Mettre en couleur les tag HTML dans un TRichedit

procedure HTMLSyntax(RichEdit: TRichEdit; TextCol, TagCol, DopCol: TColor);
var
i, iDop: Integer;
s: string;
Col: TColor;
isTag, isDop: Boolean;
begin
iDop := 0;
isDop := False;
isTag := False;
Col := TextCol;
RichEdit.SetFocus;

for i := 0 to Length(RichEdit.Text) do
begin
RichEdit.SelStart := i;
RichEdit.SelLength := 1;
s := RichEdit.SelText;

if (s = '<') or (s = '{') then isTag := True;

if isTag then
if (s = '"') then
if not isDop then
begin
iDop := 1;
isDop := True;
end
else
isDop := False;

if isTag then
if isDop then
begin
if iDop <> 1 then Col := DopCol;
end
else
Col := TagCol
else
Col := TextCol;
RichEdit.SelAttributes.Color := Col;
iDop := 0;
if (s = '>') or (s = '}') then isTag := False;
end;
RichEdit.SelLength := 0;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
RichEdit1.Lines.BeginUpdate;
HTMLSyntax(RichEdit1, clBlue, clRed, clGreen);
RichEdit1.Lines.EndUpdate;
end;