Elixir Tooling Integration Into Emacs

Alchemist comes with a bunch of features, which are:

• Mix integration
• Compile & Execution of Elixir code
• Inline code evaluation
• Documentation lookup
• Definition lookup
• Powerful IEx integration
• Smart code completion
• Elixir project management
• Integration with company-mode

---

• Installation
  • Requirements
  • ELPA
  • Via el-get
  • Manual
• Configuration
  • Mix setup
  • IEx setup
  • Execute setup
  • Compile setup
  • Modeline setup
  • Keybindings
  • Testing-Mode
  • Hooks
• Mix
• Compile & Execute
  • Compile
  • Execute
• Project
• Documentation lookup
  • Keymap
• Definition lookup
  • Symbol definitions
• Auto-completion
• IEx
  • Complete & Documentation lookup
• Eval
• Testing
• Modeline
• Keymap
• Contributing

Installation

Requirements

• Emacs 24.4 or later
• Elixir 1.0 or later

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].

Manual

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)

Configuration

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

Mix setup

• Use a different shell command for mix.

(setq alchemist-mix-command "/usr/local/bin/mix")

• Use a different task for running tests.

(setq alchemist-mix-test-task "espec")

• Use custom mix test task options.

(setq alchemist-mix-test-default-options "--exclude pending:true") ;; default

• Use a different environment variable in which mix tasks will run.

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

• Use a different shell command for iex.

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

Execute setup

• Use a different shell command for elixir.

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

Compile setup

• Use a different shell command for elixirc.

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

Modeline setup

• Disable the change of the modeline color with the last compilation status.

(setq alchemist-buffer-status-modeline nil)

Keybindings

• Use a different keybinding prefix than C-c a

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

Testing Mode

• Disable the use of a more significant syntax highlighting on functions like test, assert_* and refute_*

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

Hooks

• Run the whole test suite with alchemist-mix-test after saving a buffer.

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

Mix

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

Project

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

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.

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)

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.

Auto-completion

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.

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.

IEx

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.

Eval

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.

Testing

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

Modeline

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-buffer-status-modeline variable via (setq alchemist-buffer-status-modeline nil) or M-x customize-group [RET] alchemist-buffer

Keymap

Alchemist comes with a default keymap.

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

Contributing

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!

License

Copyright © 2014-2015 Samuel Tonini and contributors.

Distributed under the GNU General Public License, version 3