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.

Usage
Contributing
Recipe Format
Build Scripts
API
Mirrors
About

Usage

To use the MELPA repository, you'll need an Emacs with package.el,
ie. Emacs 24.1 or greater. To test TLS support you can visit a HTTPS
URL, for example with M-x eww RET https://wikipedia.org RET.

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)
;; Comment/uncomment this line to enable MELPA Stable if desired.  See `package-archive-priorities`
;; and `package-pinned-packages`. Most users will not need or want to do this.
;;(add-to-list 'package-archives '("melpa-stable" . "https://stable.melpa.org/packages/") t)
(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.

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

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, and hg (Mercurial).
:url
specifies the URL of the version control repository. required for
the git, and hg fetchers.
:repo specifies the github or gitlab repository and is of the form
user/repo-name. required for the github and gitlab 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. This must be specified when
using a branch other than the default branch.
: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"))
```
Note that elisp in subdirectories is never included by default, so
you might find it convenient to keep your package's elisp in the root
of your repository, and separate auxiliary files such as tests into
subdirectories to keep packaging simple.

The elements of the :files list are glob-expanded and processed
from left to right to make a list of paths that will be copied
into the root of the new package, as if by using cp -R [SRCPATHS] DEST. This means a directory like "foo/bar" would become "bar" in
the new package. To specify a destination subdirectory, use a list
element of the form (SUBDIR SRCPATH ...). Likewise, to filter
out paths expanded earlier in the list, use (:exclude SRCPATH ...).

If your package requires some additional files, but is
otherwise fine with the defaults, it's recommended to use the special
element :defaults as the very first element of the :files list,
which causes the default value shown above to be prepended to the
specified file list. For example :files (:defaults "snippets") would
cause the "snippets" subdir to be copied in addition to the defaults.

:old-names specifies former names of the package, if any. The value is
a list of symbols.

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:

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.

ruediger/melpa