[Haskell-cafe] Re: parallel and distributed haskell?

[Johann Höchtl]

On Dec 16, 8:21 pm, "Scott A. Waterman" <tswater... at gmail.com> wrote:
> It looks like there was a recent hackathon focusing on implementing  
> distributed haskell.
>    http://hackage.haskell.org/trac/ghc/wiki/HackPar
>
> I feel there is quite a bit of latent interest in the subject here,
> but relatively little active development (compared to erlang, clojure,  
> etc.)

With cloud services on the rise, profound distribution support will be
vital in the future. Fully ack.

> Can anyone involved give a quick overview (or pointers to one)?
> It would be good to hear what directions people are taking, and why,
> and where it's going.
>
>   Personally, I'd love to know the current thinking on a variety of  
> subjects:
>
> *  erlang-like port/actor implementations v. more implicit constructs
> *  serialization
> *  node failure/error handling

There has been some discussion lately on that topic.There are  two
limitations:
- Exceptions can only be caught in impure code
- The lack of an agreed model for "stack traces", i.e. where and why
an error / exception occured (I blur the distinction here)

This is only about error/exception handling. I would assume that a
node failure is sthg. which should be handled by a supervising
process.

> *  "grid" compatibility v. various ad-hoc cluster approaches.
>

I assume you know
http://www.haskell.org/haskellwiki/Applications_and_libraries/Concurrency_and_parallelism#Data_Parallel_Haskell

There are libraries for actors and the the concurrency-library should
support messages comparable to that of Erlang. Clearly, supporting
applications (e.g. to monitor running "processes") are missing. While
e.g. Erlang supports only one interaction pattern between processes,
it was natural to develop a solid framework and supporting tools
around that concept. AFAIK Haskell is exploring numerous ways to
handle that challenge (see the link above),that's wy there is no
"standard way" to handle concurrency and only very limited tools
support for monitoring. Actually, are there any?


> Anyone actively looking at this kind of question who would want to  
> talk about it?
>

Well, Christmas is approaching. I wrote some simple Erlang style
distributed toy applications and found the message passing / actor
approach dead simple and effective. Would be nice if this model would
be fully supported by eg. GHC.

So add me to the wish-list ;)

> Thanks,
> --ts
>
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