Auto-installing packages in Emacs with ELPA and el-get

Those who live in emacs all know the pain of manually installing extra modes and extensions, especially on different hosts. System packages sometimes help, but they differ on every OS (Debian packages, MacPorts, etc.), don’t always exist, and need to be installed manually.

A better alternative is to use emacs itself to manage, install and update all the required extra code. The ELPA project provides a way to install packages from different repositories, while el-get can help you declare recipes to install and update code from ELPA, or even Github or Emacswiki.

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It’s been a while

So this tech blog is back with a new theme after a long hiatus (and major hardware failure).

Hopefully, I’ll be talking about Ruby, Javascript, thick web apps, REST, Git, emacs and other things here soon.

Let’s see how long I can keep it going.

Internet Explorer strips leading whitespaces in text nodes

For some mysterious reason, Internet Explorer (tested in IE7 and IE8) strips leading spaces in text nodes preceded by an empty element, such as this:

<div><span></span> foo</div>

While innoccuous in static pages, it becomes problematic when DOM nodes get updated after a delay by some Javascript, as the separating whitespace has disappeared, hence ruining the layout of your text.

Surprisingly, I haven’t found any reference to this IE bug (not that there is a shortage of complaints about other IE idiosyncrasies), so I thought I’d share the problem and the solution I have found here. It’s all demonstrated in the following example:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
  <title>IE Whitespace Bug</title>
  <script type="text/javascript">
    function fill(name) {
      var e = document.getElementById(name);
      e.innerHTML = ‘hello’;
<body onload="fill(‘hello1′); fill(‘hello2′);">
<h1><span id="hello1"></span> world</h1>
<h1><span id="hello2">&nbsp;</span> world</h1>


In the first case, the whitespace gets stripped, thus resulting in “Helloworld”. In the second example, the non-breaking space prevents IE from stripping the whitespace, so that when the span is filled by Javascript, the text reads “Hello world” as expected.

If you know other solutions or whether it’s considered a bug that will be fixed, please post in the comments!

“XMMS2 Collections” presentation at Metaweb

On my way to the Google Summer of Code Mentor Summit 2009, I accepted DraX’s invitation to give a 1-hour talk about XMMS2 Collections at his work, i.e. Metaweb, in San Francisco.

The topic was somewhat relevant for them as it’s reminiscent of MQL, the query language they developed for Freebase. It’s worth noting that although both share a pool of buzzwords such as “graph”, “loosely-structured”, “querying”, etc., they are not quite the same:

  • Freebase is essentially a giant graph-database, which you query with MQL to retrieve graph fragments.
  • The XMMS2 database is a flat denormalized store, which you query with graph-structured Collections to retrieve a list of entries.

Note: Collections 2.0 should however allow fancier querying to retrieve tree-shaped structures.

About 10-20 people showed up and listened to me babbling about the concept of Collections, the rationale behind them, the API, Collections 2.0, possible UI uses, what it represents for the user, pointers to S4, etc.

It’s all in those over-engineered slides that I have no choice but to put online, under Creative Commons Attribution-Share Alike 2.5 License, for them to live on forever on the internets. And yes, it’s still either in evil Keynote format (source), or in PDF.

Oh and Metaweb, thanks for the food!

“Music Player” session at the GSoC Mentor Summit 2009

Thanks to Google’s everlasting generosity, mentors from all Open Source projects that participated to the Google Summer of Code 2009 have flocked en masse to Mountain View to meet up and talk about code and drink beer. More in pictures in my Bay Area Flickr set, if you’re curious.

Sessions were organised spontaneously around various topics, and one of which, proposed by Amarok2’s Lydia/nightrose, was “Problems Audio Players face today”. Which resulted in 15-20 people from various projects (incl. Amarok2, Rockbox, Maemo, XMMS2 & others) talking about solving problems encountered by all music player developers (e.g. lyrics and cover art fetching), as well as features on our beloved users’ wishlists (portable player support, tags, musicbrainz, etc).

And if you weren’t there, don’t despair, for I just (finally) posted minutes for this session on the GSoC wiki. Some interesting ideas in there, so go and have a look, and get to work!

Embrace the community (Ep. I: The Fandom Menace)

Or why and how the new XMMS2 GUI client should be extensible (and what I mean by extensible anyway).

Quizz: What do Winamp, Foobar2000, Emacs, Eclipse and Firefox have in common?

(Vim users, we love you too, but shut up for now please.)

They are very popular and they highly promote extensibility.

Now, we all know that correlation != causation. What is certain, however, is that all those projects boast many fan(boy)s, some of whom even get quite religious about it.

This enthusiasm reflects itself in the emergence of strong communities: people who share content, tips, modules, extensions, themes, configurations, scripts, etc. And those people usually aren’t even core developers of the software, sometimes not developers at all; just users or hobbyists who like the project.

Paradoxically, most of what they share is aimed at personalizing the software, i.e. making it the user’s own, fitting the user’s wishes and needs. This creates a feeling of ownership and satisfaction, because the user can bend it the way she likes and master it like a pro.

In essence, the idea here is give power to people to shape the software the way they want, and they will extend it in creative ways and get together to share these extensions. And I think that encouraging this creative freedom is one of the many factors which contribute to popularity.

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