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Today's Topics:
1. basic use of Applicative (Imants Cekusins)
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Message: 1
Date: Thu, 25 Jun 2015 12:48:51 +0200
From: Imants Cekusins <[email protected]>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <[email protected]>
Subject: [Haskell-beginners] basic use of Applicative
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<CAP1qinYXuhKGXvJ0+OMA1Zo8eu2FAuqa7ewXHp=i3bZ=szx...@mail.gmail.com>
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module BasicApplicative where
-- 2 arg
upd2:: Int -> Int -> Int
upd2 x1 x2 = x1 * x2
-- 3 arg
upd3:: Int -> Int -> Int -> Int
upd3 x1 x2 x3 = x1 * x2 + x3
-- pure
pureMaybe::Int -> Maybe Int
pureMaybe = pure
pureList::Int -> [Int]
pureList = pure
-- maybe
maybe2::Maybe Int -> Maybe Int -> Maybe Int
maybe2 mi1 mi2 = upd2 <$> mi1 <*> mi2
-- list
list2::[Int] -> [Int] -> [Int]
list2 l1 l2 = upd2 <$> l1 <*> l2
-- same result as list2
list2p::[Int] -> [Int] -> [Int]
list2p l1 l2 = pure upd2 <*> l1 <*> l2
list3::[Int] -> [Int] -> [Int] -> [Int]
list3 l1 l2 l3 = upd3 <$> l1 <*> l2 <*> l3
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