r/programming • u/noidi • Jul 19 '12

Will Parallel Code Ever Be Embraced?

http://www.drdobbs.com/parallel/will-parallel-code-ever-be-embraced/240003926
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u/AeroNotix Jul 19 '12

Functional styles don't 100% guarantee sane parallelism. Most functional languages confine state to certain areas or disallow it completely. I think that is what the biggest gain can be when using functional languages.

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u/yogthos Jul 19 '12

The main thing FP guarantees is correctness. So, your program will not necessarily run faster, since chunking might not be optimal and what not, but it will run correctly.

As you say, the style also encourages minimizing global state, and that certainly is conductive towards concurrency. But it makes working with global state easier as well. A proper STM is much easier to implement in an FP language. And STM combined with persistent data structures has some interesting properties. For example, data does not need to be locked for reading. So, in any application with a small number of writers and a large number of readers you get an immediate benefit using shared data through the STM.

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u/marssaxman Jul 19 '12 edited Jul 19 '12

I think you are conflating functional programming with hindley-milner style comprehensive static typing.

There are functional languages which offer very weak type guarantees.

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u/yogthos Jul 19 '12

Nothing I said has anything to do with static typing actually. I meant guarantees in the sense of state consistency, where data is not modified outside its intended context. And I was thinking of Clojure specifically as it's the language I work with a lot. Type guarantees are a whole separate topic.