Skip to main content

Tetris in Dart


For my first Dart program, I decided to implement Tetris. I was inspired by Alexei Kourbatov at javascripter.net which contains an implementation of Tetris he wrote way back in 1999!

You can play my version here. The source code is here.

Overall, I like Dart. The Dart version of my code is about the same length as the JavaScript version of my code (the Dart version is slightly longer because I switched from using innerHTML to using the DOM). The combination of the optional static typing and Dart Editor helped me avoid many, many bugs. I'm still a Python guy at heart, but my experience with Dart was a very pleasant one.


I jotted down some lessons I learned. Warning: This is my first Dart program, and I haven't even read the tutorial yet, so I could be missing the boat on some of these points!

Don't try to play with DOM elements before the DOM is loaded. The easiest way to achieve this is to import your Dart-compiled JavaScript at the bottom of the page.

Dart has generics. This is a little unfamiliar for a scripting guy like me.

I had a hard time finding methods like JavaScript's Math.abs and Math.floor. They're now members of num.

This is how you add to the DOM:
HTMLDocument doc = window.document;
HTMLParagraphElement p = doc.createElement('p');
p.textContent = message;
doc.body.appendChild(p);
Using innerHTML works too, but I suspect it's frowned upon.

DOM manipulation isn't as easy as using innerHTML. It's not quite as horrible as I feared, but it's still a pain in the butt.

Sometimes you need to use a temporary variable to help out the type system. If you write:
doc.getElementById("s-" + i + "-" + j).src = 'images/s0.png';
it'll say "'src' is not a member of Element." However, you can easily fix this by writing:
HTMLImageElement img = doc.getElementById("s-" + i + "-" + j);
img.src = 'images/s0.png';
Translating from JavaScript to well-typed Dart is a linearly time-consuming, but relatively straightforward progress.

The intelligent code completion in Dart Editor was really helpful since I don't really know the language or its APIs. I can edit text a lot faster in Vim, but code completion helps me know what to write.

Trying to figure out the proper way to handle keyboard events in Dart is hard because of the DOM. I'm looking at developer.mozilla.org/en/DOM/KeyboardEvent, and it looks like there are two ways to do things, the deprecated way, and the way that isn't implemented yet.

Command-g is the usual Apple shortcut to find the next occurrence of something, but it doesn't work in Dart Editor.

They're working on a new DOM API. I've decided not to use it until they say it's stable.

The way main() works in the Sunflower Example doesn't match the way main() works in sample applications generated by Dart Editor. I'm not sure why.

Comments

Eric Walstad said…
Very cool, JJ, thanks for sharing. It'll be interesting to see where Dart goes.
I like the insight you shared about Dart. Thanks.
jjinux said…
Moved the code to a new repository. Updated the links. Many changes have been made since originally posting this.

Popular posts from this blog

Drawing Sierpinski's Triangle in Minecraft Using Python

In his keynote at PyCon, Eben Upton, the Executive Director of the Rasberry Pi Foundation, mentioned that not only has Minecraft been ported to the Rasberry Pi, but you can even control it with Python. Since four of my kids are avid Minecraft fans, I figured this might be a good time to teach them to program using Python. So I started yesterday with the goal of programming something cool for Minecraft and then showing it off at the San Francisco Python Meetup in the evening.

The first problem that I faced was that I didn't have a Rasberry Pi. You can't hack Minecraft by just installing the Minecraft client. Speaking of which, I didn't have the Minecraft client installed either ;) My kids always play it on their Nexus 7s. I found an open source Minecraft server called Bukkit that "provides the means to extend the popular Minecraft multiplayer server." Then I found a plugin called RaspberryJuice that implements a subset of the Minecraft Pi modding API for Bukkit s…

Apple: iPad and Emacs

Someone asked my boss's buddy Art Medlar if he was going to buy an iPad. He said, "I figure as soon as it runs Emacs, that will be the sign to buy." I think he was just trying to be funny, but his statement is actually fairly profound.

It's well known that submitting iPhone and iPad applications for sale on Apple's store is a huge pain--even if they're free and open source. Apple is acting as a gatekeeper for what is and isn't allowed on your device. I heard that Apple would never allow a scripting language to be installed on your iPad because it would allow end users to run code that they hadn't verified. (I don't have a reference for this, but if you do, please post it below.) Emacs is mostly written in Emacs Lisp. Per Apple's policy, I don't think it'll ever be possible to run Emacs on the iPad.

Emacs was written by Richard Stallman, and it practically defines the Free Software movement (in a manner of speaking at least). Stal…

Creating Windows 10 Boot Media for a Lenovo Thinkpad T410 Using Only a Mac and a Linux Machine

TL;DR: Giovanni and I struggled trying to get Windows 10 installed on the Lenovo Thinkpad T410. We struggled a lot trying to create the installation media because we only had a Mac and a Linux machine to work with. Everytime we tried to boot the USB thumb drive, it just showed us a blinking cursor. At the end, we finally realized that Windows 10 wasn't supported on this laptop :-/I've heard that it took Thomas Edison 100 tries to figure out the right material to use as a lightbulb filament. Well, I'm no Thomas Edison, but I thought it might be noteworthy to document our attempts at getting it to boot off a USB thumb drive:Download the ISO. Attempt 1: Use Etcher. Etcher says it doesn't work for Windows. Attempt 2: Use Boot Camp Assistant. It doesn't have that feature anymore. Attempt 3: Use Disk Utility on a Mac. Erase a USB thumb drive: Format: ExFAT Scheme: GUID Partition Map Mount the ISO. Copy everything from the I…