Merge #521

521: refresh docs r=matklad a=matklad



Co-authored-by: Aleksey Kladov <aleksey.kladov@gmail.com>

README.md

@@ -2,15 +2,13 @@
 
 [![Build Status](https://travis-ci.org/rust-analyzer/rust-analyzer.svg?branch=master)](https://travis-ci.org/rust-analyzer/rust-analyzer)
 
-Rust Analyzer is an **experimental** modular compiler frontend for the
+Rust Analyzer is an **experimental** modular compiler frontend for the Rust
-Rust language, which aims to lay a foundation for excellent IDE
+language, which aims to lay a foundation for excellent IDE support.
-support.
 
-It doesn't implement much of compiler functionality yet, but the
+It doesn't implement much of compiler functionality yet, but the white-space
-white-space preserving Rust parser works, and there are significant
+preserving Rust parser works, and there are significant chunks of overall
-chunks of overall architecture (indexing, on-demand & lazy
+architecture (indexing, on-demand & lazy computation, snapshotable world view)
-computation, snapshotable world view) in place. Some basic IDE
+in place. Some basic IDE functionality is provided via a language server.
-functionality is provided via a language server.
 
 Work on the Rust Analyzer is sponsored by
 
@@ -30,53 +28,45 @@ $ cargo run --package ra_cli parse < crates/ra_syntax/src/lib.rs
 
 # show symbols of a Rust file
 $ cargo run --package ra_cli symbols < crates/ra_syntax/src/lib.rs
+
+# install the language server
+$ cargo install --path crates/ra_lsp_server
 ```
 
-To try out the language server, see [these
+See [these instructions](./editors/README.md) for VS Code setup and the list of
-instructions](./editors/README.md). Please note that the server is not
+features (some of which are VS Code specific).
-ready for general use yet. If you are looking for a Rust IDE that
-works, use [IntelliJ
-Rust](https://github.com/intellij-rust/intellij-rust) or
-[RLS](https://github.com/rust-lang-nursery/rls). That being said, the
-basic stuff works, and rust analyzer is developed in the rust analyzer
-powered editor.
-
 
 ## Current Status and Plans
 
-Rust analyzer aims to fill the same niche as the official [Rust
+Rust analyzer aims to fill the same niche as the official [Rust Language
-Language Server](https://github.com/rust-lang-nursery/rls), but uses a
+Server](https://github.com/rust-lang-nursery/rls), but uses a significantly
-significantly different architecture. More details can be found [in
+different architecture. More details can be found [in this
-this
 thread](https://internals.rust-lang.org/t/2019-strategy-for-rustc-and-the-rls/8361),
-but the core issue is that RLS works in the "wait until user stops
+but the core issue is that RLS works in the "wait until user stops typing, run
-typing, run the build process, save the results of the analysis" mode,
+the build process, save the results of the analysis" mode, which arguably is the
-which arguably is the wrong foundation for IDE.
+wrong foundation for IDE.
 
-Rust Analyzer is a hobby project at the moment, there's exactly zero
+Rust Analyzer is an experimental project at the moment, there's exactly zero
 guarantees that it becomes production-ready one day.
 
-The near/mid term plan is to work independently of the main rustc
+The near/mid term plan is to work independently of the main rustc compiler and
-compiler and implement at least simplistic versions of name
+implement at least simplistic versions of name resolution, macro expansion and
-resolution, macro expansion and type inference. The purpose is two
+type inference. The purpose is two fold:
-fold:
 
-* to quickly bootstrap usable and useful language server: solution
+* to quickly bootstrap usable and useful language server: solution that covers
-  that covers 80% of Rust code will be useful for IDEs, and will be
+  80% of Rust code will be useful for IDEs, and will be vastly simpler than 100%
-  vastly simpler than 100% solution.
+  solution.
 
 * to understand how the consumer-side of compiler API should look like
-  (especially it's on-demand aspects). If you have
+  (especially it's on-demand aspects). If you have `get_expression_type`
-  `get_expression_type` function, you can write a ton of purely-IDE
+  function, you can write a ton of purely-IDE features on top of it, even if the
-  features on top of it, even if the function is only partially
+  function is only partially correct. Pluging in the precise function afterwards
-  correct. Plugin in the precise function afterwards should just make
+  should just make IDE features more reliable.
-  IDE features more reliable.
 
-The long term plan is to merge with the mainline rustc compiler,
+The long term plan is to merge with the mainline rustc compiler, probably around
-probably around the HIR boundary? That is, use rust analyzer for
+the HIR boundary? That is, use rust analyzer for parsing, macro expansion and
-parsing, macro expansion and related bits of name resolution, but
+related bits of name resolution, but leave the rest (including type inference
-leave the rest (including type inference and trait selection) to the
+and trait selection) to the existing rustc.
-existing rustc.
 
 ## Getting in touch
 

editors/README.md

@@ -4,72 +4,96 @@ To install experimental VS Code plugin:
 $ git clone https://github.com/rust-analyzer/rust-analyzer.git --depth 1
 $ cd rust-analyzer
 $ cargo install-code
+
+# for stdlib support
+$ rustup component add rust-src
 ```
 
-This will run `cargo install --packge ra_lsp_server` to install the
+This will run `cargo install --packge ra_lsp_server` to install the server
-server binary into `~/.cargo/bin`, and then will build and install
+binary into `~/.cargo/bin`, and then will build and install plugin from
-plugin from `editors/code`. See
+`editors/code`. See
-[this](https://github.com/matklad/rust-analyzer/blob/cc76b0d31d8ba013c499dd3a4ca69b37004795e6/crates/tools/src/main.rs#L192)
+[this](https://github.com/rust-analyzer/rust-analyzer/blob/0199572a3d06ff66eeae85a2d2c9762996f0d2d8/crates/tools/src/main.rs#L150)
-for details
+for details. The installation is expected to *just work*, if it doesn't, report
+bugs!
 
 It's better to remove existing Rust plugins to avoid interference.
 
-### Features:
+## Rust Analyzer Specifc Features
 
-* syntax highlighting (LSP does not have API for it, so impl is hacky
+These features are implemented as extensions to the langauge server protocol.
-  and sometimes fall-backs to the horrible built-in highlighting)
+They are more experimental in nature and work only with VS Code.
 
-* **Go to symbol in workspace** (`ctrl+t`)
+### Syntax highlighting
-  - `#Foo` searches for `Foo` type in the current workspace
-  - `#foo#` searches for `foo` function in the current workspace
-  - `#Foo*` searches for `Foo` type among dependencies, excluding `stdlib`
-  - Sorry for a weired UI, neither LSP, not VSCode have any sane API for filtering! :)
 
-* **Go to symbol in file** (`alt+shift+o`)
+It overrides built-in highlighting, and works only with a specific theme
+(zenburn). `ra-lsp.highlightingOn` setting can be used to disable it.
 
-* **Go to definition** ("correct" for `mod foo;` decls, approximate for other things).
+### Go to symbol in workspace <kbd>ctrl+t</kbd>
 
-* commands (`ctrl+shift+p` or keybindings)
+It mostly works on top of the built-in LSP functionality, however `#` and `*`
-  - **Show Rust Syntax Tree** (use it to verify that plugin works)
+symbols can be used to narrow down the search. Specifically,
-  - **Rust Extend Selection**. Extends the current selection to the
-    encompassing syntactic construct (expression, statement, item,
-    module, etc). It works with multiple cursors. Do bind this command
-    to a key, its super-useful!
-  - **Rust Matching Brace**. If the cursor is on any brace
-    (`<>(){}[]`) which is a part of a brace-pair, moves cursor to the
-    matching brace.
-  - **Rust Parent Module**. Navigate to the parent module of the current module
-  - **Rust Join Lines**. Join selected lines into one, smartly fixing
-    up whitespace and trailing commas.
-  - **Run test at caret**. When cursor is inside a function marked
-    `#[test]`, this action runs this specific test. If the cursor is
-    outside of the test function, this re-runs the last test. Do bind
-    this to a shortcut!
-  - **Format document**. Formats the current file with rustfmt.
-    Rustfmt must be installed separately with `rustup component add rustfmt`.
 
-* Typing assists
+- `#Foo` searches for `Foo` type in the current workspace
-  - typing `let =` tries to smartly add `;` if `=` is followed by an existing expression.
+- `#foo#` searches for `foo` function in the current workspace
-  - Enter inside comments continues comment (`<|>` signifies cursor position):
+- `#Foo*` searches for `Foo` type among dependencies, excluding `stdlib`
+- `#foo#*` seaches for `foo` function among dependencies.
 
-```
+That is, `#` switches from "types" to all symbols, `*` switches from the current
-/// Docs<|>
+workspace to dependencies.
-fn foo() {}
-```
 
-```
+### Commands <kbd>ctrl+shift+p</kbd>
-/// Docs
-/// <|>
-fn foo() {}
-```
 
-* code actions (use `ctrl+.` to activate).
+#### Show Rust Syntax Tree
 
+Shows the parse tree of the current file. It exists mostly for debugging
+rust-analyzer itself.
+
+#### Extend Selection
+
+Extends the current selection to the encompassing syntactic construct
+(expression, statement, item, module, etc). It works with multiple cursors. Do
+bind this command to a key, its super-useful! Expected to be upstreamed to LSP soonish:
+https://github.com/Microsoft/language-server-protocol/issues/613
+
+#### Matching Brace
+
+If the cursor is on any brace (`<>(){}[]`) which is a part of a brace-pair,
+moves cursor to the matching brace. It uses the actual parser to determine
+braces, so it won't confuse generics with comparisons.
+
+#### Parent Module
+
+Navigates to the parent module of the current module.
+
+#### Join Lines
+
+Join selected lines into one, smartly fixing up whitespace and trailing commas.
+
+#### Run
+
+Shows popup suggesting to run a test/benchmark/binary **at the current cursor
+location**. Super useful for repeatedly running just a single test. Do bind this
+to a shortcut!
+
+
+### On Typing Assists
+
+Some features trigger on typing certain characters:
+
+- typing `let =` tries to smartly add `;` if `=` is followed by an existing expression.
+- Enter inside comments automatically inserts `///`
+- typing `.` in a chain method call auto-indents
+
+
+### Code Actions (Assists)
+
+These are triggered in a particular context via lightbulb. We use custom code on
+the VS Code side to be able to position cursor.
 
 
 - Flip `,`
 
-```
+```rust
 // before:
 fn foo(x: usize,<|> dim: (usize, usize))
 // after:
@@ -78,7 +102,7 @@ fn foo(dim: (usize, usize), x: usize)
 
 - Add `#[derive]`
 
-```
+```rust
 // before:
 struct Foo {
     <|>x: i32
@@ -92,7 +116,7 @@ struct Foo {
 
 - Add `impl`
 
-```
+```rust
 // before:
 struct Foo<'a, T: Debug> {
     <|>t: T
@@ -106,3 +130,90 @@ impl<'a, T: Debug> Foo<'a, T> {
     <|>
 }
 ```
+
+- Change visibility
+
+```rust
+// before:
+fn<|> foo() {}
+
+// after
+pub(crate) fn foo() {}
+```
+
+- Introduce variable:
+
+```rust
+// before:
+fn foo() {
+    foo(<|>1 + 1<|>);
+}
+
+// after:
+fn foo() {
+    let var_name = 1 + 1;
+    foo(var_name);
+}
+```
+
+- Replace if-let with match:
+
+```rust
+// before:
+impl VariantData {
+    pub fn is_struct(&self) -> bool {
+        if <|>let VariantData::Struct(..) = *self {
+            true
+        } else {
+            false
+        }
+    }
+}
+
+// after:
+impl VariantData {
+    pub fn is_struct(&self) -> bool {
+        <|>match *self {
+            VariantData::Struct(..) => true,
+            _ => false,
+        }
+    }
+}
+```
+
+- Split import
+
+```rust
+// before:
+use algo:<|>:visitor::{Visitor, visit};
+//after:
+use algo::{<|>visitor::{Visitor, visit}};
+```
+
+## LSP features
+
+* **Go to definition**: works correctly for local variables and some paths,
+  falls back to heuristic name matching for other things for the time being.
+
+* **Completion**: completes paths, including dependencies and standard library.
+  Does not handle glob imports and macros. Completes fields and inherent methods
+
+* **Outline** <kbd>alt+shift+o</kbd>
+
+* **Signature Info**
+
+* **Format document**. Formats the current file with rustfmt. Rustfmt must be
+  installed separately with `rustup component add rustfmt`.
+
+* **Hover** shows types of expressions and docstings
+
+* **Rename** works for local variables
+
+* **Code Lens** for running tests
+
+* **Folding**
+
+* **Diagnostics**
+  - missing module for `mod foo;` with a fix to create `foo.rs`.
+  - struct field shorthand
+  - unnessary braces in use item