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: +97,036 / -13,578

Top 5 Removed Lines	Top 5 Added Lines
`- }` × 112`- },` × 93`- );` × 87`- ///` × 72`- },` × 64	`+}` × 75`+///` × 75`+ },` × 72`+ }` × 65`+ }` × 53

Top 20 Most Impacted Files

Rank	Size Rank	Diff Rank	Impact	+	-	File
1	7	1	41.0%	1,560	3,801	`rust_analyzer/src_config`
2	2	10	3.9%	248	6,433	`hir/src_lib`
3	1	21	1.8%	202	11,160	`ide/src_hover_tests`
4	3	16	3.7%	227	6,083	`ide_assists/src_handlers_extract_function`
5	15	4	12.5%	378	3,019	`rust_analyzer/src_lsp_to_proto`
6	60	2	53.4%	793	1,486	`hir_expand/src_builtin_derive_macro`
7	6	20	5.2%	202	3,915	`ide/src_goto_definition`
8	29	5	16.5%	377	2,290	`hir_ty/src_next_solver_interner`
9	88	3	38.0%	436	1,147	`ide/src_navigation_target`
10	8	38	4.0%	152	3,788	`ide/src_rename`
11	73	6	26.8%	344	1,283	`hir_def/src_lib`
12	46	12	13.5%	239	1,768	`ide_assists/src_handlers_auto_import`
13	33	18	9.4%	207	2,194	`ide_assists/src_handlers_add_missing_match_arms`
14	14	43	4.6%	140	3,029	`ide/src_references`
15	13	50	4.2%	131	3,088	`ide_assists/src_handlers_generate_function`
16	139	7	35.2%	305	867	`rust_analyzer/tests_slow-tests_ratoml`
17	124	8	29.1%	268	921	`hir_def/src_signatures`
18	21	48	5.3%	136	2,571	`ide_assists/src_handlers_extract_variable`
19	11	93	2.8%	93	3,267	`ide_completion/src_render`
20	43	25	10.4%	191	1,832	`ide_assists/src_handlers_generate_delegate_trait`

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 0.6.6