TDataValue as new global variant type

Src/Data/Myc.Data.Value.pas

@@ -0,0 +1,208 @@
+unit Myc.Data.Value;
+
+interface
+
+uses
+    System.SysUtils,
+    Myc.Data.Scalar,
+    Myc.Data.Series,
+    Myc.Data.Decimal;
+
+type
+    TDataValueKind = (vkVoid, vkScalar, vkCallable, vkText, vkSeries, vkRecordSeries, vkRecord, vkMemberSeries);
+
+    TDataValue = record
+    public
+        type
+            ICallable = interface
+                function GetArity: Integer;
+                function Invoke(const AVisitor: IInterface; const ASelf: TDataValue; const AArgs: TArray<TDataValue>): TDataValue;
+                property Arity: Integer read GetArity;
+            end;
+
+            TVal<T> = class(TInterfacedObject)
+                Value: T;
+                constructor Create(const AValue: T);
+            end;
+
+    private
+        var
+            FKind: TDataValueKind;
+            FScalar: TScalar;
+            FInterface: IInterface;
+        function GetKind: TDataValueKind; inline;
+        function GetIsVoid: Boolean; inline;
+    public
+        class operator Initialize(out Dest: TDataValue);
+        class function Void: TDataValue; inline; static;
+
+        class operator Implicit(const AValue: TScalar): TDataValue; overload; inline;
+        class operator Implicit(const AValue: ICallable): TDataValue; overload; inline;
+        class operator Implicit(const AValue: String): TDataValue; overload; inline;
+
+        class function FromSeries(const [ref] AValue: TScalarSeries): TDataValue; static; inline;
+        class function FromRecordSeries(const [ref] AValue: TScalarRecordSeries): TDataValue; static; inline;
+        class function FromRecord(const [ref] AValue: TScalarRecord): TDataValue; static; inline;
+        class function FromMemberSeries(const [ref] AValue: TScalarMemberSeries): TDataValue; static; inline;
+
+        function AsScalar: TScalar; inline;
+        function AsCallable: ICallable; inline;
+        function AsText: String; inline;
+        function AsRecordSeries: TVal<TScalarRecordSeries>; inline;
+        function AsRecord: TVal<TScalarRecord>; inline;
+        function AsMemberSeries: TVal<TScalarMemberSeries>; inline;
+        function AsSeries: TVal<TScalarSeries>; inline;
+
+        function ToString: String;
+        property IsVoid: Boolean read GetIsVoid;
+        property Kind: TDataValueKind read GetKind;
+    end;
+
+implementation
+
+{ TDataValue.TVal<T> }
+
+constructor TDataValue.TVal<T>.Create(const AValue: T);
+begin
+    inherited Create;
+    Value := AValue;
+end;
+
+{ TDataValue }
+
+class operator TDataValue.Initialize(out Dest: TDataValue);
+begin
+    Dest.FKind := vkVoid; // Geändert
+    Dest.FInterface := nil;
+end;
+
+function TDataValue.AsCallable: ICallable;
+begin
+    if (FKind <> vkCallable) then
+        raise EInvalidCast.Create('Cannot read value as a Callable.');
+    Result := ICallable(FInterface);
+end;
+
+function TDataValue.AsMemberSeries: TVal<TScalarMemberSeries>;
+begin
+    if (FKind <> vkMemberSeries) then
+        raise EInvalidCast.Create('Cannot read value as MemberSeries.');
+    Result := TVal<TScalarMemberSeries>(FInterface);
+end;
+
+function TDataValue.AsRecord: TVal<TScalarRecord>;
+begin
+    if (FKind <> vkRecord) then
+        raise EInvalidCast.Create('Cannot read value as Record.');
+    Result := (FInterface as TVal<TScalarRecord>);
+end;
+
+function TDataValue.AsRecordSeries: TVal<TScalarRecordSeries>;
+begin
+    if (FKind <> vkRecordSeries) then
+        raise EInvalidCast.Create('Cannot read value as RecordSeries.');
+    Result := TVal<TScalarRecordSeries>(FInterface);
+end;
+
+function TDataValue.AsScalar: TScalar;
+begin
+    if (FKind <> vkScalar) then
+        raise EInvalidCast.Create('Cannot read value as a Scalar.');
+    Result := FScalar;
+end;
+
+function TDataValue.AsSeries: TVal<TScalarSeries>;
+begin
+    if (FKind <> vkSeries) then
+        raise EInvalidCast.Create('Cannot read value as Series.');
+    Result := TVal<TScalarSeries>(FInterface);
+end;
+
+function TDataValue.AsText: String;
+begin
+    if (FKind <> vkText) then
+        raise EInvalidCast.Create('Cannot read value as Text.');
+    Result := (FInterface as TVal<String>).Value;
+end;
+
+class function TDataValue.FromMemberSeries(const [ref] AValue: TScalarMemberSeries): TDataValue;
+begin
+    Result.FKind := vkMemberSeries;
+    Result.FInterface := TVal<TScalarMemberSeries>.Create(AValue);
+    Result.FScalar := Default(TScalar);
+end;
+
+class function TDataValue.FromRecord(const [ref] AValue: TScalarRecord): TDataValue;
+begin
+    Result.FKind := vkRecord;
+    Result.FInterface := TVal<TScalarRecord>.Create(AValue);
+    Result.FScalar := Default(TScalar);
+end;
+
+class function TDataValue.FromRecordSeries(const [ref] AValue: TScalarRecordSeries): TDataValue;
+begin
+    Result.FKind := vkRecordSeries;
+    Result.FInterface := TVal<TScalarRecordSeries>.Create(AValue);
+    Result.FScalar := Default(TScalar);
+end;
+
+class function TDataValue.FromSeries(const [ref] AValue: TScalarSeries): TDataValue;
+begin
+    Result.FKind := vkSeries;
+    Result.FInterface := TVal<TScalarSeries>.Create(AValue);
+    Result.FScalar := Default(TScalar);
+end;
+
+class operator TDataValue.Implicit(const AValue: ICallable): TDataValue;
+begin
+    Result.FKind := vkCallable;
+    Result.FInterface := AValue;
+    Result.FScalar := Default(TScalar);
+end;
+
+class operator TDataValue.Implicit(const AValue: TScalar): TDataValue;
+begin
+    Result.FKind := vkScalar;
+    Result.FScalar := AValue;
+    Result.FInterface := nil;
+end;
+
+class operator TDataValue.Implicit(const AValue: String): TDataValue;
+begin
+    Result.FKind := vkText;
+    Result.FInterface := TVal<String>.Create(AValue);
+    Result.FScalar := Default(TScalar);
+end;
+
+function TDataValue.GetIsVoid: Boolean;
+begin
+    Result := FKind = vkVoid; // Geändert
+end;
+
+function TDataValue.GetKind: TDataValueKind;
+begin
+    Result := FKind;
+end;
+
+function TDataValue.ToString: String;
+begin
+    case FKind of
+        vkScalar: Result := FScalar.ToString;
+        vkCallable: Result := '<callable>';
+        vkText: Result := AsText;
+        vkSeries: Result := '<series>';
+        vkRecordSeries: Result := '<record_series>';
+        vkRecord: Result := '<record>';
+        vkMemberSeries: Result := '<member_series>';
+        vkVoid: Result := '<void>'; // Geändert
+    else
+        Result := '[Unknown DataValue]';
+    end;
+end;
+
+class function TDataValue.Void: TDataValue;
+begin
+    Result := Default(TDataValue);
+end;
+
+end.