用作参数时`*`的含义(不像*arg，只是*) [英] The meaning of `*` when using as a param(not like *arg, just *)

问题描述

当我在阅读 Rails 代码时，我发现了这个

When I was reading Rails code, I found this

def save(*)
  create_or_update || raise(RecordNotSaved)
end

* 有什么作用?:O我知道当我们像 *args 一样使用它时会发生什么，但在这种情况下，它只是普通的 *.

What does the * do? :O I know what happens when we use it like *args, but in this case, it's just plain *.

ref https://github.com/rails/rails/blob/master/activerecord/lib/active_record/persistence.rb#L119

推荐答案

在这种特定情况下， save 不接受任何参数.这就是赤裸裸的啪啪会发生的事情.但是，正如您可能知道的，在 ActiveRecord 模型上调用 save 接受选项，因为此方法在此处被 ActiveRecord::Validations 覆盖:

In this specific case, save doesn't take any arguments. That's what happens with a naked splat. But, as you may be aware, calling save on an ActiveRecord model accepts options because this method gets overridden by ActiveRecord::Validations here:

https://github.com/rails/rails/blob/v3.1.3/activerecord/lib/active_record/validations.rb#L47

# The validation process on save can be skipped by passing <tt>:validate => false</tt>. The regular Base#save method is
# replaced with this when the validations module is mixed in, which it is by default.
def save(options={})
 perform_validations(options) ? super : false
end

这篇关于用作参数时`*`的含义(不像*arg，只是*)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！