14、Ruby编程：操作符与控制结构详解

Ruby编程：操作符与控制结构详解

一、触发器函数

触发器函数在编程中用于根据特定条件改变状态。在Ruby中，我们可以定义如下两个触发器函数。

$state = false            # Global storage for flip-flop state
def flipflop(x)           # Test value of x against flip-flop
  if !$state              # If saved state is false
    result = (x == 3)     # Result is value of lefthand operand
    if result             # If that result is true
      $state = !(x == 5)  # Then saved state is not of the righthand operand
    end
    result                # Return result
  else                    # Otherwise, if saved state is true
    $state = !(x == 5)    # Then save the inverse of the righthand operand
    true                  # And return true without testing lefthand
  end
end

(1..10).each {|x| print x