[Haskell-cafe] Best Actor system?

[Christopher Allen]

To make the point more explicit.

Usually people use actors or agents because they want effect isolation, but
in Haskell nothing is going to escape your notice on that front.

If you want to expand the scope of what in your codebase is *pure*, thereby
relegating side-effects to only the functions that *have* to be
side-effecting, then you might consider turning your problem into a Free
Monad, where there's a pure DSL and pure functions that manipulate only the
DSL with a separate effectful interpreter for execution. New people without
a firm grasp of monadic DSLs can sometimes find the concept alien, so it's
not something you should feel is obligatory. I would first seek to simply
write code that solves your problem in Haskell, maybe with the use of
Async, then refine afterward with a couple of tests written.

Relevant links:

http://www.haskellforall.com/2012/06/you-could-have-invented-free-monads.html
https://www.fpcomplete.com/user/dolio/many-roads-to-free-monads
http://www.haskellforall.com/2012/07/purify-code-using-free-monads.html
http://www.haskellforall.com/2012/07/free-monad-transformers.html

Cheers,
Chris



On Thu, Mar 27, 2014 at 2:32 AM, Carter Schonwald <
carter.schonwald at gmail.com> wrote:

> I'm inclined to agree with Chris,
> in the shared heap setting, you really should try those other approaches
> first!
>
>
> On Thu, Mar 27, 2014 at 2:32 AM, Christopher Allen <cma at bitemyapp.com>wrote:
>
>> Have you looked at the Async library or Marlow's book?
>>
>> http://hackage.haskell.org/package/async
>>
>> http://chimera.labs.oreilly.com/books/1230000000929/
>>
>> Neither involve actors but I think many Haskellers, myself included, are
>> skeptical of actor/agent systems. I've written a fair bit of Clojure and
>> Scala code and don't much care for the model.
>>
>> If all you really need is message passing/dispatch, you don't strictly
>> speaking need actors. Channels, messages, and dataflow might very well be
>> enough. Perhaps look into functional reactive programming as well?
>>
>> Cheers, hope this helps.
>>
>> --- Chris
>>
>>
>>
>> On Thu, Mar 27, 2014 at 1:29 AM, james <james at mansionfamily.plus.com>wrote:
>>
>>> Having been introduced to actors by looking at Erlang, I discovered Akka.
>>>
>>> It seems that the performance is pretty impressive and I like the model.
>>>
>>> There seem to be several basic Actor libraries in Hackage, but they
>>> don't seem
>>> to be very actively developed.
>>>
>>> I'm more interested in the model for programming within a single runtime
>>> than I am for distributed systems, but message and dispatch performance
>>> definitely is important.
>>>
>>> Can anyone share experiences with the different packages?  Is any one
>>> of them stand-out?
>>>
>>> Thanks
>>> James
>>>
>>>
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>>> Haskell-Cafe mailing list
>>> Haskell-Cafe at haskell.org
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>>>
>>
>>
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