Question

Ruby 有 if、case 和 while 表达式，它们都以通常的方式工作：

>> if 2 < 3
    'less'
   else
    'more'
   end
=> "less"
>> quantify =
   -> number {
    case number
    when 1
     'one'
     when 2
      'a couple'
     else
      'many'
     end
    }
=> #<Proc (lambda)>
>> quantify.call(2)
=> "a couple"
>> quantify.call(10)
=> "many"
>> x = 1
=> 1
>> while x < 1000
     x = x * 2
    end
=> nil
>> x
=> 1024