For fun, I did the same for OCaml:

Ex 1

    let say = "I love OCaml"
    let () = print_endline say

    (* Requires linking in the 'str' library *)
    let say = Str.replace_first (Str.regexp {|\(.*\)love\(.*\)|}) {|\1*love*\2|} say;;
    let () = print_endline (String.uppercase_ascii say)

    let () = ignore |> Seq.init 5 |> Seq.iter (fun () -> print_endline say)

Ex 2

    module StringSet = Set.Make(String)

    let cities = StringSet.of_list [
      "London";
      "Oslo";
      "Paris";
      "Amsterdam";
      "Berlin";
    ]
    let visited = StringSet.of_list ["Berlin"; "Oslo"]

    (* Requires the 'fmt' library *)
    let string_set fmt v = Fmt.Dump.list Fmt.string fmt (StringSet.to_list v)

    let () =
      Format.printf "I still need to visit the following cities: %a\n"
        string_set
        (StringSet.diff cities visited)

Ex 3

  module Greeter : sig
    type t

    val make : string -> t
    val salute : t -> unit
  end = struct
    type t = { name : string }

    let make name = { name = String.uppercase_ascii name }
    let salute t = Format.printf "Hello %s\n" t.name
  end

  let g = Greeter.make "world"
  let () = Greeter.salute g

Obviously, OCaml is a much lower-level language than Ruby or Raku–notably, regex support is not as great, and we have to explicitly tell it how to print values of custom types. Still, I find its lack of syntax sugar makes it easy to read nearly any OCaml code I come across in the wild!