On 2/20/07, skaller <[EMAIL PROTECTED]> wrote: > On Tue, 2007-02-20 at 12:24 +0100, Ramon Diaz-Uriarte wrote: > > > > > Now, following with the tradition of "it is sooo easy to ask for > > > > stuff": my superficial understanding is that distributed, concurrent, > > > > and parallel computing using shared memory can be a lot harder and > > > > error prone (e.g., "Concepts, Techniques, and Models of Comp. Progr", > > > > from van Roy and Haridi). If at all possible, when/why/how to choose > > > > Felix over Erlang (or Oz) and how to complement both (your sentence of > > > > "Felix to create ... that Erlang would manage ...") would be something > > > > great to have in the docs. > > > > > > Because it isn't a lot harder, that's crap. Message passing > > > is easier to analyse, but some kinds of things will require > > > much more complex programs. > > > > > > > Please, do not make Van Roy and Haridi responsible for my above > > statement. It might just be my lack of understanding. > > It's like saying functional programming is better than > imperative programming. That's crap for the same reason. > > They're actually equivalent .. FP is better suited for > some things, and imperative for others .. which is why > most FPL's give you both. Even Haskell has its monadic > style .. which demonstrates the equivalence. > > There's no doubt functions are better understood than mutations, > but that's a weakness in research being studied now. > > FPLs usually have multiple features. For example some > people would say declarative style was good, and FPL's > provide that. As does logic programming. Even imperative > systems provide declarations.. and what is a regular > expression but a declarative form of what is usually > considered an imperative operation (executing a > state machine)? > > The idea in Felix is as for C++: to provide the programmer > several techniques and let them choose. >
Thanks, I appreciate the detail. > > > > Of course you can also use mutexes etc. With fibres this > > > kind of things is rarely needed, since they can't be > > > pre-empted. > > > > > > > Aha. I need to go through this much, much more carefully. But this > > looks really mind blowing. Thanks a lot for the comments! Do you know > > where I can find a (gentle) introduction to these issues? I actually > > think "I just don't get Felix". > > Very little documentation exists for the cooperative multi-tasking > system. > I'll wait then :-). > > > > > So the actual model is a variant of CSP plus shared memory. > > > An arbitrary program isn't easy to reason about .. but > > > it is possible to write code which is if you want. > > > > > > Just as an example -- fibres cannot deadlock! > > > > > > Hehe! This is a trick statement. The way the model > > > is built, if fibres deadlock they're unreachable > > > and get reaped by the collector, and so they don't > > > exist, and hence can't be deadlocked. > > > > > > > That is funny. Sounds a lot like magic, though ... > > It just dropped out of the model. > > Felix is basically an operating system: it has a scheduler, > channels, and kernel calls (service requests). > > Apart from the fibres and your ordinary pthreads > (both with channels), it also does asynchronous I/O. > > Basically if you read a socket, your fibre blocks .. > but the pthread it is in doesn't. Async I/O is standard, > and optimised for your OS. > This is really neat!! And seems quite different from most anything else I had heard about! I'll keep my eyes open. Thanks, R. > Again .. not many examples of how to do this .. especially > as the interface is being changed (to use typeclasses). > > > -- > John Skaller <skaller at users dot sf dot net> > Felix, successor to C++: http://felix.sf.net > -- Ramon Diaz-Uriarte Statistical Computing Team Structural Biology and Biocomputing Programme Spanish National Cancer Centre (CNIO) http://ligarto.org/rdiaz ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Felix-language mailing list Felix-language@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/felix-language
