https://github.com/t-sasaki915/consoleask
Simple CLI user input library
https://github.com/t-sasaki915/consoleask
haskell-library stdin
Last synced: 8 months ago
JSON representation
Simple CLI user input library
- Host: GitHub
- URL: https://github.com/t-sasaki915/consoleask
- Owner: t-sasaki915
- License: mit
- Created: 2025-06-21T16:33:39.000Z (about 1 year ago)
- Default Branch: main
- Last Pushed: 2025-07-08T12:16:54.000Z (12 months ago)
- Last Synced: 2025-08-16T13:56:01.307Z (10 months ago)
- Topics: haskell-library, stdin
- Language: Haskell
- Homepage: https://hackage.haskell.org/package/ConsoleAsk
- Size: 85.9 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# ConsoleAsk
Simple CLI user input library
## Example
```haskell
import Data.Functor ((<&>))
import Data.Text (Text)
import Text.Parsec (char, digit, many1)
import Text.Regex.TDFA ((=~))
import System.Console.Ask (Ask, ask, askOptional, askOrElse, runAsk, defaultBehaviour)
import System.Console.Ask.Askable (Askable (fromText), fromParsec)
data UserInformation = UserInformation
{ name :: Text
, age :: Maybe Int
, birthday :: Date
, notificationPreference :: NotificationPreference
} deriving Show
data NotificationPreference = NotificationPreference
{ needNotifications :: Bool
, emailAddress :: Maybe EmailAddress
} deriving Show
askUserInformation :: Ask UserInformation
askUserInformation =
UserInformation
<$> ask "What is your name?"
<*> askOptional "How old are you?"
<*> ask "When is your birthday?"
<*> askNotificationPreference
askNotificationPreference :: Ask NotificationPreference
askNotificationPreference = do
needNotifications' <- askOrElse "Do you need our update notifications?" False
emailAddress' <-
if needNotifications'
then Just <$> ask "What is your email address?"
else pure Nothing
pure NotificationPreference
{ needNotifications = needNotifications'
, emailAddress = emailAddress'
}
newtype EmailAddress = EmailAddress Text deriving Show
instance Askable EmailAddress where
fromText text =
if text =~ ("[a-zA-Z0-9+._-]+@[a-zA-Z-]+\\.[a-z]+" :: Text)
then Just (EmailAddress text)
else Nothing
data Date = Date Int Int deriving Show
instance Askable Date where
fromText = fromParsec $ do
day <- many1 digit <&> read
_ <- char '/'
month <- many1 digit <&> read
pure (Date day month)
main :: IO ()
main = do
userInfo <- runAsk defaultBehaviour askUserInformation
print userInfo
```
```
What is your name?
> Toma Sasaki
How old are you?
>
When is your birthday?
> 15/9
Do you need our update notifications? (Default: False)
> aye
What is your email address?
> me@t-sasaki.net
UserInformation
{ name = "Toma Sasaki"
, age = Nothing
, birthday = Date 15 9
, notificationPreference =
NotificationPreference
{ needNotifications = True
, emailAddress = Just (EmailAddress "me@t-sasaki.net")
}
}
```
## Features
- Automatically parses input values to `Askable` instances. (See also: [Askable.hs](https://github.com/t-sasaki915/ConsoleAsk/blob/main/src/System/Console/Ask/Askable.hs))
```haskell
import Control.Monad.IO.Class (liftIO)
import Data.Text (Text)
import qualified Data.Text as Text
import qualified Data.Text.IO as TextIO
import System.Console.Ask (Ask, ask, askOptional, askOrElse, defaultBehaviour, runAsk)
main :: IO ()
main = runAsk defaultBehaviour $ do
name <- ask "What is your name?" :: Ask Text
age <- askOptional "How old are you?" :: Ask (Maybe Int)
needNotifications <- askOrElse "Do you need notifications?" False :: Ask Bool
liftIO $ do
TextIO.putStrLn ("Name: " <> name)
TextIO.putStrLn ("Age: " <> Text.show age)
TextIO.putStrLn ("Need notifications: " <> Text.show needNotifications)
```
```
What is your name?
> Toma Sasaki
How old are you?
> a
Invalid input.
How old are you?
> 18
Do you need notifications? (Default: False)
> no
Name: Toma Sasaki
Age: 18
Need notifications: False
```
- `Askable` supports both `Text -> Maybe a` and parsec.
```haskell
import Data.Functor ((<&>))
import Data.Text (Text)
import Text.Parsec (char, digit, many1)
import Text.Regex.TDFA ((=~))
import System.Console.Ask.Askable (Askable (fromText), fromParsec)
newtype EmailAddress = EmailAddress Text deriving Show
instance Askable EmailAddress where
fromText text =
if text =~ ("[a-zA-Z0-9+._-]+@[a-zA-Z-]+\\.[a-z]+" :: Text)
then Just (EmailAddress text)
else Nothing
data Date = Date Int Int deriving Show
instance Askable Date where
fromText = fromParsec $ do
day <- many1 digit <&> read
_ <- char '/'
month <- many1 digit <&> read
pure (Date day month)
```
- Custom prompt
```haskell
import Control.Monad.IO.Class (liftIO)
import Data.Text (Text)
import qualified Data.Text as Text
import qualified Data.Text.IO as TextIO
import System.Console.Ask (Ask, ask', askOptional', askOrElse', defaultBehaviour, runAsk)
main :: IO ()
main = runAsk defaultBehaviour $ do
name <- ask' "What is your name?" "Text> " :: Ask Text
age <- askOptional' "How old are you?" "Int > " :: Ask (Maybe Int)
needNotifications <- askOrElse' "Do you need notifications?" False "Y/N > " :: Ask Bool
liftIO $ do
TextIO.putStrLn ("Name: " <> name)
TextIO.putStrLn ("Age: " <> Text.show age)
TextIO.putStrLn ("Need notifications: " <> Text.show needNotifications)
```
```
What is your name?
Text> Toma Sasaki
How old are you?
Int > 18
Do you need notifications? (Default: False)
Y/N > True
Name: Toma Sasaki
Age: 18
Need notifications: True
```
- Customisable behaviour (See also: [Behaviour.hs](https://github.com/t-sasaki915/ConsoleAsk/blob/main/src/System/Console/Ask/Behaviour.hs))
```haskell
import Control.Monad.IO.Class (liftIO)
import Data.Text (Text)
import qualified Data.Text as Text
import qualified Data.Text.IO as TextIO
import System.Console.Ask (Ask, ask, askOptional, askOrElse, defaultBehaviour, runAsk, withBehaviour)
import System.Console.Ask.Behaviour (DefaultValueStyle (..), defaultValueStyle, invalidInputErrorMsg, set)
main :: IO ()
main = runAsk defaultBehaviour $ do
let customBehaviour1 = set invalidInputErrorMsg (Just "??????") defaultBehaviour
customBehaviour2 = set defaultValueStyle OnNewline defaultBehaviour
name <- ask "What is your name?" :: Ask Text
age <- withBehaviour customBehaviour1 (askOptional "How old are you?") :: Ask (Maybe Int)
needNotifications <- withBehaviour customBehaviour2 (askOrElse "Do you need notifications?" False) :: Ask Bool
liftIO $ do
TextIO.putStrLn ("Name: " <> name)
TextIO.putStrLn ("Age: " <> Text.show age)
TextIO.putStrLn ("Need notifications: " <> Text.show needNotifications)
```
```
What is your name?
> Toma Sasaki
How old are you?
> a
??????
How old are you?
> 18
Do you need notifications?
Default: False
> True
Name: Toma Sasaki
Age: 18
Need notifications: True
```