basic example of a user-defined enumerator.. limited to invoking

`findAll' on it.

cp-demo/UserDefinedSolver.scala

+import cp.Definitions._
+import cp.Terms._
+
+@spec object Specs {
+  sealed abstract class List
+  case class Cons(head : Int, tail : List) extends List
+  case class Nil() extends List
+}
+object UserDefinedSolver {
+  import Specs._
+
+  def main(args: Array[String]): Unit = {
+    val myEnumerator = Iterator[List](Nil(), Cons(42, Nil()))
+    val userDefined = customSolver(myEnumerator)
+
+    for (l <- userDefined.findAll) {
+      println("Here is a solution: " + l)
+    }
+
+    userDefined.solve
+  }
+}