-----------------------------------------------------------------------------
--
-- Module : Main
-- Copyright : (c) Phil Freeman 2013
-- License : MIT
--
-- Maintainer : Phil Freeman <paf31@cantab.net>
-- Stability : experimental
-- Portability :
--
-- |
-- PureScript Compiler Interactive.
--
-----------------------------------------------------------------------------
{-# LANGUAGE DataKinds, DoAndIfThenElse, FlexibleContexts, GeneralizedNewtypeDeriving #-}
module Main where
import Data.Foldable (traverse_)
import Data.List (intercalate, isPrefixOf, nub, sortBy, sort)
import Data.Maybe (mapMaybe)
import Data.Traversable (traverse)
import Data.Version (showVersion)
import Data.Char (isSpace)
import qualified Data.Map as M
import Control.Applicative
import Control.Monad
import Control.Monad.Error (ErrorT(..), MonadError)
import Control.Monad.Error.Class (MonadError(..))
import Control.Monad.Trans.Class
import Control.Monad.Trans.Maybe (MaybeT(..), runMaybeT)
import Control.Monad.Trans.State.Strict
import qualified Control.Monad.Trans.State.Lazy as L
import Options.Applicative as Opts
import System.Console.Haskeline
import System.Directory (createDirectoryIfMissing, getModificationTime, doesFileExist, findExecutable, getHomeDirectory, getCurrentDirectory)
import System.Exit
import System.FilePath (pathSeparator, takeDirectory, (</>), isPathSeparator)
import System.IO.Error (tryIOError)
import System.Process (readProcessWithExitCode)
import qualified System.IO.UTF8 as U (writeFile, putStrLn, print, readFile)
import qualified Text.Parsec as Par (ParseError)
import qualified Language.PureScript as P
import qualified Language.PureScript.AST as D
import qualified Language.PureScript.Names as N
import qualified Paths_purescript as Paths
import Commands as C
import Parser
data PSCiOptions = PSCiOptions
{ psciSingleLineFlag :: Bool
, psciInputFile :: [FilePath]
}
-- |
-- The PSCI state.
-- Holds a list of imported modules, loaded files, and partial let bindings.
-- The let bindings are partial,
-- because it makes more sense to apply the binding to the final evaluated expression.
--
data PSCiState = PSCiState
{ psciImportedFilenames :: [FilePath]
, psciImportedModuleNames :: [P.ModuleName]
, psciLoadedModules :: [(Either P.RebuildPolicy FilePath, P.Module)]
, psciLetBindings :: [P.Expr -> P.Expr]
}
-- State helpers
-- |
-- Updates the state to have more imported modules.
--
updateImportedFiles :: FilePath -> PSCiState -> PSCiState
updateImportedFiles filename st = st { psciImportedFilenames = filename : psciImportedFilenames st }
-- |
-- Updates the state to have more imported modules.
--
updateImports :: P.ModuleName -> PSCiState -> PSCiState
updateImports name st = st { psciImportedModuleNames = name : psciImportedModuleNames st }
-- |
-- Updates the state to have more loaded files.
--
updateModules :: [(Either P.RebuildPolicy FilePath, P.Module)] -> PSCiState -> PSCiState
updateModules modules st = st { psciLoadedModules = psciLoadedModules st ++ modules }
-- |
-- Updates the state to have more let bindings.
--
updateLets :: (P.Expr -> P.Expr) -> PSCiState -> PSCiState
updateLets name st = st { psciLetBindings = name : psciLetBindings st }
-- File helpers
-- |
-- Load the necessary modules.
--
defaultImports :: [P.ModuleName]
defaultImports = [P.ModuleName [P.ProperName "Prelude"]]
-- |
-- Locates the node executable.
-- Checks for either @nodejs@ or @node@.
--
findNodeProcess :: IO (Maybe String)
findNodeProcess = runMaybeT . msum $ map (MaybeT . findExecutable) names
where names = ["nodejs", "node"]
-- |
-- Grabs the filename where the history is stored.
--
getHistoryFilename :: IO FilePath
getHistoryFilename = do
home <- getHomeDirectory
let filename = home </> ".purescript" </> "psci_history"
mkdirp filename
return filename
-- |
-- Loads a file for use with imports.
--
loadModule :: FilePath -> IO (Either String [P.Module])
loadModule filename = do
content <- U.readFile filename
return $ either (Left . show) (Right . map snd) $ P.parseModulesFromFiles id [(filename, content)]
-- |
-- Load all modules, including the Prelude
--
loadAllModules :: [FilePath] -> IO (Either Par.ParseError [(Either P.RebuildPolicy FilePath, P.Module)])
loadAllModules files = do
filesAndContent <- forM files $ \filename -> do
content <- U.readFile filename
return (Right filename, content)
return $ P.parseModulesFromFiles (either (const "") id) $ (Left P.RebuildNever, P.prelude) : filesAndContent
-- |
-- Expands tilde in path.
--
expandTilde :: FilePath -> IO FilePath
expandTilde ('~':p:rest) | isPathSeparator p = (</> rest) <$> getHomeDirectory
expandTilde p = return p
-- Messages
-- |
-- The help message.
--
helpMessage :: String
helpMessage = "The following commands are available:\n\n " ++
intercalate "\n " (map line C.help)
where line :: (String, String, String) -> String
line (cmd, arg, desc) = intercalate " " [cmd, arg, replicate (11 - length arg) ' ', desc]
-- |
-- The welcome prologue.
--
prologueMessage :: String
prologueMessage = intercalate "\n"
[ " ____ ____ _ _ "
, "| _ \\ _ _ _ __ ___/ ___| ___ _ __(_)_ __ | |_ "
, "| |_) | | | | '__/ _ \\___ \\ / __| '__| | '_ \\| __|"
, "| __/| |_| | | | __/___) | (__| | | | |_) | |_ "
, "|_| \\__,_|_| \\___|____/ \\___|_| |_| .__/ \\__|"
, " |_| "
, ""
, ":? shows help"
, ""
, "Expressions are terminated using Ctrl+D"
]
-- |
-- The quit message.
--
quitMessage :: String
quitMessage = "See ya!"
-- Haskeline completions
data CompletionContext = Command String | FilePath String | Module | Identifier
| Type | Fixed [String] | Multiple [CompletionContext]
deriving (Show)
-- |
-- Decide what kind of completion we need based on input.
completionContext :: String -> String -> Maybe CompletionContext
completionContext cmd@"" _ = Just $ Multiple [Command cmd, Identifier]
completionContext cmd@(':' : _ ) _
| cmd `elem` C.commands || cmd == ":" = Just $ Command cmd
completionContext (':' : c : _) word = case c of
'i' -> Just Module
'b' -> Just Module
'm' -> Just $ FilePath word
'q' -> Nothing
'r' -> Nothing
'?' -> Nothing
's' -> Just $ Fixed ["import", "loaded"]
't' -> Just Identifier
'k' -> Just Type
_ -> Nothing
completionContext _ _ = Just Identifier
-- |
-- Loads module, function, and file completions.
--
completion :: CompletionFunc (StateT PSCiState IO)
completion = completeWordWithPrev Nothing " \t\n\r" findCompletions
where
findCompletions :: String -> String -> StateT PSCiState IO [Completion]
findCompletions prev word = do
let ctx = completionContext ((dropWhile isSpace (reverse prev)) ++ word) word
completions <- case ctx of
Nothing -> return []
(Just c) -> (mapMaybe $ either (\cand -> if word `isPrefixOf` cand
then Just $ simpleCompletion cand
else Nothing) Just)
<$> getCompletion c
return $ sortBy sorter completions
getCompletion :: CompletionContext -> StateT PSCiState IO [Either String Completion]
getCompletion (Command s) = return $ (map Left) $ nub $ filter (isPrefixOf s) C.commands
getCompletion (FilePath f) = (map Right) <$> listFiles f
getCompletion Module = (map Left) <$> getModuleNames
getCompletion Identifier = (map Left) <$> ((++) <$> getIdentNames <*> getDctorNames)
getCompletion Type = (map Left) <$> getTypeNames
getCompletion (Fixed list) = return $ (map Left) list
getCompletion (Multiple contexts) = concat <$> mapM getCompletion contexts
getLoadedModules :: StateT PSCiState IO [P.Module]
getLoadedModules = map snd . psciLoadedModules <$> get
getModuleNames :: StateT PSCiState IO [String]
getModuleNames = moduleNames <$> getLoadedModules
mapLoadedModulesAndQualify :: (Show a) => (P.Module -> [a]) -> StateT PSCiState IO [String]
mapLoadedModulesAndQualify f = do
ms <- getLoadedModules
q <- sequence [qualifyIfNeeded m (f m) | m <- ms]
return $ concat q
getIdentNames :: StateT PSCiState IO [String]
getIdentNames = mapLoadedModulesAndQualify identNames
getDctorNames :: StateT PSCiState IO [String]
getDctorNames = mapLoadedModulesAndQualify dctorNames
getTypeNames :: StateT PSCiState IO [String]
getTypeNames = mapLoadedModulesAndQualify typeDecls
qualifyIfNeeded :: (Show a) => P.Module -> [a] -> StateT PSCiState IO [String]
qualifyIfNeeded m decls = do
let name = P.getModuleName m
imported <- psciImportedModuleNames <$> get
let qualified = map (P.Qualified $ Just name) decls
if name `elem` imported then
return $ map show $ qualified ++ (map (P.Qualified Nothing) decls)
else
return $ map show qualified
typeDecls :: P.Module -> [N.ProperName]
typeDecls m = mapMaybe getTypeName $ filter P.isDataDecl (P.exportedDeclarations m)
where getTypeName :: P.Declaration -> Maybe N.ProperName
getTypeName (P.TypeSynonymDeclaration name _ _) = Just name
getTypeName (P.DataDeclaration _ name _ _) = Just name
getTypeName (P.PositionedDeclaration _ _ d) = getTypeName d
getTypeName _ = Nothing
identNames :: P.Module -> [N.Ident]
identNames (P.Module _ ds exports) = nub [ ident | ident <- mapMaybe (getDeclName exports) (D.flattenDecls ds) ]
where getDeclName :: Maybe [P.DeclarationRef] -> P.Declaration -> Maybe P.Ident
getDeclName exts decl@(P.ValueDeclaration ident _ _ _) | P.isExported exts decl = Just ident
getDeclName exts decl@(P.ExternDeclaration _ ident _ _) | P.isExported exts decl = Just ident
getDeclName exts (P.PositionedDeclaration _ _ d) = getDeclName exts d
getDeclName _ _ = Nothing
dctorNames :: P.Module -> [N.ProperName]
dctorNames m = nub $ concat $ map (P.exportedDctors m) dnames
where getDataDeclName :: P.Declaration -> Maybe N.ProperName
getDataDeclName (P.DataDeclaration _ name _ _) = Just name
getDataDeclName (P.PositionedDeclaration _ _ d) = getDataDeclName d
getDataDeclName _ = Nothing
dnames :: [N.ProperName]
dnames = (mapMaybe getDataDeclName onlyDataDecls)
onlyDataDecls :: [P.Declaration]
onlyDataDecls = (filter P.isDataDecl (P.exportedDeclarations m))
moduleNames :: [P.Module] -> [String]
moduleNames ms = nub [show moduleName | P.Module moduleName _ _ <- ms]
sorter :: Completion -> Completion -> Ordering
sorter (Completion _ d1 _) (Completion _ d2 _) = if ":" `isPrefixOf` d1 then LT else compare d1 d2
-- Compilation
-- | Compilation options.
--
options :: P.Options P.Make
options = P.Options False False False Nothing False False P.MakeOptions
-- |
-- PSCI monad
--
newtype PSCI a = PSCI { runPSCI :: InputT (StateT PSCiState IO) a } deriving (Functor, Applicative, Monad)
psciIO :: IO a -> PSCI a
psciIO io = PSCI (lift (lift io))
newtype Make a = Make { unMake :: ErrorT String IO a } deriving (Functor, Applicative, Monad, MonadError String)
runMake :: Make a -> IO (Either String a)
runMake = runErrorT . unMake
makeIO :: IO a -> Make a
makeIO = Make . ErrorT . fmap (either (Left . show) Right) . tryIOError
instance P.MonadMake Make where
getTimestamp path = makeIO $ do
exists <- doesFileExist path
if exists
then Just <$> getModificationTime path
else return Nothing
readTextFile path = makeIO $ U.readFile path
writeTextFile path text = makeIO $ do
mkdirp path
U.writeFile path text
liftError = either throwError return
progress s = unless (s == "Compiling $PSCI") $ makeIO . U.putStrLn $ s
mkdirp :: FilePath -> IO ()
mkdirp = createDirectoryIfMissing True . takeDirectory
-- |
-- Makes a volatile module to execute the current expression.
--
createTemporaryModule :: Bool -> PSCiState -> P.Expr -> P.Module
createTemporaryModule exec PSCiState{psciImportedModuleNames = imports, psciLetBindings = lets} val =
let
moduleName = P.ModuleName [P.ProperName "$PSCI"]
importDecl m = P.ImportDeclaration m P.Unqualified Nothing
traceModule = P.ModuleName [P.ProperName "Debug", P.ProperName "Trace"]
trace = P.Var (P.Qualified (Just traceModule) (P.Ident "print"))
itValue = foldl (\x f -> f x) val lets
mainValue = P.App trace (P.Var (P.Qualified Nothing (P.Ident "it")))
itDecl = P.ValueDeclaration (P.Ident "it") P.Value [] $ Right itValue
mainDecl = P.ValueDeclaration (P.Ident "main") P.Value [] $ Right mainValue
decls = if exec then [itDecl, mainDecl] else [itDecl]
in
P.Module moduleName ((importDecl `map` imports) ++ decls) Nothing
-- |
-- Makes a volatile module to hold a non-qualified type synonym for a fully-qualified data type declaration.
--
createTemporaryModuleForKind :: PSCiState -> P.Type -> P.Module
createTemporaryModuleForKind PSCiState{psciImportedModuleNames = imports} typ =
let
moduleName = P.ModuleName [P.ProperName "$PSCI"]
importDecl m = P.ImportDeclaration m P.Unqualified Nothing
itDecl = P.TypeSynonymDeclaration (P.ProperName "IT") [] typ
in
P.Module moduleName ((importDecl `map` imports) ++ [itDecl]) Nothing
-- |
-- Makes a volatile module to execute the current imports.
--
createTemporaryModuleForImports :: PSCiState -> P.Module
createTemporaryModuleForImports PSCiState{psciImportedModuleNames = imports} =
let
moduleName = P.ModuleName [P.ProperName "$PSCI"]
importDecl m = P.ImportDeclaration m P.Unqualified Nothing
in
P.Module moduleName (importDecl `map` imports) Nothing
modulesDir :: FilePath
modulesDir = ".psci_modules" ++ pathSeparator : "node_modules"
indexFile :: FilePath
indexFile = ".psci_modules" ++ pathSeparator : "index.js"
-- |
-- Takes a value declaration and evaluates it with the current state.
--
handleDeclaration :: P.Expr -> PSCI ()
handleDeclaration val = do
st <- PSCI $ lift get
let m = createTemporaryModule True st val
e <- psciIO . runMake $ P.make modulesDir options (psciLoadedModules st ++ [(Left P.RebuildAlways, m)]) []
case e of
Left err -> PSCI $ outputStrLn err
Right _ -> do
psciIO $ writeFile indexFile "require('$PSCI').main();"
process <- psciIO findNodeProcess
result <- psciIO $ traverse (\node -> readProcessWithExitCode node [indexFile] "") process
case result of
Just (ExitSuccess, out, _) -> PSCI $ outputStrLn out
Just (ExitFailure _, _, err) -> PSCI $ outputStrLn err
Nothing -> PSCI $ outputStrLn "Couldn't find node.js"
-- |
-- Takes a let declaration and updates the environment, then run a make. If the declaration fails,
-- restore the pre-let environment.
--
handleLet :: (P.Expr -> P.Expr) -> PSCI ()
handleLet l = do
st <- PSCI $ lift get
let st' = updateLets l st
let m = createTemporaryModule False st' (P.ObjectLiteral [])
e <- psciIO . runMake $ P.make modulesDir options (psciLoadedModules st' ++ [(Left P.RebuildAlways, m)]) []
case e of
Left err -> PSCI $ outputStrLn err
Right _ -> PSCI $ lift (put st')
-- |
-- Show actual loaded modules in psci.
--
handleShowLoadedModules :: PSCI ()
handleShowLoadedModules = do
PSCiState { psciLoadedModules = loadedModules } <- PSCI $ lift get
psciIO $ readModules loadedModules >>= putStrLn
return ()
where readModules = return . unlines . sort . nub . map toModuleName
toModuleName = N.runModuleName . (\ (D.Module mdName _ _) -> mdName) . snd
-- |
-- Show the imported modules in psci.
--
handleShowImportedModules :: PSCI ()
handleShowImportedModules = do
PSCiState { psciImportedModuleNames = importedModuleNames } <- PSCI $ lift get
psciIO $ readModules importedModuleNames >>= putStrLn
return ()
where readModules = return . unlines . sort . map N.runModuleName
-- |
-- Imports a module, preserving the initial state on failure.
--
handleImport :: P.ModuleName -> PSCI ()
handleImport moduleName = do
st <- updateImports moduleName <$> PSCI (lift get)
let m = createTemporaryModuleForImports st
e <- psciIO . runMake $ P.make modulesDir options (psciLoadedModules st ++ [(Left P.RebuildAlways, m)]) []
case e of
Left err -> PSCI $ outputStrLn err
Right _ -> do
PSCI $ lift $ put st
return ()
-- |
-- Takes a value and prints its type
--
handleTypeOf :: P.Expr -> PSCI ()
handleTypeOf val = do
st <- PSCI $ lift get
let m = createTemporaryModule False st val
e <- psciIO . runMake $ P.make modulesDir options (psciLoadedModules st ++ [(Left P.RebuildAlways, m)]) []
case e of
Left err -> PSCI $ outputStrLn err
Right env' ->
case M.lookup (P.ModuleName [P.ProperName "$PSCI"], P.Ident "it") (P.names env') of
Just (ty, _, _) -> PSCI . outputStrLn . P.prettyPrintType $ ty
Nothing -> PSCI $ outputStrLn "Could not find type"
-- |
-- Pretty print a module's signatures
--
printModuleSignatures :: P.ModuleName -> P.Environment -> PSCI ()
printModuleSignatures moduleName env =
PSCI $ let namesEnv = P.names env
moduleNamesIdent = (filter ((== moduleName) . fst) . M.keys) namesEnv
in case moduleNamesIdent of
[] -> outputStrLn $ "This module '"++ P.runModuleName moduleName ++"' does not export functions."
_ -> ( outputStrLn
. unlines
. sort
. map (showType . findType namesEnv)) moduleNamesIdent
where findType :: M.Map (P.ModuleName, P.Ident) (P.Type, P.NameKind, P.NameVisibility) -> (P.ModuleName, P.Ident) -> (P.Ident, Maybe (P.Type, P.NameKind, P.NameVisibility))
findType envNames m@(_, mIdent) = (mIdent, M.lookup m envNames)
showType :: (P.Ident, Maybe (P.Type, P.NameKind, P.NameVisibility)) -> String
showType (mIdent, Just (mType, _, _)) = show mIdent ++ " :: " ++ P.prettyPrintType mType
showType _ = error "The impossible happened in printModuleSignatures."
-- |
-- Browse a module and displays its signature (if module exists).
--
handleBrowse :: P.ModuleName -> PSCI ()
handleBrowse moduleName = do
st <- PSCI $ lift get
let loadedModules = psciLoadedModules st
env <- psciIO . runMake $ P.make modulesDir options loadedModules []
case env of
Left err -> PSCI $ outputStrLn err
Right env' ->
if moduleName `notElem` (nub . map ((\ (P.Module modName _ _ ) -> modName) . snd)) loadedModules
then PSCI $ outputStrLn $ "Module '" ++ N.runModuleName moduleName ++ "' is not valid."
else printModuleSignatures moduleName env'
-- |
-- Takes a value and prints its kind
--
handleKindOf :: P.Type -> PSCI ()
handleKindOf typ = do
st <- PSCI $ lift get
let m = createTemporaryModuleForKind st typ
mName = P.ModuleName [P.ProperName "$PSCI"]
e <- psciIO . runMake $ P.make modulesDir options (psciLoadedModules st ++ [(Left P.RebuildAlways, m)]) []
case e of
Left err -> PSCI $ outputStrLn err
Right env' ->
case M.lookup (P.Qualified (Just mName) $ P.ProperName "IT") (P.typeSynonyms env') of
Just (_, typ') -> do
let chk = P.CheckState env' 0 0 (Just mName)
k = L.runStateT (P.unCheck (P.kindOf mName typ')) chk
case k of
Left errStack -> PSCI . outputStrLn . P.prettyPrintErrorStack False $ errStack
Right (kind, _) -> PSCI . outputStrLn . P.prettyPrintKind $ kind
Nothing -> PSCI $ outputStrLn "Could not find kind"
-- Commands
-- |
-- Parses the input and returns either a Metacommand or an expression.
--
getCommand :: Bool -> InputT (StateT PSCiState IO) (Either String (Maybe Command))
getCommand singleLineMode = do
firstLine <- getInputLine "> "
case firstLine of
Nothing -> return (Right Nothing)
Just "" -> return (Right Nothing)
Just s | singleLineMode || head s == ':' -> return . either Left (Right . Just) $ parseCommand s
Just s -> either Left (Right . Just) . parseCommand <$> go [s]
where
go :: [String] -> InputT (StateT PSCiState IO) String
go ls = maybe (return . unlines $ reverse ls) (go . (:ls)) =<< getInputLine " "
-- |
-- Performs an action for each meta-command given, and also for expressions..
--
handleCommand :: Command -> PSCI ()
handleCommand (Expression val) = handleDeclaration val
handleCommand Help = PSCI $ outputStrLn helpMessage
handleCommand (Import moduleName) = handleImport moduleName
handleCommand (Let l) = handleLet l
handleCommand (LoadFile filePath) = do
absPath <- psciIO $ expandTilde filePath
exists <- psciIO $ doesFileExist absPath
if exists then do
PSCI . lift $ modify (updateImportedFiles absPath)
m <- psciIO $ loadModule absPath
case m of
Left err -> PSCI $ outputStrLn err
Right mods -> PSCI . lift $ modify (updateModules (map ((,) (Right absPath)) mods))
else
PSCI . outputStrLn $ "Couldn't locate: " ++ filePath
handleCommand Reset = do
files <- psciImportedFilenames <$> PSCI (lift get)
modulesOrFirstError <- psciIO $ loadAllModules files
case modulesOrFirstError of
Left err -> psciIO $ print err >> exitFailure
Right modules -> PSCI . lift $ put (PSCiState files defaultImports modules [])
handleCommand (TypeOf val) = handleTypeOf val
handleCommand (KindOf typ) = handleKindOf typ
handleCommand (Browse moduleName) = handleBrowse moduleName
handleCommand (Show "loaded") = handleShowLoadedModules
handleCommand (Show "import") = handleShowImportedModules
handleCommand _ = PSCI $ outputStrLn "Unknown command"
loadUserConfig :: IO (Maybe [Command])
loadUserConfig = do
configFile <- (</> ".psci") <$> getCurrentDirectory
exists <- doesFileExist configFile
if exists
then do
ls <- lines <$> U.readFile configFile
case mapM parseCommand ls of
Left err -> U.print err >> exitFailure
Right cs -> return $ Just cs
else
return Nothing
-- |
-- The PSCI main loop.
--
loop :: PSCiOptions -> IO ()
loop (PSCiOptions singleLineMode files) = do
config <- loadUserConfig
modulesOrFirstError <- loadAllModules files
case modulesOrFirstError of
Left err -> print err >> exitFailure
Right modules -> do
historyFilename <- getHistoryFilename
let settings = defaultSettings { historyFile = Just historyFilename }
flip evalStateT (PSCiState files defaultImports modules []) . runInputT (setComplete completion settings) $ do
outputStrLn prologueMessage
traverse_ (mapM_ (runPSCI . handleCommand)) config
go
where
go :: InputT (StateT PSCiState IO) ()
go = do
c <- getCommand singleLineMode
case c of
Left err -> outputStrLn err >> go
Right Nothing -> go
Right (Just Quit) -> outputStrLn quitMessage
Right (Just c') -> runPSCI (handleCommand c') >> go
singleLineFlag :: Parser Bool
singleLineFlag = switch $
long "single-line-mode"
<> Opts.help "Run in single-line mode"
inputFile :: Parser FilePath
inputFile = strArgument $
metavar "FILE"
<> Opts.help "Optional .purs files to load on start"
psciOptions :: Parser PSCiOptions
psciOptions = PSCiOptions <$> singleLineFlag
<*> many inputFile
main :: IO ()
main = execParser opts >>= loop
where
opts = info (version <*> helper <*> psciOptions) infoModList
infoModList = fullDesc <> headerInfo <> footerInfo
headerInfo = header "psci - Interactive mode for PureScript"
footerInfo = footer $ "psci " ++ showVersion Paths.version
version :: Parser (a -> a)
version = abortOption (InfoMsg (showVersion Paths.version)) $ long "version" <> Opts.help "Show the version number" <> hidden