From: Joel VanderWerf <vjoel@...>
Date: 2007-09-07T04:34:05+09:00
Subject: Re: Symbols and frozen strings

Brian Candler wrote:
>> Setting aside the question of freezing, why can't ruby share string data 
>> for all strings generated from the same symbol?
> 
> Because it could generate unexpected aliasing. The normal, expected
> behaviour is no aliasing:
> 
> irb(main):001:0> a = :foo.to_s
> => "foo"
> irb(main):002:0> b = :foo.to_s
> => "foo"
> irb(main):003:0> b << "bar"
> => "foobar"
> irb(main):004:0> a
> => "foo"

This was what I was thinking of:

irb(main):001:0> a = :foo.to_s
=> "foo"
irb(main):002:0> b = a.dup
=> "foo"
irb(main):003:0> b << "bar"
=> "foobar"
irb(main):004:0> a
=> "foo"

Internally, a and b use the same storage, but copy-on-write prevents 
aliasing.

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407