chloro

chloro is a minimal Rust code formatter.

Motivation

For when you want to format two source files in a consistent way, as fast as possible.

How it works

Using rowan from the rust-analyzer project, which can give both green and red trees. The latter are notoriously expensive, but a formatter should only need the former.

Proof of concept library/CLI to explore a fast and low memory code formatter [WIP], with use cases of code diffing in mind.

Rustfmt Conformance

Diff 'leaderboard' for how well formatting with chloro matches rustfmt, as tested on rust-analyzer's crates:

Summary: +101,906 / -13,957

Top 5 Removed Lines	Top 5 Added Lines
`- )` × 219`- r#"` × 140`- },` × 108`- check(` × 90`- );` × 87	`+ },` × 137`+"#)` × 104`+ }` × 87`+ check(r#"` × 79`+}` × 75

Top 20 Most Impacted Files

Rank	Size Rank	Diff Rank	Impact	+	-	File
1	2	8	4.8%	312	6,475	`hir/src_lib`
2	7	3	9.8%	379	3,856	`ide/src_goto_definition`
3	3	10	4.3%	264	6,086	`ide_assists/src_handlers_extract_function`
4	1	38	1.4%	161	11,159	`ide/src_hover_tests`
5	55	1	46.9%	728	1,551	`hir_expand/src_builtin_derive_macro`
6	15	4	12.3%	371	3,014	`rust_analyzer/src_lsp_to_proto`
7	28	6	15.0%	353	2,346	`hir_ty/src_next_solver_interner`
8	10	17	6.3%	219	3,495	`hir_def/src_expr_store_lower`
9	5	37	4.0%	166	4,157	`rust_analyzer/src_config`
10	95	2	39.9%	448	1,123	`ide/src_navigation_target`
11	8	33	4.6%	175	3,769	`ide/src_rename`
12	41	7	18.4%	346	1,881	`ide_assists/src_handlers_auto_import`
13	58	5	23.7%	358	1,513	`hir_def/src_lib`
14	14	30	5.8%	178	3,067	`ide/src_references`
15	13	34	5.6%	172	3,087	`ide_assists/src_handlers_generate_function`
16	26	18	8.8%	215	2,446	`ide/src_highlight_related`
17	44	13	13.5%	241	1,788	`ide_assists/src_handlers_generate_delegate_trait`
18	11	62	3.8%	125	3,267	`ide_completion/src_render`
19	33	22	9.0%	198	2,197	`ide_assists/src_handlers_add_missing_match_arms`
20	37	21	10.2%	205	2,013	`ide_assists/src_handlers_destructure_tuple_binding`

Installation

Add chloro to your Cargo.toml:

[dependencies]
chloro = "0.5"

CLI Installation

pre-built binary: cargo binstall chloro (requires cargo-binstall),
build from source: cargo install chloro --features cli

License

This project is licensed under either of:

Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

chloro 0.7.1