This module defines "type-safe" bindings to some of the UNIX shell tools.

We demonstrate the use of Kleene.Type (and KleenePlugin) to program in Haskell in completely structural way (i.e. non-nominal).

Disclaimer: the fact that we can doesn't mean that we should.

We may define self-proxy types instead of using K for flags. Then the usage will be more nice. However, we don't, to emphasise the point, as in this module we only use three types:

• REList - lists
• String - strings (for FilePath)
• K - symbols / keywords

Example

{-# LANGUAGE DataKinds                #-}
{-# LANGUAGE OverloadedLabels         #-}
{-# OPTIONS_GHC -fplugin=KleenePlugin #-}
{-# OPTIONS_GHC -dcore-lint           #-}
module Main (main) where

import Kleene.Type.Examples.KleeneSH

main :: IO ()
main = do
    (( ls_, #l, ".", #h ))
    (( find_, #type, #f, "plugin", "src" ))

We get very close to the dynamic feeling, compare to:

(do
  (ls :l "." :h)
  (ls :type :f "plugin" "src"))