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Alchemist Logo

Elixir Tooling Integration Into Emacs

Alchemist comes with a bunch of features, which are:



Installation via package.el

package.el is the built-in package manager in Emacs.

Alchemist.el is available on the three major community maintained repositories - MELPA STABLE, MELPA and Marmalade.

You can install Alchemist with the following command:

M-x package-install [RET] alchemist [RET]

or by adding this bit of Emacs Lisp code to your Emacs initialization file (.emacs or init.el):

(unless (package-installed-p 'alchemist)
  (package-install 'alchemist))

If the installation doesn't work try refreshing the package list:

M-x package-refresh-contents [RET]

Keep in mind that MELPA packages are built automatically from the master branch, meaning bugs might creep in there from time to time. Never-the-less, installing from MELPA is the recommended way of obtaining Alchemist, as the master branch is normally quite stable and “stable” (tagged) builds are released somewhat infrequently.

With the most recent builds of Emacs, you can pin Alchemist to always use MELPA Stable by adding this to your Emacs initialization:

(add-to-list 'package-pinned-packages '(alchemist . "melpa-stable") t)

Via el-get

el-get is another popular package manager for Emacs. If you're an el-get user just do M-x el-get-install [RET] alchemist [RET].


You can install Alchemist manually by placing Alchemist on your load-path and require ing it. Many people favour the folder ~/.emacs.d/vendor.

(add-to-list 'load-path "~/.emacs.d/vendor/alchemist.el/")
(require 'alchemist)


There are some ways Alchemist can be adjusted that certain workflows operating differently.

Mix setup

(setq alchemist-mix-command "/usr/local/bin/mix")
(setq alchemist-mix-test-task "espec")
(setq alchemist-mix-test-default-options '("--exclude pending:true")) ;; default

Mix tasks could always be executed in a specific environment with the usage of C-u (universal-argument). But if you like to change the run of Mix task permanently to a specific environment set it through the variable.

(setq alchemist-mix-env "prod")

IEx setup

(setq alchemist-iex-program-name "/usr/local/bin/iex") ;; default: iex

Execute setup

(setq alchemist-execute-command "/usr/local/bin/elixir") ;; default: elixir

Compile setup

(setq alchemist-compile-command "/usr/local/bin/elixirc") ;; default: elixirc

Modeline setup

(setq alchemist-test-status-modeline nil)


(setq alchemist-key-command-prefix (kbd "C-c ,")) ;; default: (kbd "C-c a")

Testing Mode

(setq alchemist-test-mode-highlight-tests nil) ;; default t


(setq alchemist-hooks-test-on-save t)


Alchemist works as a server & client model, where the Alchemist server is written in Elixir and Emacs takes the part of the client.

For each Elixir mix project Alchemist starts an independent server in the background. If an Elixir file gets opened in a buffer, Alchemist checks if a server is running for the current project or not and starts a new one if needed. If there is no Elixir mix project found, Alchemist starts a general unique server.

An Alchemist server can be started/restarted by hand with the call of the function alchemist-server-start. A prompt for the environment in which the server should run (default: dev) gets opened and the server will start/restart in the selected environment.


| Keybinding | Description | |——————-|————-| |C-c a x|Prompt for a mix command including a list of all available mix commands. alchemist-mix| |C-c a t|Run the whole elixir test suite. alchemist-mix-test| |C-c a r|Rerun the last test that was run by alchemist. alchemist-mix-rerun-last-test| |C-c a t f|Run alchemist-mix--test-file with the FILENAME. alchemist-mix-test-file| |C-c a t b|Run the current buffer through mix test. alchemist-mix-test-this-buffer| |C-c a t .|Run the test at point. alchemist-mix-test-at-point| |C-c a m c|Compile the whole elixir project. Prompt for the mix env if the prefix arg is set. alchemist-mix-compile|

Command (For the M-x prompt.) Description
alchemist-mix Prompt for a mix command including a list of all available mix commands.
alchemist-mix-new Create a new Elixir application.
alchemist-mix-run Runs the given expression in the Elixir application context.
alchemist-mix-deps Prompt for mix deps commands.
alchemist-mix-local Prompt for mix local commands.
alchemist-mix-local-install Prompt for mix local.install PATH or URL.
alchemist-mix-local-install-with-path Runs mix local.install and prompt for a PATH as argument.
alchemist-mix-local-install-with-url Runs mix local.install and prompt for a URL as argument.
alchemist-mix-help Show help output for a specific mix command.
alchemist-mix-execute Prompt for a mix command.
alchemist-mix-hex-search Display packages matching the given search query.

Mix tasks could also be executed in a specific environment with the usage of C-u (universal-argument). Default environments are prod, dev and test. Mix environments

Compile And Execute

Compile functions

| Keybinding | Description | |——————-|————-| |C-c a c c|Compile the current buffer with the elixirc command. alchemist-compile-this-buffer| |C-c a c f|Compile the given FILENAME with the elixirc command. alchemist-compile-file| |C-c a c b|Run a custom compile command with elixirc. alchemist-compile|

Execute functions

| Keybinding | Description | |——————-|————-| |C-c a e e|Run the current buffer through elixir command. alchemist-execute-this-buffer| |C-c a e f|Run elixir command with the given FILENAME. alchemist-execute-file | |C-c a e b|Run a custom execute command with elixir. alchemist-execute |


| Keybinding | Description | |——————-|————-| |C-c a p f|Open project test directory and list all test files. alchemist-project-find-test| |C-c a p s|Toggle between a file and its tests in the current window. alchemist-project-toggle-file-and-tests |C-c a p o|Toggle between a file and its tests in other window. alchemist-project-toggle-file-and-tests-other-window |C-c a p t|Run the tests related to the current file.. alchemist-project-run-tests-for-current-file

Documentation lookup

There is the alchemist-help-minor-mode for a complete fully functional interface to the Elixir documentation. The alchemist-help-minor-mode uses the same functions like Elixir's IEx.

What does that mean? It means no matter which Elixir version is currently installed on the system, the documentation you get by alchemist is the same IEx would deliver.

| Keybinding | Description | |————|————————————————-| |C-c a h h| Run a custom search. alchemist-help | |C-c a h i| Look through search history. alchemist-help-history | |C-c a h e| Run alchemist-help with the expression under the cursor. (example: is_binary  or Code.eval_string). alchemist-help-search-at-point | |C-c a h m| Run alchemist-help with the current marked region. alchemist-help-search-marked-region| |C-c a h r| Open a buffer with a refcard of alchemist bindings. alchemist-refcard|

Alchemist Help Minor Mode Keymap

Inside of the alchemist-help-minor-mode (*elixir help* buffer) the key ? will open a keymap summary in the minibuffer with the following functionality:

You're always be able to continue to search inside the *elixir help* buffer.

Alchemist Help Minor Mode Key Summary

| Keybinding | Description | |————|————————————————-| |q| Quit *elixir help* buffer window | |e| alchemist-help-search-at-point | |m| alchemist-help-search-marked-region | |s| alchemist-help | |h| alchemist-help-history | |?| alchemist-help-minor-mode-key-binding-summary |

Definition lookup

With the function alchemist-goto-definition-at-point, which is bound to M-., you can jump to module and function definitions. If you want to jump back, just use M-, which calls alchemist-goto-jump-back.

You also can jump to the current selected completion candidate with just hit the same key as normally, M-..

By default you're able to jump to definitions of your own mix project codebase and dependencies. But if you would like to also jump to Elixir and Erlang source code you need to tell Alchemist where it can find the source code of Elixir and Erlang.

For that purpose there're two variables you can set:

(setq alchemist-goto-erlang-source-dir "/path/to/erlang/source/")
(setq alchemist-goto-elixir-source-dir "/path/to/elixir/source/")

If you inside an Erlang file and the erlang-mode is enabled you can't use alchemist-goto-jump-back anymore. But if you would like to use it also inside the erlang-mode just setup the following custom hook:

(defun custom-erlang-mode-hook ()
  (define-key erlang-mode-map (kbd "M-,") 'alchemist-goto-jump-back))

(add-hook 'erlang-mode-hook 'custom-erlang-mode-hook)

Definition Lookup

Symbol definitions

There is the function alchemist-goto-list-symbol-definitions which lets you jump to a specific module, function or macro definitions in the current file.


Alchemist users are advised to use company-mode to enable auto-completion inside of Elixir source code.

Alchemist enables a company-mode elixir backend by default if company-mode is installed.

Alchemist Company

There are the same keybindings for documentation lookup and definition opening for the selected candidate available like company-mode provides.

C-h and <f1> for documentation lookup for the current selected candidate. C-w to jump to the definition of the current selected candidate.

Alchemist Completion Candidate Functionalities


Alchemist provides a REPL buffer, connected to an Elixir IEx subprocess.

To start an IEx process just run M-x alchemist-iex-run

To start an IEx process in the context of an Elixir project (iex -S mix) just run M-x alchemist-iex-project-run

To start a custom IEx process with additional arguments (like: iex --sname custom) just use the universal-argument C-u before run M-x alchemist-iex-run

| Keybinding | Description | |——————–|——————————————| |C-c a i i| Start an IEx process. alchemist-iex-run| |C-c a i p| Start an IEx process with mix (iex -S mix). alchemist-iex-project-run| |C-c a i l| Sends the current line to the IEx process. alchemist-iex-send-current-line| |C-c a i c| Sends the current line to the IEx process and jump to the buffer.. alchemist-iex-send-current-line-and-go| |C-c a i r| Sends the marked region to the IEx process. alchemist-iex-send-region| |C-c a i m| Sends the marked region to the IEx process and jump to the buffer. alchemist-iex-send-region-and-go| |C-c a i b| Compiles the current buffer in the IEx process. alchemist-iex-compile-this-buffer|

Complete & Documentation lookup

When Alchemist finds company-mode it enables if for completion inside the IEx process buffer.


Alchemist comes with the functionality to evaluate code inside the buffer.

| Keybinding | Description | |——————–|——————————————| |C-c a v l| Evaluate the Elixir code on the current line. alchemist-eval-current-line.| |C-c a v k| Evaluate the Elixir code on the current line and insert the result. alchemist-eval-print-current-line.| |C-c a v j| Get the Elixir code representation of the expression on the current line. alchemist-eval-quoted-current-line. | |C-c a v h| Get the Elixir code representation of the expression on the current line and insert the result. alchemist-eval-print-quoted-current-line. | |C-c a v o| Evaluate the Elixir code on marked region. alchemist-eval-region.| |C-c a v i| Evaluate the Elixir code on marked region and insert the result. alchemist-eval-print-region.| |C-c a v u| Get the Elixir code representation of the expression on marked region. alchemist-eval-quoted-region.| |C-c a v y| Get the Elixir code representation of the expression on marked region and insert the result. alchemist-eval-print-quoted-region.| |C-c a v q| Evaluate the Elixir code in the current buffer. alchemist-eval-buffer.| |C-c a v w| Evaluate the Elixir code in the current buffer and insert the result. alchemist-eval-print-buffer.| |C-c a v e| Get the Elixir code representation of the expression in the current buffer. alchemist-eval-quoted-buffer.| |C-c a v r| Get the Elixir code representation of the expression in the current buffer and insert result. alchemist-eval-print-quoted-buffer.|


Alchemist comes with an minor mode for testing which will be enabled by default inside *_test.exs files.

| Keybinding | Description | |——————–|——————————————| |C-c , s| Run the test at point. alchemist-mix-test-at-point | |C-c , v| Run all tests in the current file. alchemist-mix-test-this-buffer | |C-c , a| Run the whole elixir test suite. alchemist-mix-test | |C-c , f| Run all tests of a specific file alchemist-mix-test-file | |C-c , n| Jump to the next test inside the current file. alchemist-test-mode-jump-to-next-test | |C-c , p| Jump to the previous test inside the current file alchemist-test-mode-jump-to-previous-test |


By default the status of alchemist-mix-test, alchemist-compile etc will be represented via the colorized mode-name. In our case that will be the elixir-mode.

If you don't like that just set the alchemist-test-status-modeline variable via (setq alchemist-test-status-modeline nil) or M-x customize-group [RET] alchemist-test

Alchemist Build Status


Alchemist comes with a default keymap.

The the default prefix keybinding is C-c a


You find and overview of all the key-bindings on the Alchemist-Refcard.

There is also a refcard for usage inside Emacs, which gets dynamically generated with the current adjusted keybindings. If you use the keybinding i on a specific row, it will call describe-function on that function.

Just M-x alchemist-refcard RET


If you hit any problems, please first ensure that you are using the latest version of this code, and that you have updated your packages to the most recent available versions. If you still experience problems, you can find me on IRC channels #elixir-lang and #emacs-elixir under the nickname tonini.


Contributions are very welcome!

  1. Fork alchemist.el
  2. Create a topic branch - git checkout -b my_branch
  3. Push to your branch - git push origin my_branch
  4. Send me a pull-request for your topic branch
  5. That's it!


Copyright © 2014-2015 Samuel Tonini and contributors.

Distributed under the GNU General Public License, version 3