anchor.diff:    out CharFrom, CharTo: atChar;
     out Kind: TATEditorBracketKind);
   var
  +  St: TATStrings;
     S: atString;
   begin
     FoundX:= -1;
  
positive.code:   CharFrom:= #0;
    CharTo:= #0;
    Kind:= bracketUnknown;
  
    if PosX<0 then exit;
    if not Ed.Strings.IsIndexValid(PosY) then exit;
  
    S:= Ed.Strings.Lines[PosY];
    if (PosX=Length(S)) and (PosX>0) then
      Dec(PosX);
  
  
negative.code:       if FoundY<0 then exit;
        PosX:= FoundX;
        PosY:= FoundY;
        S:= St.Lines[PosY];
        CharFrom:= S[PosX+1];
        EditorBracket_GetCharKind(CharFrom, Kind, CharTo);
      end;
  