1 files changed, 22 insertions, 0 deletions
diff --git a/engine/stack.go b/engine/stack.go
new file mode 100644
index 0000000..d7fc7be
--- /dev/null
+++ b/engine/stack.go
@@ -0,0 +1,22 @@
+package engine
+
+type Stack []*Card
+
+func (s Stack) Contains(predicate func(c IsCard) bool) bool {
+	for _, c := range s {
+		if predicate(c) {
+			return true
+		}
+	}
+	return false
+}
+
+func (s Stack) Filter(predicate func(c IsCard) bool) Stack {
+	res := make(Stack, 0, len(s))
+	for _, c := range s {
+		if predicate(c) {
+			res = append(res, c)
+		}
+	}
+	return res
+}