An Emacs major mode for ReasonML.
Note: the following setup assumes Reason and Merlin are installed. This can be achieved by installing them from OPAM (opam install reason merlin
).
If you are using bucklescript, make sure you are using a compatible OCaml version (you can find the version of ocaml compatible with your bucklescript installation by running npm bsc -version
).
At the time of writing this documentation, install OCaml 4.06.1 (for bucklescript 7.*)
Please verify your installation:
ocamlc -version # 4.06.1 if you are using bucklescript
which ocamlmerlin # a valid path to the ocamlmerlin binary, mandatorily
which ocamlmerlin-reason # a valid path to the ocamlmerlin-reason binary, mandatorily
If your Emacs has package.el
(which is automatically the case for Emacs >= 24), you can install reason-mode
from the package in MELPA.
Alternatively, you can use quelpa and the following recipe:
(quelpa '(reason-mode :repo "reasonml-editor/reason-mode" :fetcher github :stable t))
Download reason-indent.el
, reason-interaction.el
, reason-mode.el
and refmt.el
at the root of this repository and place it in a vendor
file next to your Emacs configuration files. Then place the following somewhere in your .emacs.el
:
(add-to-list 'load-path "/path/to/vendor")
Add the following to your ~/.emacs
or ~/.emacs.d/init.el
file:
;;----------------------------------------------------------------------------
;; Reason setup
;;----------------------------------------------------------------------------
(defun shell-cmd (cmd)
"Returns the stdout output of a shell command or nil if the command returned
an error"
(car (ignore-errors (apply 'process-lines (split-string cmd)))))
(defun reason-cmd-where (cmd)
(let ((where (shell-cmd cmd)))
(if (not (string-equal "unknown flag ----where" where))
where)))
(let* ((refmt-bin (or (reason-cmd-where "refmt ----where")
(shell-cmd "which refmt")
(shell-cmd "which bsrefmt")))
(merlin-bin (or (reason-cmd-where "ocamlmerlin ----where")
(shell-cmd "which ocamlmerlin")))
(merlin-base-dir (when merlin-bin
(replace-regexp-in-string "bin/ocamlmerlin$" "" merlin-bin))))
;; Add merlin.el to the emacs load path and tell emacs where to find ocamlmerlin
(when merlin-bin
(add-to-list 'load-path (concat merlin-base-dir "share/emacs/site-lisp/"))
(setq merlin-command merlin-bin))
(when refmt-bin
(setq refmt-command refmt-bin)))
(require 'reason-mode)
(require 'merlin)
(add-hook 'reason-mode-hook (lambda ()
(add-hook 'before-save-hook 'refmt-before-save)
(merlin-mode)))
(setq merlin-ac-setup t)
If you have iedit mode set up:
(require 'merlin-iedit)
(defun evil-custom-merlin-iedit ()
(interactive)
(if iedit-mode (iedit-mode)
(merlin-iedit-occurrences)))
(define-key merlin-mode-map (kbd "C-c C-e") 'evil-custom-merlin-iedit)
(Thanks @sgrove: https://gist.github.com/sgrove/c9bdfed77f4da8db108dfb2c188f7baf)
This associates reason-mode
with .re
and .rei
files. To enable it explicitly, do M-x reason-mode.
If you're using different versions of refmt
between projects, you can use the project-specific installed version via the special config values:
'npm
(callsnpx refmt ...
to use the version ofrefmt
installed in the project'snode_modules
)'opam
(callsopam exec -- refmt ...
to use the version ofrefmt
on the currentopam
switch):
;; can also be set via M-x `customize-mode`
(setq refmt-command 'npm)
Reason-mode provides (opt-in) rtop
support. At the moment only the native workflow is supported.
First of all you need to install the Utop Emacs integration. Make sure it is latest master
because the feature is fairly new.
Then in your Emacs init file add:
(require 'utop)
(setq utop-command "opam config exec -- rtop -emacs")
(add-hook 'reason-mode-hook #'utop-minor-mode) ;; can be included in the hook above as well
After this, the function utop
(C-c C-s
) will start rtop
in Reason buffers.
The reasonml
layer is available in the develop version of spacemacs.
For the stable version of spacemacs, you can install the reason-mode
package automatically.
dotspacemacs-additional-packages
'(
(reason-mode
:location (recipe
:repo "reasonml-editor/reason-mode"
:fetcher github
:files ("reason-mode.el" "refmt.el" "reason-indent.el" "reason-interaction.el")))
)
Afterwards add the snippet to your dotspacemacs/user-config
.
If you have refmt installed, you can add this to your .emacs
file to enable
auto-format:
(add-hook 'reason-mode-hook (lambda ()
(add-hook 'before-save-hook #'refmt-before-save)))
The test
folder contains tests that can be run via Cask.
Once you install cask
, if it is the first time run:
cask install
cask exec ./run_tests.sh
If it is not the first time you can omit the first line and execute the tests with the second one only. The environment variable EMACS controls the program that runs emacs.
reason-mode
is distributed under the terms of both the MIT license and the
Apache License (Version 2.0).
See LICENSE-MIT and LICENSE-APACHE for details.