Result.hs

-- Copyright 2020 United States Government as represented by the Administrator
-- of the National Aeronautics and Space Administration. All Rights Reserved.
--
-- Disclaimers
--
-- No Warranty: THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY
-- OF ANY KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT
-- LIMITED TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO
-- SPECIFICATIONS, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
-- PARTICULAR PURPOSE, OR FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT THE
-- SUBJECT SOFTWARE WILL BE ERROR FREE, OR ANY WARRANTY THAT DOCUMENTATION, IF
-- PROVIDED, WILL CONFORM TO THE SUBJECT SOFTWARE. THIS AGREEMENT DOES NOT, IN
-- ANY MANNER, CONSTITUTE AN ENDORSEMENT BY GOVERNMENT AGENCY OR ANY PRIOR
-- RECIPIENT OF ANY RESULTS, RESULTING DESIGNS, HARDWARE, SOFTWARE PRODUCTS OR
-- ANY OTHER APPLICATIONS RESULTING FROM USE OF THE SUBJECT SOFTWARE. FURTHER,
-- GOVERNMENT AGENCY DISCLAIMS ALL WARRANTIES AND LIABILITIES REGARDING
-- THIRD-PARTY SOFTWARE, IF PRESENT IN THE ORIGINAL SOFTWARE, AND DISTRIBUTES
-- IT "AS IS."
--
-- Waiver and Indemnity: RECIPIENT AGREES TO WAIVE ANY AND ALL CLAIMS AGAINST
-- THE UNITED STATES GOVERNMENT, ITS CONTRACTORS AND SUBCONTRACTORS, AS WELL AS
-- ANY PRIOR RECIPIENT. IF RECIPIENT'S USE OF THE SUBJECT SOFTWARE RESULTS IN
-- ANY LIABILITIES, DEMANDS, DAMAGES, EXPENSES OR LOSSES ARISING FROM SUCH USE,
-- INCLUDING ANY DAMAGES FROM PRODUCTS BASED ON, OR RESULTING FROM, RECIPIENT'S
-- USE OF THE SUBJECT SOFTWARE, RECIPIENT SHALL INDEMNIFY AND HOLD HARMLESS THE
-- UNITED STATES GOVERNMENT, ITS CONTRACTORS AND SUBCONTRACTORS, AS WELL AS ANY
-- PRIOR RECIPIENT, TO THE EXTENT PERMITTED BY LAW. RECIPIENT'S SOLE REMEDY
-- FOR ANY SUCH MATTER SHALL BE THE IMMEDIATE, UNILATERAL TERMINATION OF THIS
-- AGREEMENT.
--
-- | Process a result of a command in a way suitable for command-line
-- interaction.
module CLI.Result where

-- External imports
import System.Exit ( ExitCode (ExitFailure, ExitSuccess), exitWith )
import System.IO   ( hPutStrLn, stderr )

-- External imports: command results
import Command.Result ( Result (Error, Success) )
import Data.Location  ( Location (..) )

{- HLINT ignore "Use exitSuccess" -}
-- | Process a result, report any pending messages, and exit with an error code
-- if necessary.
processResult :: Result Int -> IO ()
processResult Success            = exitWith ExitSuccess
processResult (Error ec msg loc) = do
    hPutStrLn stderr $ showLocation loc ++ "error: " ++ msg
    exitWith (ExitFailure ec)
  where
    -- | Show locations in a standard way in user messages.
    showLocation :: Location -> String
    showLocation LocationNothing        = "<no location info>: "
    showLocation (LocationFile f)       = f ++ ": "
    showLocation (LocationFileLine f l) = f ++ ":" ++ show l ++ ": "
    showLocation (LocationFileLC f l c) = f ++ ":" ++ show l ++ ":" ++ show c ++ ": "