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: +91,179 / -11,823

Top 5 Removed Lines	Top 5 Added Lines
`- }` × 98`- },` × 93`- );` × 87`- },` × 64`- )` × 63	`+}` × 75`+ },` × 72`+ }` × 65`+ }` × 52`+//` × 45

Top 20 Most Impacted Files

Rank	Size Rank	Diff Rank	Impact	+	-	File
1	2	11	3.4%	218	6,479	`hir/src_lib`
2	1	28	1.5%	165	11,159	`ide/src_hover_tests`
3	3	12	3.6%	216	6,084	`ide_assists/src_handlers_extract_function`
4	15	3	12.4%	373	3,020	`rust_analyzer/src_lsp_to_proto`
5	61	1	52.0%	784	1,509	`hir_expand/src_builtin_derive_macro`
6	7	14	5.1%	201	3,916	`ide/src_goto_definition`
7	28	6	13.0%	305	2,354	`hir_ty/src_next_solver_interner`
8	90	2	37.3%	428	1,147	`ide/src_navigation_target`
9	41	5	17.8%	335	1,882	`ide_assists/src_handlers_auto_import`
10	5	45	3.2%	132	4,173	`rust_analyzer/src_config`
11	59	4	23.6%	357	1,512	`hir_def/src_lib`
12	8	33	4.0%	152	3,788	`ide/src_rename`
13	14	26	5.6%	171	3,066	`ide/src_references`
14	33	13	9.3%	204	2,197	`ide_assists/src_handlers_add_missing_match_arms`
15	95	7	24.4%	273	1,121	`rust_analyzer/tests_slow-tests_ratoml`
16	13	52	4.0%	123	3,100	`ide_assists/src_handlers_generate_function`
17	44	16	10.5%	193	1,838	`ide_assists/src_handlers_generate_delegate_trait`
18	37	23	8.6%	174	2,034	`ide_assists/src_handlers_destructure_tuple_binding`
19	19	46	5.0%	132	2,635	`ide_assists/src_handlers_extract_variable`
20	52	17	11.6%	189	1,625	`ide/src_typing`

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 0.7.0