Friday, September 7, 2012

Dart Language Nears M1 State

Posted by Seth Ladd

Dart Team Updates - August 18-Sept 4th


Learn more at http://dartlang.org

Summary
  • The language spec is nearing its M1 state, the core libraries have been unified, the VM and dart2js implement more M1 features, and the editor improves on static analysis, refactorings, and quick fixes.

Details

Dart language specification:
  • 0.11 spec nearing completion: all M1 features covered.

Dart libraries [core, unittest, i18n, etc]:
  • The core and coreimpl libraries have been unified across dart2js and the VM. There are still implementation-dependent sources, but there is only one corelib and the SDK only contains implementation-independent files.

Dart VM:
  • New compiler: Deoptimization support, class hierarchy analysis, unboxing of doubles in select instructions, smi and class check elimination, stackmaps for live registers and simple inlining.
  • Language features: Argument definition test (aka '?' prefix operator), abstract class handling, disabled legacy try-catch.
  • Started removal of explicit interfaces in core library code, added Expando implementation.
  • Tuned performance of string operations and native calls.
  • Working down the queue of security fixes.
  • Resolved a few stability issues caused by missing store barriers.

Dart to JavaScript Compiler:
  • Language features: Added support for annotations (metadata), enabled calling non-functions through the call method, removed #resource directive.
  • Re-triaged all bugs so we have a clearer picture on what goes into the M1 release.

Dart Editor:
  • M1 language migration wizard: Right click on your project and choose 'Clean up...'. We've implemented cleanups for catch blocks, the new getter syntax, operator equals, and library/import/source changes.
  • Dart syntax highlighting in the compare and refactoring dialogs.
  • Dart Editor build hook. If a build.dart script exists in a project, we'll invoke it as part of the Editor's build process. This allows for custom processing of changed resources, like for templating systems, generating Dart code, or scss --> css processing. There are sample scripts available at dart/samples/buildhook1 and dart/samples/buildhook2, as well as online at https://github.com/dart-lang/dart-web-components/blob/master/build.dart.
  • Our type inference engine has been enhanced to add support for inferring types from dart:html select().
  • The type inference engine now handles the case where a variable is assigned different types at different times, and will show you the intersection of legal method and field references. In addition we now infer the type of List and Map literals.
  • Added basic scss (http://sass-lang.com/) syntax highlighting.
  • dart:mirrors has been added to the SDK; the editor can now resolve the mirrors library and the types within it.
  • Added warnings for use of obsolete getter and catch syntaxes.
  • We now highlight single line /// dartdoc comments.
  • We now do a better job of displaying when the debugger halts at an uncaught exception.
  • The Editor workspace location has changed. The workspace is where we store information about your open files and folders. We had stored this in a 'workspace' directory co-located with the Editor application. We now always locate it in the user's home directory. The first time you run this new build you'll have to re-open the folders you had been working on. For more info, see http://www.dartlang.org/docs/editor/#settings.
  • Several libraries have moved from dart-sdk/lib to dart-sdk/pkg. This means that they will not show up in the Files view and will no longer be accessible (erroneously) as a dart: import. You'll want to use pub to access these pkg libraries.
  • 17 analysis issues fixed, as well as ongoing changes to support the M1 language.
  • General fixes and enhancements to the rename refactoring, code completion, the extract variable refactoring, hyperlinking, searchbox UX, and the debugger UX.

Dart UI [dart:html, web components]:
  • XMLHttpRequest is now HttpRequest. Because seriously, when is the last time you sent XML over XMLHttpRequest? :)

Dart SDK and build:
  • SDK no longer contains VM-specific files for core and coreimpl libraries.

Pub:
  • Lots of bug fixing (7 issues fixed, more merged or re-routed).
  • More pub documentation.
  • Move some internal packages (args, yaml, etc.) over to pub.dartlang.org.
  • Dogfood pub.dartlang.org with Dart team.

Dart Server [dart:io, etc.]:
  • Bug fixes.
  • Work in progress on HTTPS support.

Dev Rel:
    • Updating Language Tour and book to M1