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Remove usage of --show comments

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This commit is contained in:
Michael Snoyman 2017-01-01 15:28:26 +02:00
parent daad8d3bdc
commit 6879a6119e
1 changed files with 2 additions and 109 deletions
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111
posts/functors-applicatives-and-monads.md
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@ -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
<div class="panel-body">
```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
```
</div></div>
@ -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
<div class="panel-body">
```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
```
</div></div>
@ -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
<div class="panel-body">
```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
```
</div></div>
@ -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
<div class="panel-body">
```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
```
</div></div>