Re: [Haskell-cafe] Filter by several predicates at once

Neil Mitchell wrote:

Hi

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passall, passany :: [a -> Bool] -> a -> Bool passall ps v = and $ map ($v) ps passany ps v = or $ map ($v) ps or something similar defined anywhere? Such that one can write

nearly; using Prelude: passall ps v = all ($v) ps passany ps v = any ($v) ps

One thing I have often wanted is something like:

or1 a b x = a x || b x or2 a b x y = a x y || b x y

yep, there's the idea of putting Bools in a typeclass that allows you to (||) functions-returning-Bool-class-instance for example, which I haven't used much but seems like a good idea (though potentially confusing, especially if the Prelude-Bool-specific names are reused) ~Isaac