Setting custom prompt in utop with UTop.prompt

Hi,

I'd like to adjust the utop prompt, and am trying to sort out what to
input to utop & place in my ~/.ocamlinit file. It says here:

    https://opam.ocaml.org/blog/about-utop/

    The prompt can be customized by the user, by setting the reference
    UTop.prompt:

        utop # UTop.prompt;;
        - : LTerm_text.t React.signal ref = {contents = <abstr>}

But I'm not sure what to do beyond entering UTop.prompt;; into utop...
following some suggestions here:

    http://irclog.whitequark.org/ocaml/2015-03-19.txt

I tried:

    #require "react";;
    UTop.prompt := React.S.const (LTerm_text.of_string "");;

but got:

    Error: Unbound module LTerm_text

also took a look at this:

    https://twitter.com/keleshev/status/573401484177612800
    UTop.prompt := fst (React.S.create LTerm_text.(eval [B_fg (LTerm_style.green); S "# "])

Which has unbalanced parentheses...not sure what it should be.
Not sure what to make of this either:

    http://stackoverflow.com/questions/6158596/setting-the-prompt-in-an-ocaml-custom-toplevel

I'm just getting started learning OCaml basics, so feeling a bit lost
here...any clarification would be much appreciated.

John

-- 
John Magolske
http://B79.net/contact