add JaCoP example

.gitignore

@@ -1 +1,3 @@
 out
+.idea
+.gradle

EinsteinsRiddle/EinsteinsRiddle.iml

@@ -125,6 +125,17 @@
         <SOURCES />
       </library>
     </orderEntry>
+    <orderEntry type="module-library">
+      <library>
+        <CLASSES>
+          <root url="jar://$MODULE_DIR$/lib/JaCoP-3.1.2.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES>
+          <root url="jar://$MODULE_DIR$/lib/JaCoP-3.1.2.jar!/" />
+        </SOURCES>
+      </library>
+    </orderEntry>
   </component>
 </module>
 

EinsteinsRiddle/README.md

@@ -3,11 +3,21 @@ Einstein's Riddle
 
 Solves a logic puzzle using the following approaches:
 
-* prolog directly
+* prolog directly (for comparative purposes)
 * prolog underneath a Groovy DSL
-* a constraint solving library beneath a Groovy DSL
+* the __choco__ constraint solving library beneath a Groovy DSL
+* the __jacop__ constraint solving library beneath a Groovy DSL
+
+The interesting thing to note is that the "business rules" are the same in all cases. The "DSL helper code" would typically be hidden from the user.
 
 The [prolog4j](https://github.com/espakm/prolog4j) generic prolog interface api is used along with the [tuprolog](http://tuprolog.alice.unibo.it/) prolog engine but
 you can try some of the other engines supported by prolog4j if you wish.
 
-The [choco](http://www.emn.fr/z-info/choco-solver/) constraint solving library is used.
+The [choco](http://www.emn.fr/z-info/choco-solver/) and [JaCoP](http://jacop.osolpro.com/) constraint solving libraries are used.
+These libraries offer similar features as far as this problem is concerned. Given that the JaCoP package isn't available in a public
+Maven repository and has a restrictive GPL license, we have a preference for Choco for this example; but see the respective
+documentation of the two packages to see which better suits your needs.
+
+To install the library needed for JaCoP you will need to run the following command (windows command shown):
+
+    ..\gradlew downloadJaCoP

EinsteinsRiddle/build.gradle

@@ -0,0 +1,4 @@
+task downloadJaCoP() {
+    def name = 'JaCoP-3.1.2'
+    ant.get(src: "http://downloads.sourceforge.net/project/jacop-solver/$name/${name}.jar", dest: "lib")
+}

EinsteinsRiddle/src/jacop/JacopSolverDSL.groovy

@@ -0,0 +1,181 @@
+package jacop
+
+import JaCoP.core.*
+import JaCoP.constraints.*
+import JaCoP.search.*
+import groovy.transform.Field
+
+enum Pet { dog, cat, bird, fish, horse }
+enum Color { green, white, red, blue, yellow }
+enum Sport { baseball, volleyball, football, hockey, tennis }
+enum Drink { water, tea, milk, coffee, beer }
+enum Nationality { Norwegian, Dane, Briton, German, Swede }
+
+import static Pet.*
+import static Color.*
+import static Sport.*
+import static Drink.*
+import static Nationality.*
+
+// define logic solver data structures
+num = 5
+center = 2
+first = 0
+println "Solving Einstein's Riddle:"
+
+@Field s = new Store()
+
+def makeEnumVar(String st, Object[] arr) { new IntVar(s, st, 0, arr.size()-1) }
+pets    = new IntVar[num]
+colors  = new IntVar[num]
+plays   = new IntVar[num]
+drinks  = new IntVar[num]
+nations = new IntVar[num]
+
+(0..<num).each { i ->
+     pets[i] = makeEnumVar("pet$i",    pets)
+   colors[i] = makeEnumVar("color$i",  colors)
+    plays[i] = makeEnumVar("plays$i",  plays)
+   drinks[i] = makeEnumVar("drink$i",  drinks)
+  nations[i] = makeEnumVar("nation$i", nations)
+}
+
+def pretty(enumClass, selected) { enumClass.values().find{ it.ordinal().toString() == selected.toString() } }
+
+// define DSL (simplistic non-refactored version)
+def neighbours(var1, val1, var2, val2) {
+  s.impose and(
+    ifOnlyIf(eq(var1[0], val1), eq(var2[1], val2)),
+    implies(eq(var1[1], val1), or(eq(var2[0], val2), eq(var2[2], val2))),
+    implies(eq(var1[2], val1), or(eq(var2[1], val2), eq(var2[3], val2))),
+    implies(eq(var1[3], val1), or(eq(var2[2], val2), eq(var2[4], val2))),
+    ifOnlyIf(eq(var1[4], val1), eq(var2[3], val2))
+  )
+}
+iff = { e1, c1, e2, c2 -> s.impose and(*(0..<num).collect{ ifOnlyIf(eq(e1[it], c1), eq(e2[it], c2)) }) }
+isEq = { a, b -> s.impose eq(a, b) }
+
+dogs = dog; birds = bird; cats = cat; horses = horse
+a = owner = house = the = abode = person = man = to = is = side = next = who = different = 'ignored'
+
+// define the DSL in terms of DSL implementation
+def the(Nationality n) {
+  def ctx = [nations, n]
+  [
+    drinks:iff.curry(*ctx, drinks),
+    plays:iff.curry(*ctx, plays),
+    keeps:iff.curry(*ctx, pets),
+    rears:iff.curry(*ctx, pets),
+    owns:{ _the -> [first:{ house -> isEq(nations[first], n)}] },
+    has:{ _a ->
+      [pet:iff.curry(*ctx, pets)] + Color.values().collectEntries{ c ->
+        [c.toString(), { _dummy -> iff(*ctx, colors, c) } ]
+      }
+    },
+    lives: { _next -> [to: { _the ->
+      Color.values().collectEntries{ c ->
+        [c.toString(), { _dummy -> neighbours(*ctx, colors, c) } ]
+      }
+    }]}
+  ]
+}
+
+def the(Color c1) {[
+  house: { _is -> [on: { _the -> [left: { _side -> [of: { __the ->
+    Color.values().collectEntries{ c2 -> [c2.toString(), { _dummy ->
+        s.impose and(*(1..<num).collect{ ifOnlyIf(eq(colors[it-1], c1), eq(colors[it], c2)) })
+    }]}
+  }]}]}]}
+]}
+
+def the(String _dummy) {[
+  of:{ _the ->
+    Color.values().collectEntries{ c -> [c.toString(), { _house -> [
+      drinks:iff.curry(colors, c, drinks),
+      plays:iff.curry(colors, c, plays)
+    ] } ] }
+  },
+  known: { _to -> [
+    play: { sport ->
+      def ctx = [plays, sport]
+      [
+        rears: iff.curry(*ctx, pets),
+        keeps: iff.curry(*ctx, pets),
+        drinks: iff.curry(*ctx, drinks),
+        lives: { _next -> [to: { _the -> [one: { _who -> [
+          keeps: { pet -> neighbours(pets, pet, *ctx) },
+          drinks: { beverage -> neighbours(drinks, beverage, *ctx) }
+        ]}]}]}
+      ]
+    },
+    keep : { pet -> [
+      lives: { _next -> [to: { _the -> [man: { _who -> [
+        plays: { sport -> neighbours(pets, pet, plays, sport) }
+      ]}]}]}
+    ]}
+  ]},
+  from: { _the -> [center: { house ->
+    [drinks: { d -> isEq(drinks[center], d)}]
+  }]}
+]}
+
+def all(IntVar[] var) {
+  [are: { _different -> s.impose new Alldifferent(var) } ]
+}
+
+// define rules
+all pets are different
+all colors are different
+all plays are different
+all drinks are different
+all nations are different
+the man from the center house drinks milk
+the Norwegian owns the first house
+the Dane drinks tea
+the German plays hockey
+the Swede keeps dogs // alternate ending: has a pet dog
+the Briton has a red house  // alternate ending: red abode
+the owner of the green house drinks coffee
+the owner of the yellow house plays baseball
+the person known to play football rears birds // alternate ending: keeps birds
+the man known to play tennis drinks beer
+the green house is on the left side of the white house
+the man known to play volleyball lives next to the one who keeps cats
+the man known to keep horses lives next to the man who plays baseball
+the man known to play volleyball lives next to the one who drinks water
+the Norwegian lives next to the blue house
+
+// invoke logic solver
+def vars = [pets, plays, drinks, colors, nations]
+def search = new DepthFirstSearch()
+def select = new SimpleMatrixSelect(vars as Var[][], new IndomainMin())
+search.solutionListener.searchAll(true)
+def result = search.labeling(s, select)
+println "Solutions found: " + result
+search.solutionListener.solutionsNo().times { i ->
+  println "Solution ${i + 1}:"
+  def sol = search.getSolution(i + 1)
+  def ps = sol.take(5); sol = sol.drop(5)
+  def ss = sol.take(5); sol = sol.drop(5)
+  def ds = sol.take(5); sol = sol.drop(5)
+  def cs = sol.take(5); sol = sol.drop(5)
+  def ns = sol.take(5)
+  5.times {
+    printSol(ns[it], ps[it], ss[it], ds[it], cs[it])
+  }
+}
+
+def printSol(n, p, s, d, c) {
+  print   'The ' + pretty(Nationality, n)
+  print   ' has a pet ' + pretty(Pet, p)
+  print   ' plays ' + pretty(Sport, s)
+  print   ' drinks ' + pretty(Drink, d)
+  println ' and lives in a ' + pretty(Color, c) + ' house'
+}
+
+def eq(IntVar x, IntVar y) { new XeqY(x, y) }
+def eq(IntVar x, enumVar) { new XeqC(x, enumVar.ordinal()) }
+def or(PrimitiveConstraint c1, PrimitiveConstraint c2) { new Or(c1, c2) }
+def and(PrimitiveConstraint[] cs) { new And(cs) }
+def ifOnlyIf(PrimitiveConstraint c1, PrimitiveConstraint c2) { new Eq(c1, c2) }
+def implies(PrimitiveConstraint c1, PrimitiveConstraint c2) { new IfThen(c1, c2) }

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Mon May 02 20:57:32 EST 2011
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=http\://gradle.artifactoryonline.com/gradle/distributions/gradle-0.9.2-bin.zip