Module: Fallback::ClassMethods

Defined in:
lib/fallback.rb

Instance Method Summary collapse

Instance Method Details

#define_fallback(method, delegate_method, options) ⇒ Object 



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# File 'lib/fallback.rb', line 20

def define_fallback(method, delegate_method, options)
  delegate_method ||= method
  # build attribute methods for AR or alias will not work
  define_attribute_methods if respond_to?(:define_attribute_methods)

  define_method "#{method}_with_fallback" do
    current = send("#{method}_without_fallback")

    conditions = options.select{|k,v| [:if, :unless].include?(k)}
    do_delegate = if conditions.empty?
      current.to_s.strip.empty? # present?
    else
      # {:if => :a, :unless => :a} --> [true, false].all? --> false
      conditions.map do |condition, value|
        result = !!(value.respond_to?(:call) ? value.call(self) : send(value))
        condition == :unless ? result : !result
      end.all?
    end

    if do_delegate
      delegate = (options[:to] ? send(options[:to]) : self )
      delegate.send(delegate_method)
    else
      current
    end
  end
  
  # alias_method_chain method, :fallback
  alias_method "#{method}_without_fallback", method
  alias_method method, "#{method}_with_fallback"
end

#fallback(*args) ⇒ Object 



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# File 'lib/fallback.rb', line 9

def fallback(*args)
  options = args.pop if args.last.is_a?(Hash) # extract_options!

  methods = options.reject{|k,v| [:if, :unless, :to].include?(k) }.to_a
  methods += args

  methods.each do |method, delegate_method|
    define_fallback(method, delegate_method, options)
  end
end