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
• Mirrors
• About

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)
(let* ((no-ssl (and (memq system-type '(windows-nt ms-dos))
                    (not (gnutls-available-p))))
       (proto (if no-ssl "http" "https")))
  (when no-ssl (warn "\
Your version of Emacs does not support SSL connections,
which is unsafe because it allows man-in-the-middle attacks.
There are two things you can do about this warning:
1. Install an Emacs version that does support SSL and be safe.
2. Remove this warning from your init file so you won't see it again."))
  ;; Comment/uncomment these two lines to enable/disable MELPA and MELPA Stable as desired
  (add-to-list 'package-archives (cons "melpa" (concat proto "://melpa.org/packages/")) t)
  ;;(add-to-list 'package-archives (cons "melpa-stable" (concat proto "://stable.melpa.org/packages/")) t)
  (when (< emacs-major-version 24)
    ;; For important compatibility libraries like cl-lib
    (add-to-list 'package-archives (cons "gnu" (concat proto "://elpa.gnu.org/packages/")))))
(package-initialize)

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

Note that you'll need to run M-x package-refresh-contents or M-x package-list-packages to ensure that Emacs has fetched the MELPA
package list before you can install packages with M-x package-install or similar.

Instead of the messy code above, you can of course use something like
the following instead:

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

Before doing so you should understand what it does though. To make
sure of that, you should read the official
documentation
from the Emacs manual. Also note that the calls to require and
package-initialize may be unnecessary depending on the Emacs version
you use.

MELPA Stable

Packages in MELPA are built directly from the latest package source
code in the upstream repositories, but we also build and publish
packages corresponding to the latest tagged code in those
repositories, where version tags exist. These packages are published
in a separate package archive called MELPA
Stable. Most users should prefer MELPA over
MELPA Stable.

Some notes:

• 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, because the development versions are higher.

• If your Emacs has the variables package-pinned-packages (available
  in 24.4 and later) and/or package-archive-priorities, you can
  customize or modify those variables as needed.

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

• 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.

Note that the MELPA maintainers do not use MELPA Stable themselves,
and do not particularly recommend its use.

Contributing

See the CONTRIBUTING.org document.

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, hg, bitbucket]
 [:url "<repo url>"]
 [:repo "github-gitlab-or-bitbucket-user/repo-name"]
 [:commit "commit"]
 [:branch "branch"]
 [:version-regexp "<regexp>"]
 [:files ("<file1>" ...)])

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

• :fetcher specifies the type of repository that :url or :repo
  points to. MELPA supports git, github,
  gitlab, hg (Mercurial), and
  bitbucket. The bitbucket fetcher derives from
  hg, so you have to use git for Git repositories hosted on
  Bitbucket.

• :url
  specifies the URL of the version control repository. required for
  the git, and hg 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. The default matches
  typical version tags such as 1.0, R16 or v4.3.5, so you should
  not override it unless necessary. For an unusual tag like
  "OTP-18.1.5", we might add :version-regexp "[^0-9]*\\(.*\\)" to
  strip the "OTP-" prefix. The captured portion of the regexp must be
  parseable by Emacs' version-to-list function.

• :files optional property specifying the elisp and info files used to build the
  package. Please do not override this if the default value (below) is adequate, which
  it should usually be:

    ("*.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 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.

  Note that elisp in subdirectories is never included by default, so
  you might find it convenient to separate auxiliary files such as tests into
  subdirectories to keep packaging simple.

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

Assume we have a repository containing three libraries mypackage.el,
helm-mypackage.el, and persp-mypackage.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 mypackage. These libraries should therefore be
distributed as separate packages.

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

(mypackage :repo "someuser/mypackage"
           :fetcher github
           :files ("mypackage.el"))

(helm-mypackage :repo "someuser/mypackage"
                :fetcher github
                :files ("helm-mypackage.el"))

(persp-mypackage :repo "someuser/mypackage"
                 :fetcher github
                 :files ("persp-mypackage.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
  date of the latest commit that modified at least one of the files
  specified by the recipe; 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 file
package-build/package-build.el. That code is maintained in a
separate repository: the version
in the MELPA repository is imported using git subtree.

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.

Mirrors

Official mirrors are available (with many thanks to mirrorservice.org)
so that if melpa.org is down, packages can still be installed. The
following are the HTTP/HTTPS URLs to use in package-archives for
MELPA and MELPA Stable respectively:

• http://www.mirrorservice.org/sites/melpa.org/packages/
• https://www.mirrorservice.org/sites/melpa.org/packages/
• http://www.mirrorservice.org/sites/stable.melpa.org/packages/
• https://www.mirrorservice.org/sites/stable.melpa.org/packages/

Only the packages are mirrored, not the web site front-end itself.

We are NOT responsible for the contents of any UNOFFICIAL mirror of
our packages.

About

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