From 6879a6119e6f27e487bb29abd2190b02462210d7 Mon Sep 17 00:00:00 2001 From: Michael Snoyman Date: Sun, 1 Jan 2017 15:28:26 +0200 Subject: [PATCH] Remove usage of --show comments --- posts/functors-applicatives-and-monads.md | 111 +--------------------- 1 file changed, 2 insertions(+), 109 deletions(-) diff --git a/posts/functors-applicatives-and-monads.md b/posts/functors-applicatives-and-monads.md index b9081a8..7b2b7df 100644 --- a/posts/functors-applicatives-and-monads.md +++ b/posts/functors-applicatives-and-monads.md @@ -386,29 +386,9 @@ special operator, `<$>`, which is a synonym for `fmap`. That means we can make our code just a little prettier: ```haskell -#!/usr/bin/env stack --- stack --resolver lts-7.14 runghc -import Text.Read (readMaybe) -import Control.Applicative ((<$>), (<*>)) - -displayAge maybeAge = - case maybeAge of - Nothing -> putStrLn "You provided invalid input" - Just age -> putStrLn $ "In that year, you will be: " ++ show age - -yearDiff futureYear birthYear = futureYear - birthYear - -main = do - putStrLn "Please enter your birth year" - birthYearString <- getLine - putStrLn "Please enter some year in the future" - futureYearString <- getLine --- show let maybeAge = yearDiff <$> readMaybe futureYearString <*> readMaybe birthYearString --- /show - displayAge maybeAge ``` Notice the distinction between `<$>` and `<*>`. The former uses a function @@ -467,9 +447,7 @@ main = do import qualified Prelude fmap :: (Applicative m, Monad m) => (a -> b) -> (m a -> m b) - -- show fmap ... ... = FIXME - -- /show main = case fmap (Prelude.+ 1) (Prelude.Just 2) of @@ -490,15 +468,9 @@ main = do
```haskell - #!/usr/bin/env stack - -- stack --resolver lts-7.14 runghc - import Control.Applicative ((<*>)) - - -- show myFmap function wrappedValue = return function <*> wrappedValue main = print $ myFmap (+ 1) $ Just 5 - -- /show ```
@@ -509,9 +481,7 @@ main = do ```haskell #!/usr/bin/env stack -- stack --resolver lts-7.14 runghc - -- show returnMaybe = FIXME - -- /show main | returnMaybe "Hello" == Just "Hello" = putStrLn "Correct!" @@ -561,11 +531,11 @@ main = do futureYear <- readMaybe futureYearString birthYear <- readMaybe birthYearString return $ - -- show + -- BEGIN CODE TO MODIFY if futureYear < birthYear then yearDiff birthYear futureYear else yearDiff futureYear birthYear - -- /show + -- END CODE TO MODIFY displayAge maybeAge ``` @@ -582,30 +552,9 @@ main = do
```haskell - #!/usr/bin/env stack - -- stack --resolver lts-7.14 runghc - import Text.Read (readMaybe) - - displayAge maybeAge = - case maybeAge of - Nothing -> putStrLn "You provided invalid input" - Just age -> putStrLn $ "In that year, you will be: " ++ show age - - main = do - putStrLn "Please enter your birth year" - birthYearString <- getLine - putStrLn "Please enter some year in the future" - futureYearString <- getLine - let maybeAge = do - futureYear <- readMaybe futureYearString - birthYear <- readMaybe birthYearString - return $ - -- show if futureYear < birthYear then birthYear - futureYear else futureYear - birthYear - -- /show - displayAge maybeAge ```
@@ -625,9 +574,7 @@ main = do Nothing -> putStrLn "You provided invalid input" Just age -> putStrLn $ "In that year, you will be: " ++ show age - -- show yearDiff futureYear birthYear = FIXME - -- /show main | yearDiff 5 6 == 1 = putStrLn "Correct!" @@ -647,34 +594,9 @@ main = do
```haskell - #!/usr/bin/env stack - -- stack --resolver lts-7.14 runghc - import Text.Read (readMaybe) - - displayAge maybeAge = - case maybeAge of - Nothing -> putStrLn "You provided invalid input" - Just age -> putStrLn $ "In that year, you will be: " ++ show age - - -- show yearDiff futureYear birthYear | futureYear > birthYear = futureYear - birthYear | otherwise = birthYear - futureYear - -- /show - - main = do - putStrLn "Please enter your birth year" - birthYearString <- getLine - putStrLn "Please enter some year in the future" - futureYearString <- getLine - let maybeAge = do - futureYear <- readMaybe futureYearString - birthYear <- readMaybe birthYearString - return $ - if futureYear < birthYear - then yearDiff birthYear futureYear - else yearDiff futureYear birthYear - displayAge maybeAge ```
@@ -694,9 +616,7 @@ main = do Just age -> putStrLn $ "In that year, you will be: " ++ show age yearDiff futureYear birthYear = futureYear - birthYear - -- show yourHelperFunction f ... - -- /show main | yourHelperFunction yearDiff 5 6 == 1 = putStrLn "Correct!" @@ -716,36 +636,9 @@ main = do
```haskell - #!/usr/bin/env stack - -- stack --resolver lts-7.14 runghc - import Text.Read (readMaybe) - - displayAge maybeAge = - case maybeAge of - Nothing -> putStrLn "You provided invalid input" - Just age -> putStrLn $ "In that year, you will be: " ++ show age - - yearDiff futureYear birthYear = futureYear - birthYear - - main = do - putStrLn "Please enter your birth year" - birthYearString <- getLine - putStrLn "Please enter some year in the future" - futureYearString <- getLine - let maybeAge = do - futureYear <- readMaybe futureYearString - birthYear <- readMaybe birthYearString - return $ - if futureYear < birthYear - then yourHelperFunction yearDiff birthYear futureYear - else yourHelperFunction yearDiff futureYear birthYear - displayAge maybeAge - - -- show yourHelperFunction f x y | x > y = f x y | otherwise = f y x - -- /show ```