Enumattr

• mapping constant value and keyword
• class knows the mapping
• instance knows its attribute value's keyword from the mapping

Installation

Add this line to your application's Gemfile:

gem 'enumattr'

And then execute:

$ bundle

Or install it yourself as:

$ gem install enumattr

Usage

Basics

1. include Enumattr::Base
2. declare enumattr :attr_name do ... end
3. enum :keyword, value in do ... end block

example:

class User
  include Enumattr::Base

  attr_accessor :status

  enumattr :status do
    enum :active,   1
    enum :inactive, 2
    enum :deleted,  3
  end

  def initialize(status)
    @status = status
  end
end

then defining class methods and instance methods.

• class methods
  • User.status_keys as {attr_name}_keys return keyword array
  • User.status_values as {attr_name}_values return value array
  • User.status_enums as {attr_name}_enums return Enum object array
  • User.status_enum(:active) as {attr_name}_enum(:keyword) return an Enum object
  • User.status_value(:active) as {attr_name}_value(:keyword) return a value
• instance methods
  • User#status_key as {attr_name}_key return a keyword correspond to mapping
  • User#status_enum as {attr_name}_enum return a Enum object correspond to mapping
  • User#status_value as {attr_name}_value return a value (alias status_value status)
  • User#status_key = :inactive as {attr_name}_key= setter by keyword
  • User#status_active? as {attr_name}_{keyword}? query method return true or false

Enum object (Enumattr::Enums::Enum) has key and value attributes

example:

User.status_keys
#=> [:active, :inactive, :deleted]

User.status_values
#=> [1, 2, 3]

User.status_enums
#=> [#<Enumattr::Enums::Enum:0x9459d00, @key=:active, @value=1, @extras=[]>, #<Enumattr::Enums::Enum:0x9459c88, @key=:inactive, @value=2, @extras=[]>, #<Enumattr::Enums::Enum:0x9459be8, @key=:deleted, @value=3, @extras=[]>]


enum = User.status_enum(:active)
#=> #<Enumattr::Enums::Enum:0x007ff58b220618 @container=#<Enumattr::Enums:0x007ff58b2207a8>, @key=:active, @value=1, @extras=[]>

# Enum object has key and value attributes
enum.key
#=> :active

enum.value
#=> 1

User.status_enum(:dummy)
#=> nil

User.status_value(:active)
#=> 1

User.status_value(:dummy)
#=> nil


user = User.new(1)
#=> #<User:0x007ff58b050dd8 @status=1>

user.status
#=> 1

user.status_key
#=> :active

user.status_value
#=> 1

user.status_key = :inactive
#=> :inactive

user.status
#=> 2

user.status_active?
#=> false

user.status_inactive?
#=> true

Options

• :on
  • specify existent attribute or method if enumattr_name attribute or method doesn't exist
  • enumattr :enumattr_name, :on => :existent_attribute do ...
• :enums
  • altenative enum defining leteral by hash instead of block
  • enumattr :enumattr_name, :enums => {:keyword1 => value1, :keyword2 => value2}
  • enumattr :enumattr_name, :enums => [[:keyword1, value1], [:keyword2, value2]] (Ruby 1.8.7 and need ordered)
• :extend
  • enum object extension
  • enumattr :enumattr_name, :extend => Extension do ...

More examples

see: examples/*.rb and spec/enumattr/*.rb

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Added some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request