Feature #12534: Refinements: refine modules as well

• Status: Closed
• Assignee: shugo (Shugo Maeda)
• Target version: -

[chucke (Tiago Cardoso)]

Refinements were added as a feature to scope monkey-patches on ruby core elements. This works for elements such as String, Array (all classes), but not for modules (Enumerable, Timeout...).

This might be related to refinements not working for singleton classes (for example, I can't define a class method inside a refine block).

This code is evaluated, but the method is undefined:

module Extension
refine Array do
def self.foo ; puts "bar" ; end
end
end

This code breaks:

module Extension
refine Kernel do
def foo ; puts "bar" ; end
end
end

[shevegen (Robert A. Heiler)]

Interesting. I was not aware of this.

It is however mentioned in the documentation:

http://ruby-doc.org/core-2.3.1/doc/syntax/refinements_rdoc.html

Quote:

"Refinements only modify classes, not modules so the argument must be a class."

As to why, I don't know either. Perhaps the documentation can add some words
to briefly state whether this is on purpose or not.

[shugo (Shugo Maeda)]

• Status changed from Open to Feedback
• Assignee set to shugo (Shugo Maeda)

There is an implementation difficulty when refining modules and calling super in that refinement.

One solution is prohibiting super in a refinement for a module.
Other proposals (and patches) are welcome.

[matz (Yukihiro Matsumoto)]

I understand the implementation difficulty. If we prohibit super in refined methods in Modules, is it possible to refine modules?
If it's reasonably possible, I'd like to accept this.

Matz.

[shugo (Shugo Maeda)]

• Status changed from Feedback to Closed

Applied in changeset r56213.

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• eval.c (rb_mod_refine): refine modules as well.
  [ruby-core:76199] [Feature #12534]