Code style linter for Crystal
(a single-celled animal that catches food and moves about by extending fingerlike projections of protoplasm)
[🎬 Watch the LuckyCast showing how to use Ameba](https://luckycasts.com/videos/ameba)
### Autocorrection
Rules that are marked as `[Correctable]` in the output can be automatically corrected using `--fix` flag:
```sh
$ ameba --fix
```
### Explain issues
Ameba allows you to dig deeper into an issue, by showing you details about the issue
and the reasoning by it being reported.
To be convenient, you can just copy-paste the `PATH:line:column` string from the
report and paste behind the `ameba` command to check it out.
```sh
$ ameba crystal/command/format.cr:26:83 # show explanation for the issue
$ ameba --explain crystal/command/format.cr:26:83 # same thing
```
### Run in parallel
Some quick benchmark results measured while running Ameba on Crystal repo:
```sh
$ CRYSTAL_WORKERS=1 ameba #=> 29.11 seconds
$ CRYSTAL_WORKERS=2 ameba #=> 19.49 seconds
$ CRYSTAL_WORKERS=4 ameba #=> 13.48 seconds
$ CRYSTAL_WORKERS=8 ameba #=> 10.14 seconds
```
## Installation
### As a project dependency:
Add this to your application's `shard.yml`:
```yaml
development_dependencies:
ameba:
github: crystal-ameba/ameba
```
Build `bin/ameba` binary within your project directory while running `shards install`.
### OS X
```sh
$ brew tap crystal-ameba/ameba
$ brew install ameba
```
### Docker
Build the image:
```sh
$ docker build -t ghcr.io/crystal-ameba/ameba .
```
To use the resulting image on a local source folder, mount the current (or target) directory into `/src`:
```sh
$ docker run -v $(pwd):/src ghcr.io/crystal-ameba/ameba
```
Also available on GitHub: https://github.com/crystal-ameba/ameba/pkgs/container/ameba
### From sources
```sh
$ git clone https://github.com/crystal-ameba/ameba && cd ameba
$ make install
```
## Configuration
Default configuration file is `.ameba.yml`.
It allows to configure rule properties, disable specific rules and exclude sources from the rules.
Generate new file by running `ameba --gen-config`.
### Sources
**List of sources to run Ameba on can be configured globally via:**
- `Globs` section - an array of wildcards (or paths) to include to the
inspection. Defaults to `%w[**/*.cr !lib]`, meaning it includes all project
files with `*.cr` extension except those which exist in `lib` folder.
- `Excluded` section - an array of wildcards (or paths) to exclude from the
source list defined by `Globs`. Defaults to an empty array.
In this example we define default globs and exclude `src/compiler` folder:
``` yaml
Globs:
- "**/*.cr"
- "!lib"
Excluded:
- src/compiler
```
**Specific sources can be excluded at rule level**:
``` yaml
Style/RedundantBegin:
Excluded:
- src/server/processor.cr
- src/server/api.cr
```
### Rules
One or more rules, or a one or more group of rules can be included or excluded
via command line arguments:
```sh
$ ameba --only Lint/Syntax # runs only Lint/Syntax rule
$ ameba --only Style,Lint # runs only rules from Style and Lint groups
$ ameba --except Lint/Syntax # runs all rules except Lint/Syntax
$ ameba --except Style,Lint # runs all rules except rules in Style and Lint groups
```
Or through the configuration file:
``` yaml
Style/RedundantBegin:
Enabled: false
```
### Inline disabling
One or more rules or one or more group of rules can be disabled using inline directives:
```crystal
# ameba:disable Style/LargeNumbers
time = Time.epoch(1483859302)
time = Time.epoch(1483859302) # ameba:disable Style/LargeNumbers, Lint/UselessAssign
time = Time.epoch(1483859302) # ameba:disable Style, Lint
```
## Editors & integrations
- Vim: [vim-crystal](https://github.com/rhysd/vim-crystal), [Ale](https://github.com/w0rp/ale)
- Emacs: [ameba.el](https://github.com/crystal-ameba/ameba.el)
- Sublime Text: [Sublime Linter Ameba](https://github.com/epergo/SublimeLinter-contrib-ameba)
- VSCode: [vscode-crystal-ameba](https://github.com/crystal-ameba/vscode-crystal-ameba)
- Codacy: [codacy-ameba](https://github.com/codacy/codacy-ameba)
- GitHub Actions: [github-action](https://github.com/crystal-ameba/github-action)
## Credits & inspirations
- [Crystal Language](https://crystal-lang.org)
- [Rubocop](https://rubocop.readthedocs.io/en/latest/)
- [Credo](http://credo-ci.org/)
- [Dogma](https://github.com/lpil/dogma)
## Contributors
- [veelenga](https://github.com/veelenga) Vitalii Elenhaupt - creator, maintainer
- [Sija](https://github.com/Sija) Sijawusz Pur Rahnama - contributor, maintainer