[ruby-core:44985] [ruby-trunk - Feature #6277] Hash#convert_key

Issue #6277 has been updated by trans (Thomas Sawyer).


It occurs to me that this issue could be solved in another way, via Subclassing. A subclass of Hash could be made with certain methods overridden to convert the keys as needed. This would offer complete flexibility (where as callbacks are limited). The only problem is, Ruby's Hash class is not very internally connascent --many different methods access the underlying data --there is no one, or few, specific methods that can be overridden to handle all cases. This leads to a very unDRY and bloated subclass.

If Ruby's Hash could be modified to follow essentially a CRUD model, with single points-of-entry for the creation, reading, updating and deletion of entries, and all other methods route through these core methods for access to the underlying data, then it would be easy enough to subclass and implement the key conversion behaviour.

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Feature #6277: Hash#convert_key
https://bugs.ruby-lang.org/issues/6277#change-26570

Author: trans (Thomas Sawyer)
Status: Assigned
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: core
Target version: 2.0.0


=begin
Many times a hash with uniform keys is needed (or is at least preferable) for a particular usecase. To this end I propose ((%Hash#convert_key%)).

  h = {}
  h.convert_key{ |k| k.to_sym }
  h['a'] = 1
  h.update('b'=>2)
  h #=> {:a=>1, :b=>2}

The idea is similar in concept to ((%#default_proc%)). 

Others solutions to fill this need have been tried and used, but almost exclusively are in the form of a new class. Most notable is Rails HashWithIndifferentAccess. But ((%#convert_key%)) has much greater flexibility since keys can be converted to anything.
=end


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