const?? When and why? This is ugly!

[Andrei Alexandrescu]

Jarrett Billingsley wrote:
> On Mon, Mar 2, 2009 at 12:25 PM, Andrei Alexandrescu
> <SeeWebsiteForEmail at erdani.org> wrote:
>> The style of programming in which you create a new thread that joyously sees
>> and can modify *all* of the memory space available to every other thread
>> will go the way of the dinosaur. It's just not tenable anymore, and I
>> predict today's mainstream programming languages abiding to that model are
>> facing major troubles in the near future.
> 
> Eheh, sounds like the dawn of protected memory 20 years ago ;)

Absolutely. The industry has cycles and a lot of its history rhymes. 
Things like multitasking, client-server computing, flat memory 
addressing, virtual memory, machine virtualization... they've all come 
and went a couple of times over decades.

As for my bet, I'm pretty confident in it. The default-isolated model is 
gaining traction in newer languages, in older languages that are seeing 
a new youth with the advent of manycores, and even in applications. 
Google Chrome figured that it must use OS-provided memory isolation for 
its tabs.

D is positioned very well, probably uniquely, to take advantage of a 
default-isolated model within a largely mutative language, and that is 
in no small part due to const and immutable. Other languages are 
struggling, see http://tinyurl.com/4apat7. I'm very glad that the tide 
on this group has effectively reversed with regard to the general 
opinion about const and immutable.


Andrei