[bug#45762] [PATCH 3/3] ocaml: Add ocaml-down * gnu/packages/ocaml.scm (ocaml-down): New variable.

[aecepoglu <aecepoglu@fastmail.fm>]

---
 gnu/packages/ocaml.scm | 56 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/gnu/packages/ocaml.scm b/gnu/packages/ocaml.scm
index 00978fa138..300bfceadd 100644
--- a/gnu/packages/ocaml.scm
+++ b/gnu/packages/ocaml.scm
@@ -391,6 +391,62 @@ repository-wide uninstallability checks.")
     ;; with static-linking exception
     (license license:lgpl2.1+)))
 
+(define-public ocaml-down
+  (package
+    (name "ocaml-down")
+    (version "0.0.3")
+    (source
+      (origin
+        (method url-fetch)
+        (uri "https://erratique.ch/software/down/releases/down-0.0.3.tbz")
+        (sha256
+          (base32
+            "1nz2f5j17frgr2vrslcz9klmi6w9sm2vqwwwpi33ngcm3rgmsrlg"))))
+    (build-system ocaml-build-system)
+    (arguments
+     `(#:tests? #f ;no tests
+       #:phases (modify-phases %standard-phases
+                               (delete 'configure))
+       #:build-flags (list "build"
+                           "--lib-dir" (string-append (assoc-ref %outputs "out")
+                                                      "/lib/ocaml/site-lib"))))
+    (native-inputs
+     `(("ocaml-findlib" ,ocaml-findlib)
+       ("ocamlbuild" ,ocamlbuild)
+       ("ocaml-topkg" ,ocaml-topkg)
+       ("opam" ,opam)))
+    (home-page "https://erratique.ch/software/down")
+    (synopsis "OCaml toplevel (REPL) upgrade")
+    (description
+      "Down is an unintrusive user experience upgrade for the `ocaml`
+toplevel (REPL). 
+
+Simply load the zero dependency `down` library in the `ocaml` toplevel
+and you get line edition, history, session support and identifier
+completion and documentation `ocp-index`.
+
+Add this to your `~/.ocamlinit`:
+
+    #use \"down.top\"
+
+You may also need to add this to your `~/.ocamlinit` and declare
+the environment variable OCAML_TOPLEVEL_PATH
+
+    let () =
+      try Topdirs.dir_directory (Sys.getenv \"OCAML_TOPLEVEL_PATH\")
+      with Not_found -> ()
+
+OR
+
+    let () = String.split_on_char ':' (Sys.getenv \"OCAMLPATH\")
+             |> List.filter (fun x -> Filename.check_suffix x \"/site-lib\")
+             |> List.map (fun x -> x ^ \"/toplevel\")
+             (* remove the line below if you don't want to see the text
+                every time you start the toplevel *)
+             |> List.map (fun x -> Printf.printf \"adding directory %s\\n\" x; x)
+             |> List.iter Topdirs.dir_directory;;")
+    (license license:isc)))
+
 (define-public ocaml-opam-file-format
   (package
     (name "ocaml-opam-file-format")
-- 
2.29.2