(** Configuration of the opam hooks (the three wrapper fields in
    [~/.opam/config]). Changes are applied with the user's own [opam option],
    never by writing the config file directly, so the file always matches the
    opam version that owns it. *)

val fields : exe:string -> (string * string * string) list
(** The wrapper fields, the command to append to each, and a substring
    identifying our command if already present. The per-package hooks are plain
    coreutils ([mkdir]/[touch]/[rm]) so they work without odd installed;
    only the post-session worker invokes the binary at [exe]. *)

val print : exe:string -> unit
(** Print the [opam option] invocations that {!apply} would run. *)

val apply : exe:string -> (unit, [ `Msg of string ]) result
(** Run them, skipping any field that already mentions [exe]. *)