Leo — ZedExt

Leo for Zed

A Zed extension for Leo and Aleo language support.

Features

Syntax highlighting for Leo files.
Syntax highlighting for Aleo files.
Outline symbols for Leo programs, structs, records, mappings, functions, transitions, and tests.
Runnable markers for Leo test functions annotated with @test.
Leo snippets.
Leo LSP integration through leo-lsp from PATH or a configured binary path.

Leo Tests

Zed currently requires a task template to bind runnable tags to commands. Add this once to your global Zed tasks.json:

[
  {
    "label": "leo test $ZED_CUSTOM_test",
    "command": "leo",
    "args": ["test", "$ZED_CUSTOM_test"],
    "cwd": "$ZED_WORKTREE_ROOT",
    "tags": ["leo-test"],
    "save": "all",
    "use_new_terminal": false,
    "allow_concurrent_runs": true
  }
]

After this is configured, Leo functions annotated with @test show a runnable marker in the editor gutter.

Tooling

The extension does not install Leo tooling. Install leo, leo-fmt, and leo-lsp separately, and make sure the commands are available on PATH.

If Zed cannot find leo-lsp on PATH, configure the binary in your Zed settings:

{
  "lsp": {
    "leo-lsp": {
      "binary": {
        "path": "/absolute/path/to/leo-lsp",
        "arguments": [],
        "env": {}
      }
    }
  }
}

The binary setting is optional. Use it only when the default leo-lsp lookup is not enough.

Formatting

leo-lsp 4.2.0 does not advertise LSP document formatting. leo-fmt currently formats files and directories in place. Zed external formatters must read source from stdin and write formatted source to stdout, so leo-fmt should not be configured as a Zed external formatter unless it gains stdin/stdout support.

To run leo-fmt manually from Zed, add a global task:

[
  {
    "label": "leo fmt current file",
    "command": "leo-fmt",
    "args": ["$ZED_FILE"],
    "cwd": "$ZED_WORKTREE_ROOT",
    "save": "current",
    "use_new_terminal": false,
    "allow_concurrent_runs": true
  }
]