DelegateKey

Provides a delegate_key class method to easily create methods which return hash value by key.

Installation

Add this line to your application's Gemfile:

gem 'delegate_key'

And then execute:

$ bundle

Or install it yourself as:

$ gem install delegate_key

Usage

Options

• :to - specifies the target object;

• :prefix - prefixes the new method with the target name or a custom prefix;

• :private - if set to true, changes method visibility to private.

delegate_key method receives one or more method names (specified as symbols or strings) and the name of the target object via the :to option (also a symbol or string).

class Foo
  delegate_key :key, to: :hash

  def hash
    { key: "value" }
  end
end

Foo.new.key # => "value"

If hash key is a string, use string as argument:

class Foo
  delegate_key "key", to: :hash

  def hash
    { "key" => "value" }
  end
end

Foo.new.key # => "value"

class Foo
  delegate_key :key, to: :hash

  def hash
    { "key" => "value" }
  end
end

Foo.new.key # => nil

Multiple delegates to the same target are allowed:

class Foo
  delegate_key :bar, :baz, to: :hash

  def hash
    { bar: "value for bar", baz: "value for baz" }
  end
end

Foo.new.bar # => "value for bar"
Foo.new.baz # => "value for baz"

Delegates can optionally be prefixed using the :prefix option. If the value is true, the delegate methods are prefixed with the name of the object being delegated to.

class Foo
  delegate_key :key, to: :hash, prefix: true

  def hash
    { key: "value" }
  end
end

Foo.new.hash_key # => "value"
Foo.new.key # => NoMethodError: undefined method `key' for #<Foo:0x00007fc2452354b0>

It is also possible to supply a custom prefix:

class Foo
  delegate_key :key, to: :hash, prefix: :custom

  def hash
    { key: "value" }
  end
end

Foo.new.custom_key # => "value"

The delegated methods are public by default. Pass private: true to change that.

class Foo
  delegate_key :key, to: :hash, private: true

  def hash
    { key: "value" }
  end
end

Foo.new.key # => NoMethodError: private method `key' called for #<Foo:0x00007fc24531dd28>

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/ilyasgaraev/delegate_key. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the DelegateKey project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.