Add documentation for the IDE support

Author: smarter

docs/docs/index.md

@@ -16,8 +16,9 @@ Contents
 
 * Usage
     - [Migrating from Scala 2](usage/migrating.md): migration information
-    - [Dotty projects with cbt](usage/cbt-projects.md): using cbt
     - [Dotty projects with sbt](usage/sbt-projects.md): using sbt
+    - [IDE support for Dotty](usage/ide-support.md)
+    - [Dotty projects with cbt](usage/cbt-projects.md): using cbt
 * Contributing
     - [Getting Started](contributing/getting-started.md): details on how to run tests, use the cli scripts
     - [Workflow](contributing/workflow.md): common dev patterns and hints

docs/docs/usage/ide-support.md

@@ -0,0 +1,58 @@
+---
+layout: doc-page
+title: "IDE support for Dotty"
+---
+
+Dotty comes built-in with the Dotty Language Server, an implementation of the
+[Language Server Protocol](https://github.com/Microsoft/language-server-protocol),
+which means that any editor that implements support for the LSP can get a great
+Dotty integration. Currently, the only IDE we officially support
+is [Visual Studio Code](https://code.visualstudio.com/).
+
+Prerequisites
+============
+To use this in your own Scala project, you must first get it to compile with
+Dotty, please follow the instructions at https://github.com/lampepfl/dotty-example-project
+
+Usage
+=====
+1. Install [Visual Studio Code](https://code.visualstudio.com/).
+2. In your project, run:
+```shell
+sbt launchIDE
+```
+
+Status
+======
+
+## Fully supported features:
+- Typechecking as you type to show compiler errors/warnings
+- Type information on hover
+- Go to definition (in the current project)
+- Find all references
+
+## Partially working features:
+- Completion
+- Renaming
+- Go to definition in external projects
+
+## Unimplemented features:
+- Documentation on hover
+- Formatting code (requires integrating with scalafmt)
+- Quick fixes (probably by integrating with scalafix)
+
+## Current limitations, to be fixed:
+- Projects should be compiled with sbt before starting the IDE, this is
+  automatically done for you if you run `sbt launchIDE`.
+- Once the IDE is started, source files that are not opened in the IDE
+  should not be modified in some other editor, the IDE won't pick up
+  these changes.
+- Not all compiler errors/warnings are displayed, just those occuring
+  during typechecking.
+
+
+Feedback
+========
+Please report issues on https://github.com/lampepfl/dotty/issues,
+you can also come chat with use on the
+[Dotty gitter channel](https://gitter.im/lampepfl/dotty)!

docs/sidebar.yml

@@ -3,10 +3,12 @@ sidebar:
       url: blog/index.html
     - title: Usage
       subsection:
-        - title: cbt-projects
-          url: docs/usage/cbt-projects.html
         - title: sbt-projects
           url: docs/usage/sbt-projects.html
+        - title: IDE support for Dotty
+          url: docs/usage/ide-support.html
+        - title: cbt-projects
+          url: docs/usage/cbt-projects.html
         - title: Dottydoc
           url: docs/usage/dottydoc.html
         - title: Migrating