Module: Memoizer::ClassMethods

Defined in:
lib/memoizer.rb

Instance Method Summary collapse

Instance Method Details

#memoize(*method_names) ⇒ Object 



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# File 'lib/memoizer.rb', line 16

def memoize(*method_names)
  method_names.each do |method_name|
    memoized_ivar_name = Memoizer.ivar_name(method_name)
    unmemoized_method = "_unmemoized_#{method_name}"

    alias_method unmemoized_method, method_name

    no_args = self.instance_method(unmemoized_method).arity == 0

    define_method method_name do |*args|

      if instance_variable_defined?(memoized_ivar_name)
        memoized_value = self.instance_variable_get(memoized_ivar_name)
      end

      # if the method takes no inputs, store the value in an array
      if no_args
        if !memoized_value.is_a?(Array)
          memoized_value = [self.send(unmemoized_method)]
          self.instance_variable_set(memoized_ivar_name, memoized_value)
        end
        memoized_value.first

      #otherwise store in a hash indexed by the arguments
      else
        if !memoized_value.is_a?(Hash)
          memoized_value = {args => self.send(unmemoized_method, *args)}
          self.instance_variable_set(memoized_ivar_name, memoized_value)
        elsif !memoized_value.has_key?(args)
          memoized_value[args] = self.send(unmemoized_method, *args)
        end
        memoized_value[args]
      end
    end

    if self.private_method_defined?(unmemoized_method)
      private method_name
    elsif self.protected_method_defined?(unmemoized_method)
      protected method_name
    end
  end
end