[#395238] rubygem: ispunity (unite all your internet connections) — Arun Tomar <tomar.arun@...>

Dear friends,

12 messages 2012/05/01

[#395250] Overwriting one Ruby array or arrays with another — Craig Law <lists@...>

Hi

14 messages 2012/05/02

[#395258] array of strings - finding letter combinations — "Sebastjan H." <lists@...>

Hi All,

16 messages 2012/05/02

[#395357] Why Enumerator#next does not return more than one value? — Földes László <lists@...>

If I have an Enumerator which yields elements of a mathematical series

10 messages 2012/05/07

[#395373] How to use Data_Wrap_Struct to assign the DATA VALUE to an exsiting Ruby object? — Iñaki Baz Castillo <ibc@...>

Hi, my code receives an arbitrary klass name (provided by the user)

8 messages 2012/05/07

[#395429] passing via instance variable or regular () — sam jam <lists@...>

def first

10 messages 2012/05/10

[#395463] I'm looking for a Metaprogramming Project — Phil Stone <lists@...>

Hello,

19 messages 2012/05/11

[#395548] A million reasons why Encoding was a mistake — Marc Heiler <lists@...>

Newcomer wants to try Ruby.

15 messages 2012/05/15
[#395561] Re: A million reasons why Encoding was a mistake — Ryan Davis <ryand-ruby@...> 2012/05/15

[#395595] Re: A million reasons why Encoding was a mistake — Brian Candler <lists@...> 2012/05/16

I will add that the OP is not entirely alone in his opinion.

[#395551] How to ensure that a block runs entirely after other threads? (Thread.exclusive does not "work") — Iñaki Baz Castillo <ibc@...>

Hi, I expected that in the following example code, thread t1 would not

8 messages 2012/05/15

[#395575] GUI with ruby on windows — David Acosta <lists@...>

hello friends, i am a begginer and i have a litlle question, how can i

17 messages 2012/05/16

[#395604] what is going wrong here? — roob noob <lists@...>

Notice the initialization of both classes in each of the examples, if

20 messages 2012/05/16

[#395646] rb_gc_register_address() or rb_gc_mark()? — Iñaki Baz Castillo <ibc@...>

Hi, I've bad experiences with rb_gc_register_address(), it does never

16 messages 2012/05/17

[#395686] reading from and writing to a Unicode encoded file — "Sebastjan H." <lists@...>

Hi,

19 messages 2012/05/18
[#395694] Re: reading from and writing to a Unicode encoded file — Regis d'Aubarede <lists@...> 2012/05/18

Hello,

[#395697] Re: reading from and writing to a Unicode encoded file — "Sebastjan H." <lists@...> 2012/05/18

Regis d'Aubarede wrote in post #1061272:

[#395698] Re: reading from and writing to a Unicode encoded file — Regis d'Aubarede <lists@...> 2012/05/18

Sebastjan H. wrote in post #1061276:

[#395699] Re: reading from and writing to a Unicode encoded file — "Sebastjan H." <lists@...> 2012/05/18

Regis d'Aubarede wrote in post #1061277:

[#395750] Re: reading from and writing to a Unicode encoded file - issues when using Shoes — "Sebastjan H." <lists@...> 2012/05/21

Hi,

[#395754] Re: reading from and writing to a Unicode encoded file - issues when using Shoes — "Sebastjan H." <lists@...> 2012/05/21

Sebastjan H. wrote in post #1061483:

[#395740] ? Ruby through CGI and Rails — Shaun Lloyd <list@...>

Hi everybody,

22 messages 2012/05/21
[#395764] Re: Ruby through CGI and Rails — Brian Candler <lists@...> 2012/05/21

Shaun Lloyd wrote in post #1061455:

[#395786] Re: Ruby through CGI and Rails — Shaun Lloyd <list@...> 2012/05/22

On 22/05/12 03:37, Brian Candler wrote:

[#395838] Re: Ruby through CGI and Rails — Brian Candler <lists@...> 2012/05/23

Shaun Lloyd wrote in post #1061602:

[#395787] Changing self class from inside a method?? — David Madison <lists@...>

Let's start off with the assumption I want a method that allows an

10 messages 2012/05/22

[#395841] Memory-efficient set of Fixnums — George Dupre <lists@...>

Hi,

25 messages 2012/05/23

[#395883] looking for a ruby idiom : r=foo; return r if r — botp <botpena@...>

Hi All,

11 messages 2012/05/24

[#395966] Am I justified to use a global variable if it must be used in all scopes? — Phil Stone <lists@...>

Hello,

12 messages 2012/05/27

[#396010] does this leak more than the size of the string via timing side channels — rooby shoez <lists@...>

string1 = "string"

16 messages 2012/05/29

[#396038] Is it possible to avoid longjmp in exceptions, Thread#kill, exit(), signals? — Iñaki Baz Castillo <ibc@...>

Hi, my Ruby C extension runs a C loop (libuv) without GVL. At some

8 messages 2012/05/29

Re: Am I justified to use a global variable if it must be used in all scopes?

From: Gennady Bystritsky <gennady-ruby@...>
Date: 2012-05-27 16:54:11 UTC
List: ruby-talk #395973
On May 27, 2012, at 5:33 AM, Phil Stone wrote:

> Hello,
> Ever since I started learning Ruby, I've been strongly discouraged
> from using global variables
> (http://www.caliban.org/ruby/rubyguide.shtml#style)
> (http://www.ruby-forum.com/topic/187685#819233).
> 
> In a program I'm making, I have a variable (which stores an instance of
> a class) that is declared outside of any functions or classes. However,
> I need to be able to call its methods from various class and function
> scopes, and nothing but a global variable would let me do that. This
> variable is simply what the program is centered around, and must be
> accessed and edited by various classes. I'm not sure why a global
> variable would be such a bad habit in this case, especially since it is
> only one.
> 
> Can I justify using it?

Avoid using globals as much as possible, variables or constants alike. The are very hard to look for where they are coming from, impossible to mock and painful while unit testing in general as they keep persistent state not being reset for individual test cases.

There are many alternatives to using globals, depending on your particular case. The best would be to design your app in a way that an instance can request what it needs from some other instance, possibly made available at instantiation (or via dependency injection). As others suggested, you can use a singleton for a class that provides state for the whole app, which I personally dislike. Or just class methods.

This is what I sometimes use when I need a quick and dirty way to do the job, to be refactored at the earliest opportunity:

=== main script
class App
  def start
    ...
  end

  def self.config
    @config ||= Config.new
  end
end

App.new.start
=== end of main script
=== player.rb
class Player
  def config
    App::config
  end

  def perform
    return if config.idle_mode?
    ...
  end
end
=== end of player.rb

While behaving exactly as a global config would, it makes it possible to mock config on several levels in your unit tests. Besides, you can clearly see where the data is coming from.

Hope this makes sense to you,
Gennady.

> 
> -- 
> Posted via http://www.ruby-forum.com/.
> 


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