arity-formatter

The deterministic, rule-based R formatter behind arity, extracted so that other tools (for example a dprint plugin) can embed it.

Output is decided solely by the formatter's rules and its best-fit layout engine---the input's existing line breaks never influence the result. The target style is the tidyverse R style guide.

use arity_formatter::format;

let formatted = format("x<-(1+2)*3^4\n").unwrap();
assert_eq!(formatted, "x <- (1 + 2) * 3^4\n");

Configure via FormatStyle and format_with_style. The optional serde feature makes FormatStyle (de)serializable (kebab-case keys, matching arity.toml); the schema feature additionally derives schemars::JsonSchema.

Use format_verified (or its _with_style / _with_options variants) when an integration should additionally check normalized R syntax, ordinary comment preservation, and formatting idempotence. Ordinary format remains the single-pass path.

This crate's API is still early and may change between releases; it is versioned independently of the arity CLI.