0

在课堂Foo上,我想Bar在某些条件下包含方法:

 module Bar
   def some_method
     "orly"
   end
 end

 class Foo
   def initialize(some_condition)
     if !some_condition
       "bar"
     else
       class << self; include Bar; end
     end
   end
 end

有没有更简洁(更清晰)的方法来实现include方法中的,而不必在单例类中进行?

4

1 回答 1

11

extend相当于include单例类:

module Bar
  def some_method
    puts "orly"
  end
end

class Foo
  def initialize(some_condition)
    extend(Bar) if some_condition
  end
end

Foo.new(true).some_method # => "orly"
Foo.new(false).some_method # raises NoMethodError
于 2010-06-01T23:09:25.283 回答