How to use synchronized() {} as the basis for a freely (un)lockable mutex, using stackthreads

[downs]

Sean Kelly wrote:
> downs wrote:
>> Disclaimer: My StackThreads are neither particularly fast (130 cycles
>> per context switch), nor particularly stable.
>> This is primarily intended as a Proof of Concept, even though I do use
>> it in some of my code. :)
>>
>> Have you ever wished D had a Mutex class that could be locked or
>> unlocked at any time?
> 
> Tango does :-)
> 

Clarification. D/Phobos.

>> D's synchronized() {} statement is nice and all, but does have some
>> weaknesses, primarily that it can only be used to
>> synchronize some scope - it is not possible to unlock the underlying
>> mutex in the middle of a block.
> 
> The Tango mutexes can also be used with the 'synchronized' statement.
> However, I'm not sure I like the idea of being inside a 'synchronized'
> block and having the mutex unlocked.  Why not just break the code into
> two sequential 'synchronized' blocks?
> 
> 
> Sean

Because the structure of the code looks like this:

foo;
synchronized {
  bar;
  whee {
    lol;
    *unsynchronized* { lmao; }
    meep;
  }
  baz;
}

So, to break it into two synchronized statements, my code would have to look like so ...

foo;
synchronized {
  bar;
  whee {
    lol;
}
      lmao;
synchronized {
    meep;
  } // closing bracket of whee
  baz;
}

See the problem? :)

 --downs