functional

[Andrei Alexandrescu]

On 03/10/2010 06:47 PM, grauzone wrote:
> Andrei Alexandrescu wrote:
>> On 03/10/2010 06:06 PM, grauzone wrote:
>>> Andrei Alexandrescu wrote:
>>>> On 03/10/2010 05:01 PM, grauzone wrote:
>>>>> Andrei Alexandrescu wrote:
>>>>>> There's one final nail in the coffin. In wake of concurrency, de jure
>>>>>> immutability becomes a necessity, not a useful and desirable de facto
>>>>>> convention. Adopting the window dressing but not the essence of FP by
>>>>>> a concurrent language evokes to me a scene in the Marx Brothers: an
>>>>>> otherwise impeccably-dressed gentleman who forgot to put his pants
>>>>>> on.
>>>>>
>>>>> Language support is not strictly necessary to get the same effects as
>>>>> immutable types, as far as multithreading is concerned: small data can
>>>>> be copied, and large data can be made read-only by OS syscalls. This
>>>>> just had to be in the message passing library. (As a bonus, it isn't
>>>>> possible to subvert these mechanisms just by casting.)
>>>>
>>>> That'll never work. The OS granularity is 4KB increments.
>>>
>>> Data this small you would simply copy. Because it's so small, copying
>>> won't have negative performance impact. The OS approach can be used for
>>> large data (at least in the order of hundreds of KB) and immutable parts
>>> of the data segment.
>>
>> Trust me, that will never work anywhere close to satisfactory. It's
>> even useless to talk about it.
>
> Just saying "it won't work" is a bit empty. Do you happen to have any
> arguments?

I'd need to build a fair amount of background, which I don't have time for.

Andrei