MELPA

MELPA is a growing collection of package.el-compatible Emacs Lisp packages built automatically on our server from the upstream source code using simple recipes. (Think of it as a server-side version of el-get, or even Homebrew.)

Packages are updated at intervals throughout the day.

To browse available packages, check out the archive index page.

Adding packages is as simple as submitting a new recipe as a pull request; read on for details.

Table of Contents

• Usage
• Contributing
• Recipe Format
• Build Scripts
• API
• About
• Stable Packages

Usage

To use the MELPA repository, you'll need an Emacs with package.el. Emacs 24 has package.el bundled with it, and there's also a version you can use with Emacs 23.

Enable installation of packages from MELPA by adding an entry to package-archives after (require 'package) and before the call to package-initialize in your init.el or .emacs file:

(require 'package)
(add-to-list 'package-archives
             '("melpa" . "https://melpa.org/packages/") t)
(when (< emacs-major-version 24)
  ;; For important compatibility libraries like cl-lib
  (add-to-list 'package-archives '("gnu" . "https://elpa.gnu.org/packages/")))
(package-initialize)

Then just use M-x package-list-packages to browse and install packages from MELPA and elsewhere.

Note: Packages from the default “bleeding-edge” repository will always have higher versions than those from other archives like Marmalade, so if you decide you need non-MELPA versions of specific packages for some reason, extra configuration will be required:

• If your Emacs has the variable package-pinned-packages (available in 24.4 and later), you can customize or modify that variable as needed.

• You can use the package-filter.el package which we provide.

• You can use MELPA Stable.

MELPA Stable

By default, MELPA provides the very latest revisions of packages. If you prefer to only receive updates for tagged releases, use [https://stable.melpa.org](MELPA Stable) instead:

(add-to-list 'package-archives
             '("melpa-stable" . "https://stable.melpa.org/packages/") t)

Versions for packages on the original MELPA server are based on the date of the last commit and will likely be higher than any version on the stable server. Keep the following things in mind,

• If you leave the original MELPA server in your package-archives then by default you will get the development versions of packages and not the stable ones.

• You will probably want to remove all packages and then reinstall them. Any packages you already have installed from MELPA will never get "updated" to the stable version because of the way version numbering is handled.

Contributing New Recipes

New recipe submissions should adhere to the following guidelines,

• One pull request per recipe. You can create multiple branches and create a pull request for each branch.

• Upstream source must be stored in an authoritative SCM repository. EmacsWiki recipes are no longer accepted.

• Packages should be built from the official package repository. Forks of the official repository will not be accepted except in extreme circumstances.

• The package name should match the name of the feature provided. See the package function for more information.

• Packages should adhere to the package.el format as specified by (info "(elisp) Packaging"). More information on this format is provided by the marmalade package manual.

• Recipes should try to minimize the size of the resulting package by specifying only files relevant to the package. See the Recipe Format section for more information on specifying package files.

• To have a stable version generated for your package simply tag the repository using a naming compatible with version-to-list. The repo state of this tag will be used to generate the stable package.

Expediting Recipe Reviews

Because we care about the quality of packages that are part of MELPA we review all submissions. The following steps can help us with this process and expedite the recipe review process,

• Use flycheck-package to help you identify common errors in your package metadata.

• Include the following information in the pull request:

  • A brief summary of what the package does.

  • A direct link to the package repository.

  • Your association with the package (e.g., are you the maintainer? have you contributed? do you just like the package a lot?).

  • Relevant communications with the upstream package maintainer (e.g., package.el compatibility changes that you have submitted).

• Test that the package builds properly via make recipes/<recipe>, or pressing C-c C-c in the recipe buffer.

• Test that the package installs properly via package-install-file, or entering "yes" when prompted after pressing C-c C-c in the recipe buffer.

• If you are not the original author or maintainer of the package you are submitting, please consider notifying the author prior to submitting and make reasonable effort to include them in the pull request process.

Testing

Let <NAME> denote the name of the recipe to submit.

1. Fork the MELPA repository.

2. Add your new file under the directory specified by package-build-recipes-dir (default: recipes/ directory where package-build was loaded). If you prefer, the interactive command package-build-create-recipe in package-build.el will guide you through this process.

3. Confirm your package builds properly by running

    make recipes/<NAME>
   

(Be sure that the emacs on your path is at least version 23, or set $EMACS_COMMAND to the location of a suitable binary.)

Alternatively, open the recipe in Emacs and press C-c C-c in the recipe buffer: this will also prompt you to install the freshly-built package.

If the repository contains tags for releases, confirm that the correct version is detected by running STABLE=t make recipes/<NAME>. The version detection can be adjusted by specifying :version-regexp in the recipe (see #recipe-format).

4. Install the file you built by running package-install-file from within Emacs and specifying the newly built package in the directory specified by package-build-archive-dir (default: packages/ directory where package-build was loaded).

You can optionally run a sandboxed Emacs in which locally-built packages will be available for installation along with those already in MELPA:

EMACS=/path/to/emacs make sandbox

then M-x package-list-packages, install and test as appropriate. This is a useful way to discover missing dependencies!

Submitting

After verifying the entry works properly please open a pull request on GitHub. Consider the hub command-line utility by defunkt which helps simplify this process.

Recipe Format

Packages are specified by files in the recipes directory. You can contribute a new package by adding a new file under recipes using the following form ([...] denotes optional or conditional values),

(<package-name>
 :fetcher [git|github|gitlab|bitbucket|bzr|hg|darcs|fossil|svn|cvs|wiki]
 [:url "<repo url>"]
 [:repo "github-gitlab-or-bitbucket-user/repo-name"]
 [:version-regexp "<regexp>"]
 [:module "cvs-module"]
 [:files ("<file1>" ...)])

• package-name a lisp symbol that has the same name as the package being specified.

• :fetcher (one of git, github, gitlab, bitbucket, bzr, hg, darcs, fossil, svn, cvs, wiki) specifies the type of repository that :url points to. Right now package-build supports git, github, gitlab, bitbucket, bazaar (bzr), mercurial (hg), subversion (svn), cvs, darcs, fossil, and EmacsWiki (deprecated) as possible mechanisms for checking out the repository. (Note: bitbucket assumes hg: git repos hosted on bitbucket should use the git fetcher.)

  package-build uses the corresponding application to update files before building the package. In the case of the github fetcher, use :repo instead of :url; the git URL will then be deduced.

  The Emacs Wiki fetcher gets the latest version of the package from http://www.emacswiki.org/emacs/download/<NAME>.el where NAME is the package name. Note that the :url property is not needed for the wiki engine unless the name of the package file on the EmacsWiki differs from the package name being built.

• :url specifies the URL of the version control repository. required for the git, bzr, hg, darcs, fossil, svn and cvs fetchers.

• :repo specifies the github/gitlab/bitbucket repository and is of the form user/repo-name. required for the github, gitlab, and bitbucket fetchers.

• :commit specifies the commit of the git repo to checkout. The value will be passed to git reset in a repo where upstream is the original repository. Can therefore be either a SHA, if pointing at a specific commit, or a full ref prefixed with "origin/". Only used by the git-based fetchers.

• :branch specifies the branch of the git repo to use. This is like :commit, but it adds the "origin/" prefix automatically.

• :version-regexp is a regular expression for extracting a version-string from the repository tags. Version-strings must be parseable by Emacs' version-to-list , so for an unusual tag like "OTP-18.1.5", we add :version-regexp "[^0-9]*\\(.*\\)" to strip the "OTP-" prefix.

• :module specifies the module of a CVS repository to check out. Defaults to to package-name. Only used with :fetcher cvs, and otherwise ignored.

• :files optional property specifying the elisp and info files used to build the package. Automatically populated by matching all .el, .info and dir files in the root of the repository and the doc directory. Excludes all files in the root directory ending in test.el or tests.el. See the default value below,

    ("*.el" "*.el.in" "dir"
     "*.info" "*.texi" "*.texinfo"
     "doc/dir" "doc/*.info" "doc/*.texi" "doc/*.texinfo"
     (:exclude ".dir-locals.el" "test.el" "tests.el" "*-test.el" "*-tests.el"))
  

  This option is necessary when there are multiple packages in the repository and thus the package should only be built from a subset of .el files. For example, elisp test files should not normally be packaged. Any file specified at any path in the repository is copied to the root of the package. More complex options are available, submit an Issue if the specified package requires more complex file specification.

  If the the package merely requires some additional files, for example for bundling external dependencies, but is otherwise fine with the defaults, it's recommended to use :defaults as the very first element of this list, which causes the default value shown above to be prepended to the specified file list.

Example: Single File Repository

smex is a repository that contains two files:

• README.markdown
• smex.el

Since there is only one .el file, this package only needs the :url and :fetcher specified,

(smex :repo "nonsequitur/smex" :fetcher github)

Example: Multiple Packages in one Repository

The projectile repository contains three libraries projectile.el, helm-projectile.el, and persp-projectile.el. The latter two libraries are optional and users who don't want to use the packages helm and/or perspective should not be forced to install them just so they can install projectile. These libraries should therefore be distributed as separate packages.

The three packages have to be declared in three separate files recipes/projectile, recipes/helm-projectile, and recipes/persp-projectile:

(projectile :repo "bbatsov/projectile"
            :fetcher github
            :files ("projectile.el"))

(helm-projectile :repo "bbatsov/projectile"
                 :fetcher github
                 :files ("helm-projectile.el"))

(persp-projectile :repo "bbatsov/projectile"
                  :fetcher github
                  :files ("persp-projectile.el"))

Example: Multiple Files in Multiple Directories

There are special cases where creation of the package comes from many different sub-directories in the repository and the destination sub-directories need to be explicitly set.

Consider the flymake-perlcritic recipe,

(flymake-perlcritic :repo "illusori/emacs-flymake-perlcritic"
                    :fetcher github
                    :files ("*.el" ("bin" "bin/flymake_perlcritic")))

which will result in a package structure of,

flymake-perlcritic-YYYMMDD
|-- bin
|   `-- flymake_perlcritic
|-- flymake-perlcritic-pkg.el
`-- flymake-perlcritic.el

Notice that specifying an entry in :files that is a list takes the first element to be the destination directory. These can be embedded further, such as the following---hypothetical---entry for :files,

("*.el" ("snippets"
         ("html-mode" "snippets/html-mode/*")
         ("python-mode" "snippets/python-mode/*")))

which would result in a package with *.el in something like,

package-YYYYMMDD
|-- snippets
|   |-- html-mode
|   |   |-- div
|   |   `-- html
|   `-- python-mode
|       |-- for
|       `-- main
`-- package.el

But a better solution, given that we probably want to copy the entire snippets directory to the root of the package, we could just specify that directory. Consider the pony-mode recipe,

(pony-mode
 :repo "davidmiller/pony-mode"
 :fetcher github
 :files ("src/*.el" "snippets"))

which generates the package,

pony-mode-YYYYMMDD
|-- pony-mode-pkg.el
|-- pony-mode.el
|-- pony-tpl.el
`-- snippets
    |-- html-mode
    |   |-- bl
    |   |-- ex
    |   |-- for
    |   |-- if
    |   |-- loa
    |   |-- sup
    |   |-- testc
    |   `-- {{
    `-- python-mode
        |-- auth-view
        |-- bn
        |-- model
        |-- modelform
        |-- render-to
        |-- testc
        `-- view

Build Scripts

Building MELPA is all based around using the Makefile included in the root repository directory. Described below are the actions that accepted by the Makefile.

• all -- Builds all packages under the recipes/ directory and compiles the index.html file for the melpa website.

• recipes/<NAME> -- Build individual recipe <NAME>. Built packages are put in the packages/ folder with version corresponding to the newest HEAD revision available; given according to the %Y%m%d format.

• json -- build all JSON files.

• archive.json -- construct the archive.json file that will contain a JSON object of all compiled packages.

• recipes.json -- construct the recipes.json file containing a JSON object of all packages available for building.

• clean -- clean everything.

• html -- build index.html.

• clean-working -- remove all repositories that have been checked out to the working/ directory.

• clean-packages -- remove all compiled packages from the packages directory.

• clean-json -- remove all JSON files.

Note that these scripts require an Emacs with package.el installed, such as Emacs 24. If you have an older version of Emacs, you can get a suitable package.el here.

API

All repository code is contained in the package-build.el.

Functions

• (package-build-all) : build packages for all recipes in the directory specified by package-build-recipes-dir.

• (package-build-archive NAME) : interactive elisp function to build a single archive. NAME is a symbol for the package to be built. Packages are staged in the directory specified by package-build-working-dir and built packages are placed in the directory specified by package-build-archive-dir. Packages are versioned based on the most recent commit date to package files based on commits to upstream package repository. For multi-file packages, the file <NAME>-pkg.el is automatically generated and contains description, version, and requires information determined by searching <NAME>-pkg.el, <NAME>.el, and <NAME>-pkg.el.in, if they exist in the repository.

Variables

• package-build-working-dir : Staging area containing package repositories and package directories being built.

• package-build-archive-dir : Location to store archive-contents and any built packages.

• package-build-recipes-dir : Directory containing MELPA compatible recipes. See Recipe Format section for more details.

Configuration

Packages end up in the packages/ directory by default. This can be configured using the package-build-archive-dir variable.

Repositories are checked out to the working/ directory by default. This can be configured using the package-build-working-dir variable.

About

MELPA is Milkypostman's ELPA or Milkypostman's Experimental Lisp Package Archive if you're not into the whole brevity thing.