or-patterns-four-out.hs

{-# LANGUAGE PatternSynonyms #-}

tasty (Cupcake; Cookie) = True
tasty (Liquorice; Raisins) = False

f :: (Eq a, Show a) => a -> a -> Bool
f a ((== a) -> True; show -> "yes") = True
f _ _ = False

small (abs -> (0; 1; 2); 3) = True -- -3 is not small
small _ = False

type Coll a = Either [a] (Set a)
pattern None <- (Left []; Right (toList -> []))

case e of
    1; 2; 3 -> x
    4; (5; 6) -> y

sane e = case e of
    1
    2
    3 ->
        a
    4
    5
    6 -> b
    7; 8 -> c

insane e = case e of
    A _ _
    B _
    C -> 3
    (D; E (Just _) Nothing) ->
        4
    F -> 5

food
    foo@( A;
            B;
            C
            ) = Just foo
food _ = Nothing