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: +94,024 / -13,420

Top 5 Removed Lines	Top 5 Added Lines
`- }` × 111`- },` × 93`- );` × 87`- ///` × 72`- },` × 64	`+}` × 75`+///` × 75`+ },` × 72`+ }` × 65`+ }` × 52

Top 20 Most Impacted Files

Rank	Size Rank	Diff Rank	Impact	+	-	File
1	7	1	40.9%	1,559	3,814	`rust_analyzer/src_config`
2	2	11	3.8%	245	6,440	`hir/src_lib`
3	1	33	1.5%	165	11,159	`ide/src_hover_tests`
4	3	16	3.6%	216	6,084	`ide_assists/src_handlers_extract_function`
5	15	5	12.4%	373	3,020	`rust_analyzer/src_lsp_to_proto`
6	6	19	5.1%	201	3,916	`ide/src_goto_definition`
7	60	2	53.4%	798	1,495	`hir_expand/src_builtin_derive_macro`
8	29	6	15.0%	346	2,313	`hir_ty/src_next_solver_interner`
9	89	3	37.3%	428	1,147	`ide/src_navigation_target`
10	67	4	30.5%	419	1,376	`hir_def/src_lib`
11	41	7	17.8%	335	1,882	`ide_assists/src_handlers_auto_import`
12	8	38	4.0%	152	3,788	`ide/src_rename`
13	14	31	5.6%	171	3,066	`ide/src_references`
14	33	17	9.3%	204	2,197	`ide_assists/src_handlers_add_missing_match_arms`
15	13	57	4.0%	123	3,100	`ide_assists/src_handlers_generate_function`
16	95	8	24.4%	273	1,121	`rust_analyzer/tests_slow-tests_ratoml`
17	44	20	10.5%	193	1,838	`ide_assists/src_handlers_generate_delegate_trait`
18	19	50	5.0%	132	2,635	`ide_assists/src_handlers_extract_variable`
19	37	28	8.6%	174	2,034	`ide_assists/src_handlers_destructure_tuple_binding`
20	11	97	2.8%	90	3,270	`ide_completion/src_render`

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 0.6.8