[Haskell-cafe] list comprehension with multiple generator|targets

[Donn Cave]

I'm guessing this isn't supported, but might be worth asking -
can I extend a list comprehension like  ['A' | A <- s] to multiple values?
Like,

data V = A | B | C

pv :: [V] -> [Char]
pv [] = []
pv (A:x) = 'A':(pv x)
pv (B:x) = 'B':(pv x)
pv (_:x) = pv x

-- can that be a list comprehension, like

pv s = [
          'A' | A <- s
          -- ??
          ]

thanks,
	Donn