From 53a3cc7b17f4cf97075b7e71720777fd84109696 Mon Sep 17 00:00:00 2001 From: Gilles Dubochet Date: Fri, 16 Dec 2005 18:44:33 +0000 Subject: Created proper 'docs' folder for new layout. --- docs/examples/Parsers.scala | 108 +++++++ docs/examples/auction.scala | 133 +++++++++ docs/examples/boundedbuffer.scala | 36 +++ docs/examples/computeserver.scala | 42 +++ .../examples/expressions/expressions-current.scala | 67 +++++ docs/examples/fors.scala | 114 +++++++ docs/examples/futures.scala | 17 ++ docs/examples/iterators.scala | 29 ++ docs/examples/jolib/Ref.scala | 56 ++++ docs/examples/jolib/parallelOr.scala | 59 ++++ docs/examples/maps.scala | 192 ++++++++++++ docs/examples/mobile/sort.scala | 17 ++ docs/examples/monads/callccInterpreter.scala | 84 ++++++ docs/examples/monads/directInterpreter.scala | 55 ++++ docs/examples/monads/errorInterpreter.scala | 86 ++++++ docs/examples/monads/simpleInterpreter.scala | 75 +++++ docs/examples/monads/stateInterpreter.scala | 86 ++++++ docs/examples/oneplacebuffer.scala | 47 +++ docs/examples/parsers1.scala | 118 ++++++++ docs/examples/parsers2.scala | 63 ++++ docs/examples/patterns.scala | 35 +++ docs/examples/pilib/elasticBuffer.scala | 77 +++++ docs/examples/pilib/handover.scala | 190 ++++++++++++ docs/examples/pilib/mobilePhoneProtocol.scala | 172 +++++++++++ docs/examples/pilib/piNat.scala | 92 ++++++ docs/examples/pilib/rwlock.scala | 331 +++++++++++++++++++++ docs/examples/pilib/scheduler.scala | 149 ++++++++++ docs/examples/pilib/semaphore.scala | 72 +++++ docs/examples/pilib/twoPlaceBuffer.scala | 67 +++++ docs/examples/sort.scala | 48 +++ docs/examples/sort1.scala | 22 ++ docs/examples/sort2.scala | 25 ++ docs/examples/typeinf.scala | 244 +++++++++++++++ 33 files changed, 3008 insertions(+) create mode 100644 docs/examples/Parsers.scala create mode 100644 docs/examples/auction.scala create mode 100644 docs/examples/boundedbuffer.scala create mode 100644 docs/examples/computeserver.scala create mode 100644 docs/examples/expressions/expressions-current.scala create mode 100644 docs/examples/fors.scala create mode 100644 docs/examples/futures.scala create mode 100644 docs/examples/iterators.scala create mode 100644 docs/examples/jolib/Ref.scala create mode 100644 docs/examples/jolib/parallelOr.scala create mode 100644 docs/examples/maps.scala create mode 100644 docs/examples/mobile/sort.scala create mode 100644 docs/examples/monads/callccInterpreter.scala create mode 100644 docs/examples/monads/directInterpreter.scala create mode 100644 docs/examples/monads/errorInterpreter.scala create mode 100644 docs/examples/monads/simpleInterpreter.scala create mode 100644 docs/examples/monads/stateInterpreter.scala create mode 100644 docs/examples/oneplacebuffer.scala create mode 100644 docs/examples/parsers1.scala create mode 100644 docs/examples/parsers2.scala create mode 100644 docs/examples/patterns.scala create mode 100644 docs/examples/pilib/elasticBuffer.scala create mode 100644 docs/examples/pilib/handover.scala create mode 100644 docs/examples/pilib/mobilePhoneProtocol.scala create mode 100644 docs/examples/pilib/piNat.scala create mode 100644 docs/examples/pilib/rwlock.scala create mode 100644 docs/examples/pilib/scheduler.scala create mode 100644 docs/examples/pilib/semaphore.scala create mode 100644 docs/examples/pilib/twoPlaceBuffer.scala create mode 100644 docs/examples/sort.scala create mode 100644 docs/examples/sort1.scala create mode 100644 docs/examples/sort2.scala create mode 100644 docs/examples/typeinf.scala (limited to 'docs/examples') diff --git a/docs/examples/Parsers.scala b/docs/examples/Parsers.scala new file mode 100644 index 0000000000..10512ab2fd --- /dev/null +++ b/docs/examples/Parsers.scala @@ -0,0 +1,108 @@ +package examples; + +abstract class Parsers { + + type inputType; + + trait Parser[a] { + + type Result = Option[Pair[a, inputType]]; + + def apply(in: inputType): Result; + + def filter(pred: a => boolean) = new Parser[a] { + def apply(in: inputType): Result = Parser.this.apply(in) match { + case None => None + case Some(Pair(x, in1)) => if (pred(x)) Some(Pair(x, in1)) else None + } + } + + def map[b](f: a => b) = new Parser[b] { + def apply(in: inputType): Result = Parser.this.apply(in) match { + case None => None + case Some(Pair(x, in1)) => Some(Pair(f(x), in1)) + } + } + + def flatMap[b](f: a => Parser[b]) = new Parser[b] { + def apply(in: inputType): Result = Parser.this.apply(in) match { + case None => None + case Some(Pair(x, in1)) => f(x).apply(in1) + } + } + + def ||| (p: => Parser[a]) = new Parser[a] { + def apply(in: inputType): Result = Parser.this.apply(in) match { + case None => p(in) + case s => s + } + } + + def &&& [b](p: => Parser[b]): Parser[b] = + for (val _ <- this; val x <- p) yield x; + } + + def succeed[a](x: a) = new Parser[a] { + def apply(in: inputType): Result = Some(Pair(x, in)) + } + + def rep[a](p: Parser[a]): Parser[List[a]] = + rep1(p) ||| succeed(List()); + + def rep1[a](p: Parser[a]): Parser[List[a]] = + for (val x <- p; val xs <- rep(p)) yield x :: xs; + + def opt[a](p: Parser[a]): Parser[List[a]] = + (for (val x <- p) yield List(x)) ||| succeed(List()); +} + +class Tokenizer(in: Iterator[char], delimiters: String) extends Iterator[String] { + + val EOI: char = 0; + + def nextChar() = + if (in.hasNext) in.next else EOI; + + private var ch = nextChar(); + + def isDelimiter(ch: Char) = { + var i = 0; + while (i < delimiters.length() && delimiters.charAt(i) != ch) { i = i + 1 } + i < delimiters.length() + } + + def hasNext: boolean = ch != EOI; + + private val buf = new StringBuffer; + + def next: String = { + while (ch <= ' ' && ch != EOI) nextChar(); + if (ch == EOI) "" + else { + if (isDelimiter(ch)) ch.toString() + else { + buf.setLength(0); buf append ch; + while (ch > ' ' && ch != EOI && !isDelimiter(ch)) { + buf append ch; nextChar(); + } + buf.toString() + } + } + } +} + +abstract class TokenParsers extends Parsers { + type inputType = Stream[String]; + def nextToken() = new Parser[String] { + def apply(in: inputType): Result = + if (in.isEmpty) None else Some(Pair(in.head, in.tail)); + } +} + +abstract class CharParsers extends Parsers { + def any: Parser[char]; + def chr(ch: char) = + for (val c <- any; c == ch) yield c; + def chr(p: char => boolean) = + for (val c <- any; p(c)) yield c; +} diff --git a/docs/examples/auction.scala b/docs/examples/auction.scala new file mode 100644 index 0000000000..c6ab223375 --- /dev/null +++ b/docs/examples/auction.scala @@ -0,0 +1,133 @@ +package examples; + +import java.util.Date; +import scala.concurrent._; + +/** A simple demonstrator program implementing an online auction service + * The example uses the actor abstraction defined in the API of + * package scala.concurrent. + */ +trait AuctionMessage; +case class + Offer(bid: int, client: Actor), // make a bid + Inquire(client: Actor) extends AuctionMessage; // inquire status + +trait AuctionReply; +case class + Status(asked: int, expiration: Date), // asked sum, expiration date + BestOffer(), // yours is the best offer + BeatenOffer(maxBid: int), // offer beaten by maxBid + AuctionConcluded(seller: Actor, client: Actor), // auction concluded + AuctionFailed(), // failed with no bids + AuctionOver() extends AuctionReply; // bidding is closed + +class Auction(seller: Actor, minBid: int, closing: Date) extends Actor { + + val timeToShutdown = 3600000; // msec + val bidIncrement = 10; + + override def run() = { + var maxBid = minBid - bidIncrement; + var maxBidder: Actor = null; + var running = true; + + while (running) { + receiveWithin (closing.getTime() - new Date().getTime()) { + + case Offer(bid, client) => + if (bid >= maxBid + bidIncrement) { + if (maxBid >= minBid) + maxBidder send BeatenOffer(bid); + maxBid = bid; + maxBidder = client; + client send BestOffer() + } else { + client send BeatenOffer(maxBid) + } + + case Inquire(client) => + client send Status(maxBid, closing) + + case TIMEOUT() => + if (maxBid >= minBid) { + val reply = AuctionConcluded(seller, maxBidder); + maxBidder send reply; + seller send reply + } else { + seller send AuctionFailed() + } + receiveWithin(timeToShutdown) { + case Offer(_, client) => client send AuctionOver() + case TIMEOUT() => running = false + } + + } + } + } +} + +// ---- Test ------------------------------------------------------------- + +object auction { + + val random = new java.util.Random(); + + val minBid = 100; + val closing = new Date(new Date().getTime() + 60000); + + val seller = new Actor { + override def run() = {} + } + val auction = new Auction(seller, minBid, closing); + + def client(i: int, increment: int, top: int) = new Actor { + val name = "Client " + i; + def log(msg: String) = Console.println(name + ": " + msg); + var running = true; + var max: int = _; + var current: int = 0; + override def run() = { + log("started"); + auction send Inquire(this); + receive { + case Status(maxBid, _) => { + log("status(" + maxBid + ")"); + max = maxBid + } + } + while (running) { + if (max >= top) + log("too high for me") + else if (current < max) { + current = max + increment; + Thread.sleep(1 + random.nextInt(1000)); + auction send Offer(current, this); + } + receive { + case BestOffer() => { + log("bestOffer(" + current + ")"); + } + case BeatenOffer(maxBid) => { + log("beatenOffer(" + maxBid + ")"); + max = maxBid; + } + case AuctionConcluded(seller, maxBidder) => { + log("auctionConcluded"); + } + case AuctionOver() => { + running = false; + log("auctionOver"); + } + } + } + } + } + + def main(args: Array[String]) = { + seller.start(); + auction.start(); + client(1, 20, 200).start(); + client(2, 10, 300).start(); + } + +} diff --git a/docs/examples/boundedbuffer.scala b/docs/examples/boundedbuffer.scala new file mode 100644 index 0000000000..983a3a7bf5 --- /dev/null +++ b/docs/examples/boundedbuffer.scala @@ -0,0 +1,36 @@ +package examples; + +object boundedbuffer { + + import concurrent.ops._; + + class BoundedBuffer[a](N: Int) { + var in, out, n = 0; + val elems = new Array[a](N); + + def await(cond: => Boolean) = while (!cond) { wait() } + + def put(x: a) = synchronized { + await (n < N); + elems(in) = x; in = (in + 1) % N; n = n + 1; + if (n == 1) notifyAll(); + } + + def get: a = synchronized { + await (n != 0); + val x = elems(out); out = (out + 1) % N ; n = n - 1; + if (n == N - 1) notifyAll(); + x + } + } + + def main(args: Array[String]) = { + val buf = new BoundedBuffer[String](10); + var cnt = 0; + def produceString = { cnt = cnt + 1; cnt.toString() } + def consumeString(ss: String) = System.out.println(ss); + spawn { while (true) { val ssss = produceString; buf.put(ssss) } } + spawn { while (true) { val s = buf.get; consumeString(s) } } + } + +} diff --git a/docs/examples/computeserver.scala b/docs/examples/computeserver.scala new file mode 100644 index 0000000000..acc4a0b93e --- /dev/null +++ b/docs/examples/computeserver.scala @@ -0,0 +1,42 @@ +package examples; + +import concurrent._, concurrent.ops._; + +class ComputeServer(n: Int) { + + private trait Job { + type t; + def task: t; + def ret(x: t): Unit; + } + + private val openJobs = new Channel[Job](); + + private def processor(i: Int): Unit = { + while (true) { + val job = openJobs.read; + Console.println("read a job"); + job.ret(job.task) + } + } + + def future[a](p: => a): () => a = { + val reply = new SyncVar[a](); + openJobs.write{ + new Job { + type t = a; + def task = p; + def ret(x: a) = reply.set(x); + } + } + () => reply.get + } + + spawn(replicate(0, n) { processor }) +} + +object computeserver with Application { + val server = new ComputeServer(1); + val f = server.future(42); + Console.println(f()) +} diff --git a/docs/examples/expressions/expressions-current.scala b/docs/examples/expressions/expressions-current.scala new file mode 100644 index 0000000000..91e5df02ae --- /dev/null +++ b/docs/examples/expressions/expressions-current.scala @@ -0,0 +1,67 @@ +package examples.expressions; + +abstract class Lang { + trait Visitor { + def caseNum(n: int): unit; + } + + abstract class Exp { + def visit(v: visitor): unit; + } + + type visitor <: Visitor; + + class Num(n: int) extends Exp { + def visit(v: visitor): unit = v.caseNum(n); + } + + class Eval(result: Ref[int]): visitor extends Visitor { + def caseNum(n: int) = result.elem = n; + } +} + +abstract class Lang2 extends Lang { + abstract class Visitor2 extends Visitor { + def casePlus(left: Exp, right: Exp): unit; + } + + type visitor <: Visitor2; + + class Plus(l: Exp, r: Exp) extends Exp { + def visit(v: visitor): unit = v.casePlus(l, r); + } + + class Eval2(result: Ref[int]): visitor extends Eval(result) with Visitor2 { + def casePlus(l: Exp, r: Exp) = + result.elem = { l.visit(this); result.elem } + { r.visit(this); result.elem } + } + + class Show2(result: Ref[String]): visitor extends Visitor2 { + def caseNum(n: int) = result.elem = n.toString(); + def casePlus(l: Exp, r: Exp) = + result.elem = + "(" + { l.visit(this); result.elem } + + "+" + { r.visit(this); result.elem } + ")"; + } +} + +object Main { + + def main(args: Array[String]) = { + //val l1 = new Lang { type visitor = Visitor } // not yet implemented + object l1 extends Lang { type visitor = Visitor } // workaround + val e1: l1.Exp = new l1.Num(42); + val iref = new Ref(0); + Console.println("eval: " + { e1.visit(new l1.Eval(iref)); iref.elem }); + + //val l2 = new Lang2 { type visitor = Visitor2 } // not yet implemented + object l2 extends Lang2 { type visitor = Visitor2 } // workaround + val e2: l2.Exp = new l2.Plus(new l2.Num(5), new l2.Num(37)); + val sref = new Ref(""); + Console.println("eval: " + { e2.visit(new l2.Eval2(iref)); iref.elem }); + Console.println("show: " + { e2.visit(new l2.Show2(sref)); sref.elem }); + e1.visit(new l1.Eval(iref)); + e2.visit(new l2.Show2(sref)); + } +} + diff --git a/docs/examples/fors.scala b/docs/examples/fors.scala new file mode 100644 index 0000000000..6c969d3519 --- /dev/null +++ b/docs/examples/fors.scala @@ -0,0 +1,114 @@ +package examples; + +import scala.xml._; + + +object fors { + + val e = Node.NoAttributes ; + + class Person(_name: String, _age: Int) { + val name = _name; + val age = _age; + } + + def printOlderThan20(xs: Seq[Person]): Iterator[String] = + printOlderThan20(xs.elements); + + def printOlderThan20(xs: Iterator[Person]): Iterator[String] = + for (val p <- xs; p.age > 20) yield p.name; + + val persons = List( + new Person("John", 40), + new Person("Richard", 68) + ); + + def divisors(n: Int): List[Int] = + for (val i <- List.range(1, n+1); n % i == 0) yield i; + + def isPrime(n: Int) = divisors(n).length == 2; + + def findNums(n: Int): Iterator[Pair[Int, Int]] = + for (val i <- Iterator.range(1, n); + val j <- Iterator.range(1, i-1); + isPrime(i+j)) yield Pair(i, j); + + def sum(xs: List[Double]): Double = + xs.foldLeft(0.0) { (x, y) => x + y } + + def scalProd(xs: List[Double], ys: List[Double]) = + sum(for(val Pair(x, y) <- xs zip ys) yield x * y); + + type Lst = List[Any]; + + val prefix = null; + val scope = TopScope; + + val books = List( + Elem(prefix, "book", e, scope, + Elem(prefix, "title", e, scope, + Text("Structure and Interpretation of Computer Programs")), + Elem(prefix, "author", e, scope, + Text("Abelson, Harald")), + Elem(prefix, "author", e, scope, + Text("Sussman, Gerald J."))), + Elem(prefix, "book", e, scope, + Elem(prefix, "title", e, scope, + Text("Principles of Compiler Design")), + Elem(prefix, "author", e, scope, + Text("Aho, Alfred")), + Elem(prefix, "author", e, scope, + Text("Ullman, Jeffrey"))), + Elem(prefix, "book", e, scope, + Elem(prefix, "title", e, scope, + Text("Programming in Modula-2")), + Elem(prefix, "author", e, scope, + Text("Wirth, Niklaus"))) + ); + + def findAuthor(books: Lst) = + for (val Elem(_, "book", _, scope, book @ _*) <- books; + val Elem(_, "title", _, scope, Text(title)) <- book; + (title indexOf "Program") >= 0; + val Elem(_, "author", _, scope, Text(author)) <- book) yield author; + + for (val Elem(_, "book", _, scope, b @ _*) <- books; + val Elem(_, "author", _, scope, Text(author)) <- b; + author startsWith "Ullman"; + val Elem(_, "title", _, scope, Text(title)) <- b) yield title; + + removeDuplicates( + for (val Elem(_, "book", _, scope, b1 @ _* ) <- books; + val Elem(_, "book", _, scope, b2 @ _*) <- books; + b1 != b2; + val Elem(_, "author", _, scope, Text(a1)) <- b1; + val Elem(_, "author", _, scope, Text(a2)) <- b2; + a1 == a2) yield Pair(a1, a2)); + + def removeDuplicates[a](xs: List[a]): List[a] = + if (xs.isEmpty) + xs + else + xs.head :: removeDuplicates(for (val x <- xs.tail; x != xs.head) yield x); + + def main(args: Array[String]) = { + Console.print("Persons over 20:"); + printOlderThan20(persons) foreach { x => Console.print(" " + x) }; + Console.println; + + Console.println("divisors(34) = " + divisors(34)); + + Console.print("findNums(15) ="); + findNums(15) foreach { x => Console.print(" " + x); }; + Console.println; + + val xs = List(3.5, 5.0, 4.5); + Console.println("average(" + xs + ") = " + + sum(xs) / xs.length); + + val ys = List(2.0, 1.0, 3.0); + Console.println("scalProd(" + xs + ", " + ys +") = " + + scalProd(xs, ys)); + } + +} diff --git a/docs/examples/futures.scala b/docs/examples/futures.scala new file mode 100644 index 0000000000..905d360612 --- /dev/null +++ b/docs/examples/futures.scala @@ -0,0 +1,17 @@ +package examples; + +import concurrent.ops._; + +object futures { + def someLengthyComputation = 1; + def anotherLengthyComputation = 2; + def f(x: Int) = x + x; + def g(x: Int) = x * x; + + def main(args: Array[String]): Unit = { + val x = future(someLengthyComputation); + anotherLengthyComputation; + val y = f(x()) + g(x()); + Console.println(y) + } +} \ No newline at end of file diff --git a/docs/examples/iterators.scala b/docs/examples/iterators.scala new file mode 100644 index 0000000000..5f951156cf --- /dev/null +++ b/docs/examples/iterators.scala @@ -0,0 +1,29 @@ +package examples; + +object iterators { + + def Array(elems: Double*): Array[Double] = { + val ar = new Array[Double](elems.length); + for (val i <- Iterator.range(0, elems.length)) + ar(i) = elems(i); + ar + } + + def printArray(xs: Array[Double]) = + Iterator.fromArray(xs) foreach { x => Console.println(x) }; + + def findGreater(xs: Array[Double], limit: Double) = + Iterator.fromArray(xs) + .zip(Iterator.from(0)) + .filter{case Pair(x, i) => x > limit } + .map{case Pair(x, i) => i} + + def main(args: Array[String]) = { + val ar = Array/*[Double]*/(6, 2, 8, 5, 1); + printArray(ar); + Console.println("Elements greater than 3.0:"); + findGreater(ar, 3.0) foreach { x => Console.println(ar(x)) } + } + +} + diff --git a/docs/examples/jolib/Ref.scala b/docs/examples/jolib/Ref.scala new file mode 100644 index 0000000000..73cc167307 --- /dev/null +++ b/docs/examples/jolib/Ref.scala @@ -0,0 +1,56 @@ +/* __ *\ +** ________ ___ / / ___ Scala API ** +** / __/ __// _ | / / / _ | (c) 2003, LAMP/EPFL ** +** __\ \/ /__/ __ |/ /__/ __ | ** +** /____/\___/_/ |_/____/_/ | | ** +** |/ ** +** $Id$ +\* */ + +package examples.jolib; +/* +import concurrent.SyncVar; +import concurrent.jolib._; + +class Ref[a](init: a) extends Join { + + object get extends Synchr[a](this) { case class C() extends SyncVar[a]; } + object set extends Synchr[unit](this) { case class C(x: a) extends SyncVar[unit]; } + object state extends Asynchr(this) { case class C(x: a); } + + rules ( + Pair(List(get, state), { case List(g @ get.C(), state.C(x) ) => + { g.set(x); state(state.C(x)) } }), + Pair(List(set, state), { case List(s @ set.C(x), state.C(y) ) => + { s.set(()); state(state.C(x)) } }) + ); + + state(state.C(init)); + + def Get: a = get(get.C()); + def Set(x: a): unit = set(set.C(x)); +} +*/ +object RefTest { + + def main(args: Array[String]) = { + System.out.println("Started."); +/* + concurrent.ops.spawn({ + val r1 = new Ref(0); + System.out.println("Reference r1 created."); + System.out.println("Value r1 (first time) = " + r1.Get); + r1.Set(42); + System.out.println("Value r1 (second time) = " + r1.Get); + }); + concurrent.ops.spawn({ + val r2 = new Ref(100); + System.out.println("Reference r2 created."); + System.out.println("Value r2 (first time) = " + r2.Get); + r2.Set(89); + System.out.println("Value r2 (second time) = " + r2.Get); + }); +*/ + } + +} diff --git a/docs/examples/jolib/parallelOr.scala b/docs/examples/jolib/parallelOr.scala new file mode 100644 index 0000000000..bff4dcd87a --- /dev/null +++ b/docs/examples/jolib/parallelOr.scala @@ -0,0 +1,59 @@ +/* __ *\ +** ________ ___ / / ___ Scala API ** +** / __/ __// _ | / / / _ | (c) 2003, LAMP/EPFL ** +** __\ \/ /__/ __ |/ /__/ __ | ** +** /____/\___/_/ |_/____/_/ | | ** +** |/ ** +** $Id$ +\* */ + +package examples.jolib; +/* +import concurrent.jolib._; +import concurrent.SyncVar; + +/** Implementation in the join-calculus of a parallel OR. */ +object or extends Join { + + object res extends Synchr[boolean](this) { case class C() extends SyncVar[boolean] }; + object res1 extends Asynchr(this) { case class C(b: boolean); } + object res2 extends Asynchr(this) { case class C(b: boolean); } + object res1False extends Synchr[boolean](this) { case class C() extends SyncVar[boolean] }; + object res2False extends Synchr[boolean](this) { case class C() extends SyncVar[boolean] }; + + rules( + Pair(List(res, res1), { case List(r @ res.C(), res1.C(b)) => + if (b) r.set(b) else r.set(res1False(res1False.C())) }), + + Pair(List(res, res2), { case List(r @ res.C(), res2.C(b)) => + if (b) r.set(b) else r.set(res2False(res2False.C())) }), + + Pair(List(res1False, res2), { case List(r @ res1False.C(), res2.C(b)) => + r.set(b) }), + + Pair(List(res2False, res1), { case List(r @ res2False.C(), res1.C(b)) => + r.set(b) }) + ); + + def apply(b1: => boolean, b2: => boolean): boolean = { + concurrent.ops.spawn(res1(res1.C(b1))); + concurrent.ops.spawn(res2(res2.C(b2))); + res(res.C()) + } +} +*/ +object parallelOr { + + def main(args: Array[String]): unit = { + def loop: boolean = { while (true) {}; true }; +/* + System.out.println("true || true = " + or(true, true)); + System.out.println("false || false = " + or(false, false)); + System.out.println("false || true = " + or(false, true)); + System.out.println("true || false = " + or(true, false)); + System.out.println("true || loop = " + or(true, loop)); + System.out.println("loop || true = " + or(loop, true)); +*/ + } + +} diff --git a/docs/examples/maps.scala b/docs/examples/maps.scala new file mode 100644 index 0000000000..87489d496d --- /dev/null +++ b/docs/examples/maps.scala @@ -0,0 +1,192 @@ +package examples; + +object maps { + + import scala.collection.immutable._; + + trait MapStruct[kt, vt] { + trait Map with Function1[kt, vt] { + def extend(key: kt, value: vt): Map; + def remove(key: kt): Map; + def domain: Stream[kt]; + def range: Stream[vt]; + } + type map <: Map; + val empty: map; + } + + class AlgBinTree[kt <: Ordered[kt], vt <: AnyRef]() extends MapStruct[kt, vt] { + type map = AlgMap; + + val empty: AlgMap = Empty(); + + private case class + Empty(), + Node(key: kt, value: vt, l: map, r: map) extends AlgMap {} + + trait AlgMap extends Map { + def apply(key: kt): vt = this match { + case Empty() => null + case Node(k, v, l, r) => + if (key < k) l.apply(key) + else if (key > k) r.apply(key) + else v + } + + def extend(key: kt, value: vt): map = this match { + case Empty()=> Node(key, value, empty, empty) + case Node(k, v, l, r) => + if (key < k) Node(k, v, l.extend(key, value), r) + else if (key > k) Node(k, v, l, r.extend(key, value)) + else Node(k, value, l, r) + } + + def remove(key: kt): map = this match { + case Empty()=> empty + case Node(k, v, l, r) => + if (key < k) Node(k, v, l.remove(key), r) + else if (key > k) Node(k, v, l, r.remove(key)) + else if (l == empty) r + else if (r == empty) l + else { + val midKey = r.domain.head; + Node(midKey, r.apply(midKey), l, r.remove(midKey)) + } + } + + def domain: Stream[kt] = this match { + case Empty()=> Stream.empty + case Node(k, v, l, r) => l.domain append Stream.cons(k, r.domain) + } + + def range: Stream[vt] = this match { + case Empty()=> Stream.empty + case Node(k, v, l, r) => l.range append Stream.cons(v, r.range) + } + } + } + + class OOBinTree[kt <: Ordered[kt], vt <: AnyRef]() extends MapStruct[kt, vt] { + type map = OOMap; + + trait OOMap extends Map { + def apply(key: kt): vt; + def extend(key: kt, value: vt): map; + def remove(key: kt): map; + def domain: Stream[kt]; + def range: Stream[vt]; + } + val empty: OOMap = new OOMap { + def apply(key: kt): vt = null; + def extend(key: kt, value: vt) = new Node(key, value, empty, empty); + def remove(key: kt) = empty; + def domain: Stream[kt] = Stream.empty; + def range: Stream[vt] = Stream.empty; + } + private class Node(k: kt, v: vt, l: map, r: map) extends OOMap { + def apply(key: kt): vt = + if (key < k) l.apply(key) + else if (key > k) r.apply(key) + else v; + def extend(key: kt, value: vt): map = + if (key < k) new Node(k, v, l.extend(key, value), r) + else if (key > k) new Node(k, v, l, r.extend(key, value)) + else new Node(k, value, l, r); + def remove(key: kt): map = + if (key < k) new Node(k, v, l.remove(key), r) + else if (key > k) new Node(k, v, l, r.remove(key)) + else if (l == empty) r + else if (r == empty) l + else { + val midKey = r.domain.head; + new Node(midKey, r(midKey), l, r.remove(midKey)) + } + def domain: Stream[kt] = l.domain append Stream.cons(k, r.domain); + def range: Stream[vt] = l.range append Stream.cons(v, r.range); + } + } + + class MutBinTree[kt <: Ordered[kt], vt <: AnyRef]() extends MapStruct[kt, vt] { + type map = MutMap; + class MutMap(key: kt, value: vt) extends Map { + val k = key; + var v = value; + var l, r = empty; + + def apply(key: kt): vt = + if (this == empty) null + else if (key < k) l.apply(key) + else if (key > k) r.apply(key) + else v; + + def extend(key: kt, value: vt): map = + if (this == empty) new MutMap(key, value) + else { + if (key < k) l = l.extend(key, value) + else if (key > k) r = r.extend(key, value) + else v = value; + this + } + + def remove(key: kt): map = + if (this == empty) this + else if (key < k) { l = l.remove(key) ; this } + else if (key > k) { r = r.remove(key) ; this } + else if (l == empty) r + else if (r == empty) l + else { + var mid = r; + while (!(mid.l == empty)) { mid = mid.l } + mid.r = r.remove(mid.k); + mid.l = l; + mid + } + + def domain: Stream[kt] = + if (this == empty) Stream.empty; + else l.domain append Stream.cons(k, r.domain); + + def range: Stream[vt] = + if (this == empty) Stream.empty; + else l.range append Stream.cons(v, r.range); + } + val empty = new MutMap(null, null); + } + + class Date(y: Int, m: Int, d: Int) with Ordered[Date] { + def year = y; + def month = m; + def day = d; + + def compareTo[b >: Date <% Ordered[b]](that: b): int = that match { + case other: Date => + if ((year == other.year) && + (month == other.month) && + (day == other.day)) + 0 + else if ((year < other.year) || + (year == other.year && month < other.month) || + (month == other.month && day < other.day)) + -1 + else + 1 + case _ => + -(that compareTo this) + } + + override def equals(that: Any): Boolean = + that.isInstanceOf[Date] && { + val o = that.asInstanceOf[Date]; + day == o.day && month == o.month && year == o.year + } + } + + def main(args: Array[String]) = { + val t = new OOBinTree[Date, String](); + () + } + +} + + + diff --git a/docs/examples/mobile/sort.scala b/docs/examples/mobile/sort.scala new file mode 100644 index 0000000000..62818467fa --- /dev/null +++ b/docs/examples/mobile/sort.scala @@ -0,0 +1,17 @@ +package examples.mobile; + +import java.net._; +import scala.mobile._; + + +object sort with Application { + val url = new URL("http://scala.epfl.ch/classes/examples.jar"); + + val location = new Location(url); + val obj = location create "examples.sort"; + val ar = Array(6, 2, 8, 5, 1); + obj[Array[Int], Unit]("println")(ar); + obj[Array[Int], Unit]("sort")(ar); + obj[Array[Int], Unit]("println")(ar); + Console.println +} diff --git a/docs/examples/monads/callccInterpreter.scala b/docs/examples/monads/callccInterpreter.scala new file mode 100644 index 0000000000..934fce1a9e --- /dev/null +++ b/docs/examples/monads/callccInterpreter.scala @@ -0,0 +1,84 @@ +object callccInterpreter { + + type Answer = Value; + + case class M[A](in: (A => Answer) => Answer) { + def bind[B](k: A => M[B]) = M[B](c => in (a => k(a) in c)); + def map[B](f: A => B): M[B] = bind(x => unitM(f(x))); + def flatMap[B](f: A => M[B]): M[B] = bind(f); + } + + def unitM[A](a: A) = M[A](c => c(a)); + + def showM(m: M[Value]): String = (m in id).toString(); + + def callCC[A](h: (A => M[A]) => M[A]) = + M[A](c => h(a => M[A](d => c(a))) in c); + + type Name = String; + + trait Term; + case class Var(x: Name) extends Term; + case class Con(n: int) extends Term; + case class Add(l: Term, r: Term) extends Term; + case class Lam(x: Name, body: Term) extends Term; + case class App(fun: Term, arg: Term) extends Term; + case class Ccc(x: Name, t: Term) extends Term; + + trait Value; + case object Wrong extends Value { + override def toString() = "wrong" + } + case class Num(n: int) extends Value { + override def toString() = n.toString(); + } + case class Fun(f: Value => M[Value]) extends Value { + override def toString() = "" + } + + type Environment = List[Pair[Name, Value]]; + + def lookup(x: Name, e: Environment): M[Value] = e match { + case List() => unitM(Wrong) + case Pair(y, b) :: e1 => if (x == y) unitM(b) else lookup(x, e1) + } + + def add(a: Value, b: Value): M[Value] = Pair(a, b) match { + case Pair(Num(m), Num(n)) => unitM(Num(m + n)) + case _ => unitM(Wrong) + } + + def apply(a: Value, b: Value): M[Value] = a match { + case Fun(k) => k(b) + case _ => unitM(Wrong) + } + + def interp(t: Term, e: Environment): M[Value] = t match { + case Var(x) => lookup(x, e) + case Con(n) => unitM(Num(n)) + case Add(l, r) => for (val a <- interp(l, e); + val b <- interp(r, e); + val c <- add(a, b)) + yield c + case Lam(x, t) => unitM(Fun(a => interp(t, Pair(x, a) :: e))) + case App(f, t) => for (val a <- interp(f, e); + val b <- interp(t, e); + val c <- apply(a, b)) + yield c + case Ccc(x, t) => callCC(k => interp(t, Pair(x, Fun(k)) :: e)) + } + + def test(t: Term): String = + showM(interp(t, List())); + + val term0 = App(Lam("x", Add(Var("x"), Var("x"))), Add(Con(10), Con(11))); + val term1 = App(Con(1), Con(2)); + val term2 = Add(Con(1), Ccc("k", Add(Con(2), App(Var("k"), Con(4))))); + + def main(args: Array[String]) = { + System.out.println(test(term0)); + System.out.println(test(term1)); + System.out.println(test(term2)); + } +} + diff --git a/docs/examples/monads/directInterpreter.scala b/docs/examples/monads/directInterpreter.scala new file mode 100644 index 0000000000..0e2aae4a7b --- /dev/null +++ b/docs/examples/monads/directInterpreter.scala @@ -0,0 +1,55 @@ +object directInterpreter { + + type Name = String; + + trait Term; + case class Var(x: Name) extends Term; + case class Con(n: int) extends Term; + case class Add(l: Term, r: Term) extends Term; + case class Lam(x: Name, body: Term) extends Term; + case class App(fun: Term, arg: Term) extends Term; + + trait Value; + case object Wrong extends Value; + case class Num(n: int) extends Value; + case class Fun(f: Value => Value)extends Value; + + def showval(v: Value): String = v match { + case Wrong => "" + case Num(n) => n.toString() + case Fun(f) => "" + } + + type Environment = List[Pair[Name, Value]]; + + def lookup(x: Name, e: Environment): Value = e match { + case List() => Wrong + case Pair(y, b) :: e1 => if (x == y) b else lookup(x, e1) + } + + def add(a: Value, b: Value): Value = Pair(a, b) match { + case Pair(Num(m), Num(n)) => Num(m + n) + case _ => Wrong + } + + def apply(a: Value, b: Value) = a match { + case Fun(k) => k(b) + case _ => Wrong + } + + def interp(t: Term, e: Environment): Value = t match { + case Var(x) => lookup(x, e) + case Con(n) => Num(n) + case Add(l, r) => add(interp(l, e), interp(r, e)) + case Lam(x, t) => Fun(a => interp(t, Pair(x, a) :: e)) + case App(f, t) => apply(interp(f, e), interp(t, e)) + } + + def test(t: Term): String = + showval(interp(t, List())); + + val term0 = App(Lam("x", Add(Var("x"), Var("x"))), Add(Con(10), Con(11))); + + def main(args: Array[String]) = + System.out.println(test(term0)); +} diff --git a/docs/examples/monads/errorInterpreter.scala b/docs/examples/monads/errorInterpreter.scala new file mode 100644 index 0000000000..05dc979621 --- /dev/null +++ b/docs/examples/monads/errorInterpreter.scala @@ -0,0 +1,86 @@ +object errorInterpreter { + + trait M[A] { + def show: String; + def bind[B](k: A => M[B]); + def map[B](f: A => B): M[B] = bind(x => unitM(f(x))); + def flatMap[B](f: A => M[B]): M[B] = bind(f); + } + + def unitM[A](a: A): M[A] = new Suc(a); + def errorM[A](msg: String): M[A] = new Err(msg); + + def showM(m: M[Value]): String = m.show; + + class Suc[A](x: T) extends M[A] { + def bind[A](k: A => M[B]): M[B] = k(x); + def show: String = "Success: " + x; + } + class Err[T](msg: String) extends M[T] { + def bind[A](k: A => M[B]): M[B] = new Err(msg); + def show: String = "Error: " + msg; + } + + type Name = String; + + trait Term; + case class Var(x: Name) extends Term; + case class Con(n: int) extends Term; + case class Add(l: Term, r: Term) extends Term; + case class Lam(x: Name, body: Term) extends Term; + case class App(fun: Term, arg: Term) extends Term; + + trait Value; + case object Wrong extends Value { + override def toString() = "wrong" + } + case class Num(n: int) extends Value { + override def toString() = n.toString(); + } + case class Fun(f: Value => M[Value]) extends Value { + override def toString() = "" + } + + type Environment = List[Pair[Name, Value]]; + + def lookup(x: Name, e: Environment): M[Value] = e match { + case List() => errorM("unbound variable: " + x); + case Pair(y, b) :: e1 => if (x == y) unitM(b) else lookup(x, e1) + } + + def add(a: Value, b: Value): M[Value] = Pair(a, b) match { + case Pair(Num(m), Num(n)) => unitM(Num(m + n)) + case _ => errorM("should be numbers: " + a + "," + b) + } + + def apply(a: Value, b: Value): M[Value] = a match { + case Fun(k) => k(b) + case _ => errorM("should be function: " + a); + } + + def interp(t: Term, e: Environment): M[Value] = t match { + case Var(x) => lookup(x, e) + case Con(n) => unitM(Num(n)) + case Add(l, r) => for (val a <- interp(l, e); + val b <- interp(r, e); + val c <- add(a, b)) + yield c + case Lam(x, t) => unitM(Fun(a => interp(t, Pair(x, a) :: e))) + case App(f, t) => for (val a <- interp(f, e); + val b <- interp(t, e); + val c <- apply(a, b)) + yield c + } + + def test(t: Term): String = + showM(interp(t, List())); + + val term0 = App(Lam("x", Add(Var("x"), Var("x"))), Add(Con(10), Con(11))); + val term1 = App(Con(1), Con(2)); + + def main(args: Array[String]) = { + System.out.println(test(term0)); + System.out.println(test(term1)); + } +} + diff --git a/docs/examples/monads/simpleInterpreter.scala b/docs/examples/monads/simpleInterpreter.scala new file mode 100644 index 0000000000..d728c620cf --- /dev/null +++ b/docs/examples/monads/simpleInterpreter.scala @@ -0,0 +1,75 @@ +object simpleInterpreter { + + case class M[A](value: A) { + def bind[B](k: A => M[B]): M[B] = k(value); + def map[B](f: A => B): M[B] = bind(x => unitM(f(x))); + def flatMap[B](f: A => M[B]): M[B] = bind(f); + } + + def unitM[A](a: A): M[A] = M(a); + + def showM(m: M[Value]): String = m.value.toString(); + + type Name = String; + + trait Term; + case class Var(x: Name) extends Term; + case class Con(n: int) extends Term; + case class Add(l: Term, r: Term) extends Term; + case class Lam(x: Name, body: Term) extends Term; + case class App(fun: Term, arg: Term) extends Term; + + trait Value; + case object Wrong extends Value { + override def toString() = "wrong" + } + case class Num(n: int) extends Value { + override def toString() = n.toString(); + } + case class Fun(f: Value => M[Value]) extends Value { + override def toString() = "" + } + + type Environment = List[Pair[Name, Value]]; + + def lookup(x: Name, e: Environment): M[Value] = e match { + case List() => unitM(Wrong) + case Pair(y, b) :: e1 => if (x == y) unitM(b) else lookup(x, e1) + } + + def add(a: Value, b: Value): M[Value] = Pair(a, b) match { + case Pair(Num(m), Num(n)) => unitM(Num(m + n)) + case _ => unitM(Wrong) + } + + def apply(a: Value, b: Value): M[Value] = a match { + case Fun(k) => k(b) + case _ => unitM(Wrong) + } + + def interp(t: Term, e: Environment): M[Value] = t match { + case Var(x) => lookup(x, e) + case Con(n) => unitM(Num(n)) + case Add(l, r) => for (val a <- interp(l, e); + val b <- interp(r, e); + val c <- add(a, b)) + yield c + case Lam(x, t) => unitM(Fun(a => interp(t, Pair(x, a) :: e))) + case App(f, t) => for (val a <- interp(f, e); + val b <- interp(t, e); + val c <- apply(a, b)) + yield c + } + + def test(t: Term): String = + showM(interp(t, List())); + + val term0 = App(Lam("x", Add(Var("x"), Var("x"))), Add(Con(10), Con(11))); + val term1 = App(Con(1), Con(2)); + + def main(args: Array[String]) = { + System.out.println(test(term0)); + System.out.println(test(term1)); + } +} + diff --git a/docs/examples/monads/stateInterpreter.scala b/docs/examples/monads/stateInterpreter.scala new file mode 100644 index 0000000000..593f2d9e3e --- /dev/null +++ b/docs/examples/monads/stateInterpreter.scala @@ -0,0 +1,86 @@ +package examples.monads; + +object stateInterpreter { + + type State = int; + + val tickS = new M(s => Pair((), s + 1)); + + case class M[A](in: State => Pair[A, State]) { + def bind[B](k: A => M[B]) = M[B]{ s0 => + val Pair(a, s1) = this in s0; k(a) in s1 + } + def map[B](f: A => B): M[B] = bind(x => unitM(f(x))); + def flatMap[B](f: A => M[B]): M[B] = bind(f); + } + + def unitM[A](a: A) = M[A](s => Pair(a, s)); + + def showM(m: M[Value]): String = { + val Pair(a, s1) = m in 0; + "Value: " + a + "; Count: " + s1 + } + + type Name = String; + + trait Term; + case class Var(x: Name) extends Term; + case class Con(n: int) extends Term; + case class Add(l: Term, r: Term) extends Term; + case class Lam(x: Name, body: Term) extends Term; + case class App(fun: Term, arg: Term) extends Term; + + trait Value; + case object Wrong extends Value { + override def toString() = "wrong" + } + case class Num(n: int) extends Value { + override def toString() = n.toString(); + } + case class Fun(f: Value => M[Value]) extends Value { + override def toString() = "" + } + + type Environment = List[Pair[Name, Value]]; + + def lookup(x: Name, e: Environment): M[Value] = e match { + case List() => unitM(Wrong) + case Pair(y, b) :: e1 => if (x == y) unitM(b) else lookup(x, e1) + } + + def add(a: Value, b: Value): M[Value] = Pair(a, b) match { + case Pair(Num(m), Num(n)) => for (val _ <- tickS) yield Num(m + n) + case _ => unitM(Wrong) + } + + def apply(a: Value, b: Value): M[Value] = a match { + case Fun(k) => for (val _ <- tickS; val c <- k(b)) yield c + case _ => unitM(Wrong) + } + + def interp(t: Term, e: Environment): M[Value] = t match { + case Var(x) => lookup(x, e) + case Con(n) => unitM(Num(n)) + case Add(l, r) => for (val a <- interp(l, e); + val b <- interp(r, e); + val c <- add(a, b)) + yield c + case Lam(x, t) => unitM(Fun(a => interp(t, Pair(x, a) :: e))) + case App(f, t) => for (val a <- interp(f, e); + val b <- interp(t, e); + val c <- apply(a, b)) + yield c + } + + def test(t: Term): String = + showM(interp(t, List())); + + val term0 = App(Lam("x", Add(Var("x"), Var("x"))), Add(Con(10), Con(11))); + val term1 = App(Con(1), Con(2)); + + def main(args: Array[String]) = { + System.out.println(test(term0)); + System.out.println(test(term1)); + } +} + diff --git a/docs/examples/oneplacebuffer.scala b/docs/examples/oneplacebuffer.scala new file mode 100644 index 0000000000..7fa2ae8dba --- /dev/null +++ b/docs/examples/oneplacebuffer.scala @@ -0,0 +1,47 @@ +package examples; + +object oneplacebuffer { + + import scala.concurrent._; + + class OnePlaceBuffer { + private val m = new MailBox() {}; // An internal mailbox + private case class Empty(), Full(x: Int); // Types of messages we deal with + + m send Empty(); // Initialization + + def write(x: Int): Unit = m receive { + case Empty() => + Console.println("put " + x); + m send Full(x) + } + + def read: Int = m receive { + case Full(x) => + Console.println("get " + x); + m send Empty() ; x + } + } + + def main(args: Array[String]) = { + val buf = new OnePlaceBuffer; + val random = new java.util.Random(); + + def producer(n: int): unit = { + Thread.sleep(random.nextInt(1000)); + buf.write(n); + producer(n + 1) + } + + def consumer: unit = { + Thread.sleep(random.nextInt(1000)); + val n = buf.read; + consumer + } + + ops.spawn(producer(0)); + ops.spawn(consumer) + } + +} + diff --git a/docs/examples/parsers1.scala b/docs/examples/parsers1.scala new file mode 100644 index 0000000000..143f354049 --- /dev/null +++ b/docs/examples/parsers1.scala @@ -0,0 +1,118 @@ +package examples; + +object parsers1 { + + abstract class Parsers { + + type inputType; + + abstract class Parser { + + type Result = Option[inputType]; + + def apply(in: inputType): Result; + + /*** p &&& q applies first p, and if that succeeds, then q + */ + def &&& (q: => Parser) = new Parser { + def apply(in: inputType): Result = Parser.this.apply(in) match { + case None => None + case Some(in1) => q(in1) + } + } + + /*** p ||| q applies first p, and, if that fails, then q. + */ + def ||| (q: => Parser) = new Parser { + def apply(in: inputType): Result = Parser.this.apply(in) match { + case None => q(in) + case s => s + } + } + } + + val empty = new Parser { + def apply(in: inputType): Result = Some(in) + } + + val fail = new Parser { + def apply(in: inputType): Result = None + } + + def opt(p: Parser): Parser = p ||| empty; // p? = (p | ) + def rep(p: Parser): Parser = opt(rep1(p)); // p* = [p+] + def rep1(p: Parser): Parser = p &&& rep(p); // p+ = p p* + } + + abstract class ListParsers extends Parsers { + def chr(p: char => boolean): Parser; + def chr(c: char): Parser = chr(d: char => d == c); + + def letter : Parser = chr(Character.isLetter); + def digit : Parser = chr(Character.isDigit); + + def ident : Parser = letter &&& rep(letter ||| digit); + def number : Parser = digit &&& rep(digit); + def list : Parser = chr('(') &&& listElems &&& chr(')'); + def listElems : Parser = expr &&& (chr(',') &&& listElems ||| empty); + def expr : Parser = ident ||| number ||| list; + } + + abstract class ExprParsers extends Parsers { + def chr(p: char => boolean): Parser; + def chr(c: char): Parser = chr(d: char => d == c); + + def digit : Parser = chr(Character.isDigit); + def number : Parser = digit &&& rep(digit); + def summand : Parser = number ||| chr('(') &&& expr &&& chr(')'); + def expr : Parser = summand &&& rep(chr('+') &&& summand) + } + + class ParseString(s: String) extends Parsers { + type inputType = int; + val input = 0; + def chr(p: char => boolean) = new Parser { + def apply(in: int): Parser#Result = + if (in < s.length() && p(s charAt in)) Some(in + 1); + else None; + } + } + + object TestList { + + def main(args: Array[String]): unit = + if (args.length == 1) { + val ps = new ListParsers with ParseString(args(0)); + ps.expr(ps.input) match { + case Some(n) => + Console.println("parsed: " + args(0).substring(0, n)); + case None => + Console.println("nothing parsed"); + } + } + else + Console.println("usage: java examples.TestList "); + } + + object TestExpr { + + def main(args: Array[String]): unit = + if (args.length == 1) { + val ps = new ExprParsers with ParseString(args(0)); + ps.expr(ps.input) match { + case Some(n) => + Console.println("parsed: " + args(0).substring(0, n)); + case None => + Console.println("nothing parsed"); + } + } + else + Console.println("usage: java examples.TestExpr "); + } + + def main(args: Array[String]): Unit = { + TestList.main(Array("(a,b,(1,2))")); + TestExpr.main(Array("2+3+(4+1)")) + } + +} diff --git a/docs/examples/parsers2.scala b/docs/examples/parsers2.scala new file mode 100644 index 0000000000..47fa8d0f2e --- /dev/null +++ b/docs/examples/parsers2.scala @@ -0,0 +1,63 @@ +package examples; + +object parsers2 { + + abstract class Tree{} + case class Id (s: String) extends Tree {} + case class Num(n: int) extends Tree {} + case class Lst(elems: List[Tree]) extends Tree {} + + abstract class ListParsers extends CharParsers { + + def ident: Parser[Tree] = + for ( + val c: char <- chr(Character.isLetter); + val cs: List[char] <- rep(chr(Character.isLetterOrDigit)) + ) yield Id((c :: cs).mkString("", "", "")); + + def number: Parser[Tree] = + for ( + val d: char <- chr(Character.isDigit); + val ds: List[char] <- rep(chr(Character.isDigit)) + ) yield Num(((d - '0') /: ds) ((x, digit) => x * 10 + digit - '0')); + + def list: Parser[Tree] = + for ( + val _ <- chr('('); + val es <- listElems ||| succeed(List()); + val _ <- chr(')') + ) yield Lst(es); + + def listElems: Parser[List[Tree]] = + for ( + val x <- expr; + val xs <- chr(',') &&& listElems ||| succeed(List()) + ) yield x :: xs; + + def expr: Parser[Tree] = + list ||| ident ||| number; + + } + + class ParseString(s: String) extends Parsers { + type inputType = int; + val input = 0; + def any = new Parser[char] { + def apply(in: int): Parser[char]#Result = + if (in < s.length()) Some(Pair(s charAt in, in + 1)) else None; + } + } + + def main(args: Array[String]): unit = + Console.println( + if (args.length == 1) { + val ps = new ListParsers with ParseString(args(0)); + ps.expr(ps.input) match { + case Some(Pair(list, _)) => Console.println("parsed: " + list); + case None => "nothing parsed" + } + } else "usage: scala examples.parsers2 " + ); + +} + diff --git a/docs/examples/patterns.scala b/docs/examples/patterns.scala new file mode 100644 index 0000000000..34b0db96ae --- /dev/null +++ b/docs/examples/patterns.scala @@ -0,0 +1,35 @@ +package examples; + +object patterns { + + trait Tree; + case class Branch(left: Tree, right: Tree) extends Tree; + case class Leaf(x: Int) extends Tree; + + val tree1 = Branch(Branch(Leaf(1), Leaf(2)), Branch(Leaf(3), Leaf(4))); + + def sumLeaves(t: Tree): Int = t match { + case Branch(l, r) => sumLeaves(l) + sumLeaves(r) + case Leaf(x) => x + } + + def find[a,b](it: Iterator[Pair[a, b]], x: a): Option[b] = { + var result: Option[b] = _; + while (it.hasNext && result == null) { + val Pair(x1, y) = it.next; + if (x == x1) result = Some(y) + } + if (result == null) None else result + } + + def printFinds[a](xs: List[Pair[a, String]], x: a) = + find(xs.elements, x) match { + case Some(y) => System.out.println(y) + case None => System.out.println("no match") + } + + def main(args: Array[String]): Unit = { + Console.println("sum of leafs=" + sumLeaves(tree1)); + printFinds(List(Pair(3, "three"), Pair(4, "four")), 4) + } +} \ No newline at end of file diff --git a/docs/examples/pilib/elasticBuffer.scala b/docs/examples/pilib/elasticBuffer.scala new file mode 100644 index 0000000000..5e52a0fdce --- /dev/null +++ b/docs/examples/pilib/elasticBuffer.scala @@ -0,0 +1,77 @@ +package examples.pilib; + +object elasticBuffer { + + import scala.concurrent.pilib._; + + /** + * Recursive type for channels that carry a "String" channel and + * an object of the type we define. + */ + class MetaChan extends Chan[Pair[Chan[String], MetaChan]]; + + def Buffer(put: Chan[String], get: Chan[String]): unit = { + + /** + * An empty buffer cell, ready to pass on (o,r) to the left. + */ + def Bl(i:Chan[String], l: MetaChan, + o: Chan[String], r: MetaChan): unit = + choice ( + l(Pair(o,r)) * (System.out.println("Removed one cell.")), + i * (inp => Cl(i, l, o, r, inp)) + ); + + /** + * A buffer cell containing a value, ready to receive (o,r) from the right. + */ + def Cl(i: Chan[String], l: MetaChan, + o: Chan[String], r: MetaChan, content: String): unit = + choice ( + o(content) * (Bl(i,l,o,r)), + i * (inp => Dl(i,l,o,r,content, inp)), + r * ( { case Pair(newo, newr) => Cl(i,l,newo,newr,content) }) + ); + + /** + * Two joined buffer cells, of type Cl. + */ + def Dl(i: Chan[String], l: MetaChan, + o: Chan[String], r: MetaChan, + content: String, inp: String): unit = { + val newlr = new MetaChan; + val newio = new Chan[String]; + spawn < Cl(i, l, newio, newlr, inp) | Cl(newio, newlr, o, r,content) >; + } + + // l and r channels for the leftmost and rightmost cell, respectively. + val unused1 = new MetaChan; + val unused2 = new MetaChan; + + Bl(put, unused1, get, unused2); + } + + val random = new java.util.Random(); + + def Producer(n: int, put: Chan[String]): unit = { + Thread.sleep(1 + random.nextInt(1000)); + val msg = "object " + n; + put.write(msg); + System.out.println("Producer gave " + msg); + Producer(n + 1, put) + } + + def Consumer(get: Chan[String]): unit = { + Thread.sleep(1 + random.nextInt(1000)); + val msg = get.read; + System.out.println("Consummer took " + msg); + Consumer(get) + } + + def main(args: Array[String]): unit = { + val put = new Chan[String]; + val get = new Chan[String]; + spawn < Producer(0, put) | Consumer(get) | Buffer(put, get) > + } + +} diff --git a/docs/examples/pilib/handover.scala b/docs/examples/pilib/handover.scala new file mode 100644 index 0000000000..85fb899555 --- /dev/null +++ b/docs/examples/pilib/handover.scala @@ -0,0 +1,190 @@ +package examples.pilib; + +/** +* Handover example with recursive types for channels. +*/ +object handoverRecursive { + + import concurrent.pilib._; + + val random = new java.util.Random(); + + /** + * Recursive type for channels that carry a channel "unit" and + * an object of the type we define. + */ + class Switch extends Chan[Pair[Chan[unit], Switch]]; + + /** + * Car. + */ + def Car(talk: Chan[unit], switch: Switch): unit = + choice ( + switch * ({ case Pair(t,s) => Car(t, s) }), + talk(()) * ( { + Thread.sleep(1 + random.nextInt(1000)); + System.out.println("Car emitted a message."); + Car(talk, switch) + }) + ); + + /** + * Control center. + */ + def Control(talk1: Chan[unit], switch1: Switch, + gain1: Switch, lose1: Switch, + talk2: Chan[unit], switch2: Switch, + gain2: Switch, lose2: Switch): unit + = { + def Control1: unit= { + Thread.sleep(1 + random.nextInt(1000)); + lose1.write(Pair(talk2, switch2)); + gain2.write(Pair(talk2, switch2)); + Control2; + } + def Control2: unit = { + Thread.sleep(1 + random.nextInt(1000)); + lose2.write(Pair(talk1, switch1)); + gain1.write(Pair(talk1, switch1)); + Control1; + } + Control1; + } + + /** + * Active transmitter. + */ + def ActiveTransmitter(id: String, talk: Chan[unit], switch: Switch, + gain: Switch, lose: Switch): unit + = + choice ( + talk * (x => { + System.out.println(id + " received a message."); + ActiveTransmitter(id, talk, switch, gain, lose) + }), + lose * ({ case Pair(t, s) => { + switch.write(Pair(t, s)); + IdleTransmitter(id, gain, lose) + }}) + ); + + /** + * Idle transmitter. + */ + def IdleTransmitter(id: String, gain: Switch, lose: Switch): unit = { + val Pair(t, s) = gain.read; + ActiveTransmitter(id, t, s, gain, lose) + } + + def main(args: Array[String]): unit = { + val talk1 = new Chan[unit]; + val switch1 = new Switch; + val gain1 = new Switch; + val lose1 = new Switch; + val talk2 = new Chan[unit]; + val switch2 = new Switch; + val gain2 = new Switch; + val lose2 = new Switch; + spawn < + Car(talk1, switch1) | + ActiveTransmitter("Transmitter 1", talk1, switch1, gain1, lose1) | + IdleTransmitter("Transmitter 2", gain2, lose2) | + Control(talk1, switch1, gain1, lose1, talk2, switch2, gain2, lose2) + > + } +} + +/** +* Handover example with type casts. +*/ +object handoverCast { + + import concurrent.pilib._; + + val random = new java.util.Random(); + + /** + * Car. + */ + def Car(talk: Chan[Any], switch: Chan[Any]): unit = + choice ( + switch * (o => { + val Pair(t,s) = o.asInstanceOf[Pair[Chan[Any],Chan[Any]]]; + Car(t, s) + }), + talk(()) * ( { + Thread.sleep(1 + random.nextInt(1000)); + System.out.println("Car emitted a message."); + Car(talk, switch) + }) + ); + + /** + * Control center. + */ + def Control(talk1: Chan[Any], switch1: Chan[Any], + gain1: Chan[Any], lose1: Chan[Any], + talk2: Chan[Any], switch2: Chan[Any], + gain2: Chan[Any], lose2: Chan[Any]): unit + = { + def Control1: unit= { + Thread.sleep(1 + random.nextInt(1000)); + lose1.write(Pair(talk2, switch2)); + gain2.write(Pair(talk2, switch2)); + Control2 + } + def Control2: unit = { + Thread.sleep(1 + random.nextInt(1000)); + lose2.write(Pair(talk1, switch1)); + gain1.write(Pair(talk1, switch1)); + Control1 + } + Control1 + } + + /** + * Active transmitter. + */ + def ActiveTransmitter(id: String, talk: Chan[Any], switch: Chan[Any], + gain: Chan[Any], lose: Chan[Any]): unit + = + choice ( + talk * (x => { + System.out.println(id + " received a message."); + ActiveTransmitter(id, talk, switch, gain, lose) + }), + lose * (o => { + val Pair(t, s) = o.asInstanceOf[Pair[Chan[Any],Chan[Any]]]; + switch.write(Pair(t, s)); + IdleTransmitter(id, gain, lose) + }) + ); + + /** + * Idle transmitter. + */ + def IdleTransmitter(id: String, gain: Chan[Any], lose: Chan[Any]): unit = { + val Pair(t, s) = gain.read.asInstanceOf[Pair[Chan[Any],Chan[Any]]]; + ActiveTransmitter(id, t, s, gain, lose) + } + + def main(args: Array[String]): unit = { + val talk1 = new Chan[Any]; + val switch1 = new Chan[Any]; + val gain1 = new Chan[Any]; + val lose1 = new Chan[Any]; + val talk2 = new Chan[Any]; + val switch2 = new Chan[Any]; + val gain2 = new Chan[Any]; + val lose2 = new Chan[Any]; + spawn < + Car(talk1, switch1) | + ActiveTransmitter("Transmitter 1", talk1, switch1, gain1, lose1) | + IdleTransmitter("Transmitter 2", gain2, lose2) | + Control(talk1, switch1, gain1, lose1, talk2, switch2, gain2, lose2) + > + } + +} + + diff --git a/docs/examples/pilib/mobilePhoneProtocol.scala b/docs/examples/pilib/mobilePhoneProtocol.scala new file mode 100644 index 0000000000..0b13f78fd3 --- /dev/null +++ b/docs/examples/pilib/mobilePhoneProtocol.scala @@ -0,0 +1,172 @@ +package examples.pilib; + +/** +* Mobile phone protocol. +* Equivalent to a three-place buffer. +* @see Bjoern Victor "A verification tool for the polyadic pi-calculus". +*/ +object mobilePhoneProtocol { + + import concurrent.pilib._; + + val random = new java.util.Random(); + + // Internal messages exchanged by the protocol. + trait Message; + + // Predefined messages used by the protocol. + case class Data() extends Message; + case class HoCmd() extends Message; // handover command + case class HoAcc() extends Message; // handover access + case class HoCom() extends Message; // handover complete + case class HoFail() extends Message; // handover fail + case class ChRel() extends Message; // release + case class Voice(s: String) extends Message; // voice + case class Channel(n: Chan[Message]) extends Message; // channel + + def MobileSystem(in: Chan[String], out: Chan[String]): unit = { + + def CC(fa: Chan[Message], fp: Chan[Message], l: Chan[Channel]): unit = + choice ( + in * (v => { fa.write(Data()); fa.write(Voice(v)); CC(fa, fp, l) }) + , + l * (m_new => { + fa.write(HoCmd()); + fa.write(m_new); + choice ( + fp * ({ case HoCom() => { + System.out.println("Mobile has moved from one cell to another"); + fa.write(ChRel()); + val Channel(m_old) = fa.read; + l.write(Channel(m_old)); + CC(fp, fa, l) + }}) + , + fa * ({ case HoFail() => { + System.out.println("Mobile has failed to move from one cell to another"); + l.write(m_new); + CC(fa, fp, l) + }}) + ) + }) + ); + + /* + * Continuously orders the MSC to switch the MS to the non-used BS. + */ + def HC(l: Chan[Channel], m: Chan[Message]): unit = { + Thread.sleep(1 + random.nextInt(1000)); + l.write(Channel(m)); + val Channel(m_new) = l.read; + HC(l, m_new) + } + + /** + * Mobile switching center. + */ + def MSC(fa: Chan[Message], fp: Chan[Message], m: Chan[Message]): unit = { + val l = new Chan[Channel]; + spawn < HC(l, m) | CC(fa, fp, l) > + } + + /** + * Active base station. + */ + def BSa(f: Chan[Message], m: Chan[Message]): unit = + (f.read) match { + case Data() => { + val v = f.read; + m.write(Data()); + m.write(v); + BSa(f, m) + } + case HoCmd() => { + val v = f.read; + m.write(HoCmd()); + m.write(v); + choice ( + f * ({ case ChRel() => { + f.write(Channel(m)); + BSp(f, m) + }}) + , + m * ({ case HoFail() => { + f.write(HoFail()); + BSa(f, m) + }}) + ) + } + }; + + /** + * Passive base station. + */ + def BSp(f: Chan[Message], m: Chan[Message]): unit = { + val HoAcc = m.read; + f.write(HoCom()); + BSa(f, m) + }; + + /** + * Mobile station. + */ + def MS(m: Chan[Message]): unit = + (m.read) match { + case Data() => { + val Voice(v) = m.read; + out.write(v); + MS(m) + } + case HoCmd() => + (m.read) match { + case Channel(m_new) => { + if (random.nextInt(1) == 0) + choice ( m_new(HoAcc()) * (MS(m_new)) ); + else + choice ( m(HoFail()) * (MS(m)) ); + } + } + }; + + def P(fa: Chan[Message], fp: Chan[Message]): unit = { + val m = new Chan[Message]; + spawn < MSC(fa, fp, m) | BSp(fp, m) > + } + + def Q(fa: Chan[Message]): unit = { + val m = new Chan[Message]; + spawn < BSa(fa, m) | MS(m) > + } + + val fa = new Chan[Message]; + val fp = new Chan[Message]; + spawn < Q(fa) | P(fa, fp) >; + } + + //***************** Entry function ******************// + + def main(args: Array[String]): unit = { + + def Producer(n: Int, put: Chan[String]): unit = { + Thread.sleep(1 + random.nextInt(1000)); + val msg = "object " + n; + put.write(msg); + System.out.println("Producer gave " + msg); + Producer(n + 1, put) + } + + def Consumer(get: Chan[String]): unit = { + Thread.sleep(1 + random.nextInt(1000)); + val msg = get.read; + System.out.println("Consummer took " + msg); + Consumer(get) + } + + val put = new Chan[String]; + val get = new Chan[String]; + spawn < Producer(0, put) | Consumer(get) | MobileSystem(put, get) > + } + +} + + diff --git a/docs/examples/pilib/piNat.scala b/docs/examples/pilib/piNat.scala new file mode 100644 index 0000000000..137c0e5e6a --- /dev/null +++ b/docs/examples/pilib/piNat.scala @@ -0,0 +1,92 @@ +package examples.pilib; + +import scala.concurrent.pilib._; +//import pilib._; + +/** Church encoding of naturals in the Pi-calculus */ +object piNat with Application { + + /** Locations of Pi-calculus natural */ + class NatChan extends Chan[Triple[Chan[unit], Chan[NatChan], Chan[NatChan]]]; + + /** Zero */ + def Z(l: NatChan): unit = choice ( + l * { case Triple(z, sd, d) => z.write(()) } + ); + + /** Successor of Double */ + def SD(n: NatChan, l: NatChan): unit = choice ( + l * { case Triple(z, sd, d) => sd.write(n) } + ); + + /** Double */ + def D(n: NatChan, l: NatChan): unit = choice ( + l * { case Triple(z, sd, d) => d.write(n) } + ); + + /** Make "l" a location representing the natural "n" */ + def make(n: int, l: NatChan): unit = + if (n == 0) Z(l) + else if (n % 2 == 0) { val l1 = new NatChan; spawn < D(l1, l) >; make(n/2, l1) } + else { val l1 = new NatChan; spawn < SD(l1, l) >; make(n/2, l1) }; + + /** Consume the natural "m" and put it successor at location "n" */ + def Succ(m: NatChan, n: NatChan): unit = { + val z = new Chan[unit]; + val sd = new Chan[NatChan]; + val d = new Chan[NatChan]; + spawn < m.write(Triple(z, sd, d)) >; + choice ( + z * { x => make(1, n) }, + sd * { m1 => { val n1 = new NatChan; spawn < D(n1, n) >; Succ(m1, n1) } }, + d * { m1 => SD(m1, n) } + ) + } + + /** Consume the natural "l" and put two copies at locations "m" and "n" */ + def Copy(l: NatChan, m: NatChan, n: NatChan): unit = { + val z = new Chan[unit]; + val sd = new Chan[NatChan]; + val d = new Chan[NatChan]; + spawn < l.write(Triple(z, sd, d)) >; + choice ( + z * { x => spawn < Z(m) >; Z(n) }, + sd * { l1 => { val m1 = new NatChan; val n1 = new NatChan; + spawn < SD(m1, m) | SD(n1, n) >; + Copy(l1, m1, n1) } }, + d * { l1 => { val m1 = new NatChan; val n1 = new NatChan; + spawn < D(m1, m) | D(n1, n) >; + Copy(l1, m1, n1) } } + ) + } + + /** Consume the natural at location "n" and return its value */ + def value(n: NatChan): int = { + val z = new Chan[unit]; + val sd = new Chan[NatChan]; + val d = new Chan[NatChan]; + spawn < n.write(Triple(z, sd, d)) >; + choice ( + z * { x => 0 }, + sd * { n1 => 2 * value(n1) + 1 }, + d * { n1 => 2 * value(n1) } + ) + } + + // Test + val i = 42; + val l = new NatChan; + val l1 = new NatChan; + val l2 = new NatChan; + val l3 = new NatChan; + + spawn < + make(i, l) | + Copy(l, l1, l2) | + Succ(l2, l3) | + System.out.println("" + i + " = " + value(l1)) | + System.out.println("succ " + i + " = " + value(l3)) + >; + +} + diff --git a/docs/examples/pilib/rwlock.scala b/docs/examples/pilib/rwlock.scala new file mode 100644 index 0000000000..0ed0f71a47 --- /dev/null +++ b/docs/examples/pilib/rwlock.scala @@ -0,0 +1,331 @@ +package examples.pilib; + +/** +* From Pi to Scala: Semaphores, monitors, read/write locks. +* Readers/writers locks. +*/ +object rwlock { + + import scala.concurrent.pilib._; + + class Signal extends Chan[unit] { + def send = write(()); + def receive = read; + } + + class CountLock { + private val busy = new Signal; + def get = busy.send; + def release = busy.receive; + spawn < release > + } + + /** A binary semaphore + */ + class Lock { + private val busy = new Signal; + private val free = new Signal; + def get = busy.send; + def release = free.send; + spawn < (while (true) { + choice ( + busy * (x => free.receive), + free * (x => ()) + ) + }) + > + } + + /** A monitor a la Java + */ + class JavaMonitor { + + private val lock = new Lock; + + private var waiting: List[Signal] = Nil; + + def Wait = { + val s = new Signal; + waiting = s :: waiting; + lock.release; + s.receive; + lock.get; + } + + def Notify = { + if (!waiting.isEmpty) { + waiting.head.send; + waiting = waiting.tail; + } + } + + def NotifyAll = { + while (!waiting.isEmpty) { + waiting.head.send; + waiting = waiting.tail; + } + } + + def await(cond: => boolean): unit = while (false == cond) (Wait) + } + + /* + class Buffer[a](size: Int) extends JavaMonitor with { + var in = 0, out = 0, n = 0; + val elems = new Array[a](size); + def put(x: a) = synchronized { + await(n < size); + elems(out) = x; + out = (out + 1) % size; + } + def get: a = synchronized { + await(n > 0); + val x = elems(in); + in = (in + 1) % size; + x + } + } + */ + + /** A readers/writers lock. */ + trait ReadWriteLock { + def startRead: unit; + def startWrite: unit; + def endRead: unit; + def endWrite: unit; + } + + /** + * A readers/writers lock, using monitor abstractions. + */ + class ReadWriteLock1 extends JavaMonitor with ReadWriteLock { + + private var nactive: int = 0; + private var nwriters: int = 0; + + def status = + System.out.println(nactive + " active, " + nwriters + " writers"); + + def startRead = synchronized { + await(nwriters == 0); + nactive = nactive + 1; + status + } + + def startWrite = synchronized { + nwriters = nwriters + 1; + await(nactive == 0); + nactive = 1; + status + } + + def endRead = synchronized { + nactive = nactive - 1; + if (nactive == 0) NotifyAll; + status + } + + def endWrite = synchronized { + nwriters = nwriters - 1; + nactive = 0; + NotifyAll; + status + } + } + + /** A readers/writers lock, using semaphores + */ + class ReadWriteLock2 extends ReadWriteLock { + + private var rc: int = 0; // reading readers + private var wc: int = 0; // writing writers + private var rwc: int = 0; // waiting readers + private var wwc: int = 0; // waiting writers + private val mutex = new Lock; + private val rsem = new Lock; + private val wsem = new Lock; + + def startRead = { + mutex.get; + if (wwc > 0 || wc > 0) { + rwc = rwc + 1; + mutex.release; + rsem.get; + rwc = rwc - 1; + } + rc = rc + 1; + if (rwc > 0) rsem.release; + mutex.release + } + + def startWrite = { + mutex.get; + if (rc > 0 || wc > 0) { + wwc = wwc + 1; + mutex.release; + wsem.get; + wwc = wwc - 1; + } + wc = wc + 1; + mutex.release; + } + + def endRead = { + mutex.get; + rc = rc - 1; + if (rc == 0 && wwc > 0) wsem.release; + mutex.release + } + + def endWrite = { + mutex.get; + wc = wc - 1; + if (rwc > 0) + rsem.release + else if (wwc > 0) wsem.release; + mutex.release + } + } + + /** A readers/writers lock, using channels, without priortities + */ + class ReadWriteLock3 extends ReadWriteLock { + + private val sr = new Signal; + private val er = new Signal; + private val sw = new Signal; + private val ew = new Signal; + + def startRead = sr.send; + def startWrite = sw.send; + def endRead = er.send; + def endWrite = ew.send; + + private def rwlock: unit = choice ( + sr * (x => reading(1)), + sw * (x => { ew.receive; rwlock }) + ); + + private def reading(n: int): unit = choice ( + sr * (x => reading(n+1)), + er * (x => if (n == 1) rwlock else reading(n-1)) + ); + + spawn < rwlock >; + } + + /** Same, with sequencing + */ + class ReadWriteLock4 extends ReadWriteLock { + + private val rwlock = new ReadWriteLock3; + + private val sr = new Signal; + private val ww = new Signal; + private val sw = new Signal; + + def startRead = sr.send; + def startWrite = { ww.send; sw.send; } + def endRead = rwlock.endRead; + def endWrite = rwlock.endWrite; + + private def queue: unit = choice ( + sr * (x => { rwlock.startRead ; queue }), + ww * (x => { rwlock.startWrite; sw.receive; queue }) + ); + + spawn < queue >; + } + + /** Readwritelock where writers always have priority over readers + */ + class ReadWriteLock5 extends ReadWriteLock { + + private val sr = new Signal; + private val er = new Signal; + private val ww = new Signal; + private val sw = new Signal; + private val ew = new Signal; + + def startRead = sr.send; + def startWrite = { ww.send; sw.send; } + def endRead = er.send; + def endWrite = ew.send; + + private def Reading(nr: int, nw: int): unit = + if (nr == 0 && nw == 0) + choice ( + sr * (x => Reading(1, 0)), + ww * (x => Reading(0, 1)) + ) + else if (nr == 0 && nw != 0) { + sw.receive; + Writing(nw); + } + else if (nr != 0 && nw == 0) + choice ( + sr * (x => Reading(nr + 1, 0)), + er * (x => Reading(nr - 1, 0)), + ww * (x => Reading(nr, 1)) + ) + else if (nr != 0 && nw != 0) + choice ( + ww * (x => Reading(nr, nw + 1)), + er * (x => Reading(nr - 1, nw)) + ); + + private def Writing(nw: int): unit = choice ( + ew * (x => Reading(0, nw - 1)), + ww * (x => Writing(nw + 1)) + ); + + spawn < Reading(0, 0) >; + + } + + /** + * Main function. + */ + def main(args: Array[String]): unit = { + val random = new java.util.Random(); + + def reader(i: int, rwlock: ReadWriteLock): unit = { + Thread.sleep(1 + random.nextInt(100)); + System.err.println("Reader " + i + " wants to read."); + rwlock.startRead; + System.err.println("Reader " + i + " is reading."); + Thread.sleep(1 + random.nextInt(100)); + rwlock.endRead; + System.err.println("Reader " + i + " has read."); + reader(i, rwlock) + } + + def writer(i: int, rwlock: ReadWriteLock): unit = { + Thread.sleep(1 + random.nextInt(100)); + System.err.println("Writer " + i + " wants to write."); + rwlock.startWrite; + System.err.println("Writer " + i + " is writing."); + Thread.sleep(1 + random.nextInt(100)); + rwlock.endWrite; + System.err.println("Writer " + i + " has written."); + writer(i, rwlock) + } + + val n = try { Integer.parseInt(args(0)) } catch { case _ => 0 } + if (n < 1 || 5 < n) { + Console.println("Usage: scala examples.pilib.rwlock (n=1..5)"); + exit + } + val rwlock = n match { + case 1 => new ReadWriteLock1 + case 2 => new ReadWriteLock2 + case 3 => new ReadWriteLock3 + case 4 => new ReadWriteLock4 + case 5 => new ReadWriteLock5 + } + List.range(0, 5) foreach (i => spawn < reader(i, rwlock) >); + List.range(0, 5) foreach (i => spawn < writer(i, rwlock) >); + } + +} + diff --git a/docs/examples/pilib/scheduler.scala b/docs/examples/pilib/scheduler.scala new file mode 100644 index 0000000000..3b08a9df66 --- /dev/null +++ b/docs/examples/pilib/scheduler.scala @@ -0,0 +1,149 @@ +package examples.pilib; + +import scala.concurrent.pilib._; + +object scheduler { + + /** + * Random number generator. + */ + val random = new java.util.Random(); + + //***************** Scheduler ******************// + + /** + * A cell of the scheduler whose attached agent is allowed to start. + */ + def A(a: Chan[unit], b: Chan[unit])(d: Chan[unit], c: Chan[unit]): unit = { + ///- ... complete here ... + choice ( a * { x => C(a, b)(d, c) }) + ///+ + } + + /** + * A cell of the scheduler in another intermediate state. + */ + def C(a: Chan[unit], b: Chan[unit])(d: Chan[unit], c: Chan[unit]): unit = { + ///- ... complete here ... + choice (c * { x => B(a, b)(d, c) }) + ///+ + } + + /** + * A cell of the scheduler whose attached agent is allowed to finish. + */ + def B(a: Chan[unit], b: Chan[unit])(d: Chan[unit], c: Chan[unit]): unit = { + ///- ... complete here ... + // choice (b * { x => D(a, b)(d, c) }) // incorrect naive solution + choice ( + b * { x => choice ( d(()) * A(a, b)(d, c) ) }, // b.'d.A + d(()) * (choice (b * { x => A(a, b)(d, c) })) // 'd.b.A + ) + ///+ + } + + /** + * A cell of the scheduler whose attached agent is not yet allowed to start. + */ + def D(a: Chan[unit], b: Chan[unit])(d: Chan[unit], c: Chan[unit]): unit = { + ///- ... complete here ... + choice (d(()) * A(a, b)(d, c)) + ///+ + } + + //***************** Agents ******************// + + def agent(i: Int)(a: Chan[unit], b: Chan[unit]): unit = { + // 50% chance that we sleep forever + if (i == 0 && random.nextInt(10) < 5) { + a.attach(x => System.out.println("Start and sleeps ----> " + i)); + Thread.sleep(random.nextInt(1000)); + a.write(()); + } + else { + a.attach(x => System.out.println("Start ----> " + i)); + b.attach(x => System.out.println("Stop -> " + i)); + Thread.sleep(random.nextInt(1000)); + a.write(()); + Thread.sleep(random.nextInt(1000)); + b.write(()); + agent(i)(a, b) + } + } + + //***************** Entry function ******************// + + /** + * Creates a scheduler for five agents (programs). + */ + + def main(args: Array[String]): unit = { + val agentNb = 5; + val agents = List.range(0, agentNb) map agent; + scheduleAgents(agents); + } + + //***************** Infrastructure *****************// + + /** + * A cell is modelled as a function that takes as parameters + * input and output channels and which returns nothing. + */ + type Cell = (Chan[unit], Chan[unit]) => unit; + + /** + * Creates a cell composed of two cells linked together. + */ + def join(cell1: Cell, cell2: Cell): Cell = + (l: Chan[unit], r: Chan[unit]) => { + val link = new Chan[unit]; + spawn < cell1(l, link) | cell2(link, r) > + }; + + /** + * Links the output of a cell to its input. + */ + def close(cell: Cell): unit = { + val a = new Chan[unit]; + cell(a, a) + } + + /** + * Creates a cell consisting of a chain of cells. + */ + def chain(cells: List[Cell]): Cell = + cells reduceLeft join; + + /** + * Creates a cell consisting of a chain of cells. + */ + def makeRing(cells: List[Cell]): unit = + close(chain(cells)); + + /** + * An agent is modelled as a function that takes as parameters channels to + * signal that it has started or finished. + */ + type Agent = (Chan[unit], Chan[unit]) => unit; + + /** + * Takes a list of agents and schedules them. + */ + def scheduleAgents(agents: List[Agent]): unit = { + var firstAgent = true; + val cells = agents map (ag => { + val a = new Chan[unit]; + val b = new Chan[unit]; + spawn < ag(a, b) >; + if (firstAgent) { + firstAgent = false; + A(a, b) + } + else + D(a, b) + }); + makeRing(cells) + } +} + + diff --git a/docs/examples/pilib/semaphore.scala b/docs/examples/pilib/semaphore.scala new file mode 100644 index 0000000000..cfb0c8e5a2 --- /dev/null +++ b/docs/examples/pilib/semaphore.scala @@ -0,0 +1,72 @@ +package examples.pilib; + +/** Solution of exercise session 6 (first question). */ +object semaphore { + + import scala.concurrent.pilib._; + + class Signal extends Chan[unit] { + def send = write(()); + def receive = read; + } + + /** Interface. */ + trait Semaphore { + def get: unit; + def release: unit; + } + + /** First implementation. */ + class Sem1 extends Semaphore { + + private val g = new Signal; + private val r = new Signal; + + def get: unit = g.send; + def release: unit = r.send; + + private def Sched: unit = choice ( + g * (x => { r.receive; Sched }), + r * (x => Sched) + ); + spawn< Sched >; + } + + /** Second implementation. */ + class Sem2 extends Semaphore { + + private val a = new Signal; + private val na = new Signal; + + def get: unit = { a.receive; spawn< na.send > } + def release: unit = choice ( + a * (x => spawn< a.send >), + na * (x => spawn< a.send >) + ); + spawn< a.send >; + } + + /** Test program. */ + def main(args: Array[String]): unit = { + val random = new java.util.Random(); + val sem = new Sem2; + def mutex(p: => unit): unit = { sem.get; p; sem.release } + + spawn< { + Thread.sleep(1 + random.nextInt(100)); + mutex( { + System.out.println("a1"); + Thread.sleep(1 + random.nextInt(100)); + System.out.println("a2") + } ) + } | { + Thread.sleep(1 + random.nextInt(100)); + mutex( { + System.out.println("b1"); + Thread.sleep(1 + random.nextInt(100)); + System.out.println("b2") + } ) + } >; + } +} + diff --git a/docs/examples/pilib/twoPlaceBuffer.scala b/docs/examples/pilib/twoPlaceBuffer.scala new file mode 100644 index 0000000000..686547b344 --- /dev/null +++ b/docs/examples/pilib/twoPlaceBuffer.scala @@ -0,0 +1,67 @@ +package examples.pilib; + +import scala.concurrent.pilib._; + +/** Two-place buffer specification and implementation. */ +object twoPlaceBuffer with Application { + + /** + * Specification. + */ + def Spec[a](in: Chan[a], out: Chan[a]): unit = { + + def B0: unit = choice ( + in * (x => B1(x)) + ); + + def B1(x: a): unit = choice ( + out(x) * (B0), + in * (y => B2(x, y)) + ); + + def B2(x: a, y: a): unit = choice ( + out(x) * (B1(y)) + ); + + B0 + } + + /** + * Implementation using two one-place buffers. + */ + def Impl[a](in: Chan[a], out: Chan[a]): unit = { + ///- ... complete here ... + // one-place buffer + def OnePlaceBuffer[a](in: Chan[a], out: Chan[a]): unit = { + def B0: unit = choice ( in * (x => B1(x)) ); + def B1(x: a): unit = choice ( out(x) * (B0)); + B0 + } + val hidden = new Chan[a]; + spawn < OnePlaceBuffer(in, hidden) | OnePlaceBuffer(hidden, out) > + ///+ + } + + val random = new java.util.Random(); + + def Producer(n: Int, in: Chan[String]): unit = { + Thread.sleep(random.nextInt(1000)); + val msg = "" + n; + choice (in(msg) * {}); + Producer(n + 1, in) + } + + def Consumer(out: Chan[String]): unit = { + Thread.sleep(random.nextInt(1000)); + choice (out * { msg => () }); + Consumer(out) + } + + val in = new Chan[String]; + in.attach(s => System.out.println("put " + s)); + val out = new Chan[String]; + out.attach(s => System.out.println("get " + s)); + //spawn < Producer(0, in) | Consumer(out) | Spec(in, out) > + spawn < Producer(0, in) | Consumer(out) | Impl(in, out) > + +} diff --git a/docs/examples/sort.scala b/docs/examples/sort.scala new file mode 100644 index 0000000000..6554a2415b --- /dev/null +++ b/docs/examples/sort.scala @@ -0,0 +1,48 @@ +package examples; + +object sort { + + def sort(a: Array[Int]): Unit = { + + def swap(i: Int, j: Int): Unit = { + val t = a(i); a(i) = a(j); a(j) = t; + } + + def sort1(l: Int, r: Int): Unit = { + val pivot = a((l + r) / 2); + var i = l; + var j = r; + while (i <= j) { + while (a(i) < pivot) { i = i + 1 } + while (a(j) > pivot) { j = j - 1 } + if (i <= j) { + swap(i, j); + i = i + 1; + j = j - 1; + } + } + if (l < j) sort1(l, j); + if (j < r) sort1(i, r); + } + + if (a.length > 0) + sort1(0, a.length - 1); + } + + def println(ar: Array[Int]) = { + def print1 = { + def iter(i: Int): String = + ar(i) + (if (i < ar.length-1) "," + iter(i+1) else ""); + if (ar.length == 0) "" else iter(0) + } + Console.println("[" + print1 + "]") + } + + def main(args: Array[String]) = { + val ar = Array(6, 2, 8, 5, 1); + println(ar); + sort(ar); + println(ar) + } + +} diff --git a/docs/examples/sort1.scala b/docs/examples/sort1.scala new file mode 100644 index 0000000000..406bf7c911 --- /dev/null +++ b/docs/examples/sort1.scala @@ -0,0 +1,22 @@ +package examples; + +object sort1 { + + def sort(a: List[Int]): List[Int] = { + if (a.length < 2) + a + else { + val pivot = a(a.length / 2); + sort(a.filter(x => x < pivot)) + ::: a.filter(x => x == pivot) + ::: sort(a.filter(x => x > pivot)) + } + } + + def main(args: Array[String]) = { + val xs = List(6, 2, 8, 5, 1); + Console.println(xs); + Console.println(sort(xs)) + } + +} diff --git a/docs/examples/sort2.scala b/docs/examples/sort2.scala new file mode 100644 index 0000000000..53b2f89174 --- /dev/null +++ b/docs/examples/sort2.scala @@ -0,0 +1,25 @@ +package examples; + +object sort2 { + + def sort(a: List[Int]): List[Int] = { + if (a.length < 2) + a + else { + val pivot = a(a.length / 2); + def lePivot(x: Int) = x < pivot; + def gtPivot(x: Int) = x > pivot; + def eqPivot(x: Int) = x == pivot; + sort(a filter lePivot) + ::: sort(a filter eqPivot) + ::: sort(a filter gtPivot) + } + } + + def main(args: Array[String]) = { + val xs = List(6, 2, 8, 5, 1); + Console.println(xs); + Console.println(sort(xs)) + } + +} diff --git a/docs/examples/typeinf.scala b/docs/examples/typeinf.scala new file mode 100644 index 0000000000..a9ac59968b --- /dev/null +++ b/docs/examples/typeinf.scala @@ -0,0 +1,244 @@ +package examples; + +object typeinf { + +trait Term {} + +case class Var(x: String) extends Term { + override def toString() = x +} +case class Lam(x: String, e: Term) extends Term { + override def toString() = "(\\" + x + "." + e + ")" +} +case class App(f: Term, e: Term) extends Term { + override def toString() = "(" + f + " " + e + ")" +} +case class Let(x: String, e: Term, f: Term) extends Term { + override def toString() = "let " + x + " = " + e + " in " + f; +} + +sealed trait Type {} +case class Tyvar(a: String) extends Type { + override def toString() = a +} +case class Arrow(t1: Type, t2: Type) extends Type { + override def toString() = "(" + t1 + "->" + t2 + ")" +} +case class Tycon(k: String, ts: List[Type]) extends Type { + override def toString() = + k + (if (ts.isEmpty) "" else ts.mkString("[", ",", "]")) +} + +object typeInfer { + + private var n: Int = 0; + def newTyvar(): Type = { n = n + 1 ; Tyvar("a" + n) } + + trait Subst with Function1[Type,Type] { + def lookup(x: Tyvar): Type; + def apply(t: Type): Type = t match { + case tv @ Tyvar(a) => val u = lookup(tv); if (t == u) t else apply(u); + case Arrow(t1, t2) => Arrow(apply(t1), apply(t2)) + case Tycon(k, ts) => Tycon(k, ts map apply) + } + def extend(x: Tyvar, t: Type) = new Subst { + def lookup(y: Tyvar): Type = if (x == y) t else Subst.this.lookup(y); + } + } + + val emptySubst = new Subst { def lookup(t: Tyvar): Type = t } + + case class TypeScheme(tyvars: List[Tyvar], tpe: Type) { + def newInstance: Type = + (emptySubst /: tyvars) ((s, tv) => s.extend(tv, newTyvar())) (tpe); + } + + type Env = List[Pair[String, TypeScheme]]; + + def lookup(env: Env, x: String): TypeScheme = env match { + case List() => null + case Pair(y, t) :: env1 => if (x == y) t else lookup(env1, x) + } + + def gen(env: Env, t: Type): TypeScheme = + TypeScheme(tyvars(t) diff tyvars(env), t); + + def tyvars(t: Type): List[Tyvar] = t match { + case tv @ Tyvar(a) => List(tv) + case Arrow(t1, t2) => tyvars(t1) union tyvars(t2) + case Tycon(k, ts) => (List[Tyvar]() /: ts) ((tvs, t) => tvs union tyvars(t)); + } + + def tyvars(ts: TypeScheme): List[Tyvar] = + tyvars(ts.tpe) diff ts.tyvars; + + def tyvars(env: Env): List[Tyvar] = + (List[Tyvar]() /: env) ((tvs, nt) => tvs union tyvars(nt._2)); + + def mgu(t: Type, u: Type, s: Subst): Subst = Pair(s(t), s(u)) match { + case Pair(Tyvar(a), Tyvar(b)) if (a == b) => + s + case Pair(Tyvar(a), _) if !(tyvars(u) contains a) => + s.extend(Tyvar(a), u) + case Pair(_, Tyvar(a)) => + mgu(u, t, s) + case Pair(Arrow(t1, t2), Arrow(u1, u2)) => + mgu(t1, u1, mgu(t2, u2, s)) + case Pair(Tycon(k1, ts), Tycon(k2, us)) if (k1 == k2) => + (s /: (ts zip us)) ((s, tu) => mgu(tu._1, tu._2, s)) + case _ => throw new TypeError("cannot unify " + s(t) + " with " + s(u)) + } + + case class TypeError(s: String) extends Exception(s) {} + + def tp(env: Env, e: Term, t: Type, s: Subst): Subst = { + current = e; + e match { + case Var(x) => + val u = lookup(env, x); + if (u == null) throw new TypeError("undefined: " + x); + else mgu(u.newInstance, t, s) + + case Lam(x, e1) => + val a, b = newTyvar(); + val s1 = mgu(t, Arrow(a, b), s); + val env1 = Pair(x, TypeScheme(List(), a)) :: env; + tp(env1, e1, b, s1) + + case App(e1, e2) => + val a = newTyvar(); + val s1 = tp(env, e1, Arrow(a, t), s); + tp(env, e2, a, s1) + + case Let(x, e1, e2) => + val a = newTyvar(); + val s1 = tp(env, e1, a, s); + tp(Pair(x, gen(env, s1(a))) :: env, e2, t, s1) + } + } + var current: Term = null; + + def typeOf(env: Env, e: Term): Type = { + val a = newTyvar(); + tp(env, e, a, emptySubst)(a) + } +} + + object predefined { + val booleanType = Tycon("Boolean", List()); + val intType = Tycon("Int", List()); + def listType(t: Type) = Tycon("List", List(t)); + + private def gen(t: Type): typeInfer.TypeScheme = typeInfer.gen(List(), t); + private val a = typeInfer.newTyvar(); + val env = List( +/* + Pair("true", gen(booleanType)), + Pair("false", gen(booleanType)), + Pair("if", gen(Arrow(booleanType, Arrow(a, Arrow(a, a))))), + Pair("zero", gen(intType)), + Pair("succ", gen(Arrow(intType, intType))), + Pair("nil", gen(listType(a))), + Pair("cons", gen(Arrow(a, Arrow(listType(a), listType(a))))), + Pair("isEmpty", gen(Arrow(listType(a), booleanType))), + Pair("head", gen(Arrow(listType(a), a))), + Pair("tail", gen(Arrow(listType(a), listType(a)))), +*/ + Pair("fix", gen(Arrow(Arrow(a, a), a))) + ) + } + + abstract class MiniMLParsers extends CharParsers { + + /** whitespace */ + def whitespace = rep{chr(' ') ||| chr('\t') ||| chr('\n')}; + + /** A given character, possible preceded by whitespace */ + def wschr(ch: char) = whitespace &&& chr(ch); + + /** identifiers or keywords */ + def id: Parser[String] = + for ( + val c: char <- rep(chr(' ')) &&& chr(Character.isLetter); + val cs: List[char] <- rep(chr(Character.isLetterOrDigit)) + ) yield (c :: cs).mkString("", "", ""); + + /** Non-keyword identifiers */ + def ident: Parser[String] = + for (val s <- id; s != "let" && s != "in") yield s; + + /** term = '\' ident '.' term | term1 {term1} | let ident "=" term in term */ + def term: Parser[Term] = + ( for ( + val _ <- wschr('\\'); + val x <- ident; + val _ <- wschr('.'); + val t <- term) + yield Lam(x, t): Term ) + ||| + ( for ( + val letid <- id; letid == "let"; + val x <- ident; + val _ <- wschr('='); + val t <- term; + val inid <- id; inid == "in"; + val c <- term) + yield Let(x, t, c) ) + ||| + ( for ( + val t <- term1; + val ts <- rep(term1)) + yield (t /: ts)((f, arg) => App(f, arg)) ); + + /** term1 = ident | '(' term ')' */ + def term1: Parser[Term] = + ( for (val s <- ident) + yield Var(s): Term ) + ||| + ( for ( + val _ <- wschr('('); + val t <- term; + val _ <- wschr(')')) + yield t ); + + /** all = term ';' */ + def all: Parser[Term] = + for ( + val t <- term; + val _ <- wschr(';')) + yield t; + } + + class ParseString(s: String) extends Parsers { + type intype = int; + val input = 0; + def any = new Parser[char] { + def apply(in: int): Parser[char]#Result = + if (in < s.length()) Some(Pair(s charAt in, in + 1)) else None; + } + } + + def showType(e: Term): String = + try { + typeInfer.typeOf(predefined.env, e).toString(); + } catch { + case typeInfer.TypeError(msg) => + "\n cannot type: " + typeInfer.current + + "\n reason: " + msg; + } + + def main(args: Array[String]): unit = + Console.println( + if (args.length == 1) { + val ps = new MiniMLParsers with ParseString(args(0)); + ps.all(ps.input) match { + case Some(Pair(term, _)) => + "" + term + ": " + showType(term) + case None => + "syntax error" + } + } else "usage: java examples.typeinf " + ); + +} + -- cgit v1.2.3