From: "Glass_saga (Masaki Matsushita)" <glass.saga@...>
Date: 2013-07-29T12:24:46+09:00
Subject: [ruby-core:56252] [ruby-trunk - Feature #8499] Importing Hash#slice, Hash#slice!, Hash#except, and Hash#except! from ActiveSupport


Issue #8499 has been updated by Glass_saga (Masaki Matsushita).

File patch2.diff added

I'm sorry for my wrong implementation.
patch2.diff makes Hash#slice! and #except! behave the same as ActiveSupport.
However, I think it isn't good idea to import Hash#slice! and #except! from ActiveSupport as it is.

Because:
* They returns self if no changes were made. It is inconsistent with other built-in methods like #select! and #reject!.
* #slice! returns rest of hash, not slice of hash like following. It may be confusing.

hash = {1=>2,3=>4,5=>6}
hash.slice!(1,3) #=> {5,6}
hash #=> {1=>2,3=>4}
----------------------------------------
Feature #8499: Importing Hash#slice, Hash#slice!, Hash#except, and Hash#except! from ActiveSupport
https://bugs.ruby-lang.org/issues/8499#change-40745

Author: mrkn (Kenta Murata)
Status: Assigned
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: core
Target version: current: 2.1.0


=begin RD
According to my experiences, the following two idioms often appeare in application codes.

(1) (({hash = other_hash.select { |k, | [:key1, :key2, :key3].include? k }}))
(2) (({hash = other_hash.reject { |k, | [:key1, :key2, :key3].include? k }}))

On Rails, they can be written in the following forms by using ActiveSupport's features.

(1) (({hash = other_hash.slice(:key1, :key2, :key3)}))
(2) (({hash = other_hash.except(:key1, :key2, :key3)}))

I think the latter forms are shorter and more readable than the former ones.

So I propose to import the following methods from ActiveSupport:

* (({Hash#slice}))
* (({Hash#slice!}))
* (({Hash#except}))
* (({Hash#except!}))
=end


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