module NumericMemoist

# File lib/numeric_memoist.rb, line 4
def memoize *method_names
  method_names.each do |method_name|
    _memoize method_name
  end
end

# File lib/numeric_memoist.rb, line 11
def _memoize method_name
  klass = self.respond_to?(:class_eval) ? self : (class<<self;self;end)
  klass.class_eval do
    unmemoized_method = instance_method method_name
    is_private = private_method_defined? method_name
    is_protected = protected_method_defined? method_name
    if unmemoized_method.arity.zero?
      cache = Hash.new do |h, num|
        h[num] = unmemoized_method.bind(num).call
      end
      define_method(method_name){cache[self]}
    else
      cache = Hash.new do |h, num|
        method = unmemoized_method.bind num
        h[num] = Hash.new do |h2, args|
          h2[args] = method[*args]
        end
      end
      define_method(method_name){|*args| cache[self][args]}
    end
    private method_name if is_private
    protected method_name if is_protected
  end
end