Thursday, October 07 2010
Emacs, Muse, el-get, Extensions, release, switch-window, cssh, mailq, rcirc

el-get reaches 1.0

It's been a week since the last commits in the el-get repository, and those were all about fixing and adding recipes, and about notifications. Nothing like core plumbing you see. Also, 0.9 was released on 2010-08-24 and felt pretty complete already, then received lots of improvements. It's high time to cross the line and call it 1.0!

Now existing users will certainly just be moderatly happy to see the tool reach that version number, depending whether they think more about the bugs they want to see fixed (ftp is supported, only called http) and the new features they want to see in ( info documentation) or more about what el-get does for them already today...

For the new users, or the yet-to-be-convinced users, let's take some time and talk about el-get. A FAQ like session might be best.

How is el-get different from ELPA?

ELPA is the Emacs Lisp Package Archive and is also known as package.el, to be included in Emacs 24. This allows emacs list extension authors to package their work. That means they have to follow some guidelines and format their contribution, then propose it for upload.

This requires licence checks (good) and for the new official ELPA mirror it even requires dead-tree papers exchange and contracts and copyright assignments, I believe.

Why have both?

While ELPA is a great thing to have, it's so easy to find some high quality Emacs extension out there that are not part of the offer. Either authors are not interrested into uploading to ELPA, or they don't know how to properly package for it (it's only simple for single file extensions, see).

So el-get is a pragmatic answer here. It's there because it so happens that I don't depend only on emacs extensions that are available with Emacs itself, in my distribution site-lisp and in ELPA. I need some more, and I don't need it to be complex to find it, fetch it, init it and use it.

Of course I could try and package any extension I find I need and submit it to ELPA, but really, to do that nicely I'd need to contact the extension author ( upstream) for him to accept my patch, and then consider a fork.

With el-get I propose distributed packaging if you will. Let's have a look at two recipes here. First, the el-get one itself:

(:name el-get
       :type git
       :url "git://github.com/dimitri/el-get.git"
       :features el-get
       :compile "el-get.el")

Then a much more complex one, the bbdb one:

(:name bbdb
       :type git
       :url "git://github.com/barak/BBDB.git"
       :load-path ("./lisp" "./bits")
       :build ("./configure" "make autoloads" "make")
       :build/darwin ("./configure --with-emacs=/Applications/Emacs.app/Contents/MacOS/Emacs" "make autoloads" "make")
       :features bbdb
       :after (lambda () (bbdb-initialize))
       :info "texinfo")

The idea is that it's much simpler to just come up with a recipe like this than to patch existing code and upload it to ELPA. And anybody can share their recipes very easily, with or without proposing them to me, even if I very much like to add some more in the official el-get list.

As a user, you don't even need to twiddle with recipes, mostly, because we already have them for you. What you do instead is list them in el-get-sources.

So, show me how you use it?

Yeah, sure. Here's a sample of my dim-packages.el file, part of my .emacs suite. Yeah a single .emacs does not suit me anymore, it's a complete .emacs.d now, but that's because that's how I like it organised, you know. So, here's the example:

;;; dim-packages.el --- Dimitri Fontaine
;;
;; Set el-get-sources and call el-get to init all those packages we need.
(require 'el-get)
(add-to-list 'el-get-recipe-path "~/dev/emacs/el-get/recipes")

(setq el-get-sources
      '(cssh el-get switch-window vkill google-maps yasnippet verbiste mailq sicp

	(:name magit
	       :after (lambda () (global-set-key (kbd "C-x C-z") 'magit-status)))

	(:name asciidoc
	       :type elpa
	       :after (lambda ()
			(autoload 'doc-mode "doc-mode" nil t)
			(add-to-list 'auto-mode-alist '("\\.adoc$" . doc-mode))
			(add-hook 'doc-mode-hook '(lambda ()
						    (turn-on-auto-fill)
						    (require 'asciidoc)))))

	(:name goto-last-change
	       :after (lambda ()
			(global-set-key (kbd "C-x C-/") 'goto-last-change)))

	(:name auto-dictionary :type elpa)
	(:name gist            :type elpa)
	(:name lisppaste       :type elpa)))

(el-get) ; that could/should be (el-get 'sync)
(provide 'dim-packages)

Ok that's not all of it, but it should give you a nice idea about what problem I solve with el-get and how. In my emacs startup sequence, somewhere inside my ~/.emacs.d/init.el file, I have a line that says (require 'dim-packages). This will set el-get-sources to the list just above, then call (el-get), the main function.

This main function will check each given package and install it if necessary (including build the package, as in make autoloads; make), then init it. What init means exactly depends on what the recipe says. That can include byte-compiling some files, caring about load-path, load and require commands, caring about Info-directory-list and ginstall-info too, and some more.

So in short, it will make it so that your emacs instance is ready for you to use. And you get the choice to use the given el-get recipes as-is, like I did for cssh, el-get, switch-window and others, up to sicp, or to tweak them partly, like in the magit example where I've added a user init function (the :after property) to bind magit-status to C-x C-z here. You can even embed a full recipe inline in the el-get-sources variable, that's the case for each item that gives its :type property, like asciidoc or gist.

And, as you see, we're using ELPA a lot in this sources, so el-get isn't striving to replace it at all, it's just trying to accomodate to a broader world.

I read that the el-get-install is asynchronous, tell me more.

Yeah, right, the example above says (el-get) at its end, and in the cases when el-get has to install or build sources, this will be done asynchronously. Which means that not only several sources will get processed at once (using your multi cores, yeah) but that it will let emacs start up as if it was ready.

It happens that's usually what I want, because I seldom add sources in my setup, but in theory that can break your emacs. What I do is start it again or fix by hand, what you can do instead is (el-get 'sync) so that emacs is blocked waiting for el-get to properly install and initialize all the sources you've setup. Your choice, just add the 'sync parameter there.

Now, explain me why it is better this way, again, please?

Well, before I wrote el-get, trying out a new extension, setting it up etc was something quite involved, and that I had to redo on several machines. The only way not to redo it was to include the extension's code into my own git repository (my emacs.d is in git, of course).

And putting code I don't maintain into my own git repository is something I frown upon. I have no business pretending I'll maintain the code, and I know I will never think to check the URL where I've found it for updates. That's when I though noting down the URL somewhere.

Also, what about sharing the extension with friends. Uneasy, at best.

Enters el-get and I can just add an entry to el-get-sources, based on a file somewhere in my own el-get-recipe-path. When I'm happy with this file, I can contribute it to el-get proper or just send it over to any interested recipient. Adding it to your sources is easy. Copy the file in your el-get-recipe-path somewhere, add its name to your el-get-sources, then M-x el-get-install it. Done. If you were given the :after function, it's all setup already.

If you contribute the recipe to el-get, then M-x el-get-update RET el-get RET and you get it on this other machine where you also use Emacs. Or you can tell your friend to do the same and benefit from your packaging.

Well, sounds good. What recipes do you have already?

I count 67 of them already. One of them is just a book in info format, with no elisp at all, can you spot it?

ELISP> (directory-files "~/dev/emacs/el-get/recipes/" nil "el$")

("auctex.el" "auto-complete-etags.el" "auto-complete-extension.el"
"auto-complete.el" "auto-install.el" "autopair.el" "bbdb.el"
"blender-python-mode.el" "color-theme-twilight.el" "color-theme.el"
"cssh.el" "django-mode.el" "el-get.el" "emacs-w3m.el" "emacschrome.el"
"emms.el" "ensime.el" "erc-highlight-nicknames.el" "erc-track-score.el"
"escreen.el" "filladapt.el" "flyguess.el" "gist.el" "google-maps.el"
"google-weather.el" "goto-last-change.el" "haskell-mode.el"
"highlight-parentheses.el" "hl-sexp.el" "levenshtein.el" "magit.el"
"mailq.el" "maxframe.el" "multi-term.el" "muse-blog.el" "nognus.el"
"nterm.el" "nxhtml.el" "offlineimap.el" "package.el" "popup-kill-ring.el"
"pos-tip.el" "pov-mode.el" "psvn.el" "pymacs.el" "rainbow-mode.el"
"rcirc-groups.el" "rinari.el" "ropemacs.el" "rt-liberation.el" "scratch.el"
"session.el" "sicp.el" "smex.el" "switch-window.el" "textile-mode.el"
"todochiku.el" "twitter.el" "twittering-mode.el" "undo-tree.el"
"verbiste.el" "vimpulse-surround.el" "vimpulse.el" "vkill.el" "xcscope.el"
"xml-rpc-el.el" "yasnippet.el")

Ok, I want to try it, what's next?

Visit the following URL http://github.com/dimitri/el-get and follow the install instructions. You're given a scratch installer there, that's some elisp code you copy paste into *scratch* then execute there, and you have el-get ready to serve.

An excellent idea I stole at ELPA!

Hey, I already know what el-get is, what's new in 1.0?

The changelog is quite full of good stuff, really:

  • Implement el-get recipes so that el-get-sources can be a simple list

of symbols. Now that there's an authoritative git repository, where to share the recipes is easy.

  • Add support for emacswiki directly, save from having to enter the URL
  • Implement package status on-disk saving so that installing over a

previously failed install is in theory possible. Currently `el-get' will refrain from removing your package automatically, though.

  • Fix ELPA remove method, adding a "removed" state too.
  • Implement CVS login support.
  • Add lots of recipes
  • Add support for `system-type' specific build commands
  • Byte compile files from the load-path entries or :compile files
  • Implement support for git submodules with the command

`git submodule update --init --recursive`

  • Add catch-all post-install and post-update hooks
  • Add desktop notification on install/update.

I'm still using the deprecated emacswiki version, what now?

That version didn't have recipes, and the new version should be perfectly happy with your current el-get-sources, so that I recommend using the scratch installer too. Don't forget to add el-get itself into your el-get-sources list, of course!