Formatting

Fatou formats Julia source without starting Julia. After installation, run it from your project directory.

Format Files

Format one file in place, or pass a directory to format its .jl files:

fatou format src/example.jl
fatou format .

You can pass several paths in one invocation. Directory walks honor .gitignore and the exclusions in fatou.toml. Explicitly named files are still processed unless you add --force-exclude; see excluding files.

Check Without Writing

Use --check to verify formatting in CI or before committing:

fatou format --check .

The command prints diffs and exits nonzero if any file would change. Add --quiet to keep the file list and summary without printing diffs. See Integrations for GitHub Actions, pre-commit, and dprint.

Verify Preservation Before Writing

Use --safe to require verification that formatting preserves the parsed program and comments:

fatou format --safe src/

Fatou refuses malformed input or a result it cannot verify. When several files are supplied, it checks the entire batch before writing any of them. Combine the flag with --check to verify preservation and check layout without writes:

fatou format --safe --check .

Format Standard Input

Pass - to read a buffer from standard input and write the formatted result to standard output:

cat src/example.jl | fatou format -

--check requires file paths. For formatting inside an editor, follow Editor Setup.

Choose Formatting Settings

Put shared settings in fatou.toml:

[format]
line-width = 100
indent-width = 4

For a single run, use fatou format --line-width 100 src/example.jl. The configuration guide explains how to choose a style, and the configuration reference lists all options and defaults.

To apply lint fixes before formatting, follow the fix-and-format workflow.