Skip to main content

Dec 3 language design meeting notes (Mixins)



Dart engineer Bob Nystrom has posted the notes from the December 3rd language design meeting. He writes:

If you're as excited about mixins as I am, you'll be happy. This week's language meeting was all about them. I tried to keep up as best as I could this week, but I'm not much of a secretary. Any omissions or mistakes are all my fault.

Lots of people were in this meeting. Except Lars, who is apparently in Austria with Katy Perry. I'm guessing that's a joke, but you can never tell...

Kasper likes the proposal but discussed some syntax changes with Peter.

They are discussing VM implementation since Ivan [VM lead] is in Aarhus [Kasper and Lars' office]. Does the mixin have to go in the superclass chain?

Gilad: There is well-defined semantic model and it has been implemented before.

Kasper: Where is it being in superclass chain visible? Reflection?

Gilad: In is checks too. You could also see it in super calls, but the current proposal says you can't have those.

Kasper: But the class mixing it in can have super calls.

Gilad: Yes, and there you should see mixin methods.

Kasper: Would a super in a class that extends a mixin application hit the superclass or the mixed in methods?

Gilad: Would hit superclass, which is mixed in methods.

Kasper: If you want to override a mixed in method...

Gilad: Yes, need to have same rules for how an override works.

Ivan: I thought a super call skips mixins and goes straight to class in extends clause.

Gilad: That's not the original intent. "Goes to superclass" means "go to the superclass which *is* the compound mixin application class".

Ivan: I thought it was more complicated then because you have to skip these other artificially created superclasses.

[More discussion here, the end result of which, I think is that this is easier to implement than Ivan originally thought.]

Kasper: Is it OK to canonicalize mixin applications?
Ivan: Is it legal to canonicalize but not forced?

Ivan is worried about class explosion. Gilad says he hasn't seen that in other languages.

I pointed out that we're doing more code generation like in web components, so there may be more artifically generated classes and mixins.

Kasper: I'm not too worried about canonicalization. It probably wouldn't be a breaking change if we changed it.

Ivan: I'd be more comfortable if it allowed but did not mandate it.

Kasper: The next step from my POV is agreeing on syntax.

Cheers!

As always, we invite you to join our Dart mailing list, ask questions on Stack Overflow, or file feature requests on dartbug.com.

Photo credit: http://arlingtonhousewife.files.wordpress.com/2010/08/batter-without-mixins.jpg

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 AdWords UI uses Dart — we asked why

Google just announced a re-designed AdWords experience. In case you’re not familiar with AdWords: businesses use it to advertise on google.com and partner websites. Advertising makes up majority of Google’s revenue, so when Google decides to completely redo the customer-facing front end to it, it’s a big deal. The Dart team is proud to say that this new front end is built with Dart and Angular 2. Whenever you asked us whether Google is ‘even using Dart for anything,’ this is what we had in mind but couldn’t say aloud. Until now. We asked Joshy Joseph, the primary technical lead on the project, some questions. Joshy is focusing on things like infrastructure, application latency and development velocity, so he’s the right person to ask about Dart.Q: What exactly did we launch on Monday?It’s a complete redesign of the AdWords customer experience that is rolling out slowly as a test to a small initial set of advertisers. The most noticeable thing is probably the Material Design look and f…