Troubleshooting Compilation Error with lwt_ppx in OCaml: Unable to Compile File

I'm encountering an issue while using lwt_ppx and the let%lwt syntax as described in the CS3110 textbook's section on promises (https://cs3110.github.io/textbook/chapters/ds/promises.html).

In the code snippet provided:

open Lwt_iolet p =  let%lwt s1 = read_line stdin in  let%lwt s2 = read_line stdin in  Lwt_io.printf "%s\n" (s1^s2)let _ = Lwt_main.run p

I'm trying to compile the code using dune. My dune file looks like this:

(executable (name main) (libraries lwt.unix lwt_ppx))

However, when I run the command dune exec ./main.exe, I'm getting the error message "Uninterpreted extension 'lwt'."

I've verified that I have the lwt_ppx package installed using opam list, and interestingly, the code works as expected in utop when I run:

#require "lwt_ppx";;#require "lwt.unix";;#use "main.ml";;

What might I be doing wrong with my dune configuration? Any help would be greatly appreciated.