{$mode objfpc}{$H+}{$J-}

uses Classes;

type
  TMyMethod = function (const A, B: Integer): Integer of object;

  TMyClass = class(TComponent)
    class function Add(const A, B: Integer): Integer; virtual;
    class procedure AddHelper; virtual;
  end;

  TMyClass2 = class(TMyClass)
    class function Add(const A, B: Integer): Integer; override;
    class procedure AddHelper; override;
  end;

class function TMyClass.Add(const A, B: Integer): Integer;
begin
  Writeln('Doing TMyClass.Add');
  Result := A + B;
  AddHelper;
end;

class procedure TMyClass.AddHelper;
begin
  Writeln('Doing TMyClass.AddHelper');
  Writeln(Self.ClassName);
end;

class function TMyClass2.Add(const A, B: Integer): Integer;
begin
  Writeln('Doing TMyClass2.Add');
  Result := A + B;
  AddHelper;
end;

class procedure TMyClass2.AddHelper;
begin
  Writeln('Doing TMyClass2.AddHelper');
  Writeln(Self.ClassName);
end;

var
  M: TMyMethod;
begin
  M := @TMyClass.Add;
  Writeln(M(10, 20));
  M := @TMyClass2.Add;
  Writeln(M(10, 20));
end.