(I'm creating an issue for the first part of my Discuss message at https://discuss.ocaml.org/t/combinator-library-for-extracting-data-for-s-exps/10153/7 ) I am using the `Sexplib` parsers ([Sexp.load_sexp](https://ocaml.org/p/sexplib/v0.15.0/doc/Sexplib/Sexp/index.html#val-load_sexp)), which return a value of type [Sexplib.Type.t](https://ocaml.org/p/sexplib/v0.15.0/doc/Sexplib/Type/index.html) which is *not* the same as `Csexp.t` -- they are two identical but incompatible type declarations. I tried to find a parsing function in `Csexp`, but my understanding is that the library only deal with the binary encoding of s-expressions, not their common textual format, so I ended up writing a conversion function by hand. ```ocaml let rec port : Sexplib.Sexp.t -> Csexp.t = function | List items -> List (List.map port items) | Atom s -> Atom s in Sexplib.Sexp.load_sexp tmp |> port ``` Note that `Csexp` itself does not suffer from this issue as it offers a functor parametrized over the sexplib type, so I could call `Csexp.Make(Sexplib.Type)` and get compatible types. Maybe `Sexp_decode` could offer a functorized interface in the same way? (Or maybe `Csexp` and `Sexplib` could agree to share their type definition with a common dependency.)