moved punishment helpers to vector.go

astar.go

@@ -141,36 +141,28 @@ func (p Pathfinder) Find(startPos, endPos Vec2) []Vec2 {
 	return []Vec2{}
 }
 
+// punishChangeDirection returns a punishment for changing direction that can be applied to g.
 func punishChangeDirection(q node, successor, end Vec2) int {
 	if q.parent == nil {
 		return 0
 	}
 	punishment := abs(successor.X-end.X) + abs(successor.Y-end.Y)
 
-	isHorizAdj := func(a, b Vec2) bool {
-		return a.Y-b.Y == 0
-	}
 	if !isHorizAdj(q.pos, successor) {
 		if isHorizAdj(q.pos, q.parent.pos) {
 			return punishment
 		}
 	}
 
-	isVertAdj := func(a, b Vec2) bool {
-		return a.X-b.X == 0
-	}
 	if !isVertAdj(q.pos, successor) {
 		if isVertAdj(q.pos, q.parent.pos) {
 			return punishment
 		}
 	}
 
 	// todo: check option if diagonal enabled
-	isDiagonal := func(a, b Vec2) bool {
-		return abs(a.X-b.X) == abs(a.Y-b.Y)
-	}
-	if !isDiagonal(q.pos, successor) {
-		if isDiagonal(q.pos, q.parent.pos) {
+	if !isDiagAdj(q.pos, successor) {
+		if isDiagAdj(q.pos, q.parent.pos) {
 			return punishment
 		}
 	}

astar_test.go

@@ -238,7 +238,7 @@ func TestPath_Diagonal2(t *testing.T) {
 }
 
 func TestPath_PunishChangeDirection(t *testing.T) {
-	t.Skip()
+	t.Skip("unimplemented")
 	weights := []int{
 		1, 1, 1, 1, 1,
 		1, 1, 1, 1, 1,
@@ -253,9 +253,9 @@ func TestPath_PunishChangeDirection(t *testing.T) {
 
 	want := []Vec2{
 		{1, 3},
-		{2, 3},
-		{3, 3},
-		{3, 2},
+		{1, 2},
+		{1, 1},
+		{2, 1},
 		{3, 1},
 	}
 	equal(t, got, want, &grid)

vector.go

@@ -5,3 +5,18 @@ type Vec2 struct {
 	X int
 	Y int
 }
+
+// isHorizAdj returns true if a and b are horizontally adjacent.
+func isHorizAdj(a, b Vec2) bool {
+	return a.Y-b.Y == 0
+}
+
+// isVertAdj returns true if a and b are vertically adjacent.
+func isVertAdj(a, b Vec2) bool {
+	return a.X-b.X == 0
+}
+
+// isDiagAdj returns true if a and b are diagonally adjacent.
+func isDiagAdj(a, b Vec2) bool {
+	return abs(a.X-b.X) == abs(a.Y-b.Y)
+}