ghc-options

The 'options' package lets library and application developers easily work with
command-line options.
The following example is a full program that can accept two options,
'--message' and '--quiet':
' import Control.Applicative import Options
data MainOptions = MainOptions   { optMessage :: String   ,
optQuiet :: Bool   }
instance 'Options' MainOptions where   defineOptions = pure MainOptions
&#x20; <> simpleOption "message" "Hello world!" &#x20; "A message to show the
user." &#x20; <> simpleOption "quiet" False &#x20; "Whether to be quiet."
main :: IO () main = runCommand $ \opts args -> do &#x20; if optQuiet opts
&#x20; then return () &#x20; else putStrLn (optMessage opts) '
>$ ./hello >Hello world! >$ ./hello --message='ciao mondo' >ciao mondo >$
./hello --quiet >$
In addition, this library will automatically create documentation options such
as '--help' and '--help-all':
>$ ./hello --help >Help Options: > -h, --help > Show option summary. >
--help-all > Show all help options. > >Application Options: > --message :: text
> A message to show the user. > default: "Hello world!" > --quiet :: bool >
Whether to be quiet. > default: false.

          

---

License: MIT
URL: https://hackage.haskell.org/package/options