RubyConf 2008 Keynote by Matsumoto

Thursday AM Keynote by Matz

This is Matz: http://en.wikipedia.org/wiki/Yukihiro_Matsumoto

He’s talking about his love of languages, and why he got into Ruby.

He’s addressing some of the criticisms, that it’s slow, poorly implemented, embedding issues…he says the list of complaints goes on forever.

But, now he’s talking about why is Ruby good. He says people say it’s enjoyable, that Ruby made programming fun again.

He says he got into BASIC in 1980, and is talking about his problems with it. He says that one thing was the lack of being able to define data types. Everything is predefined, and you can’t change much.

He is talking a bit about LISP, and says some good things about it. He then complains about the parentheses in LISP, then puts up a slide that just says “No.”

He says he likes the aristocracy, as long as he is in power. BASIC gives you no power, LISP gives you full power. But, the problem is that at both ends of the spectrum, we lose popularity. It’s all about balance. You don’t want to go off the cliff of power with LISP, but you want to be able to be near the edge of the cliff — where BASIC isn’t.

He’s talking about why people choose Ruby. When he asks how many people choose Ruby because of Rails, about 60-70% of the room raises their hand. Matz points out that Rails is basically just a DSL for turning Ruby into a web language. He also points out that they are not at RailsConf, they are at RubyConf. This gets a laugh.

Again, talking about LISP, he says it’s a good DSL.

“There are under one million professional Ruby developers now, and we’re projecting there will be four million plus by 2013″ — Mark Driver, Gartner analyst

Matz says “The future is bright…too bright maybe. Beware commercial success” He says, right now, we have the community and enthusiasm. In the coming years, we’ll have more money and more job titles. With these resources, come better implementations of Ruby. He says some of these are here now, but there will be more to make Ruby faster, more feature rich, and providing more satisfaction to us, the developers. He also says one of the great things will be all the new developers who are coming to Ruby, and he says “Welcome them, nourish them”. He says there are people who learn Ruby as a first language, and they go on to become great programmers. [Tim: I wonder what happens to people who start in Ruby, and then see C++]

He says he loves us all.

RubyConf 2008!

I’m here at RubyConf with some of the Cloudspace team. Also, Corey has come in from North Carolina, gracing us with his presence, and his beard.

I’ll probably be posting from some of the sessions as I go. Long posts will be on this blog, short things and ‘overheards’ will be on my Twitter.

If you’re here, get in touch and say hi.

Arduino Follow-up

As a follow-up to yesterday’s post about Matt Williams’s presentation on Ruby and Arduino, here are some videos, slides, and notes from the ORUG site.

You absolutely must check this out. The field of robotics is going to play such a massive role in all of our lives over the next few years, and this is the ground floor.

*Going up?*

Physical Computing with Ruby and Arduino

Just got back from this month’s ORUG, where Matthew Williams gave a presentation on using Ruby to control an Arduino. Matt is a very natural speaker, and the presentation was great. He even demoed a bartending robot he built, which should be featured on Make very soon.

I took notes during the presentation, and they are as follows, with links where possible.

Arduino is an open-source board

There’s Bluetooth Arduino boards

There’s an Arduino board that was developed in a circular shape. People have combined this with conductive thread and sewn it into clothing. Someone even integrated this with some LEDs into their clothing and made a shirt with turn signals for biking.

Matt showed a video of a Wii nunchuck integrated with an Arduino, hooked up to some servos, and made a robotic puppet that works just by moving the nunchuck (not the control stick, just the accelerometer motion).

There’s also a YouTube video with someone who built a 1-wheel Segway-esque skateboard. Matt claims there are only about 50 lines of code controlling this device.

So, onto the Ruby Arduino Framework.
http://rad.rubyforge.org/ << outdated
http://github.com/atduskgreg/rad/ << more up to date

Matt says that the Arduino Google Group is fantastic.

[Tim: The Arduino IDE looks a *lot* like the Processing IDE (the Java-based graphics language).]

RubyToC – Ruby To C project; converts your Ruby code into C++, then compile it into Arduino bytecode. Then, there are Rake tasks which will load it onto the board for you. Most — but not all — of the Arduino API has been ported to Ruby.

RAD Methods
input_pin(s)
output_pin(s)
digitalWrite | digitalRead
analogWrite | analogRead
serial_print | serial_read

He mentions a slick trick for controlling the 7-segment LED displays. Since there’s 7 segments, you need to set 7 values separately, OR just create an array of those, and set them all with a single assignment.

Coming soon to RAD framework:

• Testing
• Arduino Simulator (for testing)
• Better RubyToC support (there’s a few hacks required because ToC isn’t perfect)
• More “out of the box” support
  • LCDs
  • OLED displays

Arduino “shields”
Shields are boards that can be plugged directly on top of the Arduino that add major new functionality.

• NYCResistor.com built a device that has sliders, like an audio mixing board. I bet it goes up to 11.
• 802.11 addons also exist
• Controlling motors
• There’s a $30 “ping” sensor from Radio Shack that detects distance in *inches*. Basically, you can add sonar to your Arduino.
• OLED touchscreen
• Pin visualizer — lets you debug pin outputs easily, shows you the voltages coming out of the board. Great for debugging. No one is sure if the code for these (debugging) takes up space on the Arduino in place of your code

Where to buy? Only $34.95 at
http://www.sparkfun.com
http://www.makezine.com (Matt strongly recommends subscribing to Make, says the dead trees copy is excellent)

Cheaper versions are available, but they either have components removed, or you must assemble it yourself

Make published a “get started with Arduino” kit, about $80, includes project info, the Arduino, extra parts. Most of the parts required for the project are included in the kit.

Barduino – DRINK MIXING ROBOT (created by Matt, who is clearly demonstrating his aptitude as a proper geek)
He used windshield washer pumps, $9/each

Matt created a DSL for describing drinks

drink ‘Screwdriver’ do
serve_in ‘Highball Glass’
ingredients do
2.ounces :vodka
5.ounces range_juice
end
end

Matt mentioned a hack, some functions that accept only one param will get converted (by RubyToC) to functions that accept none, so, the following line fixes it

def dispense(pump)
foo = pump + 0 /* This is the fix */
…
end

For more Ruby Arduino…

RubyConf 2008, Friday, 10:25 – 11:05, Room 3
Greg Borenstein — author of the Ruby Arduino framework — is presenting

Questions:

Can you “brick” an Arduino?
Not via code, but you could put too much power into it and fry it. Matt thinks there’s a little surge protection on it.

Can you sync Arduinos?
He’s seen something like it, and thinks that the serial comm lines would make it fairly easy to do.

Twitter Autocomplete (Tw-autocomplete Firefox Extension)

After lots of code, tests, and fun, I’ve produced a Firefox extension to add a useful, new feature to Twitter, as opposed to writing Twitter extensions as a joke

Simply put, the extension provides autocomplete for Twitter usernames from your own list of friends while you’re using the web interface at twitter.com. It’s totally secure — no separate login required. Just install it, and use Twitter naturally.

When you start typing messages to people — using “@user” or “d user” — a list of matching contacts (along with icons) will drop in. You can click the person’s name to fill their username into the text box, or use the arrow keys along with tab/enter to select. As an added bonus, if you can’t remember their username at all, just type their first name, and the extension will figure it out.

There is another autocomplete script for Twitter, but it requires installing extra libraries, and I think this is simpler. Clearly it’s a feature in-demand.

The extension is hosted at addons.mozilla.org, a highly reputable site. They also provide lots of great management features that are handy to developers. I hope you enjoy using Tw-autocomplete.

Javascript Events, the DOM, and Firefox/Gecko

OK, here’s the deal, as quick as I can put it, but with enough words that Google will correctly index this post and make this information easier to find for the next person who needs it.

Let’s say you’re developing a Firefox extension, and you need to look at the HTML of the page. You know that Firefox is constantly throwing event notifications — there’s the MouseEvent “click” when something is clicked, the KeyboardEvent “keyup” when a key is release, and so on.

So, you figure “well, I need the HTML of the page, so I’ll wait until it loads, then grab the source/parse the DOM tree/unleash flying monkeys”. You know that the style of

window.onload = the_function_name;

is bad, because it only lets one function receive the load event. So, you write some code like

gBrowser.addEventListener(“load”, the_function_name, true);

because this is what you want. You wait for the “load” event to fire, and then run your function. Test this code out, and it will work well-enough, most of the time. Sometimes, it lags, sometimes it doesn’t even fire at all. WTF? Well, I’ve been there.

Here’s the thing: the “load” event fires when loading is done. If you’re looking at the whole window/document, it’s not done loading until the whole document is loaded, including bandwith-and-time-heavy images. And these things can be slow to load, or hang entirely. This can seriously mess with the concept of “loading”. You don’t care about any of these things, you just want the HTML.

Well, Firefox is a very deep project, and there’s a few secret events that aren’t widely used or documented. If you want to know when the HTML is loaded — or more accurately, when the DOM Tree’s content is loaded — there’s a special event you can monitor: “DOMContentLoaded”

gBrowser.addEventListener(“DOMContentLoaded”, the_function_name, true);

This is a very reliable way of knowing when the browser has loaded only the page. The catch is that it’s Firefox-internal only. Which means it only works from an extension — you can’t use this in a web page. There are techniques for duplicating this functionality in other browsers, but that’s getting beyond this post.

Javascript, Dates, Times, and One Man’s Dream

OK, so the title of this post might be a bit overstating.

But, if you work with Javascript and need to use dates/times, you should absolutely check out a JS library for formatted dates and times by Steven Levithan (who is obviously cool; his blog is titled “Flagrant Badassery”).

It’s a library that extends the stock Date object in Javascript to let you easily generate nicely formatted dates. Just put the code in a file and load it up. Then you can do neat things like this (adapted from his blog)

var now = new Date();

now.format(“m/dd/yy”);
// Returns, e.g., 6/09/07

// You can use one of several named masks
now.format(“isoDateTime”);
// 2007-06-09T17:46:21

// …Or add your own
dateFormat.masks.hammerTime = ‘HH:MM! “Can\’t touch this!”‘;
now.format(“hammerTime”);
// 17:46! Can’t touch this!

Detecting page loads in a Firefox Extension

Detecting page loads is a useful ability. It’s easy enough to throw in a

gBrowser.addEventListener(“load”, function_name, true);

But, it causes extra events to get generated. There’s load events occurring in the browser that aren’t page loads. The trick to detecting real page loads (but not Back/Forward navigation when the page is still in memory — only page loads that have a server hit) is to look at the event’s target. In this example, “event” has been passed into the function specified in the addEventListener call above.

if(event.originalTarget instanceof HTMLDocument) {

will make sure that the load event came from a web page being loaded. You can even go a step further and filter out different types of HTMLDocuments.

if(event.originalTarget.defaultView.frameElement) {

will catch events that were triggered as the result of a frame or iframe. It’s an important step, because lots of advertising networks embed their ads in iframes, and you probably are more interested in the actual web page than the ads on that page.

Mash it yourself

Corey sent me a link to Ubiquity, a dynamic-mashup-maker-that-reminds-me-of-Quicksilver. The video is cool looking, I may keep an eye on this project to see where they go with it. I think it’s a useful tool if you have these specific tasks coming up often, and the ability to make new commands is neat.

Trash aware rm for OSX — never lose a file again

OK, so let’s say you’re an OSX user, and you use the command line a lot. I bet you’ve accidentally deleted a file using rm, and wished that it had gone to the Trash.

We had this problem a few days ago, and fortunately the file was under version control. But we looked for a solution that would rm into the trash. There was only one solution and it didn’t work in Leopard (10.5)

I mentioned this on Twitter, and my buddy Jason threw a working version of trash-aware-rm for OSX together in no time flat. Check it out.