From: "shugo (Shugo Maeda)" <redmine@...>
Date: 2013-12-04T11:54:53+09:00
Subject: [ruby-core:58843] [Backport 200 - Backport #8872] Case statements	do not honor a refinement of the '===' method


Issue #8872 has been updated by shugo (Shugo Maeda).


jballanc (Joshua Ballanco) wrote:
> To play devil's advocate, I think the opposing question to be asked is "how would you alter the behavior of case evaluation using refinements"?
> 
> It may be, as shugo states, that refinements are not meant to be used for altering the behavior of expressions. In this case, the answer to the question I posed is, simply, "you don't."
> 
> That said, I think it is fairly well understood in the Ruby community that "===" is related to case. I've even heard the operator described as "case equality". Playing devil's advocate again, what is the use case for refining "===" if it _doesn't_ affect the evaluation of a case...when clause?

I don't come up with any use case for refining "===" regardless of whether it affects the evaluation of a case expression or not.
I'm neutral about this issue, and really want to know use cases.
----------------------------------------
Backport #8872: Case statements do not honor a refinement of the '===' method
https://bugs.ruby-lang.org/issues/8872#change-43402

Author: jconley88 (Jon Conley)
Status: Assigned
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: 
Target version: 


=begin
Below, I've redefined the ((|===|)) method of symbol to always return true.  In ((|RefineTest#uses_refinement|)), I call ((|===|)) directly and the refined method is called.  In ((|RefineTest#does_not_use_refinement|)), the ((|===|)) method is called indirectly through a case statement.  If the refined ((|===|)) method was called, the result should be ((*'The refinement was used'*)), but this code currently returns ((*'The refinement was not used'*)).

 module RefineSymbol
   refine Symbol do
     def ===(other)
       true
     end
   end
 end
 
 using RefineSymbol
 
 class RefineTest
   def uses_refinement
     :a === :b
   end
 
   def does_not_use_refinement
     case :a
     when :b
       'The refinement was used'
     else
       'The refinement was not used'
     end
   end
 end
 
 rt = RefineTest.new
 rt.uses_refinement   # => true
 rt.does_not_use_refinement  # => expected 'The refinement was used' but got 'The refinement was not used'
=end



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