Module: Enumlogic

Defined in:
lib/enumlogic.rb

Overview

See the enum class level method for more info.

Instance Method Summary collapse

Instance Method Details

#enum(field, values, options = {}) ⇒ Object

Allows you to easily specify enumerations for your models. Specify enumerations like:

class Computer < ActiveRecord::Base
  enum :kind, ["apple", "dell", "hp"]
  enum :kind, {"apple" => "Apple", "dell" => "Dell", "hp" => "HP"}
end

You can now do the following:

Computer::KINDS # passes back exactly what you specified, Array or Hash
Computer.kind_options # gives you a friendly hash that you can easily pass into the select helper for forms
Computer.new(:kind => "unknown").valid? # false, automatically validates inclusion of the enum field

c = Computer.new(:kind => "apple")
c.apple? # true
c.apple_key # :apple
c.apple_text # "apple" or "Apple" if you gave a hash with a user friendly text value



22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
 
# File 'lib/enumlogic.rb', line 22

def enum(field, values, options = {})
  values_hash = if values.is_a?(Array)
    hash = {}
    values.each { |value| hash[value] = value }
    hash
  else
    values
  end
  
  values_array = values.is_a?(Hash) ? values.keys : values
  
  message = options[:message] || "#{field} is not included in the list"
  constant_name = options[:constant] || field.to_s.pluralize.upcase
  const_set constant_name, values_array unless const_defined?(constant_name)
  
  new_hash = {}
  values_hash.each { |key, text| new_hash[text] = key }
  (class << self; self; end).send(:define_method, "#{field}_options") { new_hash }
  
  define_method("#{field}_key") do
    value = send(field)
    return nil if value.nil?
    value.to_s.gsub(/[-\s]/, '_').downcase.to_sym
  end
  
  define_method("#{field}_text") do
    value = send(field)
    return nil if value.nil?
    values_hash.find { |key, text| key == value }.last
  end
  
  values_array.each do |value|
    method_name = value.downcase.gsub(/[-\s]/, '_')
    method_name = "#{method_name}_#{field}" if options[:namespace]
    define_method("#{method_name}?") do
      self.send(field) == value
    end
  end

  validates_inclusion_of field, :in => values_array, :message => message, :allow_nil => options[:allow_nil]
end