[ruby-core:83585] [Ruby trunk Feature#14059] Refine multiple classes in one call

Issue #14059 has been updated by duerst (Martin D端rst).


I'm really not sure about this. If we need this for refinements, why don't we have for classes in the first place? E.g.:

```ruby
class Foo, Bar, Baz
  def positive_integer?
    false
  end
end
```

It seems strange to introduce syntactic sugar just for refinements.

----------------------------------------
Feature #14059: Refine multiple classes in one call
https://bugs.ruby-lang.org/issues/14059#change-67611

* Author: kddeisz (Kevin Deisz)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
Consider the following problem - I would like to be able to validate that a JSON string contains all things that can represent positive integers. In this case, it works well with refinements, because I can:

~~~
class PositiveJSONValidator < ActiveModel::EachValidator
  using Module.new {
    refine String do
      def positive_integer?
        match?(/[1-9](?:[0-9])*/)
      end
    end

    refine Integer do
      def positive_integer?
        self > 0
      end
    end

    refine Float do
      def positive_integer?
        self == self.to_i
      end
    end

    refine NilClass do
      def positive_integer?
        false
      end
    end

    refine Array do
      def positive_integer?
        false
      end
    end

    refine Hash do
      def positive_integer?
        false
      end
    end
  }

  def validate_each(record, attribute, value)
    return if valid_positive_json?(value)
    record.errors[attribute] << options[:message] || 'is invalid'
  end

  private

  def valid_positive_json?(value)
    JSON.parse(value).all? do |key, value|
      key.positive_integer? && value.positive_integer?
    end
  rescue JSON::ParserError
    false
  end
end
~~~

However, this is kind of annoying because I need to specify each class manually. What I'd love to be able to do is group classes by passing all of the ones that need to be refined in the same way, as in:

~~~
refine NilClass, Array, Hash do
  def positive_integer?
    false
  end
end
~~~

Is this something that people would consider? It seems like a good use case for refinements because I just want to send a message to an object, so basically I want a default case. I could just refine Object but that feels wrong, I'd rather get an undefined method exception so that I know something unexpected occurred. If accepted I'd be happy to submit a patch.



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