anchor.diff:      public
         procedure LoadFromFile(path:string);
         procedure SaveToFile(path:string);
  +      procedure LoadFromStrings( strings : TStrings );
  +      function ToStrings : TStrings;
  +      function ToString : string; override;
       public
  +      procedure Clear;
         function  GetLength : cardinal; override;
         function  GetLine(i:cardinal) : string; override;
         procedure SetLine(i:cardinal; s:string); override;
  
positive.code:   type GSpan<t> = class
      public type
        tag = class( anchor )
  	public
            is_start, is_end : boolean;
            span		 : GSpan<T>;
          end;
      public
        start_tag, end_tag : tag;
  
negative.code:       procedure DelLine(i:cardinal); override;
        property length : cardinal read GetLength;
        property lines[i:cardinal]:string
          read GetLine write SetLine; default;
        property strings : TStrings read ToStrings write LoadFromStrings;
      end;
  
  