prose-formatter 0.8.0

A Python typesetter for the reader.

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🪻 About

Prose formats Python source to be legible at a glance. It aligns equals signs and colons vertically across consecutive lines, places one entry per line in dictionaries and lists, alphabetizes methods and fields within their groups, applies a singleton rule for colon padding, and treats code like prose rather than minified text.

[!NOTE] Prose is still pre-1.0. The rule catalog and configuration facets continue to grow across release lines.

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🗞️ Philosophy

Code is read far more often than it is written. A reader's eye moves down a page and across adjacent lines looking for parallels, patterns, and shape. When every = sits at a different column and every collection is compressed onto one line, that shape disappears, forcing the eye to slow down. Prose restores it, with aligned columns letting the eye skim, one-per-line collections making each entry a unit, and alphabetized groupings giving every reader the same landmarks.

The trade-offs minimalist formatters were built to avoid (wider diffs, more vertical scrolling, occasional re-alignment churn) no longer dominate the equation. Agentic assistants do much of the typing, and every modern code host offers whitespace-ignoring diffs. What remains is the daily experience of reading code.

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🪄 Install & Usage

uv tool install prose-formatter

The binary exposes format, check, rules, server, cache, completions, and schema:

prose format path/             # rewrite files in place
prose check path/              # exit non-zero on violations
prose format --diff path/      # show the diff without writing
prose check --stdin < file.py  # read from stdin
prose format - < file.py       # `-` reads from stdin too
prose rules                    # list the rules in pipeline order
prose schema                   # print the config's JSON Schema
prose server                   # language server over stdio

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📰 Further Reading

The full edition lives at prose.fyi:

• The interactive sandbox formats Python live in the browser, so a reader can watch a snippet settle into shape without installing anything.
• The rule catalog walks every rule with before/after fixtures and per-facet configuration.
• The configuration reference covers the prose.toml, .config/prose.toml, and pyproject.toml config files, every key, and the [rules] toggles.
• The cache reference covers the cache directory, --no-cache, the [cache] table, and the prose cache subcommands.
• The exit-code matrix is the contract CI gates and pre-commit hooks compile against.
• Suppression directives cover # prose: off, # prose: skip, and the rest of the directive surface.
• Composition with Ruff pairs the token-level formatter with prose format.
• Editor, pre-commit, and CI integrations wire Prose into the development loop.

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🗜️ Development

Prose is a Rust crate that ships as a Python wheel through maturin, with mise managing the Rust toolchain, Python interpreter, and every supporting CLI through a single mise config. After installing mise and activating it in your shell, three commands provision the rest:

git clone https://github.com/Jybbs/prose.git
cd prose
mise install

mise tasks lists every available task, and mise ci runs the full local sweep that mirrors GitHub Actions.

For the architecture, the primitive surface walks every public type (Source, Pipeline, BindingAnalysis, SuppressionMap, RuleId, Edit), and the pipeline order explains how each rule reads a settled AST between reparses.