# structured-cli
#### Haskell library for building structured CLI applications

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.

* How to use this module:

The following code illustrates a simple but complete
CLI app:

```haskell
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](https://github.com/erickg/structured-cli/blob/master/example/Main.hs) and modify it to suit your needs.