Skip to main content

Notes from the June 10 Dart language design meeting

The incomporable Bob Nystrom fills us in on the language design discussions taking place amongst Dart engineers. Here are his notes from the June 10th language meeting:

Here's my notes from this week's (short) meeting:

Name collisions with dart: imports

[A customer recently ran into an issue where a new type appeared in dart:html whose name collided with a name they were importing from elsewhere. This broke their app.]

Gilad brought up this issue. Pete's suggestion is if there's a collision between a "dart:" import and another library, the other library wins. That way, we can add stuff to "dart:" libraries without breaking people. I explained some more details here.

Lars asked if there are any negative consequences from that suggestion and when it needs to be fixed. Kasper suggested we start making it a warning [instead of an error?] now.

Ivan asked how JS handles this. Kasper said DOM names are usually higher up on the prototype chain so you get similar shadowing behavior there to what we're suggesting for Dart now.

Type guards

Folks in Aarhus had a discussion about type guards. When you do "if (x is Foo)" in the then branch can you statically tell x is of type Foo? The conclusion they came to is that if locals aren't final, the rules are so complicated it's not worth doing. With mutable locals, you get lots of problems with closures that assign to that local.

For finals, though, they are fine with inferring the type here as long as it doesn't make the rules too weird.

I asked about parameters which are non-final by default. Kasper says you can mark those final.

Cheers!

As always, view the changelog for the full list of changes, and to get started with the Editor see our tutorial.

Popular posts from this blog

Dart in 2016: The fastest growing programming language at Google, 2nd fastest growing in TIOBE Index

Dart was the fastest growing programming language at Google in 2016 with millions of lines of code written. It also made it to TIOBE Index Top 20 this month (see TIOBE's methodology).

It takes time to build something as ambitious as Dart and, in some ways, Dart is still in its infancy. But we're glad the hard work is starting to pay off.

Many thanks to our amazing community!

We're going to celebrate by ... releasing 1.22 next week (as per our usual 6 week release schedule).

AngularDart is going all Dart

Until now, the multiple language flavors of Angular 2 were written as TypeScript source, and then automatically compiled to both JavaScript and Dart. We're happy to announce that we’re splitting the Angular 2 codebase into two flavors – a Dart version and a TypeScript/JavaScript version – and creating a dedicated AngularDart team.

This is amazing news for Dart developers because:

The framework will feel more like idiomatic Dart.It will make use of Dart features that couldn't work with the TypeScript flavor. It will be faster.
This is equally great news for our TypeScript and JavaScript developers, by the way. Cleaner API, performance gains, easier contributions. Read more on the Angular blog.

Angular 2 for Dart is used by many teams at Google. Most famously by the AdWords team, but many other Google teams build large, mobile-friendly web apps. Some of the top requests from these teams were: make the API feel like Dart, provide a faster edit-refresh cycle, and improve applicat…

The new Google AdSense user interface: built with AngularDart

AdSense is a free, simple way to earn money by placing ads on your website. The team just launched a completely new version of their app for publishers. Read all about it here. We asked Daniel White, the tech lead for the project, some questions because the new UI happens to be built with Dart and Angular2.


AdSense launched way back in 2003. How long is it since the last big redesign?
Last big redesign was called ‘AdSense 3’ and launched about 6 years ago. It was written in Google Web Toolkit (GWT) and the UI has evolved through several iterations - but this is the first ground-up redesign in 6 years. There are a number of long-standing UX issues that we’ve taken the opportunity to solve. A big shout-out to our UX team who’ve been 100% behind this project. We couldn’t have done it without them!

How many software engineers worked on the project?
Purely on the AdSense applications, we have a team of close to 100. Around 25% of them write Dart.

How many lines of code?
We have around 160K LO…