Impressions of Mozart-Oz

Klacke <>
Mon Dec 9 10:19:02 CET 2002

On Fri, Dec 06, 2002 at 09:31:08AM -0800, Eric Merritt wrote:
> Hello All,
>  I have been spending a bit of time playing with the
> mozart-oz ( system. I was curious as
> to what the impressions of some of you Erlang Gurus
> are. This is just an exercise in curiosity.

I played around with it a couple of years ago. I think 
they have changed the language considerably since then ...
actually, I think they took some of the ideas from Erlang.
In particular they toook the idea of explicit concurrency.

The LP world had the idea of implicit concurrency whereby
each goal, in a series of goals was evaluated as a process.
Syncronization between theses goals/processes was/is done by
logical variables. I personally think that that model of
concurrency sucks.

Anyway, oz has explicit concurrency and logical variables.
So message passing is done (correct me if i'm wrong) by sending
a uninstantiated logical variable, the sender can wait until
someone instantiates  a sent variable.  (possibly on another machine)

I prefer messages the way we have them in erlang. On the
other hand, imagine Erlang _with_ logical variables, it makes
for some pretty interesting/complicated programs. 

I think, that logical variables is programming concept that 
is too hard to be used in large (many not so very talented
programmers) projects. The code becomes hard to read/understand 
and it's to easy to write unnecessary complicated code.

My 2 öre.


Claes Wikstrom                        -- Caps lock is nowhere and
Alteon WebSystems                     -- everything is under control       
cellphone: +46 70 2097763
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