Syntax proposal for or-patterns in Haskell

Or.txt

-- Examples

data Foo = A | B | C

foo :: Foo -> Int
foo A = 10
foo B
foo C = 20

foo :: Foo -> Int
foo x = case x of
  A -> 10
  B
  C -> 20
  
foo :: Foo -> Int
foo x = case x of A -> 10; B; C -> 20

foo :: Foo -> Int
foo x = case x of
  A -> 10;
  B;C -> 20
  
foo :: Foo -> Int
foo = \case A -> 10; B;C -> 20
  
-- pattern vars

data Foo = A Int | B Int | C Int

foo :: Foo -> Int
foo (A n)
foo (B n)
foo (C n) = n + 10

foo :: Foo -> Int
foo = \case A n; B n; C n -> n + 10