Optional monitors suggestion

[Yuriy via Digitalmars-d]

On Sunday, 18 May 2014 at 19:57:34 UTC, Walter Bright wrote:
> The "_monitor" slot is also used for std.signals. It's been set 
> up in druntime to support more than just being a monitor.
>
> We've also considered it for a hook for a reference count 
> (though that design had other problems).
>
> I'm not saying your design is wrong, just that we should 
> consider what to do with these other issues.

My current PR doesn't affect that also. The signals and 
finalization callbacks do work as they used to. What changes is 
just monitors are looked up in an external hash table, when they 
are not declared inside the class, by applying @monitor attr to 
it. synchronized blocks are also not affected in the same way.
However, if you're planning to use monitors for reference 
counting, such external lookup may become a huge performance 
issue. But current reference counts of monitors themselves are 
not an issue at all.

I'm on my way to DConf now, so we can talk about details there if 
you wish.