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RE: callcc/cps-style programming
-
Dave Berry
-
Chet Murthy
- T. Kurt Bond
-
Julian Assange
- Chet Murthy
-
Chet Murthy
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| Date: | -- (:) |
| From: | Chet Murthy <chet@w...> |
| Subject: | Re: callcc/cps-style programming |
>>>>> "JA" == Julian Assange <proff@iq.org> writes:
JA> Chet Murthy <chet@watson.ibm.com> writes:
>> Stuff like:
>>
>> (i) allocating memory in the middle of a finalizer -- e.g., a
>> finalizer which is pushing some reusable resource onto some
>> stack (and the stack needs to be grown)
>>
>> (ii) locking some object in a finalizer, which can also be
>> locked by some thread that which would allocate memory with
>> that lock held.
>>
>> (iii) SMP-unsafe code galore -- race conditions,
>> memory-incoherence, thrash-prone code.
JA> If code is written in a functional manner, almost all of these
JA> problems disappear. This is why functional languages and
JA> concurrency dovetail so nicely together. Further, in some
JA> cases you can use concurrency to hide state changes; allowing
JA> one to write functional code where previously it was unatural
JA> to do so.
The sorts of code I described cannot be written functionally. It
talks to the outside world, or pools resources (and no, the GC isn't
perfect, so you _do_ have to pool resoruces from time to time), or
does any of a number of other things that make it necessary to use
shared variables.
I'm an old ML programmer. I've written lots and lots of ML code
(including what I believe was the first thread-safe SUNRPC stack -- in
SML/NJ). But quite simply, there are things that can only be done in
a imperative manner. Or that can only be done with shared variables.
--chet--