data Bar a = Bar Int String a

data Foo = Foo1 (Bar Int) | Foo2 (Bar String) | Foo3 (Bar Int) | Foo4 (Bar Bool)

someBarFunction :: Bar a -> Bool
someBarFunction (Bar x _ _) = (x > 5) --or something

someFooFunction :: Foo a -> Bool
someFooFunction = ??? --how can we avoid having to manually pattern match every FooX?