executor-0.0.4: src/Executor.hs

module Executor (execSync, exec, execSequenceSync, execListSync) where

import System.Process (readProcess)

-- | Simple split a string using a delimiter
-- for example:
-- split "foo bar" " " will return ["foo", "bar"]
split' :: String -> Char -> [String]
split' [] _ = [""]
split' (c:cs) delimiter
   | c == delimiter = "" : rest
   | otherwise = (c : head rest) : tail rest
   where
       rest = split' cs delimiter


-- | Alias for exec
execSync :: String -> IO String
execSync = exec
-- | Alias for execSequenceSync
execListSync :: [String] -> IO [String]
execListSync = execSequenceSync

-- | Execute a single shell command returning its output
-- for example:
--
-- >>> execSync "echo hi"
-- "hi\n"
--
exec :: String -> IO String
exec c =  readProcess command arguments []
            where
              commandList = split' c ' '
              command = head commandList
              arguments = tail commandList

-- | Execute a list of shell commands in sequence synchronously
-- for example:
--
-- >>> execSequenceSync ["echo hi", "sleep 1", "echo goodbye"]
-- ["hi\n","","goodbye\n"]
--
execSequenceSync :: [String] -> IO [String]
execSequenceSync = mapM execSync