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Diffstat (limited to 'docs/examples/pilib/piNat.scala')
-rw-r--r-- | docs/examples/pilib/piNat.scala | 89 |
1 files changed, 0 insertions, 89 deletions
diff --git a/docs/examples/pilib/piNat.scala b/docs/examples/pilib/piNat.scala deleted file mode 100644 index a1a0e682e1..0000000000 --- a/docs/examples/pilib/piNat.scala +++ /dev/null @@ -1,89 +0,0 @@ -package examples.pilib - -import scala.concurrent.pilib._ - -/** Church encoding of naturals in the Pi-calculus */ -object piNat extends 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) { - 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) { - 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) | - println("" + i + " = " + value(l1)) | - println("succ " + i + " = " + value(l3)) > - -} |