[Python-ideas] Fwd: Concurrent safety?

[Terry Reedy]

On 11/1/2011 1:32 AM, Mike Meyer wrote:

> As you point out, this is a hard problem. I know I haven't covered all
> the issues. That's why the second thing I said was that I'm hoping to
> get people smarter than me to look at things.

This is one of the hard problems that keep getting swept under the rug 
while we do easier things. Well, we have overhauled unicode and 
packaging for 3.3, so maybe concurrency can get some attention.

I keep thinking that CPython's design of allowing C coded modules either 
outside or inside the stdlib should allow some progress.

Would it be helpful, for instance, to have truly immutable restricted 
tuples and frozensets, whose __new__ methods only allowed true 
immutables (None, booleans, numbers, strings, other restricted tuples 
and frozensets) as members?

How about a metaclass, say 'immutable', that made the instances of a 
user class truly immutable? (I don't know how to do this, but lets 
assume it can be done -- perhaps with a new frozendict.) If such were 
possible, instances of instances of such a metaclass could be added to 
the list above.

Could a metaclass automatically add fine-grained locks around around 
attribute mutations?

-- 
Terry Jan Reedy