Skip to content
Switch branches/tags

Latest commit


Git stats


Failed to load latest commit information.
Latest commit message
Commit time
                                 __    __
                                |  \  |  \
                  ______    ____| $$ _| $$_     _______
                 /      \  /      $$|   $$ \   /       \
                |  $$$$$$\|  $$$$$$$ \$$$$$$  |  $$$$$$$
                | $$    $$| $$  | $$  | $$ __  \$$    \
                | $$$$$$$$| $$__| $$  | $$|  \ _\$$$$$$\
                 \$$     \ \$$    $$   \$$  $$|       $$
                  \$$$$$$$  \$$$$$$$    \$$$$  \$$$$$$$

                -- The Erlang Development Tool Suite --


Copyright (C) 2012 by Thomas Järvstrand, Håkan Nilsson 2013 by Thomas Järvstrand

EDTS is licensed under the Lesser Gnu General Public License. See COPYING.LESSER for details.


The Erlang Development Tool Suite (EDTS) is a package of useful development tools for working with the Erlang programming language in Emacs. It bundles a number of useful external packages, together with specialized Erlang plugins for them, and its own features to create a complete and efficient development environment that is easy to set up.

Currently EDTS provides:

  • A snazzy erlang shell wrapper with syntax highlighting and auto-completion.
  • In-buffer flymake-like compilation
  • In-buffer xref checks
  • Dialyzer integration
  • Rudimentary project support
  • Code navigation.
  • Auto-completion, using auto-complete-mode
  • Auto-highlighting, using auto-highlight-mode
  • Convenient access to Erlang documentation
  • In-buffer running of unit tests
  • A usable interface to the erlang debugger

For more information, hit M-x describe-minor-mode RET edts-mode RET.

Getting started


For questions or support, please sign up for the EDTS mailing list

Please use the Github issue tracker to report bugs.


  • Emacs 24 or later

First of all, ensure your environment is setup correctly:

  • You will need make and Erlang installed or the package installation will fail.

  • You will also need both elpa and melpa package repositories added to your sources. Add these lines to your .emacs:

    • (add-to-list 'package-archives '("elpa" . ""))
    • (add-to-list 'package-archives '("melpa" . ""))
    • (add-to-list 'package-archives '("marmalade" . ""))
  • Make sure your code is compiled with the debug_info option set.


M-x package-install RET edts RET

Make sure EDTS gets loaded in your .emacs:

An easy way is to load edts-start:

(add-hook 'after-init-hook 'my-after-init-hook)
(defun my-after-init-hook ()
  (require 'edts-start))

Configure your projects.

EDTS projects are configured by creating a file called .edts in your project's root. The configuration file is a number of lines, where each line is in the format: :<property> <value>

Values that are lists must be prefixed with a single-quote, eg. '("lib"). See example below.

Valid properties are:

  • name <string>

    The name of the project. Defaults to the last component of the project root-directory (eg a root set to ~/src/p would yield p as the project name if not explicitly set.

  • node-name <string>

The name that the project's erlang node should have. It can be either a short or long Erlang node name and defaults to the name of the project.

  • node-sname <string>

Deprecated. This is now an alias for node-name.

  • erlang-cookie <string>

The erlang cookie to use for the connection to the project's erlang node. If EDTS can connect to the node with its default cookie, the project node's cookie for the EDTS server will also be updated.

  • lib-dirs <list of strings>

A list of paths (relative to the project's root) where the project's code is located. All subdirectories of lib-dirs are assumed to be otp-applications. If you're using rebar, this variable should contain your deps_dir and all lib_dirs from your rebar.config. Defaults to '("lib" "deps").

  • start-command <string>

A custom command that EDTS should execute to start the project's Erlang node. If this is set, the command must set the node's sname to be the same as the value specified in the project's node-sname. The command must also not set the erlang cookie to anything other than the default ~/.erlang.cookie. Defaults to erl -sname <node-sname>.

  • otp-path <string>

The path to any custom OTP-version to use for the project. You only have to set this if the project uses a different OTP-release than the one that comes first in your exec-path. The OTP-release's bin-directory will be added to the head of the exec-path and the PATH environment variable when starting the project node.

  • dialyzer-plt <string>

The absolute path to any custom PLT-file on which to base the creation of the project's own PLT-file. You only have to set this if the plt in dialyzer's default location ($DIALYZER_PLT or $HOME/.dialyzer_plt, in that order) is not appropriate for the project. The plt-file pointed to will not be overwritten, but instead used as a base when building the new plt-file for the project, which will be located in your edts-data-directory.

  • app-include-dirs <list of strings>

A list of directories to search for include files inside each application. Eg. if set to '("include"), files in any application's include directory can be included with -include("file.hrl") instead of -include("../file.hrl"). This is useful if you have a build configuration that sets up your paths for you during your normal build process. If set, '("include") is usually the only reasonable value for this property.

  • project-include-dirs <list of strings>

A list of directories to search for include files inside at the project-level. Eg. if set to '("test/include"), files in any module can include files from <project-root>/test/include with just a -include("file.hrl"). This is useful if you have a build configuration that sets up your paths for you during your normal build process.

  • xref-error-whitelist <list of strings>

A list of regular expressions that will be applied as a whitelist to xref error descriptions. Useful if you are using external libraries (such as Quickcheck) for which you don't have access to binaries compiled with debug_info.

  • xref-file-whitelist <list of strings>

Same as xref-error-whitelist, but the regular expressions will be applied to the path of file the file where the errors occur rather than the description of the error.

Example configuration:
:name "awesome_stuff"
:node-sname "awesome"
:lib-dirs '("lib" "test")
:app-include-dirs '("include")
:project-include-dirs '("test/shared/include")

Local modifications to project configurations - useful when working on more than one checkout of the same project - can be done in two ways:

  • Edit the project configuration file directly. If you do this in Emacs, the project will be automatically re-initialized as soon as you save the .edts- file.

  • Add overrides by calling edts-project-override in your .emacs. edts-project-override takes a project-root and a plist of configuration values to override.


    (edts-project-override "~/my-project" '(:name "my-project-dev"
                                            :node-sname "my-project-dev")
                                            :lib-dirs '("lib" "test" "hacks"))

Get the Erlang documentation (optional).

  • This is now a guided procedure. Just hit M-x edts-man-setup RET and follow the instructions.

    NB. Requires an internet connection and the process will make a small change to you .emacs-file.

That should be all it takes. If it's not, please report any issues on github.

Multiuser systems

For EDTS to work in multiuser systems, each user needs to configure the environment variable EDTS_PORT to something unique. It defaults to 4587, which is the port that the REST-interface of which the EDTS-node listens on.

Backward compatibility note

If you have previously configured EDTS 'the old way' in edts-projects, you can still keep this configuration and everything should work as before. However, EDTS will conveniently convert your old configuration and create a .edts file in your project root. You can turn off this behaviour by setting edts-project-inhibit-conversion to a non-nil value.

How it works

Once set up, EDTS will automatically fire up it's own Erlang node when you start your Emacs. Once you open the first file that is located inside one of your projects, then EDTS will automatically fire up the corresponding project node and initiate communication between the EDTS-node and the project-node. If a node with the same name as the project's node is already registered with the Erlang port mapper daemon (epmd), then EDTS will initiate communication with that node instead. The EDTS-node exposes a REST-interface (using mochiweb) through which emacs can then communicate with the project node.

EDTS and Distel

EDTS is meant to be a able to replace Distel but only provides part of the most commonly used of Distel's features, specifically the equivalents of erl-find-module, erl-find-source-under-point, erl-who-calls and erl-refactor-subfunction. As far as I know, those are the only Distel features that 98% of people use, but if there is anything from Distel that you are missing in EDTS, please let me know.

If you are using EDTS, please remove Distel from your configuration, since running both can create some confusion.

Known Issues

Some users are experiencing serious performance issues with the auto-completion during the first use after startup. This is usually solved by typing C-g a couple (two or three, it seems to vary) of times when Emacs "hangs" the first time. It is most likely caused by a bug in the emacs c-code that affects the auto-complete package. If you experience these issues, it's recommended to switch to emacs 24.2 where the problem is fixed, but if the problems persist, any help in debugging the issue would be appreciated since I have never myself been able to reproduce it.

When killing some buffers, Emacs 23 decides to move point to (point-max) in a seemingly completely unrelated buffer. This will sometimes happen as an effect of EDTS' after-save-hook. The issue does not exist in Emacs 24.

If you're using proxy server, you have to make sure that the proxy is not used for communicating with EDTS: (add-to-list 'url-proxy-services '("no_proxy" . "0:4587"))

Setup edts from source instructions

To setup from source (assuming that you have rebar3 installed and added to your PATH), you first need to clone and compile edts:

$ git clone
$ cd edts
$ make

Next you need to ensure the edts directory is added to the emacs load-path. Add to your .emacs.d or init.el file:

(add-to-list 'load-path "<path to the cloned edts repo>")

(add-hook 'after-init-hook 'my-after-init-hook)
(defun my-after-init-hook ()
  (require 'edts-start))

With this edts fork the .edts file shouldn't be need. Just ensure that you have compiled first your rebar3 project and start emacs.


Erlang Development Tool Suite




No packages published