impots

impots.hs

tranche :: Int -> Int -> Float -> Int -> Float
tranche min max taux revenu = if revenu > max then (max - min) * taux else (revenu - min) * taux

tranches :: [Int]
tranches = [0, 9807, 27086, 72617, 153783]

rates :: [Float]
rates = [0.0, 0.14, 0.30, 0.41, 0.45]

-- Jusqu'à 9 807 euros	0 %
t1 = tranche tranches!!0 tranches!!1 rates!!0

-- De 9 807 à 27 086 euros	14 %
t2 = tranche tranches!!1 tranches!!2 rates!!1

-- De 27 086 à 72 617 euros	30 %
t3 = tranche tranches!!2 tranches!!3 rates!!2

-- De 72 617 à 153 783 euros	41 %
t4 = tranche tranches!!3 tranches!!4 rates!!3

-- Au-dessus de 153 783 euros	45 %
t5 = tranche tranches!!4 (maxBound :: Int) rates!!4

funT = [t1, t2, t3, t4, t5]

getTranchesTax :: Int -> Int -> [Float]
getTranchesTax numT revenu = do
    trancheAmount <- tranches!!numT
    rest          <- revenu - trancheAmount
    case rest > 0 of
        True  -> [funT!!numT trancheAmount] ++ getTranchesTax (numT + 1) rest
        False -> [funT!!numT revenu]

total = sum $ getTranchesTax 0 revenu