This module provides the tools to build a complete "structured" CLI application, similar to those found in systems like Cisco IOS or console configuration utilities etc. It aims to be easy for implementors to use.

The following code illustrates a simple but complete CLI app:

import Control.Monad.IO.Class (liftIO)
import System.Console.StructuredCLI

root :: Commands ()
root = do
  world >+ do
    hello
    bye
    exit $ Just "return to previous level"

world :: Commands ()
world = command "world" (Just "enter into world") Nothing

hello :: Commands ()
hello = command "hello" (Just "prints a greeting") $ Just $ do
          liftIO . putStrLn $ "Hello world!"
          return 0

bye :: Commands ()
bye = command "bye" (Just "say goodbye") $ Just $ do
        liftIO . putStrLn $ "Sayonara!"
        return 0

main :: IO ()
main = runCLI "Hello CLI" Nothing root

resulting example session:

>>> Hello CLI > ?
- world: enter into world
>>> Hello CLI > world
>>> Hello CLI world >
bye    exit   hello
>>> Hello CLI world > hello
Hello world!
>>> Hello CLI world > exit

A good way to get you started is to grab the example code available under example/Main.hs and modify it to suit your needs.