Software:JoCaml
From HandWiki
| Developer(s) | INRIA |
|---|---|
| Stable release | 4.01
/ March 2014 |
| Operating system | Cross-platform |
| Type | Programming language |
| License | LGPL |
| Website | http://jocaml.inria.fr/ |
JoCaml[1][2] is an experimental functional programming language derived from OCaml. It integrates the primitives of the join-calculus to enable flexible, type-checked concurrent and distributed programming. The current version of JoCaml is a re-implementation of the now unmaintained JoCaml[3] made by Fabrice Le Fessant, featuring a modified syntax and improved OCaml compatibility compared to the original.
JoCaml was used by team Camls 'R Us to implement a distributed ray tracer,[4] earning 2nd place on the ICFP 2000 programming contest.
The name is a reference to Joe Camel, a cartoon camel used in advertisements for Camel-brand cigarettes.
Example
type coins = Nickel | Dime
and drinks = Coffee | Tea
and buttons = BCoffee | BTea | BCancel;;
(* def defines a Join-pattern alternatives set clause
* '&' in the left side of '=' means join (channel synchronism)
* '&' in the right hand side is parallel processing
* synchronous_reply :== "reply" [x] "to" channel_name
* synchronous channels have function-like types (`a -> `b)
* while asynchronous ones have type `a Join.chan
* only the last statement in a pattern rhs expression can be an asynchronous message
* 0 in an asynchronous message position means STOP ("no sent message" in CSP terminology).
*)
def put(s) = print_endline s ; 0 (* STOP *)
;; (* put: string Join.chan *)
def give(d) = match d with
Coffee -> put("Coffee")
| Tea -> put("Tea")
;; (* give: drink Join.chan *)
def refund(v) = let s = Printf.sprintf "Refund %d" v in put(s)
;; (* refund: int Join.chan *)
let new_vending give refund =
let vend (cost:int) (credit:int) = if credit >= cost
then (true, credit - cost)
else (false, credit)
in
def coin(Nickel) & value(v) = value(v+5) & reply to coin
or coin(Dime) & value(v) = value(v+10) & reply to coin
or button(BCoffee) & value(v) =
let should_give, remainder = vend 10 v in
(if should_give then give(Coffee) else 0 (* STOP *))
& value(remainder) & reply to button
or button(BTea) & value(v) =
let should_give, remainder = vend 5 v in
(if should_give then give(Tea) else 0 (* STOP *))
& value(remainder) & reply to button
or button(BCancel) & value(v) = refund( v) & value(0) & reply to button
in spawn value(0) ;
coin, button (* coin, button: int -> unit *)
;; (* new_vending: drink Join.chan -> int Join.chan -> (int->unit)*(int->unit) *)
let ccoin, cbutton = new_vending give refund in
ccoin(Nickel); ccoin(Nickel); ccoin(Dime);
Unix.sleep(1); cbutton(BCoffee);
Unix.sleep(1); cbutton(BTea);
Unix.sleep(1); cbutton(BCancel);
Unix.sleep(1) (* let the last message show up *)
;;
execution
$ jocamlc example.ml -o test $ ./test Coffee Tea Refund 5
See also
References
- ↑ Qin Ma and Luc Maranget (2004). "Compiling Pattern-Matching in Join-Patterns". Proc. Of the 15th International Conference on Concurrency Theory. LNCS (Springer-Verlag) 3170.
- ↑ Ma, Qin; Maranget, Luc (2008). "Algebraic Pattern Matching in Join Calculus". Logical Methods in Computer Science 4 (1). doi:10.2168/LMCS-4(1:7)2008. Bibcode: 2008arXiv0802.4018M.
- ↑ Conchon, S.; Le Fessant, F. (1999). "Jocaml: Mobile agents for Objective-Caml". Proceedings. First and Third International Symposium on Agent Systems Applications, and Mobile Agents. pp. 22–29. doi:10.1109/ASAMA.1999.805390. ISBN 0-7695-0342-X. http://moscova.inria.fr/oldjocaml/asa99.ps.gz.
- ↑ "Programming in JoCaml". Inria research report 6261. http://moscova.inria.fr/~maranget/papers/jocamlrus/index.html.
External links
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