On Jul 30, 2008, at 9:06 AM, Colin Putney wrote:

>
> On 29-Jul-08, at 1:24 PM, Eliot Miranda wrote:
>
>> BTW, immutability involves primitive error codes and I will be  
>> introducing primitive error codes, because the performance hit is  
>> essentially zero and there is no backward compatibility issue  
>> (strange but true :) ).
>
> I'm all for general immutability support in the VM.
>
> I suspect, though, that this isn't what Stéphane was driving at.  
> Immutable strings is kind of a language-level thing, and could be  
> done without VM support.  One way would be to factor out a  
> MutableString class and keep it distinct from regular strings. Going  
> further, we could just remove the mutation protocol and require all  
> string creation to be either stream-based or functional (ie,  
> producing new strings rather than mutating existing ones).

for example.
>
>
> Once strings are immutable, interning them is a useful space  
> optimization, and that *would* make symbols redundant.
>
> Clearly there are huge compatibility issues here, but it's a  
> reasonable thing to consider if building a system from scratch.
>
> Colin
>