142 lines
4.2 KiB
Markdown
142 lines
4.2 KiB
Markdown
# libsyntax2.0
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[](https://travis-ci.org/matklad/libsyntax2)
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[](https://ci.appveyor.com/project/matklad/libsyntax2/branch/master)
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libsyntax2.0 is an **experimental** parser of the Rust language,
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intended for the use in IDEs.
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[RFC](https://github.com/rust-lang/rfcs/pull/2256).
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## Quick Start
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```
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$ cargo test
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$ cargo parse < crates/libsyntax2/src/lib.rs
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```
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## Trying It Out
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This installs experimental VS Code plugin
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```
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$ cargo install-code
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```
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It's better to remove existing Rust plugins to avoid interference.
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Warning: plugin is not intended for general use, has a lot of rough
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edges and missing features (notably, no code completion). That said,
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while originally libsyntax2 was developed in IntelliJ, @matklad now
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uses this plugin (and thus, libsytax2) to develop libsyntax2, and it
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doesn't hurt too much :-)
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### Features:
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* syntax highlighting (LSP does not have API for it, so impl is hacky
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and sometimes fall-backs to the horrible built-in highlighting)
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* commands (`ctrl+shift+p` or keybindings)
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- **Show Rust Syntax Tree** (use it to verify that plugin works)
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- **Rust Extend Selection** (works with multiple cursors)
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- **Rust Matching Brace** (knows the difference between `<` and `<`)
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- **Rust Parent Module**
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- **Rust Join Lines** (deals with trailing commas)
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* **Go to symbol in file**
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* **Go to symbol in workspace**
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- `#Foo` searches for `Foo` type in the current workspace
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- `#foo#` searches for `foo` function in the current workspace
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- `#Foo*` searches for `Foo` type among dependencies, excluding `stdlib`
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- Sorry for a weired UI, neither LSP, not VSCode have any sane API for filtering! :)
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* code actions:
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- Flip `,` in comma separated lists
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- Add `#[derive]` to struct/enum
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- Add `impl` block to struct/enum
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- Run tests at caret
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* **Go to definition** ("correct" for `mod foo;` decls, index-based for functions).
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## Code Walk-Through
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### `crates/libsyntax2`
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- `yellow`, red/green syntax tree, heavily inspired [by this](https://github.com/apple/swift/tree/ab68f0d4cbf99cdfa672f8ffe18e433fddc8b371/lib/Syntax)
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- `grammar`, the actual parser
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- `parser_api/parser_impl` bridges the tree-agnostic parser from `grammar` with `yellow` trees
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- `grammar.ron` RON description of the grammar, which is used to
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generate `syntax_kinds` and `ast` modules.
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- `algo`: generic tree algorithms, including `walk` for O(1) stack
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space tree traversal (this is cool) and `visit` for type-driven
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visiting the nodes (this is double plus cool, if you understand how
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`Visitor` works, you understand libsyntax2).
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### `crates/libeditor`
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Most of IDE features leave here, unlike `libanalysis`, `libeditor` is
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single-file and is basically a bunch of pure functions.
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### `crates/libanalysis`
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A stateful library for analyzing many Rust files as they change.
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`WorldState` is a mutable entity (clojure's atom) which holds current
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state, incorporates changes and handles out `World`s --- immutable
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consistent snapshots of `WorldState`, which actually power analysis.
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### `crates/server`
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An LSP implementation which uses `libanalysis` for managing state and
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`libeditor` for actually doing useful stuff.
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### `crates/cli`
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A CLI interface to libsyntax
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### `crate/tools`
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Code-gen tasks, used to develop libsyntax2:
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- `cargo gen-kinds` -- generate `ast` and `syntax_kinds`
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- `cargo gen-tests` -- collect inline tests from grammar
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- `cargo install-code` -- build and install VS Code extension and server
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### `code`
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VS Code plugin
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## Performance
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Non-incremental, but seems pretty fast:
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```
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$ cargo build --release --package cli
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$ wc -l ~/projects/rust/src/libsyntax/parse/parser.rs
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7546 /home/matklad/projects/rust/src/libsyntax/parse/parser.rs
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$ ./target/release/cli parse < ~/projects/rust/src/libsyntax/parse/parser.rs --no-dump > /dev/null
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parsing: 21.067065ms
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```
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## Getting in touch
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@matklad can be found at Rust
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[discord](https://discordapp.com/invite/rust-lang), in
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#ides-and-editors.
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## License
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libsyntax2 is primarily distributed under the terms of both the MIT license
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and the Apache License (Version 2.0).
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See LICENSE-APACHE and LICENSE-MIT for details.
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