsEnum: IDataEnumValue;
 
         class operator Implicit(const A: IDataValue): TDataValue; overload;
         class operator Implicit(const A: TDataValue): IDataValue; overload;
@@ -173,7 +192,8 @@ uses
     Myc.Data.Types.Timestamp,
     Myc.Data.Types.Arrays,
     Myc.Data.Types.Records,
-    Myc.Data.Types.Tuple;
+    Myc.Data.Types.Tuple,
+    Myc.Data.Types.Enum;
 
 { TRecordField }
 
@@ -262,6 +282,11 @@ begin
     Result := RecordOf(tFields);
 end;
 
+class function TDataType.EnumOf(const AName: string; const AIdentifiers: array of string): IDataEnumType;
+begin
+    Result := TImplDataEnumType.Create(AName, AIdentifiers);
+end;
+
 class function TDataType.Text: IDataTextType;
 begin
     Result := TImplDataTextType.Singleton;
@@ -343,6 +368,13 @@ begin
     Result := IDataTupleValue(FDataValue);
 end;
 
+function TDataValue.AsEnum: IDataEnumValue;
+begin
+    if FDataValue.DataType.Kind <> dkEnum then
+        raise EInvalidCast.Create('Enum expected');
+    Result := IDataEnumValue(FDataValue);
+end;
+
 class function TDataValue.FromOrdinal(const AValue: Int64): IDataOrdinalValue;
 begin
     Result := TImplDataOrdinalType.Singleton.CreateValue(AValue);