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https://github.com/ruby/forwardable
Provides delegation of specified methods to a designated object
https://github.com/ruby/forwardable
ruby
Last synced: 27 days ago
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Provides delegation of specified methods to a designated object
- Host: GitHub
- URL: https://github.com/ruby/forwardable
- Owner: ruby
- License: bsd-2-clause
- Created: 2018-06-23T04:56:12.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2024-08-19T22:05:30.000Z (3 months ago)
- Last Synced: 2024-09-29T21:01:20.700Z (about 1 month ago)
- Topics: ruby
- Language: Ruby
- Homepage:
- Size: 192 KB
- Stars: 41
- Watchers: 28
- Forks: 17
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
Awesome Lists containing this project
README
# Forwardable
The Forwardable module provides delegation of specified methods to a designated object, using the methods `#def_delegator` and `#def_delegators`.
## Installation
Add this line to your application's `Gemfile`:
```ruby
gem 'forwardable'
```
And then execute:
```sh
$ bundle
```
Or install it yourself as:
```sh
$ gem install forwardable
```
## Usage
For example, say you have a class `RecordCollection` which contains an array `@records`. You could provide the lookup method `#record_number()`, which simply calls `#[]` on the `@records` array, like this:
```ruby
require 'forwardable'
class RecordCollection
attr_accessor :records
extend Forwardable
def_delegator :@records, :[], :record_number
end
```
We can use the lookup method like so:
```ruby
r = RecordCollection.new
r.records = [4,5,6]
r.record_number(0) # => 4
```
Further, if you wish to provide the methods `#size`, `#<<`, and `#map`, all of which delegate to `@records`, this is how you can do it:
```ruby
class RecordCollection # re-open RecordCollection class
def_delegators :@records, :size, :<<, :map
end
r = RecordCollection.new
r.records = [1,2,3]
r.record_number(0) # => 1
r.size # => 3
r << 4 # => [1, 2, 3, 4]
r.map { |x| x * 2 } # => [2, 4, 6, 8]
```
You can even extend regular objects with Forwardable.
```ruby
my_hash = Hash.new
my_hash.extend Forwardable # prepare object for delegation
my_hash.def_delegator "STDOUT", "puts" # add delegation for STDOUT.puts()
my_hash.puts "Howdy!"
```
## Development
After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).
## Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/ruby/forwardable.
## License
The gem is available as open source under the terms of the [2-Clause BSD License](https://opensource.org/licenses/BSD-2-Clause).