non associative with precedence 90
for @{'Nil}.
-notation "hvbox( hd break :: tl )"
+notation "hvbox( hd :: break tl )"
right associative with precedence 47
for @{'Cons $hd $tl}.
-notation "hvbox( l1 break @ l2 )"
+notation "hvbox( l1 @ break l2 )"
right associative with precedence 47
for @{'Append $l1 $l2 }.
+
+notation "hvbox( ⟠ )"
+ non associative with precedence 90
+ for @{'Nil2}.
+
+notation "hvbox( { hd1 , break hd2 } :: break tl )"
+ non associative with precedence 47
+ for @{'Cons $hd1 $hd2 $tl}.