Add minor improvements

domain/src/main/kotlin/ch/dissem/yaep/domain/clues.kt

@@ -41,6 +41,8 @@ class NeighbourClue<A : ItemClass<A>, B : ItemClass<B>>(val a: Item<A>, val b: I
         }
         return true
     }
+
+    override fun toString() = "$aType is next to $bType"
 }
 
 class OrderClue<L : ItemClass<L>, R : ItemClass<R>>(val left: Item<L>, val right: Item<R>) :
@@ -66,6 +68,8 @@ class OrderClue<L : ItemClass<L>, R : ItemClass<R>>(val left: Item<L>, val right
 
         return rowLeft.indexOfFirst { it.mayBe(left) } >= rowRight.indexOfLast { it.mayBe(right) }
     }
+
+    override fun toString() = "$leftType is left of $rightType"
 }
 
 class TripletClue<A : ItemClass<A>, B : ItemClass<B>, C : ItemClass<C>>(
@@ -152,6 +156,9 @@ class TripletClue<A : ItemClass<A>, B : ItemClass<B>, C : ItemClass<C>>(
         }
         return true
     }
+
+    override fun toString(): String =
+        "$bType is between the neighbours $aType and $cType to both sides"
 }
 
 class SameColumnClue<A : ItemClass<A>, B : ItemClass<B>>(val a: Item<A>, val b: Item<B>) : Clue() {
@@ -184,13 +191,19 @@ class SameColumnClue<A : ItemClass<A>, B : ItemClass<B>>(val a: Item<A>, val b:
         }
         return true
     }
+
+    override fun toString(): String = "$aType and $bType are in the same column"
 }
 
 class PositionClue<C : ItemClass<C>>(val item: Item<C>, val index: Int) : Clue() {
+    val itemType = item.itemType
+
     override fun isRuleViolated(grid: Grid): Boolean {
         val i = grid.indexOf(item.itemType)
         if (i != -1) return i != index
 
         return grid[item].mayBe(item)
     }
+
+    override fun toString() = "$itemType is at position $index"
 }

domain/src/main/kotlin/ch/dissem/yaep/domain/generator.kt

@@ -19,7 +19,7 @@ fun generateGame(size: Int = 6): Game {
     // (There are a finite and in fact quite small number of possible clues: for example
     // if there are 5 houses, there are 5 possible clues of the form "Person A lives in
     // house B", 8 possible clues of the form "Person A lives next to house B", and so on.)
-    var clues = getAllClues(grid).toList() //.shuffled()
+    var clues = getAllClues(grid).sortedBy { it.toString() } //.shuffled()
 
     var i = 0
 
@@ -47,9 +47,9 @@ private fun solve(
 
     // First, set the positions of the items that are already known.
     clues.filterIsInstance<PositionClue<ItemClass<*>>>().forEach { position ->
-        val row = grid[position.item.itemType.companion]
+        val row = grid[position.itemType.companion]
         val cell = row[position.index]
-        cell.options.retainAll { it == cell.selection }
+        cell.options.retainAll { it == position.item }
         row.cleanupOptions(cell)
     }