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"]
  # or....
  enum :kind, {"apple" => "Apple", "dell" => "Dell", "hp" => "HP"}
end

You can now do the following:

Computer::KINDS # passes back the defined enum keys as array
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.kind_apple? # true, or c.apple? if :namespace => false
c.kind_key # :apple
c.kind_text # "apple" or "Apple" if you gave a hash with a user friendly text value
c.enum?(:kind) # true



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# File 'lib/enumlogic.rb', line 24

def enum(field, values, options = {})
  namespace = options.key?(:namespace) ? options[:namespace] : true

  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

  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[value]
  end

  values_array.each do |value|
    method_name = value.underscore.gsub(/[-\s]/, '_')
    method_name = "#{field}_#{method_name}" if namespace
    define_method("#{method_name}?") do
      self.send(field) == value
    end
  end

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

#enum?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/enumlogic.rb', line 67

def enum?(name)
  method_defined?("#{name}_key")
end