Javari's Reference Immutability

[Regan Heath]

On Thu, 27 Jul 2006 20:27:06 -0600, Hasan Aljudy <hasan.aljudy at gmail.com>  
wrote:
> Regan Heath wrote:
>> On Thu, 27 Jul 2006 18:39:29 -0600, Hasan Aljudy  
>> <hasan.aljudy at gmail.com>  wrote:
>>
>>> You say that Java's String class implies alot of copying, therefor  
>>> it's  bad. However, you fail to realize that copying when modifying is  
>>> exactly  what COW stands for. COW is a kind of honor-system protocol  
>>> implemented  by phobos. Everytime phobos thinks it needs to modify a  
>>> string which it  doesn't own, it makes a copy first to keep the  
>>> original string intact.  In Java, this can be done by creating a  
>>> StringBuffer from the String  (which creates a copy), after that, any  
>>> modification you make to  StringBuffer happens in-place; no needless  
>>> copying.
>>   Sure. But are you trying to tell me that this..
>>  String foo(String a) { .. return modified a .. }
>> String bar(String a) { .. return modified a .. }
>> String baz(String a) { .. return modified a .. }
>> String bob(String a) { .. return modified a .. }
>>  String s = foo(bar(baz(bob("test"))));
>>  Will result in _no_ needless copying?
>>  Regan
>
> Same thing will happen will happen with phobos COW

At present. This is the 'problem' I'd like to solve somehow.

> P.S. Are you (or Reiner Pope) saying that Javari provides a better  
> solution to this? <g>

No. I was just pointing out that Java's solution doesn't work for all  
cases.

The reason it doesn't work is that String and StringBuffer are seperate  
types. I think we need a single type (or 2 types which can be passed as an  
argument of the same name, perhaps 2 types where one is implicitly  
convertable to the other). Either way, we need to know whether we need to  
.dup or not.

Regan