From: Rob Biedenharn <Rob@...>
Date: 2009-04-02T13:17:01+09:00
Subject: Re: Symbols garbage collector in Ruby1.9, fixed?

On Apr 1, 2009, at 8:03 PM, Iñaki Baz Castillo wrote:
> El Jueves 02 Abril 2009, Tony Arcieri escribió:
>
>> Use symbols... FOR SPEED!  Unfortunately that speed comes at a  
>> price... you
>> really want to globally internalize arbitrary input?  Symbols are
>> effectively a freeform enumeration... the reason you're running into
>> problems is because you're trying to enumerate arbitrary inputs.
>
> Yes. It's a parser so custom headers could arrive. I want to store  
> them in a
> hash like:
>
>  headers = { :from => "alice@qweeq", ":to => "bob@qweqwe }
>
> So after parsing the message I create these entries. The problem is  
> that any
> custom header would create a Symbol.
>
>
>> Is this really an important bottleneck in your application?
>
> I think it's important since after parsing hte main task of the  
> server will be
> accessing some headers to read their content. But since it's just in  
> a very
> early stage I cannot sure it.
>
> Thanks.
> -- 
> Iñaki Baz Castillo <ibc@aliax.net>


Just key the hash with Strings:
  headers = { 'from' => "alice@qweeq", 'to' => "bob@qweeq" }

If you really need to use symbols, perhaps add methods to a subclass  
of Hash like the HashWithIndifferentAccess from Rails which mostly  
eliminates the need to care whether you actually stored against a  
Symbol or a String key.

There's also nothing stopping you from having both kinds of keys at  
once:
  headers = { :from => "alice@qweeq", :to => "bob@qweeq", 'snack' =>  
"raisins" }

but then you might have to "worry" about having both :to and 'to' as  
keys.

Symbols are only faster because they are immutable and don't get  
garbage collected. But I'd go with Tony and just use String all the  
time.

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com