In script can't access item from property of type TArray<Variant>

[Franc_BURDIAN]

The problem is shown in the example below

// Delphi ---------------------------------------
  TMyClass = class
  ...
  public
    ...
    property Names: TArray<Variant> read GetNames write SetNames;
    ...
  end;
  
  TMyUtilsLibrary = class(TatScripterLibrary)
  private
    ...
    procedure _TMyClass_GetNames(M: TatVirtualMachine);
    procedure _TMyClass_SetNames(M: TatVirtualMachine);
    ...
  public
    procedure Init; override;
  end;
  
procedure TMyUtilsLibrary._TMyClass_GetNames(M: TatVirtualMachine);
begin
  M.ReturnOutputArg(TMyClass(M.CurrentObject).Names);
end;

procedure TMyUtilsLibrary._TMyClass_SetNames(M: TatVirtualMachine);
var
  Arg: Variant;
  Names: TArray<Variant>;
  I: Integer;
begin
  Arg := M.GetInputArgAsVariant(0);
  if not VarIsArray(Arg) then
  begin
    SetLength(Names, 1);
    Names[0] := Arg;
  end
  else begin
    SetLength(Names, VarArrayHighBound(Arg, 1) + 1);
    for I := 0 to High(Names)
      Names[I] := Arg[I];
  end;
  TMyClass(M.CurrentObject).Names := Names;
end;

procedure TMyUtilsLibrary.Init;
var
  oClass: TatClass;
begin
  ...
  oClass := Scripter.DefineClassByRTTI(TMyClass);
  oClass.DefineProp('Names', TatTypeKind.tkDynArray, _TMyClass_GetNames, _TMyClass_SetNames);
  ...
end;

// Script ---------------------------------------
procedure Test;
var
  C: TMyClass;
  V: Variant;
begin
  C := TMyClass.Create;
  try
    C.Names := ['A', 'B', 'C'];

    // Compile error: Invalid array indexing for property 'Names'. Expected 0 dimensions. ...
    // ShowMessage(C.Names[1]);
    
    // Workaround
    V := C.Names;
    ShowMessage(V[1]);  // ok, 'B'
  finally
    C.Free;
  end;
end;

How should I define a property to fix this problem?

TIA and best regards

[wlandgraf (Wagner Landgraf)]

Here it how you can implement it:

  TMyUtilsLibrary = class(TatScripterLibrary)
  private
    procedure _TMyClass_GetNames(M: TatVirtualMachine);
    procedure _TMyClass_SetNames(M: TatVirtualMachine);
    procedure _TMyClass_GetNameValue(M: TatVirtualMachine);
    procedure _TMyClass_SetNameValue(M: TatVirtualMachine);
  public
    procedure Init; override;
  end;

...

procedure TMyUtilsLibrary._TMyClass_GetNames(M: TatVirtualMachine);
begin
  M.ReturnOutputArg(TMyClass(M.CurrentObject).Names);
end;

procedure TMyUtilsLibrary._TMyClass_GetNameValue(M: TatVirtualMachine);
begin
  M.ReturnOutputArg(TMyClass(M.CurrentObject).Names[M.GetArrayIndexAsInteger(0)]);
end;

procedure TMyUtilsLibrary._TMyClass_SetNames(M: TatVirtualMachine);
var
  Arg: Variant;
  Names: TArray<Variant>;
  I: Integer;
begin
  Arg := M.GetInputArgAsVariant(0);
  if not VarIsArray(Arg) then
  begin
    SetLength(Names, 1);
    Names[0] := Arg;
  end
  else begin
    SetLength(Names, VarArrayHighBound(Arg, 1) + 1);
    for I := 0 to High(Names) do
      Names[I] := Arg[I];
  end;
  TMyClass(M.CurrentObject).Names := Names;
end;

procedure TMyUtilsLibrary._TMyClass_SetNameValue(M: TatVirtualMachine);
begin
  TMyClass(M.CurrentObject).Names[M.GetArrayIndexAsInteger(0)] :=
    M.GetInputArg(0);
end;

procedure TMyUtilsLibrary.Init;
var
  oClass: TatClass;
begin
  oClass := Scripter.DefineClassByRTTI(TMyClass);
  oClass.DefineProp('Names', TatTypeKind.tkVariant, _TMyClass_GetNameValue,
    _TMyClass_SetNameValue, nil, False, 1);
  oClass.DefineMethod('GetNames', 0, TatTypeKind.tkVariant, nil, _TMyClass_GetNames);
  oClass.DefineMethod('SetNames', 1, TatTypeKind.tkVariant, nil, _TMyClass_SetNames);
end;

Script:

// Script ---------------------------------------
procedure Test;
var
  C: TMyClass;
  V: Variant;
begin
  C := TMyClass.Create;
  try          
    C.SetNames(['A', 'B', 'C']);

    // Compile error: Invalid array indexing for property 'Names'. Expected 0 dimensions. ...
    ShowMessage(C.Names[1]);
    C.Names[1] := 'Z';

    // Workaround
    V := C.GetNames;             
    ShowMessage(V[1]);  // ok, 'B'
  finally
    C.Free;
  end;
end;                                      

[Franc_BURDIAN]

Thanks, the solution to define Names as an indexed property is really smart!
Best regards