Re: [Haskell-cafe] Matching constructors

Creighton Hogg writes:

data Patootie = Pa Int | Tootie Int and I want to pull out the indices of all elements of a list that have type constructor Tootie, how would I do that?

x = [Pa 3, Tootie 5, Pa 7, Tootie 9, Pa 11] y = [ i | Tootie i <- x ] z = [ i | i@(Tootie _) <- x ] y or z might be helpful. -- Mark