Rein for VS Code
Syntax highlighting, snippets, and language server support for .rein files.
Rein mimics TypeScript syntax and types, except @ references (for example @./ci/fix). The grammar follows TypeScript's scope names.
Every language feature comes from the Rust language server, rein lsp, in the rein repo. The extension starts the server and passes requests to it. It holds no feature logic.
Requirements
VS Code 1.85 or later.
The rein CLI on your PATH, or the full path to it in rein.serverPath. Install it from the rein repo:
cargo install --git https://github.com/rein-lang/rein rein
Install
Install Rein Language from the Marketplace:
code --install-extension rein-lang.rein-language
To install a local build instead, package this repo and install the vsix:
pnpm install
pnpm run package
code --install-extension rein-language-0.1.1.vsix
If VS Code cannot find rein, set rein.serverPath to the full binary path.
Features
A program is one folder with a main.rein. A reference cannot leave its program, so references, call hierarchy and rename stay in one program.
| Feature |
VS Code command |
What it does |
| Diagnostics |
(live) |
The checker's errors and warnings, on every change. |
| References |
Find All References |
On a function's name, on a @./ reference, or anywhere else in a function's file: every reference to that function. On a parameter, or on name= in a call: its uses, and name= in every call to its function. |
| Reference count |
Code lens |
N references above each function, and above each shared struct. Click it to list them. |
| Go to definition |
Go to Definition |
A reference goes to its function. A parameter or name= goes to the parameter. A struct type goes to its interface. A field goes to its place in the interface. A std template, such as delegate, opens its source. |
| Call hierarchy |
Show Call Hierarchy |
Incoming: the functions that reference this one. Outgoing: the functions this one references. |
| Hover |
(mouse) |
On a function or reference: the doc comment and the parameters. On a parameter, field or name=: its type and question. On a struct: its doc and fields. On a std name: its doc. |
| Rename |
Rename Symbol |
A parameter: its uses and name= in every call. A field: its interface, its uses, and name= in every call. A function: its file, in the same folder, and every reference to it. A shared struct: its file and every type that names it. |
| Outline |
Go to Symbol in Editor |
The function, with its parameters and const answers. Each struct, with its fields. |
| Workspace symbols |
Go to Symbol in Workspace |
Every function of every program in the workspace, by its path, such as billing/refund. Each shared struct, by its path. |
| Completion |
(typing) |
After @./: the functions of the program. After }: : the shared structs. In call parentheses: the parameter names (or struct fields) not given yet, as name=. After x === " or case ": the union members. Elsewhere: parameters, std names, and keywords. |
| Signature help |
(typing) |
In call parentheses: the callee's parameters (or struct fields), with the current one marked. |
| Quick fixes |
Quick Fix |
Add a missing doc comment to a function or a parameter. Add name= to a positional argument. |
Development
- Clone the rein repo and build its CLI, for example
cargo build -p rein.
- Run
pnpm install in this repo.
- Open this repo in VS Code and press F5. Enter the path to the rein checkout when asked. The Extension Development Host opens that checkout.
- In that window, the extension uses
target/debug/rein or target/release/rein from the checkout when either exists. This lookup applies only to a rein.serverPath set to its default, rein. It assumes the Cargo layout of the rein repo.
Test
pnpm test runs the findServer tests and the grammar tests. The grammar tests tokenize sample code with vscode-textmate and check the scopes. They need no editor and no network.
The language features have their tests in the rein repo: cargo test -p rein --test lsp.
Commands
Rein: Restart Language Server restarts the language server.rein.showReferences is internal. The reference code lens uses it to open the references view.
Settings
rein.serverPath (default rein): path to the rein binary. It starts as <path> lsp.rein.trace.server (off, messages, verbose): traces the messages between VS Code and the server.
Release
Releases come from git; nobody publishes by hand.
- Give each pull request a Conventional Commits title, such as
feat: ... or fix: .... The PR title check flags a bad title; do not merge while it is red. The repo allows squash merge only, so the title becomes the changelog line.
- On each merge to
main, release-please keeps a release pull request open. It bumps package.json and writes CHANGELOG.md.
- Merge the release pull request. It tags the version, makes a GitHub release, and the publish workflow publishes the version to the Marketplace.
License
MIT. See LICENSE.
