Semantics of shared

[Walter Bright]

Robert Jacques wrote:
> On Thu, 14 May 2009 02:13:37 -0400, Walter Bright 
> <newshound1 at digitalmars.com> wrote:
> 
>> Robert Jacques wrote:
>>> I agree for POD, but what classes where the synchronization is 
>>> encapsulated behind a virtual function call?
>>
>> synchronization can make a shared reference "tail shared".
> 
> I agree, but that doesn't seem answer my question. Put another way, if I 
> have an interface I which is implemented by both a thread local class L 
> and a shared class S, then does some function F need to know about 
> whether the implementor of I is S or L?

Since a reference to thread local cannot be implicitly cast to shared, 
then this scenario cannot happen - i.e. a shared function is not 
covariant with an unshared one.


> P.S. There will obviously be some interfaces S can't implement, but that 
> a separate issue.
> 
>>> Also, does this mean 'scope' as a type is going away?
>>
>> Scope never was a type, it's a storage class.
> 
> Sorry for the confusion of terminology. However, you talk blog about 
> using the 'scope' keyword to support escape analysis, ettc. i.e. 'scope' 
> would become the 'const' of the shared-thread local-stack storage type 
> system. Is this still the plan?

I'm not sure what you mean by that.