let f ?email ?nick ?password request =

%   begin match email, nick, password with
%   | Some email, Some nick, Some password ->
%     begin match User.register ~email ~nick ~password with
%     | Error e ->
Error: <%s e %>
%     | Ok _ ->
User created !
%     end;
%   | _ ->
    <%s! Dream.form_tag ~action:"/register" request %>
      <div class="mb-3">
        <label for="nick" class="form-label">Nick</label>
        <input name="nick" type="text" class="form-control" id="nick" aria-describedby="nickHelp">
        <div id="nickHelp" class="form-text">Who are u ?</div>
      </div>
      <div class="mb-3">
        <label for="email" class="form-label">Email address</label>
        <input name="email" type="email" class="form-control" id="email" aria-describedby="emailHelp">
        <div id="emailHelp" class="form-text">We'll never share your email with anyone else.</div>
      </div>
      <div class="mb-3">
        <label for="password" class="form-label">Password</label>
        <input name="password" type="password" class="form-control" id="password">
      </div>
      <button type="submit" class="btn btn-primary">Submit</button>
    </form>
%   end;