Update spec page (#1130)

Author: kwalrath

src/_guides/language/spec.md

@@ -1,73 +1,34 @@
 ---
-layout: default
-title: "Dart Language Specification"
-description: "The Dart language specification and proposed changes."
+title: Dart Language Specification
+description: The formal specification for the Dart language.
 ---
 
-Download the _Dart Programming Language Specification_ from
-the Ecma website:
+Use this page to find the formal Dart language specification.
+For a gentler introduction to Dart, see the
+[language tour](/guides/language/language-tour).
 
-* <a href="http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-408.pdf"
-   target="_blank">Dart Programming Language Specification, 4<sup>th</sup> Edition</a>
-
-For a gentler introduction to the Dart language, see the
-[Dart language tour](/guides/language/language-tour).
-
-You can find previous editions of the specification at
-[Standard ECMA-408](http://www.ecma-international.org/publications/standards/Ecma-408-arch.htm).
-
-
-## Dart 2 changes
+## Dart 2
 
 Dart 2 has changed the Dart language in many ways,
 some of which are not backward-compatible.
-For information about changes and implementation status,
-see the following resources:
-
-* [Dart 2 Updates](/dart-2)
-* [Dart Language and Library Newsletters](https://github.com/dart-lang/sdk/tree/master/docs/newsletter#dart-language-and-library-newsletters)
-* [Language specification source file (TeX format)](https://github.com/dart-lang/sdk/blob/master/docs/language/dartLangSpec.tex)
-* [Informal specifications](https://github.com/dart-lang/sdk/tree/master/docs/language/informal)
-
-
-## Changes in the 4<sup>th</sup> edition
-
-The 4<sup>th</sup> edition of the specification has fewer restrictions on mixins.
-The restrictions on mixins up until this edition were:
+For details, see the [Dart 2 page](/dart-2).
 
-* Mixins must inherit directly from Object.
-* Mixins cannot contain super calls.
-* Mixins cannot define constructors.
+The formal language specification is not yet up-to-date.
+For information about Dart 2 changes, see the following resources.
 
-Only the last one, mixins cannot define constructors, remains.
+* Feature specifications in the dart-lang/sdk repo:
+  * [docs/language/informal](https://github.com/dart-lang/sdk/tree/master/docs/language/informal)
+* Feature specifications in the dart-lang/language repo:
+  * [accepted](https://github.com/dart-lang/language/tree/master/accepted)
+  * [working](https://github.com/dart-lang/language/tree/master/working)
+* Dart language specification work in progress:
+  * [Source file (LaTeX format)](https://github.com/dart-lang/sdk/blob/master/docs/language/dartLangSpec.tex)
+  * [Community-contributed PDF built from the source file](https://github.com/chalin/dart-spec-and-grammar/blob/master/doc/dartLangSpec.pdf)
 
-## Changes in the 3<sup>rd</sup> edition
+## Dart 1.x
 
-The 3<sup>rd</sup> edition of the specification added information
-about the following new language features:
+Download the formal language specification from the Ecma International
+website:
 
-* Null-aware operators
-
-* [Generalized tear offs](https://github.com/gbracha/generalizedTearOffs/blob/master/proposal.md)
-
-{% comment %}
-Do we want to save this info on this page or delete it?
-
-## Changes in the 2<sup>nd</sup> edition
-
-The 2<sup>nd</sup> edition of the specification added information about
-the following new language features:
-
-* Enumerations (`enum`)<br>
-  Implemented in 1.8. For details, see the language tour:
-  [Enumerated types](/guides/language/language-tour#enums).
-
-* Asynchrony support (`async`, `await`, and more)<br>
-  Partially implemented in 1.8.
-  For details, see the language tour:
-  [Asynchrony support](/guides/language/language-tour#asynchrony).
-
-* Deferred loading (`import ... deferred as`)<br>
-  Implemented in 1.6. For details, see the language tour:
-  [Lazily loading a library](/guides/language/language-tour#deferred-loading).
-{% endcomment %}
+* <a href="http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-408.pdf"
+   target="_blank" rel="noopener">Dart Programming Language Specification, 4<sup>th</sup> Edition</a>

src/dart-2.md

@@ -58,7 +58,7 @@ from either Dart 1.x or an earlier version of Dart 2.
 
 1. **Get an up-to-date version of the Flutter or Dart SDK.**
    * [Flutter SDK instructions][Flutter SDK install]
-   * [Dart SDK instructions][Dart SDK install] (VM or web)
+   * [Dart SDK instructions][Dart SDK install] (server-side or web)
 2. **Upgrade the packages your app depends on.**
    * Flutter: [`flutter packages upgrade`][flutter package upgrade]
    * Server-side or web: [`pub upgrade`][pub upgrade]
@@ -81,8 +81,6 @@ from either Dart 1.x or an earlier version of Dart 2.
      `unnecessary_new` and `unnecessary_const` to the `linter` section of your
      [analysis options file][].
 
-Each time the SDK has a significant release, repeat the process.
-
 {% comment %}
 TODO:
 - talk about library vs. app migration?
@@ -144,7 +142,7 @@ environment:
 ## More resources
 
 * [DartPad](/tools/dartpad)
-* [Dart 2 changes][] section of the [Dart Language Specification][] page
+* [Dart Language Specification][]
 * [About Dart SDK release channels and version strings][pre-release]
 * [SDK constraints][]
 * [Updating your pub package to Dart 2,][]
@@ -167,7 +165,6 @@ environment:
 [build_runner web]: {{site.webdev}}/tools/build_runner
 [compile-time errors]: /guides/language/sound-problems#static-errors-and-warnings
 [creating library packages]: /guides/libraries/create-library-packages
-[Dart 2 changes]: /guides/language/spec#dart-2-changes
 [Dart 2 announcement]: https://medium.com/dartlang/announcing-dart-2-80ba01f43b6
 [Dart Language Specification]: /guides/language/spec
 [dart-lang/sdk CHANGELOG]: https://github.com/dart-lang/sdk/blob/master/CHANGELOG.md#200