From b9661b6d185fcb92e9106cfd174484489e0c8d78 Mon Sep 17 00:00:00 2001 From: Camil Staps Date: Mon, 2 Oct 2017 20:15:34 +0200 Subject: dos2unix --- assignment-4/monad.dcl | 70 +++---- assignment-4/monad.icl | 16 +- assignment-4/serialize4.icl | 462 ++++++++++++++++++++++---------------------- assignment-4/student.icl | 324 ++++++++++++++++--------------- 4 files changed, 445 insertions(+), 427 deletions(-) (limited to 'assignment-4') diff --git a/assignment-4/monad.dcl b/assignment-4/monad.dcl index 6b0b2b5..531a191 100644 --- a/assignment-4/monad.dcl +++ b/assignment-4/monad.dcl @@ -1,35 +1,35 @@ -definition module monad - -/* - Pieter Koopman, pieter@cs.ru.nl - Advanced Programming, week 4 -*/ - -import StdMisc - -class Functor f where - fmap :: (a->b) (f a) -> (f b) - (<$>) infixl 4 :: (a->b) (f a) -> (f b) | Functor f - (<$>) f x :== fmap f x - -class Applicative f | Functor f where - pure :: a -> f a - (<*>) infixl 4 :: (f (a->b)) (f a) -> f b - -class Monad m | Applicative m where - bind :: (m a) (a->m b) -> m b - (>>=) infixl 1 :: (m a) (a->m b) -> m b | Monad m - (>>=) a f :== bind a f - (>>|) infixl 1 :: (m a) (m b) -> m b | Monad m - (>>|) a b :== a >>= \_.b - rtrn :: a -> m a | Monad m - rtrn a :== pure a - -class fail m | Applicative m where - fail :: m a - guard :: Bool -> m a | fail m - guard b :== if b (pure undef) fail - -class OrMonad m where - (<|>) infixl 0 :: (m a) (m a) -> m a - +definition module monad + +/* + Pieter Koopman, pieter@cs.ru.nl + Advanced Programming, week 4 +*/ + +import StdMisc + +class Functor f where + fmap :: (a->b) (f a) -> (f b) + (<$>) infixl 4 :: (a->b) (f a) -> (f b) | Functor f + (<$>) f x :== fmap f x + +class Applicative f | Functor f where + pure :: a -> f a + (<*>) infixl 4 :: (f (a->b)) (f a) -> f b + +class Monad m | Applicative m where + bind :: (m a) (a->m b) -> m b + (>>=) infixl 1 :: (m a) (a->m b) -> m b | Monad m + (>>=) a f :== bind a f + (>>|) infixl 1 :: (m a) (m b) -> m b | Monad m + (>>|) a b :== a >>= \_.b + rtrn :: a -> m a | Monad m + rtrn a :== pure a + +class fail m | Applicative m where + fail :: m a + guard :: Bool -> m a | fail m + guard b :== if b (pure undef) fail + +class OrMonad m where + (<|>) infixl 0 :: (m a) (m a) -> m a + diff --git a/assignment-4/monad.icl b/assignment-4/monad.icl index fb9b491..bb0a2ac 100644 --- a/assignment-4/monad.icl +++ b/assignment-4/monad.icl @@ -1,8 +1,8 @@ -implementation module monad - -/* - Pieter Koopman, pieter@cs.ru.nl - Advanced Programming, week 4 -*/ - - +implementation module monad + +/* + Pieter Koopman, pieter@cs.ru.nl + Advanced Programming, week 4 +*/ + + diff --git a/assignment-4/serialize4.icl b/assignment-4/serialize4.icl index edbcc32..9abccbc 100644 --- a/assignment-4/serialize4.icl +++ b/assignment-4/serialize4.icl @@ -1,231 +1,231 @@ -module serialize4 - -import StdEnv, StdMaybe, monad - -/* - * Pieter Koopman, pieter@cs.ru.nl - * Advanced Programming, week 4, 2017 - * - * import StdMaybe from Libraries/StdLib - * use StdEnv or StdEnv 64 - * use Basic Values Only as conclose option for a nicer output. - */ - -// --- - -:: State s a = S (s -> (Maybe a,s)) - -unS :: (State s a) -> s -> (Maybe a,s) -unS (S f) = f - -instance Functor (State s) where - fmap f s = fail -instance Applicative (State s) where - pure a = fail - (<*>) f x = fail -instance fail (State s) where - fail = S \s.(Nothing,s) -instance Monad (State s) where - bind a f = fail -instance OrMonad (State s) where - (<|>) f g = fail - -// --- - -:: Serialized = Serialized - -ser :: Serialized -ser = Serialized - -toStrings :: Serialized -> [String] -toStrings _ = ["to be done\n"] - -:: Serialize a :== State Serialized a - -wrt :: a -> Serialize String | toString a -wrt a = fail - -rd :: Serialize String -rd = fail - -match :: a -> Serialize a | toString a -match a = fail - -pred :: (String->Bool) -> Serialize String -pred f = fail - -// --- - -:: UNIT = UNIT -:: EITHER a b = LEFT a | RIGHT b -:: PAIR a b = PAIR a b -:: CONS a = CONS String a - -:: Write a :== a -> Serialize String -:: Read a :== Serialize a - -class serialize a | isUNIT a where - write :: a -> Serialize String - read :: Serialize a - -class serialize1 t where - write1 :: (Write a) (t a) -> Serialize String - read1 :: (Read a) -> Serialize (t a) - -class serializeCONS a where - writeCons :: (Write a) (CONS a) -> Serialize String - readCons :: String (Read a) -> Serialize (CONS a) - -class serialize2 t where - write2 :: (Write a) (Write b) (t a b) -> Serialize String - read2 :: (Read a) (Read b) -> Serialize (t a b) - -class isUNIT a :: a -> Bool -instance isUNIT UNIT where isUNIT _ = True -instance isUNIT a where isUNIT _ = False - -instance serialize Bool where - write b = fail - read = fail - -instance serialize Int where - write i = fail - read = fail - -instance serialize String where - write s = wrt s - read = fail - -instance serialize UNIT where - write _ = fail - read = fail - -instance serializeCONS UNIT where - writeCons wa (CONS name a) = fail - readCons name ra = fail - -instance serializeCONS a where - writeCons wa (CONS name a) = fail - readCons name ra =fail - -instance serialize2 EITHER where - write2 wa wb (LEFT a) = fail - write2 wa wb (RIGHT b) = fail - read2 ra rb = fail - -instance serialize2 PAIR where - write2 wa wb (PAIR a b) = fail - read2 ra rb = fail - -// --- - -:: ListG a :== EITHER (CONS UNIT) (CONS (PAIR a [a])) - -fromList :: [a] -> ListG a -fromList [] = LEFT (CONS NilString UNIT) -fromList [a:x] = RIGHT (CONS ConsString (PAIR a x)) - -toList :: (ListG a) -> [a] -toList (LEFT (CONS NilString UNIT)) = [] -toList (RIGHT (CONS ConsString (PAIR a x))) = [a:x] - -NilString :== "Nil" -ConsString :== "Cons" - -instance serialize [a] | serialize a where - write a = write1 write a - read = read1 read - -instance serialize1 [] where - write1 writea l = fail - read1 reada = fail -// --- - -:: Bin a = Leaf | Bin (Bin a) a (Bin a) - -:: BinG a :== EITHER (CONS UNIT) (CONS (PAIR (Bin a) (PAIR a (Bin a)))) - -fromBin :: (Bin a) -> BinG a -fromBin Leaf = LEFT (CONS LeafString UNIT) -fromBin (Bin l a r) = RIGHT (CONS BinString (PAIR l (PAIR a r))) - -toBin :: (BinG a) -> Bin a -toBin (LEFT (CONS _ UNIT)) = Leaf -toBin (RIGHT (CONS _ (PAIR l (PAIR a r)))) = Bin l a r - -LeafString :== "Leaf" -BinString :== "Bin" - -instance == (Bin a) | == a where - (==) Leaf Leaf = True - (==) (Bin l a r) (Bin k b s) = l == k && a == b && r == s - (==) _ _ = False - -instance serialize (Bin a) | serialize a where - write b = fail - read = fail - -instance serialize1 Bin where - write1 writea b = fail - read1 reada = fail -// --- - -:: Coin = Head | Tail -:: CoinG :== EITHER (CONS UNIT) (CONS UNIT) - -fromCoin :: Coin -> CoinG -fromCoin Head = LEFT (CONS "Head" UNIT) -fromCoin Tail = RIGHT (CONS "Tail" UNIT) - -toCoin :: CoinG -> Coin -toCoin (LEFT (CONS _ UNIT)) = Head -toCoin (RIGHT (CONS _ UNIT)) = Tail - -instance == Coin where - (==) Head Head = True - (==) Tail Tail = True - (==) _ _ = False - -instance serialize Coin where - write c = fail - read = fail - -// --- - -instance serialize (a,b) | serialize a & serialize b where - write (a,b) = fail - read = fail - -// --- - -Start = - [ test True - , test False - , test 0 - , test 123 - , test -36 - , test Head - , test Tail - , test [42] - , test [0..4] - , test [[True],[]] - , test [[[1]],[[2],[3,4]],[[]]] - , test [[True],[]] - , test (Bin Leaf True Leaf) - , test [Bin (Bin Leaf [1] Leaf) [2] (Bin Leaf [3] (Bin Leaf [4,5] Leaf))] - , test [Bin (Bin Leaf [1] Leaf) [2] (Bin Leaf [3] (Bin (Bin Leaf [4,5] Leaf) [6,7] (Bin Leaf [8,9] Leaf)))] - , test Head - , test Tail - , test (7,True) - , test (Head,(7,[Tail])) - , ["End of the tests.\n"] - ] - -test :: a -> [String] | serialize, == a -test a = toStrings (snd ((unS t) ser)) -where - t = write a - >>| read - >>= \b. guard (a == b) - >>| write "Oke " - <|> write "Failure " +module serialize4 + +import StdEnv, StdMaybe, monad + +/* + * Pieter Koopman, pieter@cs.ru.nl + * Advanced Programming, week 4, 2017 + * + * import StdMaybe from Libraries/StdLib + * use StdEnv or StdEnv 64 + * use Basic Values Only as conclose option for a nicer output. + */ + +// --- + +:: State s a = S (s -> (Maybe a,s)) + +unS :: (State s a) -> s -> (Maybe a,s) +unS (S f) = f + +instance Functor (State s) where + fmap f s = fail +instance Applicative (State s) where + pure a = fail + (<*>) f x = fail +instance fail (State s) where + fail = S \s.(Nothing,s) +instance Monad (State s) where + bind a f = fail +instance OrMonad (State s) where + (<|>) f g = fail + +// --- + +:: Serialized = Serialized + +ser :: Serialized +ser = Serialized + +toStrings :: Serialized -> [String] +toStrings _ = ["to be done\n"] + +:: Serialize a :== State Serialized a + +wrt :: a -> Serialize String | toString a +wrt a = fail + +rd :: Serialize String +rd = fail + +match :: a -> Serialize a | toString a +match a = fail + +pred :: (String->Bool) -> Serialize String +pred f = fail + +// --- + +:: UNIT = UNIT +:: EITHER a b = LEFT a | RIGHT b +:: PAIR a b = PAIR a b +:: CONS a = CONS String a + +:: Write a :== a -> Serialize String +:: Read a :== Serialize a + +class serialize a | isUNIT a where + write :: a -> Serialize String + read :: Serialize a + +class serialize1 t where + write1 :: (Write a) (t a) -> Serialize String + read1 :: (Read a) -> Serialize (t a) + +class serializeCONS a where + writeCons :: (Write a) (CONS a) -> Serialize String + readCons :: String (Read a) -> Serialize (CONS a) + +class serialize2 t where + write2 :: (Write a) (Write b) (t a b) -> Serialize String + read2 :: (Read a) (Read b) -> Serialize (t a b) + +class isUNIT a :: a -> Bool +instance isUNIT UNIT where isUNIT _ = True +instance isUNIT a where isUNIT _ = False + +instance serialize Bool where + write b = fail + read = fail + +instance serialize Int where + write i = fail + read = fail + +instance serialize String where + write s = wrt s + read = fail + +instance serialize UNIT where + write _ = fail + read = fail + +instance serializeCONS UNIT where + writeCons wa (CONS name a) = fail + readCons name ra = fail + +instance serializeCONS a where + writeCons wa (CONS name a) = fail + readCons name ra =fail + +instance serialize2 EITHER where + write2 wa wb (LEFT a) = fail + write2 wa wb (RIGHT b) = fail + read2 ra rb = fail + +instance serialize2 PAIR where + write2 wa wb (PAIR a b) = fail + read2 ra rb = fail + +// --- + +:: ListG a :== EITHER (CONS UNIT) (CONS (PAIR a [a])) + +fromList :: [a] -> ListG a +fromList [] = LEFT (CONS NilString UNIT) +fromList [a:x] = RIGHT (CONS ConsString (PAIR a x)) + +toList :: (ListG a) -> [a] +toList (LEFT (CONS NilString UNIT)) = [] +toList (RIGHT (CONS ConsString (PAIR a x))) = [a:x] + +NilString :== "Nil" +ConsString :== "Cons" + +instance serialize [a] | serialize a where + write a = write1 write a + read = read1 read + +instance serialize1 [] where + write1 writea l = fail + read1 reada = fail +// --- + +:: Bin a = Leaf | Bin (Bin a) a (Bin a) + +:: BinG a :== EITHER (CONS UNIT) (CONS (PAIR (Bin a) (PAIR a (Bin a)))) + +fromBin :: (Bin a) -> BinG a +fromBin Leaf = LEFT (CONS LeafString UNIT) +fromBin (Bin l a r) = RIGHT (CONS BinString (PAIR l (PAIR a r))) + +toBin :: (BinG a) -> Bin a +toBin (LEFT (CONS _ UNIT)) = Leaf +toBin (RIGHT (CONS _ (PAIR l (PAIR a r)))) = Bin l a r + +LeafString :== "Leaf" +BinString :== "Bin" + +instance == (Bin a) | == a where + (==) Leaf Leaf = True + (==) (Bin l a r) (Bin k b s) = l == k && a == b && r == s + (==) _ _ = False + +instance serialize (Bin a) | serialize a where + write b = fail + read = fail + +instance serialize1 Bin where + write1 writea b = fail + read1 reada = fail +// --- + +:: Coin = Head | Tail +:: CoinG :== EITHER (CONS UNIT) (CONS UNIT) + +fromCoin :: Coin -> CoinG +fromCoin Head = LEFT (CONS "Head" UNIT) +fromCoin Tail = RIGHT (CONS "Tail" UNIT) + +toCoin :: CoinG -> Coin +toCoin (LEFT (CONS _ UNIT)) = Head +toCoin (RIGHT (CONS _ UNIT)) = Tail + +instance == Coin where + (==) Head Head = True + (==) Tail Tail = True + (==) _ _ = False + +instance serialize Coin where + write c = fail + read = fail + +// --- + +instance serialize (a,b) | serialize a & serialize b where + write (a,b) = fail + read = fail + +// --- + +Start = + [ test True + , test False + , test 0 + , test 123 + , test -36 + , test Head + , test Tail + , test [42] + , test [0..4] + , test [[True],[]] + , test [[[1]],[[2],[3,4]],[[]]] + , test [[True],[]] + , test (Bin Leaf True Leaf) + , test [Bin (Bin Leaf [1] Leaf) [2] (Bin Leaf [3] (Bin Leaf [4,5] Leaf))] + , test [Bin (Bin Leaf [1] Leaf) [2] (Bin Leaf [3] (Bin (Bin Leaf [4,5] Leaf) [6,7] (Bin Leaf [8,9] Leaf)))] + , test Head + , test Tail + , test (7,True) + , test (Head,(7,[Tail])) + , ["End of the tests.\n"] + ] + +test :: a -> [String] | serialize, == a +test a = toStrings (snd ((unS t) ser)) +where + t = write a + >>| read + >>= \b. guard (a == b) + >>| write "Oke " + <|> write "Failure " diff --git a/assignment-4/student.icl b/assignment-4/student.icl index 0356a04..96c01e0 100644 --- a/assignment-4/student.icl +++ b/assignment-4/student.icl @@ -1,153 +1,171 @@ -module student - -import StdEnv, StdMaybe, monad -/* - * Pieter Koopman, pieter@cs.ru.nl - * Advanced Programming, week 4 - */ - -// ---- an IO monad with maybe results --- // - -:: *State = {w :: *World, c :: *Maybe *File} -:: IO a = IO (State -> *(Maybe a, State)) - -open :: State -> State -open {w, c=Nothing} - # (console, w) = stdio w - = {w = w, c = Just console} -open s = s - -close :: State -> State -close { w, c=Just f} = { w = snd (fclose f w), c = Nothing} -close s = s - -unIO :: (IO a) -> State -> *(Maybe a, State) -unIO (IO f) = f - -run :: (IO a) *World -> *World -run m w = (close (snd (unIO m {w=w, c=Nothing}))).w - -// ---- reading from console --- // - -class read a :: IO a - -instance read String where - read = IO r where - r s - #! {w,c=Just c} = open s - (line, c) = freadline c - s = rmNL line - | size s > 0 - = (Just s,{w = w, c = Just c}) - #! c = c <<< "String must be not empty " - (line, c) = freadline c - s = rmNL line - | size s > 0 - = (Just s, {w = w, c = Just c}) - = (Nothing, {w = w, c = Just c}) - -instance read Int where - read = IO r where - r s - #! {w,c=Just c} = open s - (b,i,c) = freadi c - | b - = (Just i, {w = w, c = Just c}) - #! (_, c) = freadline c - c = c <<< "An integer please " - (b,i,c) = freadi c - | b - = (Just i, {w = w, c = Just c}) - #! (_, c) = freadline c - = (Nothing, {w = w, c = Just c}) - -write :: String -> IO String -write mess = IO w where - w s - #! {w,c=Just c} = open s - = (Just mess,{w=w,c=Just (c <<< mess)}) - -// ---- make IO a monad --- // - -instance Functor IO where - fmap f (IO g) - = IO \s.case g s of - (Just a, s) = (Just (f a),s) - (Nothing,s) = (Nothing , s) - -instance Applicative IO where - pure a = IO \s.(Just a, s) - (<*>) (IO f) (IO g) = IO \s.case f s of - (Just f,s) = case g s of - (Just a,s) = (Just (f a),s) - (n, s) = (Nothing, s) - (n, s) = (Nothing, s) - -instance Monad IO where - bind (IO f) g = IO \s.case f s of - (Just a, s) = unIO (g a) s - (n, s) = (Nothing, s) - -instance fail IO where fail = IO \s.(Nothing,s) - -instance OrMonad IO where - <|> (IO f) (IO g) = - IO \s.case f s of - (Nothing, s) = g s - other = other - -// ---- reading a student record --- // - -Start w = run f2 w - -:: Student = - { fname :: String - , lname :: String - , snum :: Int - } - -instance toString Student where - toString {fname,lname,snum} = "{Student|fname=" + fname + ",lname=" + lname + ",snum=" + toString snum + "}" -instance + String where + s t = s +++ t - -f0 :: *World -> (Student, *World) -f0 world = ({fname = rmNL fname, lname = rmNL lname, snum = snum}, world2) where - (console1, world1) = stdio world - console2 = console1 <<< "Your first name please: " - (fname,console3) = freadline console2 - console4 = console3 <<< "Your last name please: " - (lname,console5) = freadline console4 - console6 = console5 <<< "Your student nmber please: " - (b1,snum,console7) = freadi console6 - (b2, world2) = fclose console7 world1 - -f1 :: *World -> (Student, *World) -f1 world -#! (console, world) = stdio world - console = console <<< "Your first name please: " - (fname,console) = freadline console - console = console <<< "Your last name please: " - (lname,console) = freadline console - console = console <<< "Your student nmber please: " - (b1,snum,console) = freadi console - (b2, world) = fclose console world -= ({fname = rmNL fname, lname = rmNL lname, snum = snum}, world) - -f2 :: IO String -f2 - = ( write "Your first name please: " - >>| read - >>= \fname.write "Your last name please: " - >>| read - >>= \lname.write "Your student nmber please: " - >>| read - >>= \snum. rtrn {fname = rmNL fname, lname = rmNL lname, snum = snum} - >>= write o toString) - <|> write "failed to read a student" - -rmNL :: String -> String -rmNL string - # len = size string - | len > 0 && string.[len-1] == '\n' - = string % (0, len - 2) - = string +module student + +import StdEnv, StdMaybe, monad +/* + * Pieter Koopman, pieter@cs.ru.nl + * Advanced Programming, week 4 + */ + +// ---- an IO monad with maybe results --- // + +:: *State = {w :: *World, c :: *Maybe *File} +:: IO a = IO (State -> *(Maybe a, State)) + +open :: State -> State +open {w, c=Nothing} + # (console, w) = stdio w + = {w = w, c = Just console} +open s = s + +close :: State -> State +close { w, c=Just f} = { w = snd (fclose f w), c = Nothing} +close s = s + +unIO :: (IO a) -> State -> *(Maybe a, State) +unIO (IO f) = f + +run :: (IO a) *World -> *World +run m w = (close (snd (unIO m {w=w, c=Nothing}))).w + +// ---- reading from console --- // + +class read a :: IO a + +instance read String where + read = IO r where + r s + #! {w,c=Just c} = open s + (line, c) = freadline c + s = rmNL line + | size s > 0 + = (Just s,{w = w, c = Just c}) + #! c = c <<< "String must be not empty " + (line, c) = freadline c + s = rmNL line + | size s > 0 + = (Just s, {w = w, c = Just c}) + = (Nothing, {w = w, c = Just c}) + +instance read Int where + read = IO r where + r s + #! {w,c=Just c} = open s + (b,i,c) = freadi c + | b + = (Just i, {w = w, c = Just c}) + #! (_, c) = freadline c + c = c <<< "An integer please " + (b,i,c) = freadi c + | b + = (Just i, {w = w, c = Just c}) + #! (_, c) = freadline c + = (Nothing, {w = w, c = Just c}) + +write :: String -> IO String +write mess = IO w where + w s + #! {w,c=Just c} = open s + = (Just mess,{w=w,c=Just (c <<< mess)}) + +// ---- make IO a monad --- // + +instance Functor IO where + fmap f (IO g) + = IO \s.case g s of + (Just a, s) = (Just (f a),s) + (Nothing,s) = (Nothing , s) + +instance Applicative IO where + pure a = IO \s.(Just a, s) + (<*>) (IO f) (IO g) = IO \s.case f s of + (Just f,s) = case g s of + (Just a,s) = (Just (f a),s) + (n, s) = (Nothing, s) + (n, s) = (Nothing, s) + +instance Monad IO where + bind (IO f) g = IO \s.case f s of + (Just a, s) = unIO (g a) s + (n, s) = (Nothing, s) + +instance fail IO where fail = IO \s.(Nothing,s) + +instance OrMonad IO where + <|> (IO f) (IO g) = + IO \s.case f s of + (Nothing, s) = g s + other = other + +// ---- reading a student record --- // + +Start w = run (f3 >>= write) w + +:: Student = + { fname :: String + , lname :: String + , snum :: Int + } + +instance toString Student where + toString {fname,lname,snum} = "{Student|fname=" + fname + ",lname=" + lname + ",snum=" + toString snum + "}" +instance + String where + s t = s +++ t + +f0 :: *World -> (Student, *World) +f0 world = ({fname = rmNL fname, lname = rmNL lname, snum = snum}, world2) where + (console1, world1) = stdio world + console2 = console1 <<< "Your first name please: " + (fname,console3) = freadline console2 + console4 = console3 <<< "Your last name please: " + (lname,console5) = freadline console4 + console6 = console5 <<< "Your student nmber please: " + (b1,snum,console7) = freadi console6 + (b2, world2) = fclose console7 world1 + +f1 :: *World -> (Student, *World) +f1 world +#! (console, world) = stdio world + console = console <<< "Your first name please: " + (fname,console) = freadline console + console = console <<< "Your last name please: " + (lname,console) = freadline console + console = console <<< "Your student nmber please: " + (b1,snum,console) = freadi console + (b2, world) = fclose console world += ({fname = rmNL fname, lname = rmNL lname, snum = snum}, world) + +f2 :: IO String +f2 + = ( write "Your first name please: " + >>| read + >>= \fname.write "Your last name please: " + >>| read + >>= \lname.write "Your student nmber please: " + >>| read + >>= \snum. rtrn {fname = rmNL fname, lname = rmNL lname, snum = snum} + >>= write o toString) + <|> write "failed to read a student" + +f3 :: IO String +f3 = + ((\f l s -> (toString {fname=rmNL f, lname=rmNL l, snum=s}) +++ "\n") <$> + input "Your first name please: " <*> + input "Your last name please: " <*> + input "Your student number please: ") + <|> write "Failed to read a student.\n" +where + input :: String -> IO a | read a + input s = write s *> read + + // It would really be much easier if we would use Platform from the start in this course. + (*>) infixl 4 :: (f a) (f b) -> f b | Applicative f + (*>) fa fb = id <$ fa <*> fb + + (<$) infixl 4 :: a (f b) -> f a | Functor f + (<$) x fa = fmap (const x) fa + +rmNL :: String -> String +rmNL string + # len = size string + | len > 0 && string.[len-1] == '\n' + = string % (0, len - 2) + = string -- cgit v1.2.3