Re: [Caml-list] Scoped Bound Resource Management just for C++?

[Andreas Rossberg <rossberg@mpi-sws.org>]

On Feb 9, 2011, at 21.45 h, Florian Weimer wrote:
>>>> Scope-bound resource management is inherently broken, at least
>>>> without sophisticated type system support.
>>>
>>> If the environment supports communicating processes with separate
>>> execution pointers, it is straightforward to bypass restrictions, no
>>> matter how evolved the type system is.
>>
>> I don't know what scenario you have in mind with "separate execution
>> pointers". In principle, I'm pretty certain that you could always
>> define some suitable (e.g. linear) type system, if your language was
>> sufficiently well-behaved.
>
> If you have coroutines or threads with communication among them, you
> can always turn type-enforced region-based handles into open handles
> with an explicit close operation.

I still don't know what you are talking about. Why should a suitable  
type system not be able to make such an operation ill-typed?

>>>> 2) or it is unsafe, i.e. you can access an object after its life
>>>> time has
>>>> ended, with potentially desastrous effects.
>>>
>>> This can be made safe with type-safe memory and run-time checks.  I
>>> don't think this is a good excuse.
>>
>> True, runtime checks can deal with some of the "disastrous effects",
>> but they cannot make it safe in a broader sense (e.g., type-safe in  
>> an
>> interesting way), and AFAICS don't apply to memory itself as a
>> resource.
>
> Like array bounds checking, integer division or other partial
> functions. 8-)

Right. But these are examples of collateral damage of useful features,  
while the one under discussion is just the damage, with no new  
expressiveness to justify it. ;)

/Andreas