TDataValue as new global variant type

Src/Data/Myc.Data.Value.pas

@@ -9,22 +9,15 @@ uses
     Myc.Data.Decimal;
 
 type
-    TDataValueKind = (vkVoid, vkScalar, vkCallable, vkText, vkSeries, vkRecordSeries, vkRecord, vkMemberSeries);
+    TDataValueKind = (vkVoid, vkScalar, vkInterface, vkText, vkSeries, vkRecordSeries, vkRecord, vkMemberSeries, vkGeneric);
 
     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;
@@ -37,8 +30,11 @@ type
         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 operator Implicit(const AValue: IInterface): TDataValue; overload; inline;
+
+        class function From<T: record>(const [ref] AValue: T): TDataValue; static; inline;
+        function AsVal<T: record>: TVal<T>; inline;
 
         class function FromSeries(const [ref] AValue: TScalarSeries): TDataValue; static; inline;
         class function FromRecordSeries(const [ref] AValue: TScalarRecordSeries): TDataValue; static; inline;
@@ -46,13 +42,15 @@ type
         class function FromMemberSeries(const [ref] AValue: TScalarMemberSeries): TDataValue; static; inline;
 
         function AsScalar: TScalar; inline;
-        function AsCallable: ICallable; inline;
+        function AsInterface: IInterface; 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;
 
+        procedure SetVoid;
+
         function ToString: String;
         property IsVoid: Boolean read GetIsVoid;
         property Kind: TDataValueKind read GetKind;
@@ -60,6 +58,9 @@ type
 
 implementation
 
+uses
+    TypInfo;
+
 { TDataValue.TVal<T> }
 
 constructor TDataValue.TVal<T>.Create(const AValue: T);
@@ -72,15 +73,15 @@ end;
 
 class operator TDataValue.Initialize(out Dest: TDataValue);
 begin
-    Dest.FKind := vkVoid; // Geändert
+    Dest.FKind := vkVoid;
     Dest.FInterface := nil;
 end;
 
-function TDataValue.AsCallable: ICallable;
+function TDataValue.AsInterface: IInterface;
 begin
-    if (FKind <> vkCallable) then
-        raise EInvalidCast.Create('Cannot read value as a Callable.');
-    Result := ICallable(FInterface);
+    if (FKind <> vkInterface) then
+        raise EInvalidCast.Create('Cannot read value as an Interface.');
+    Result := FInterface;
 end;
 
 function TDataValue.AsMemberSeries: TVal<TScalarMemberSeries>;
@@ -90,6 +91,13 @@ begin
     Result := TVal<TScalarMemberSeries>(FInterface);
 end;
 
+function TDataValue.AsVal<T>: TVal<T>;
+begin
+    if (FKind <> vkGeneric) then
+        raise EInvalidCast.Create('Cannot read value as ' + PTypeInfo(TypeInfo(T)).Name + '.');
+    Result := TVal<T>(FInterface);
+end;
+
 function TDataValue.AsRecord: TVal<TScalarRecord>;
 begin
     if (FKind <> vkRecord) then
@@ -125,6 +133,12 @@ begin
     Result := (FInterface as TVal<String>).Value;
 end;
 
+class function TDataValue.From<T>(const [ref] AValue: T): TDataValue;
+begin
+    Result.FKind := vkGeneric;
+    Result.FInterface := TVal<T>.Create(AValue);
+end;
+
 class function TDataValue.FromMemberSeries(const [ref] AValue: TScalarMemberSeries): TDataValue;
 begin
     Result.FKind := vkMemberSeries;
@@ -153,9 +167,9 @@ begin
     Result.FScalar := Default(TScalar);
 end;
 
-class operator TDataValue.Implicit(const AValue: ICallable): TDataValue;
+class operator TDataValue.Implicit(const AValue: IInterface): TDataValue;
 begin
-    Result.FKind := vkCallable;
+    Result.FKind := vkInterface;
     Result.FInterface := AValue;
     Result.FScalar := Default(TScalar);
 end;
@@ -176,7 +190,7 @@ end;
 
 function TDataValue.GetIsVoid: Boolean;
 begin
-    Result := FKind = vkVoid; // Geändert
+    Result := FKind = vkVoid;
 end;
 
 function TDataValue.GetKind: TDataValueKind;
@@ -184,17 +198,23 @@ begin
     Result := FKind;
 end;
 
+procedure TDataValue.SetVoid;
+begin
+    FKind := vkVoid;
+    FInterface := nil;
+end;
+
 function TDataValue.ToString: String;
 begin
     case FKind of
         vkScalar: Result := FScalar.ToString;
-        vkCallable: Result := '<callable>';
+        vkInterface: Result := '<interface>';
         vkText: Result := AsText;
         vkSeries: Result := '<series>';
         vkRecordSeries: Result := '<record_series>';
         vkRecord: Result := '<record>';
         vkMemberSeries: Result := '<member_series>';
-        vkVoid: Result := '<void>'; // Geändert
+        vkVoid: Result := '<void>';
     else
         Result := '[Unknown DataValue]';
     end;