ruby-on-rails - 使用 Ruby gem aasm，是否可以在返回布尔结果的保护函数上定义 not(!) 运算符？

Question

class Ticket
  include AASM

  state :new
  state :open
  state :closed

  event :open do
    transitions :from => :new,:to => :closed, :guard => :cancelled?
    transitions :from => :new,:to => :open, :guard => !:cancelled?
  end
  def cancelled?
    true
  end
  def not_cancelled?
    true
  end
end

##Would I need the below?
transitions :from => :new,:to => :open, :guard => :not_cancelled?

为了减少我必须编写的代码量，是否可以在保护函数中使用 !:cancelled 之类的东西？还是我必须单独写一个 not_cancelled？功能（我怀疑是这种情况）。

我正在使用 Ruby 2.1 和 gem 'aasm', '~> 3.1.1'

Answer 1

首先，!:cancelled?表达式的计算结果为false始终，因此 aasm 在这种情况下甚至不会调用cancelled?方法。为了减少代码量，你可以像下面这样

transitions :from => :new, :to => :closed, :guard => :cancelled?
transitions :from => :new, :to => :open, :guard => Proc.new { |ticket| !ticket.cancelled? }