function parser(doc, home, eend: string; nacpos: integer = 0; parstype: integer
  = 0): string;
var
  raz: integer;
begin
  if parstype = 0 then
  begin
    if ((trim(home) <> '') and (trim(eend) = '')) then
    begin
      result := copy(doc, posex(home, doc, nacpos) + length(home), length(doc) -
        (posex(home, doc, nacpos) + length(home)) + 1);
    end
    else if ((trim(home) = '') and (trim(eend) <> '')) then
    begin
      result := copy(doc, 1, posex(eend, doc, nacpos) - 1);
    end
    else if ((trim(home) <> '') and (trim(eend) <> '')) then
    begin
      if copy(doc, posex(home, doc, nacpos) + length(home), 1) <> copy(eend, 1,
        1) then
      begin
        raz := posex(eend, doc, posex(home, doc, nacpos) + length(home) + 1) -
          posex(home, doc, nacpos) - length(home);
        result := copy(doc, posex(home, doc, nacpos) + length(home), raz);
      end
      else
        result := '';
    end;
  end
  else if parstype = 1 then
  begin
    if copy(doc, posex(eend, doc, nacpos) + length(eend), 1) <> copy(home, 1, 1) then
    begin
      raz := posex(home, doc, nacpos) - posex(eend, doc, nacpos) - length(eend);
      result := copy(doc, posex(eend, doc, nacpos) + length(eend), raz);
    end
    else
      result := '';
  end;
  exit;
end;