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Don’t write your examples in CoffeeScript

Recently, I stumbled upon a growing number of articles about frontend coding that used CoffeeScript in their examples. In particular, articles about Backbone.js.

While I’m not a fan of CoffeeScript, for various reasons, and wouldn’t tend to use it myself, I completely respect your right to disagree and don’t mind at all if you use it for your projects.

What I do mind, though, is the use of CoffeeScript to reason and present information about JavaScript and JavaScript libraries.

The reason should be self-evident from the previous sentence. If not, bear with me.

The best analogy I can think of for the transpiled relationship between JavaScript/CoffeeScript is HTML/Haml.

Take the following example:

%blockquote.film{:cite => "http://www.imdb.com/title/tt0062622/quotes"}
    %p= Just what do you think you're doing, Dave?
    %footer
        = — HAL in 2001: A Space Odyssey

Which translates to:

<blockquote class="film"
            cite="http://www.imdb.com/title/tt0062622/quotes">
    <p>Just what do you think you're doing, Dave?</p>
    <footer>— HAL in 2001: A Space Odyssey</footer>
</blockquote>

Even though there is a somewhat guessable syntactic mapping between the two, would you use such a Haml snippet to illustrate the use of <blockquote> and <footer>? Hopefully not.

No matter how much you enjoy the power of an alternative syntax, using it for anything else than demonstrating that syntax distracts the attention from what you’re actually writing about.

Just because you know how to map CoffeeScript to JavaScript (and really, you should know) doesn’t mean everybody does, or cares to.

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">
<html>
<head>
  <title>IE Whitespace Bug</title>
  <script type="text/javascript">
    function fill(name) {
      var e = document.getElementById(name);
      e.innerHTML = ‘hello’;
    }
  </script>
</head>
<body onload="fill(‘hello1′); fill(‘hello2′);">
<h1><span id="hello1"></span> world</h1>
<h1><span id="hello2">&nbsp;</span> world</h1>

</body>
</html>

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!