From: "nobu (Nobuyoshi Nakada)" <nobu@...>
Date: 2012-11-20T11:48:34+09:00
Subject: [ruby-core:49632] [ruby-trunk - Feature #5448][Rejected] Singleton module's ::instance method should forward parameters


Issue #5448 has been updated by nobu (Nobuyoshi Nakada).

Status changed from Feedback to Rejected

I think that "an extra layer of complexity where none is needed" is the parameter here.
If it were really needed, you may want to use multiton instead.
What you want doesn't sound singleton.
----------------------------------------
Feature #5448: Singleton module's ::instance method should forward parameters
https://bugs.ruby-lang.org/issues/5448#change-33147

Author: Quintus (Marvin G��lker)
Status: Rejected
Priority: Normal
Assignee: 
Category: lib
Target version: next minor


Hi there, 

Classes mixing in the Singleton module currently aren't allowed to have parameters for their initialize method. This should be changed, because sometimes it's necessary to give some initial state information to the single(ton) instance.

Example code (no way to create the instance):
================================================
require "singleton"

class Foo
  include Singleton
  
  def initialize(arg)
    puts "arg is: #{arg}"
  end
  
end

f = Foo.instance(1) #=> ArgumentError 1 for 0
f = Foo.instance    #=> ArgumentError 0 for 1
================================================

The arguments given to the ::instance method should be forwarded to #initialize, which in turn may raise the appropriate ArgumentError if necessary.

ruby -v: ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-linux]
OS: Arch Linux

Marvin


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