You're now looking at the difference between: -- list of booleans but the end has an Int data T1 = End1 Int | Node1 Bool T1 whatInt1 (End1 i) = i whatInt1 (Node1 _ xs) = whatInt1 xs and -- list of booleans but the end has an Int again but different data T2 = End2 Int | FalseNode2 T2 | TrueNode2 T2 whatInt2 (End2 i) = i -- the following two cases are unmergeable -- but there is a mitigation if you find out about "record syntax" whatInt2 (FalseNode2 xs) = whatInt2 xs whatInt2 (TrueNode2 xs) = whatInt2 xs Record syntax can mitigate it: data T3 = End3 Int | FalseNode3 {tail3 :: T3} | TrueNode3 {tail3 :: T3} whatInt3 (End3 i) = i whatInt3 r = whatInt3 (tail3 r) But I say "mitgate", not "solve", because it doesn't generalize to data Q = QI Int | QF {qtail :: Q} | QT {qtail :: Q} | BF{qleft, qright :: Q} | BT{qleft, qright :: Q} On 2021-03-12 7:59 p.m., Galaxy Being wrote:
However, I'm still wondering how to have an abstracted (x:xs) - like pattern to collapse all the ingredients, i.e.,
whatHolder2 (Holder2 (sh)) = sh whatHolder2 (shish2-head (shish2-tail)) = whatHolder2 shish2-tail