ruby-on-rails - Ruby - 是否可以将方法别名为安全导航运算符

Question

Ruby 2.3 引入了安全导航运算符，但我发现它的语法过于离散，在快速扫描代码时很容易错过。相反，我更喜欢 try 的语法，因为它看起来更加明显和有意。

所以我的问题是在 Ruby 2.3+ 中，有没有一种方法可以将安全导航运算符 &. 的方法别名或猴子修补为自定义方法名称，即。 s.fast_try(:upcase!).fast_try(:downcase) 而不是写 s&.upcase!&.downcase

主要思想是尝试提高另一种实现(例如 try 方法)的性能。不，我不关心 try 和 safe 导航操作符之间的细微行为差异。另外，如果无法避免，我不介意一些模糊的论证限制，只需指出即可。

Answer 1

我猜你可以选择像这样简单的东西

class Object
  def fast_try(meth,*args,&block)
    self&.public_send(meth,*args,&block)
  end
end

例如:

["string","STRING","pOw"].map do |s| 
  s.fast_try(:upcase!)
     .fast_try(:chars)
     .fast_try(:find, ->{"No S"}) { |a| a == "S" }
     .fast_try(:prepend, "!")
end
#=> ["!S",nil,"!No S"]

虽然您的问题表明，“不，我不关心 try 和 safe 导航运算符之间的细微行为差异。”，鉴于您已经编写了 gem 并注意到以下内容

Differences between FastTry and ActiveSupport#try

It is not our goal to maintain any consistency with the ActiveSupport version of the try method. I do however want to maintain a simple list of the differences. Please create a PR or Issue if you find a difference that should be documented here.

Nothing reported yet

我觉得值得一提的是，这里的 2 之间存在明显且可能令人心酸的差异，即 Repl Spec为了显示差异并为了这个答案以及链接可能会死亡的事实，本规范的输出如下:

ActiveSupport#try vs. Safe Navigation (&.)
  #try
    handles would be NoMethodError with nil (using #respond_to?)
    does not work on a BasicObject
    behaves like a method call
      with no method name given
        when block_given?
          yields self to a block with arity > 0
          evaluates block with arity == 0 in the context of self
        when no block_given?
          raises an ArgumentError
      with a method_name given
        a non nil object
          uses public_send for message transmission
        nil
          calls NilClass#try and returns nil
  #try!
    does not handle NoMethodError
    does not work on a BasicObject
    behaves like a method call
      with no method name given
        when block_given?
          yields self to a block with arity > 0
          evaluates block with arity == 0 in the context of self
        when no block_given?
          raises an ArgumentError
      with a method_name given
        a non nil object
          uses public_send for message transmission
        nil
          calls NilClass#try and returns nil
  &. (safe navigation)
    does not handle NoMethodError
    raises a SyntaxError with no method name given when block_given?
    raises a SyntaxError with no method name given when no block_given?
    works on a BasicObject
    does not act like a method call
      with a method_name given
        a non nil object
          &. is not called
        nil
          returns nil without a method call