From: "marcandre (Marc-Andre Lafortune)" <ruby-core@...>
Date: 2012-11-25T11:17:37+09:00
Subject: [ruby-core:50060] [ruby-trunk - Feature #6589] Set#rehash


Issue #6589 has been updated by marcandre (Marc-Andre Lafortune).


headius (Charles Nutter) wrote:
> Is it specified that Set must be hashtable-based forever? There are alternate ways to implement a Set.

Alternate ways of implementing Set with check/insertion in O(1) that would also work if structures change without a `rehash` functionality?

In any case, the documentation states that "Set uses Hash as storage", but more importantly that "The equality of each couple of elements is determined according to
# Object#eql? and Object#hash".

----------------------------------------
Feature #6589: Set#rehash
https://bugs.ruby-lang.org/issues/6589#change-33839

Author: marcandre (Marc-Andre Lafortune)
Status: Assigned
Priority: Normal
Assignee: knu (Akinori MUSHA)
Category: lib
Target version: next minor


There should be a way to rehash a `Set`.

    s = Set.new([[]])
    s.first << 1
    # s.rehash # Does not exist!
    s.include? [1] # => false, want true

See also:

http://stackoverflow.com/questions/10992423/is-this-expected-behaviour-for-a-set-of-arrays-in-ruby
http://stackoverflow.com/questions/10361400/deleting-a-modified-object-from-a-set-in-a-no-op




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