synchronized (this[.classinfo]) in druntime and phobos

[Alex Rønne Petersen]

On 30-05-2012 21:10, Andrei Alexandrescu wrote:
> On 5/30/12 11:41 AM, Jacob Carlborg wrote:
>> On Wednesday, 30 May 2012 at 15:45:05 UTC, Andrei Alexandrescu wrote:
>>> On 5/30/12 2:14 AM, Jacob Carlborg wrote:
>>>> It seems more and more that D2 is not a designed language. Instead new
>>>> features are just slapped on without considering how it would impact
>>>> the
>>>> rest of the language.
>>>
>>> What features are you referring to?
>>
>> The concurrency model as this thread shows. There is no bridge between
>> shared and unshared data like const is to immutable and mutable.
>
> We considered that (maybe_synchronized) , but decided not to go with it
> amid fear of overcomplicating things.

The result is a feature that is arguably only useful in small laboratory 
cases. Are you sure we shouldn't revisit shared and try to work out a 
bridge between the unshared and shared world?

Not to mention that shared is fundamentally x86-biased, which seems to 
be annoying trend in D development in general...

>
>> Perhaps
>> the monitor on every object should have been removed when the new
>> concurrency model was designed, as this thread suggests.
>
> This thread does a good job at arguing that scoped locking does not
> prevent deadlocks, but this is not new or interesting. Unfortunately I
> fail to derive significant proposed value.
>
> There exist type systems that avoid locks. They are very restrictive and
> difficult to work with.

I can think of 3 languages that have monitors in the "type" system: D, 
C# (as a result of the CLR's design; mostly because they wanted Java 
interoperability), and Java. Are you really saying all other type 
systems are difficult to work with just because of this little thing?

>
>> "inout" was added long after the const system was added to D. If done
>> correctly this should have come up as a problem when designing the const
>> system. You cannot apply const/immutable to an object reference in the
>> same way as you can to a pointer.
>>
>> "const" doesn't play nice with ranges.
>
> I see how these can be annoying, but they're not the result of us not
> designing things. We designed things best we could.
>
>
> Andrei

-- 
Alex Rønne Petersen
alex at lycus.org
http://lycus.org