Issue #9696 has been updated by Thomas Sawyer.


If there "could be better design" could this ticket be set to feedback? Maybe others have some ideas about it. 

Am I wrong to think that the most applicable use-cases for refinements by-far are the ActiveSupport and Facets core extension libraries? And if those two projects find it impractical to support refinements, then a better solution really does need to be found. Otherwise refinements will simply be an unused (hence useless) feature.

@Rodrigo Thanks for the suggestion. I have considered that. While most extensions would work fine, edge cases tend to make maintaining such a pre-processor a real headache. I won't rule it out, but that's not an approach I'd readily jump into.


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Feature #9696: More Flexible Refinement Syntax
https://bugs.ruby-lang.org/issues/9696#change-46063

* Author: Thomas Sawyer
* Status: Rejected
* Priority: Normal
* Assignee: 
* Category: core
* Target version: current: 2.2.0
----------------------------------------
I am the maintainer of Ruby Facets, the core extensions library. For the next release of Facets I have long planned to provide support for Refinements. Unfortunately, after working with the code to determine what would be necessary to support them, I've come to the conclusion that it's just not reasonable to do so. The problem lies in the fact that Facets must still be backward compatible with it's "monkey-patch" usage. In fact, that usage is sometimes preferable b/c you can require once and don't have to write `using Foo` in every file that a core extension might be needed. But, b/c of the syntax that refinements use, to support both patching and refining I would have to maintain TWO COPIES of every extension, which simply isn't practical.

For example, the normal definition of a String#foo:

~~~
class String
  def foo
    ...
  end
end
~~~

And the refinement:

~~~
module Facets
  refine String do
    def foo
      ...
    end
  end
end
~~~

There does not appear to be any reasonable way to have the definition defined once and still be able to be use it in either manner. (Also, I want to point out that refinements do not lend themselves to cherry picking specific methods per-file either.)

So, unless someone has a clever approach that I have not thought of, I wonder if it would not be a good idea to reconsider the syntax of refinements. Would it be possible to simplify the definition to use `class` instead of `refine`, e.g.

~~~
module Facets
  class String
    def foo
      ...
    end
  end
end
~~~

And then allow `using Facets` which would refine any common class is the scope. And further, allowing also `using Facets::String` and even `using Facets::String::foo` to cherry pick refinements? In addition, a way to "apply" a module as if it were evaluated in the scope. This would then allow the same code to be used either as a refinement or as an extension.

Alternatively, maybe refinements should just be a require --if they will forever remain at the file-level. Then no special syntax would be needed at all. Simply defining them in a separate file, e.g.

~~~
# string/foo.rb
class String
  def foo
    ...
  end
end
~~~

And then "using" them by file name instead would do the trick.

~~~
using 'string/foo'
~~~





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