{- Exercise 4.1 -}

-- 1) using if-then-else, and, or, not
boolFunIf :: Bool -> Bool -> Bool -> Bool
boolFunIf = undefined

-- 2) using if-then-else, and, or, not
boolFunAon :: Bool -> Bool -> Bool -> Bool
boolFunAon = undefined

-- 3) using pattern matching
boolFunPm :: Bool -> Bool -> Bool -> Bool
boolFunPm = undefined


{- Exercise 4.2 -}

-- 4.2.1
-- define this datatype and the functions below
data Party = CHANGE_ME

mps :: Party -> Party -> Integer
mps = undefined

coalition :: Party -> Party -> Bool
coalition = undefined

-- 4.2.2
-- define this datatype and the functions below
data Season = CHANGE_ME_TOO

-- define the function and write the type signature
-- pattern matching
-- daysInSeasonPM ::
daysInSeasonPM = undefined

-- if-then-else
-- daysInSeasonITE ::
daysInSeasonITE = undefined


{- Exercise 4.3 -}

-- 4.3.1
foo :: a -> a -> a
foo = undefined

bar :: a -> a -> a
bar = undefined

-- 4.3.2
-- ADD ANSWER TO 4.3.2 HERE
--


{- Exercise 4.4 -}

isDivisible :: Integer -> Integer -> Bool
isDivisible x y = div x y * y == x

g :: Integer -> Integer
g x = error "TODO g not implemented"

c :: Integer -> Integer
c x = error "TODO c not implemented"


{- Tests -}
{- You don't have to understand the Haskell-code in the tests,
   but you can just invoke them after having implemented 
   some exercises -}

testData :: [((Bool, Bool, Bool), Bool)]
testData =
  [ ((False, False, False), False)
  , ((False, False, True) , False)
  , ((False, True, False) , True)
  , ((False, True, True)  , True)
  , ((True, False, False) , False)
  , ((True, False, True)  , True)
  , ((True, True, False)  , True)
  , ((True, True, True)   , False)
  ]

testBool :: (Bool -> Bool -> Bool -> Bool) -> Bool
testBool f = all (\((x,y,z),s) -> f x y z == s) testData

testBoolIf, testBoolAon, testBoolPm :: Bool
testBoolIf = testBool boolFunIf || error "test for boolFunIf failed"
testBoolAon = testBool boolFunAon || error "test for boolFunIf failed"
testBoolPm = testBool boolFunPm || error "test for boolFunIf failed"

test_g =
     g 25 == 76
  && g 2 == 1
  || error "test_g failed"

test_c =
     c 1 == 0
  && c 8 == 3
  && c 103 == 87
  || error "test_c failed"

-- test for all exercises
test_all = test_c && test_g && testBoolIf && testBoolAon && testBoolPm