Notes and intervals

tests/forth/stack.rs

@@ -15,6 +15,31 @@ fn dup_underflow() {
     expect_error("dup", "stack underflow");
 }
 
+#[test]
+fn dupn() {
+    expect_stack("2 4 dupn", &[int(2), int(2), int(2), int(2)]);
+}
+
+#[test]
+fn dupn_one() {
+    expect_stack("5 1 dupn", &[int(5)]);
+}
+
+#[test]
+fn dupn_zero() {
+    expect_stack("5 0 dupn", &[]);
+}
+
+#[test]
+fn dupn_underflow() {
+    expect_error("3 dupn", "stack underflow");
+}
+
+#[test]
+fn bang_alias() {
+    expect_stack("c4 3 !", &[int(60), int(60), int(60)]);
+}
+
 #[test]
 fn drop() {
     expect_stack("1 2 drop", &[int(1)]);