From: Sigurd <cu9ypd@...>
Date: 2012-02-17T19:17:22+09:00
Subject: Re: Symbol garbage collection


On Feb 17, 2012, at 11:58 AM, Ronnie Collinson wrote:

> But two equal strings can be two separate objects ("a" == "a" could be
> false),

It always be true. In a sense of how they are stored - yes, they can be stored in different places, but in terms of ruby code that strings always would be equal.
Also string === method is also comparing strings by their content, not by are they the same object

a = "a"
b = "b"
a.object_id => 2181707380
b.object_id => 2181676040
a === b => true
a == b => true

> two equal symbols will be (including your example, all
> variables are still pointing to your new/hacked symbol ) the same
> object, its not how the data is stored, saving memory but how it can
> be a single instance for the lifetime of the process.
> 
> If space is the only gain, then gcing symbols would remove some other
> nice properties such as single instance, Id rather pay a small bit of
> space for nice properties.
> 
> When/If the symbols were in a separate area in memory to the gc's
> heap, then the gc would never waste time looking at the symbols, would
> that make a measurable/worthwhile improvement to the gc speed?
>