From c41969dc620aa84f3102a201687588c6c278fd19 Mon Sep 17 00:00:00 2001
From: Jeremie Dimino <jdimino@janestreet.com>
Date: Thu, 29 Oct 2015 10:07:28 +0000
Subject: [PATCH] allow to configure the external editor

---
 man/utoprc.5              | 7 +++++++
 src/lib/uTop.cppo.ml      | 5 +++++
 src/lib/uTop.mli          | 5 +++++
 src/lib/uTop_main.cppo.ml | 2 ++
 src/lib/uTop_styles.ml    | 3 +++
 5 files changed, 22 insertions(+)

diff --git a/man/utoprc.5 b/man/utoprc.5
index 5c890ab..609258d 100644
--- a/man/utoprc.5
+++ b/man/utoprc.5
@@ -35,6 +35,13 @@ to disable the autoloading of files in
 .I $OCAML_TOPLEVEL_PATH/autoload
 at startup.
 
+The key
+.I external-editor
+can be set to a command line. It is used to edit the input when
+pressing C-x C-e. It defaults to the contents of the
+.I EDITOR
+environment variable.
+
 The key
 .I profile
 may have the value
diff --git a/src/lib/uTop.cppo.ml b/src/lib/uTop.cppo.ml
index 02cc6c8..3827400 100644
--- a/src/lib/uTop.cppo.ml
+++ b/src/lib/uTop.cppo.ml
@@ -75,6 +75,11 @@ let phrase_terminator, get_phrase_terminator, set_phrase_terminator = make_varia
 let auto_run_lwt, get_auto_run_lwt, set_auto_run_lwt = make_variable true
 let auto_run_async, get_auto_run_async, set_auto_run_async = make_variable true
 let topfind_verbose, get_topfind_verbose, set_topfind_verbose = make_variable false
+let external_editor, get_external_editor, set_external_editor =
+  make_variable
+    (match Sys.getenv "EDITOR" with
+     | exception Not_found -> "vi"
+     | s                   -> s)
 
 (* Ugly hack until the action system of lambda-term is improved *)
 let end_and_accept_current_phrase : LTerm_read_line.action =
diff --git a/src/lib/uTop.mli b/src/lib/uTop.mli
index b7ecfcb..e77f9de 100644
--- a/src/lib/uTop.mli
+++ b/src/lib/uTop.mli
@@ -177,6 +177,11 @@ val end_and_accept_current_phrase : LTerm_read_line.action
      ]}
  *)
 
+(** External editor command. [None] for default. *)
+val external_editor : string signal
+val set_external_editor : string -> unit
+val get_external_editor : unit -> string
+
 (** {6 History} *)
 
 val history : LTerm_history.t
diff --git a/src/lib/uTop_main.cppo.ml b/src/lib/uTop_main.cppo.ml
index 8fe47c1..f613ea7 100644
--- a/src/lib/uTop_main.cppo.ml
+++ b/src/lib/uTop_main.cppo.ml
@@ -146,6 +146,8 @@ class read_phrase ~term = object(self)
   method create_temporary_file_for_external_editor =
     Filename.temp_file "utop" ".ml"
 
+  method external_editor = UTop.get_external_editor ()
+
   val mutable return_value = None
 
   method eval =
diff --git a/src/lib/uTop_styles.ml b/src/lib/uTop_styles.ml
index dcba4b3..2ed77ef 100644
--- a/src/lib/uTop_styles.ml
+++ b/src/lib/uTop_styles.ml
@@ -87,6 +87,9 @@ let load () =
          | str -> raise (LTerm_resources.Error (Printf.sprintf "invalid profile %S" str)));
       UTop_private.error_style := styles.style_error;
       UTop_private.autoload := LTerm_resources.get_bool "autoload" res <> Some false;
+      (match LTerm_resources.get "external-editor" res with
+       | "" -> ()
+       | s  -> UTop.set_external_editor s);
       return ())
     (function
     | Unix.Unix_error(Unix.ENOENT, _, _) ->