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ddellacosta/BasicLens.hs

Last active September 14, 2018 20:23
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BasicLens.hs
data A = A { _af :: B, _bs :: [Int] } deriving Show
data B = B { _bf :: Int, _bs1 :: Char } deriving Show
makeLenses ''A
makeLenses ''B
a = A (B 1 'a') []
-- λ> (over bf (+1) . view af) a
-- B {_bf = 2, _bs1 = 'a'}
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