Skip to main content

Dart Lang meeting: All objects hashable, and more

Posted by Bob Nystrom


Here's my notes from this week's Dart language meeting:


Getters and implicit "abstract"

Peter raised an interesting corner case with the new getter syntax and the
optional "abstract" keyword. Given this:

  class Foo {
    get bar;
  }

Does it define an abstract getter "bar" whose type is Dynamic, or a field "bar" whose type is "get"?

Gilad says the grammar isn't actually ambiguous here, so there's no problem. (get bar always defines an abstract getter because the spec disallows "get" as a type name.)

We discussed whether "abstract" should be optional or simply removed. Gilad says we should leave it optional in case people want to use it for emphasis. He also wonders if there's a case we aren't thinking of (maybe like the above?) where having it would be helpful to make something clear.

All objects hashable

This is coming in M1. (Woo!) It's just a matter of implementation. We want this in particular so that closures are hashable.

Doc comments

Lars wants to have the language specify the doc comment syntax so that things like the Editor can parse it. The plan is to go through our existing comments and see what subset of markdown we are actually using in practice and then specify that.

We also would like a doc comment form that works for single-line docs. With lots of short members, it's annoying to have to do:

  /**
   * Tiny comment.
   */
  void tinyMember() => 'blah';

I pointed out that I already borrowed "///" from C# and added support for it in Dartdoc, so they said we'll go with that.

Streaming string interpolation

Lars brought up an issue that he wonders if we'll want language support for at some point. The problem comes when you're getting some recursive structure and stringifying it to a stream. If you use interpolation in that, you can end up back at n^2 complexity.

Should we look into some kind of streaming support for string interpolation? No resolution yet.

Cheers!

Popular posts from this blog

A stronger Dart for everyone

We are constantly asking ourselves:
How do we make developers even more productive when writing Dart apps? We believe that a critical part of the answer to this question is to make strongmode – a sound static type system for Dart – the standard for all Dart developers.

Teams that use Dart to build apps like Soundtrap, AdWords, AdSense, and Greentea say they really enjoy using strong mode features, such as early error detection. In fact, teams that have switched completely to strong mode cite not only early error detection but also better code readability and maintainability as major benefits. We hear this both from small teams and Рeven more so Рfrom large teams with hundreds of developers writing and maintaining millions of lines of Dart code. As Björn Sperber from Soundtrap says,
Strong mode and the smooth integration with IntelliJ is a joy to use and a huge improvement. If you’ve tried out Flutter, you’ve already used strong mode checks from the Dart analyzer.

Given the benefits …

AngularDart 3.0: Easy upgrade, better performance

AngularDart 3.0 is now available. It brings better performance and smaller generated code, while also making you more productive.


Version 3.0 is an evolution: although it has some breaking changes (detailed below), it is a smooth upgrade due to minimal public API adjustments. Most of the progress is under the hood—in code quality, stability, generated code size, performance, and developer experience.

Code quality:
2731 instances of making the framework code more type safe (using sound Dart).The AngularDart framework code size is down by 12%.Many additional style updates to the codebase:Changed to use idiomatic <T> for generic methods.Removed NgZoneImpl, all the code exists in NgZone now.Stability:
Many CSS encapsulation fixes due to update with csslib package.Fixed bugs with IE11.

Performance:
For the Mail sample app, we see 30% faster time-to-interactive (currently 3812 ms on a simulated 3G connection, measured via Lighthouse).Our large app benchmark shows 2x faster render times of…

Dart 1.24: Faster edit-refresh cycle on the web & new function type syntax

Dart 1.24 is now available. It includes the Dart Development Compiler and supports a new generic function type syntax. Get it now!


Figure 1: DDC debugging in Chrome.

Some notable changes in this release:
pub serve now has support for the Dart Development Compiler. Unlike dart2js, this new compiler is modular, which allows pub to do incremental re-builds for pub serve.In practice what that means is you can edit your Dart files, refresh in Chrome (or other supported browsers), and see your edits almost immediately. This is because pub is only recompiling your package, not all packages that you depend on.There is one caveat with the new compiler, which is that your package and your dependencies must all be strong mode clean.You can also use the new compiler to run your tests in Chrome much more quickly than you can with dart2js.Read more in the changelog.You can now publish packages that depend on the Flutter SDK to pub. Moreover, pub.dartlang.org has started tagging Flutter plugins with …