Refactoring with Class Interceptors and Anonymous Methods

When it comes to database manipulation, there are few tools as convenient and easy to use as Delphi DataSets. Instanciate any TDataset, run a sql query, call the open method and bingo! We have a copy of the records (and a multitude of metadata) in memory, ready to be manipulated.

You may be very familiar with some variation of this code:

procedure Foo;
var
  qry: TSqlQuery;
begin
  qry := TSqlQuery.Create;
  try
    qry.CommandText := 'select some fields from some table';
    qry.Open;
    while not qry.Eof do
    begin
      { some proccessing oncurrent row  }
      qry.Next; 
   end;
   finally
     qry.Close;
     FreeAndNil(qry);
   end;
end;

Simple, isn't?

Yes, but... Well, image maintain a system where there are thousands of functions exactly the same as this, spreaded over hundreds or thousands of units and you will start to feel chills.