options

A powerful and easy-to-use command-line option parser. https://john-millikin.com/software/haskell-options/

Version on this page:1.2.1.1
LTS Haskell 8.15:1.2.1.1
Stackage Nightly 2017-05-24:1.2.1.1
Latest on Hackage:1.2.1.1
MIT licensed and maintained by John Millikin

Module documentation for 1.2.1.1

There are no documented modules for this package.

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
        <*> simpleOption "message" "Hello world!"
            "A message to show the user."
        <*> simpleOption "quiet" False
            "Whether to be quiet."

main :: IO ()
main = runCommand $ \opts args -> do
    if optQuiet opts
        then return ()
        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
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