Complete Set16

Author: luckycatx

Set16a.hs

@@ -18,7 +18,7 @@ import Data.List
 --  +++ OK, passed 1 test.
 
 isSorted :: (Show a, Ord a) => [a] -> Property
-isSorted = todo
+isSorted xs = sort xs === xs
 
 ------------------------------------------------------------------------------
 -- Ex 2: In this and the following exercises, we'll build a suite of
@@ -50,7 +50,7 @@ isSorted = todo
 --  +++ OK, passed 1 test.
 
 sumIsLength :: Show a => [a] -> [(a,Int)] -> Property
-sumIsLength input output = todo
+sumIsLength input output = length input === sum (map snd output)
 
 -- This is a function that passes the sumIsLength test but is wrong
 freq1 :: Eq a => [a] -> [(a,Int)]
@@ -79,7 +79,7 @@ freq1 (x:y:xs) = [(x,1),(y,length xs + 1)]
 --  +++ OK, passed 100 tests.
 
 inputInOutput :: (Show a, Eq a) => [a] -> [(a,Int)] -> Property
-inputInOutput input output = todo
+inputInOutput input output = forAll (elements input) (\x -> x `elem` map fst output)
 
 -- This function passes both the sumIsLength and inputInOutput tests
 freq2 :: Eq a => [a] -> [(a,Int)]
@@ -110,7 +110,7 @@ freq2 xs = map (\x -> (x,1)) xs
 --  +++ OK, passed 100 tests.
 
 outputInInput :: (Show a, Eq a) => [a] -> [(a,Int)] -> Property
-outputInInput input output = todo
+outputInInput input output = forAll (elements output) (\(x,n) -> n === length (filter (==x) input))
 
 -- This function passes the outputInInput test but not the others
 freq3 :: Eq a => [a] -> [(a,Int)]
@@ -139,7 +139,8 @@ freq3 (x:xs) = [(x,1 + length (filter (==x) xs))]
 --  +++ OK, passed 100 tests.
 
 frequenciesProp :: ([Char] -> [(Char,Int)]) -> NonEmptyList Char -> Property
-frequenciesProp freq input = todo
+frequenciesProp freq input = conjoin $ map ($ freq xs) [sumIsLength xs, inputInOutput xs, outputInInput xs]
+  where xs = getNonEmpty input
 
 frequencies :: Eq a => [a] -> [(a,Int)]
 frequencies [] = []
@@ -170,7 +171,10 @@ frequencies (x:ys) = (x, length xs) : frequencies others
 --  [2,4,10]
 
 genList :: Gen [Int]
-genList = todo
+genList = do
+  n <- choose (3,5)
+  xs <- vectorOf n (choose (0,10))
+  return $ sort xs
 
 ------------------------------------------------------------------------------
 -- Ex 7: Here are the datatypes Arg and Expression from Set 15. Write
@@ -208,7 +212,7 @@ data Expression = Plus Arg Arg | Minus Arg Arg
   deriving (Show, Eq)
 
 instance Arbitrary Arg where
-  arbitrary = todo
+  arbitrary = oneof [Number <$> choose (0,10), Variable <$> elements "abcxyz"]
 
 instance Arbitrary Expression where
-  arbitrary = todo
+  arbitrary = oneof [Plus <$> arbitrary <*> arbitrary, Minus <$> arbitrary <*> arbitrary]

Set16b.hs

@@ -10,7 +10,10 @@ import Data.Char (toUpper)
 -- 3. The type Money is imported from Example.Phantom but you'll need
 -- to introduce GBP yourself.
 
-pounds = todo
+data GBP
+
+pounds :: Money GBP
+pounds = Money 3
 
 ------------------------------------------------------------------------------
 -- Ex 2: Implement composition for Rates. Give composeRates a
@@ -27,7 +30,8 @@ pounds = todo
 usdToChf :: Rate USD CHF
 usdToChf = Rate 1.11
 
-composeRates rate1 rate2 = todo
+composeRates :: Rate from to -> Rate to to' -> Rate from to'
+composeRates (Rate r1) (Rate r2) = Rate (r1 * r2)
 
 ------------------------------------------------------------------------------
 -- Ex 3: Tracking first, last and full names with phantom types. The
@@ -47,18 +51,23 @@ composeRates rate1 rate2 = todo
 --  toFirst "bob" :: Name First
 --  toLast "smith" :: Name Last
 
+data First
+data Last
+data Full
+
+data Name a = Name String
 
 -- Get the String contained in a name
---fromName :: Name a -> String
-fromName = todo
+fromName :: Name a -> String
+fromName (Name a) = a
 
 -- Build a Name First
---toFirst :: String -> Name First
-toFirst = todo
+toFirst :: String -> Name First
+toFirst s = Name s
 
 -- Build a Name Last
---toLast :: String -> Name Last
-toLast = todo
+toLast :: String -> Name Last
+toLast s = Name s
 
 ------------------------------------------------------------------------------
 -- Ex 4: Implement the functions capitalize and toFull.
@@ -78,9 +87,11 @@ toLast = todo
 --  capitalize (toLast "smith") :: Name Last
 --  fromName (capitalize (toLast "smith")) ==> "Smith"
 
-capitalize = todo
+capitalize :: Name a -> Name a
+capitalize (Name a) = Name (toUpper (head a) : tail a)
 
-toFull = todo
+toFull :: Name First -> Name Last -> Name Full
+toFull (Name first) (Name last) = Name (first ++ " " ++ last)
 
 ------------------------------------------------------------------------------
 -- Ex 5: Type classes can let you write code that handles different
@@ -94,3 +105,11 @@ toFull = todo
 class Render currency where
   render :: Money currency -> String
 
+instance Render EUR where
+  render (Money a) = show a ++ "e"
+
+instance Render USD where
+  render (Money a) = "$" ++ show a
+
+instance Render CHF where
+  render (Money a) = show a ++ "chf"