https://github.com/wojtekmach/attrs
Yet another attributes on steroids gem
https://github.com/wojtekmach/attrs
Last synced: 7 months ago
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Yet another attributes on steroids gem
- Host: GitHub
- URL: https://github.com/wojtekmach/attrs
- Owner: wojtekmach
- License: mit
- Created: 2013-08-10T02:37:14.000Z (about 12 years ago)
- Default Branch: master
- Last Pushed: 2013-08-11T00:57:37.000Z (about 12 years ago)
- Last Synced: 2025-03-15T14:57:01.615Z (7 months ago)
- Language: Ruby
- Size: 160 KB
- Stars: 17
- Watchers: 4
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
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README
# Attrs
[](http://travis-ci.org/wojtekmach/attrs)
Yet another attributes on steroids gem.
Heavily inspired by [Virtus](https://github.com/solnic/virtus) and
[Values](https://github.com/tcrayford/Values) which both are great projects.
The purpose of this project is to have a small & simple codebase and minimum number of features.
For a more complex solution I strongly recommend **Virtus** which I'm happily using in production.
## Features
* immutability
* all attributes must be specified on initialisation. Hopefully less `nil`'s flying around
* uses `attr_reader` and `attr_writer`. Can be easily overwritten
* just ~50 LOC (not including coercion support)
* no external dependencies (again, not counting coercion which requires coercible gem)
## Usage
Let's write a `Person` class:
```ruby
require 'attrs'
class Person < Attrs(:name, :age)
private
def default_name
"Anonymous"
end
def age=(new_age)
super(new_age.to_i)
end
end
person = Person.new(name: 'John Doe', age: '26')
```
with this code we can:
* get the attributes hash: `person.attributes # => {:name => "John Doe", :age => 26}`
* get the attribute names: `Person.attribute_names # => [:name, :age]`
* compare with other objects: `person == {:name => "John Doe", :age => 26} # => true`
* Explicitly set default values: `Person.new(age: 26).name # => "Anonymous"
and more! See:
### Coercion
Notice in previous example we added custom `age=` writer to coerce argument to integer.
One of my favourite features of **Virtus** is attribute coercion, and you can use it here too.
In fact it's using the same library that was extracted out from **Virtus**:
```
gem install coercible
```
```ruby
require 'attrs/coercible'
class Person < Attrs(name: String, age: Integer)
end
```
or, simply:
```ruby
Person = Attrs(name: String, age: Integer)
```
(note, using 2nd style you won't be able to use `super` when overwriting methods)
## Installation
Add this line to your application's Gemfile:
gem 'attrs'
And then execute:
$ bundle
Or install it yourself as:
$ gem install attrs
## Contributing
1. Fork it
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Add some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create new Pull Request