John Nagle <na...@animats.com> writes: > Right. Tracking mutablity and ownership all the way down without > making the language either restrictive or slow is tough. > > In multi-thread programs, though, somebody has to be clear on who owns > what. I'm trying to figure out a way for the language, rather than the > programmer, to do that job. It's a major source of trouble in threaded > programs.
Python's threading system is modelled after Java's, which basically uses explicit locks under programmer control. That has its hazards but does manage to multiprocess effectively. CPython's multiprocessing is limited by the notorious GIL, but that's an implementation artifact. Having the language automatically manage ownership of mutable objects without a fancy type system sounds self-contradictory. Erlang (which is typeless like Python) does it by not allowing mutation at all. Haskell uses a type-based scheme around software transactional memory (STM) primitives: http://book.realworldhaskell.org/read/software-transactional-memory.html The Microsoft Research "Singularity" OS may also be of interest. -- http://mail.python.org/mailman/listinfo/python-list
