content: -----------------------------------------------------------------------------
  -- |
  -- Module      :  Distribution.Simple.Hugs
  -- Copyright   :  Isaac Jones 2003-2006
  --                Duncan Coutts 2009
  --
  -- Maintainer  :  cabal-devel@haskell.org
  -- Portability :  portable
  --
  -- This module contains most of the NHC-specific code for configuring, building
  -- and installing packages.
  
  {- Copyright (c) 2003-2005, Isaac Jones
  All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are
  met:
  
      * Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
  
      * Redistributions in binary form must reproduce the above
        copyright notice, this list of conditions and the following
        disclaimer in the documentation and/or other materials provided
        with the distribution.
  
      * Neither the name of Isaac Jones nor the names of other
        contributors may be used to endorse or promote products derived
        from this software without specific prior written permission.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -}
  
  module Distribution.Simple.Hugs (
      configure,
      getInstalledPackages,
      buildLib,
      buildExe,
      install,
      registerPackage,
    ) where
  
  import Distribution.Package
           ( PackageName, PackageIdentifier(..), InstalledPackageId(..)
           , packageName )
  import Distribution.InstalledPackageInfo
           ( InstalledPackageInfo, emptyInstalledPackageInfo
           , InstalledPackageInfo_( InstalledPackageInfo, installedPackageId
                                  , sourcePackageId )
           , parseInstalledPackageInfo, showInstalledPackageInfo )
  import Distribution.PackageDescription
           ( PackageDescription(..), BuildInfo(..), hcOptions, allExtensions
           , Executable(..), withExe, Library(..), withLib, libModules )
  import Distribution.ModuleName (ModuleName)
  import qualified Distribution.ModuleName as ModuleName
  import Distribution.Simple.Compiler
           ( CompilerFlavor(..), CompilerId(..)
           , Compiler(..), Flag, languageToFlags, extensionsToFlags
           , PackageDB(..), PackageDBStack )
  import qualified Distribution.Simple.PackageIndex as PackageIndex
  import Distribution.Simple.PackageIndex (PackageIndex)
  import Distribution.Simple.Program
           ( Program(programFindVersion)
           , ProgramConfiguration, userMaybeSpecifyPath
           , requireProgram, requireProgramVersion
           , rawSystemProgramConf, programPath
           , ffihugsProgram, hugsProgram )
  import Distribution.Version
           ( Version(..), orLaterVersion )
  import Distribution.Simple.PreProcess   ( ppCpp, runSimplePreProcessor )
  import Distribution.Simple.PreProcess.Unlit
                                  ( unlit )
  import Distribution.Simple.LocalBuildInfo
           ( LocalBuildInfo(..), ComponentLocalBuildInfo(..)
           , InstallDirs(..), absoluteInstallDirs )
  import Distribution.Simple.BuildPaths
                                  ( autogenModuleName, autogenModulesDir,
                                    dllExtension )
  import Distribution.Simple.Setup
           ( CopyDest(..) )
  import Distribution.Simple.Utils
           ( createDirectoryIfMissingVerbose
           , installOrdinaryFiles, setFileExecutable
           , withUTF8FileContents, writeFileAtomic, writeUTF8File
           , copyFileVerbose, findFile, findFileWithExtension, findModuleFiles
           , rawSystemStdInOut
           , die, info, notice )
  import Language.Haskell.Extension
           ( Language(Haskell98), Extension(..), KnownExtension(..) )
  import System.FilePath          ( (</>), takeExtension, (<.>),
                                    searchPathSeparator, normalise, takeDirectory )
  import Distribution.System
           ( OS(..), buildOS )
  import Distribution.Text
           ( display, simpleParse )
  import Distribution.ParseUtils
           ( ParseResult(..) )
  import Distribution.Verbosity
  
  import Data.Char                ( isSpace )
  import Data.Maybe               ( mapMaybe, catMaybes )
  import Data.Monoid              ( Monoid(..) )
  import Control.Monad            ( unless, when, filterM )
  import Data.List                ( nub, sort, isSuffixOf )
  import System.Directory
           ( doesFileExist, doesDirectoryExist, getDirectoryContents
           , removeDirectoryRecursive, getHomeDirectory )
  import System.Exit
           ( ExitCode(ExitSuccess) )
  import Distribution.Compat.Exception
  import Distribution.System ( Platform )
  
  import qualified Data.ByteString.Lazy.Char8 as BS.Char8
  
  -- -----------------------------------------------------------------------------
  -- Configuring
  
  configure :: Verbosity -> Maybe FilePath -> Maybe FilePath
            -> ProgramConfiguration -> IO (Compiler, Maybe Platform, ProgramConfiguration)
  configure verbosity hcPath _hcPkgPath conf = do
  
    (_ffihugsProg, conf') <- requireProgram verbosity ffihugsProgram
                              (userMaybeSpecifyPath "ffihugs" hcPath conf)
    (_hugsProg, version, conf'')
                          <- requireProgramVersion verbosity hugsProgram'
                              (orLaterVersion (Version [2006] [])) conf'
  
    let comp = Compiler {
          compilerId             = CompilerId Hugs version,
          compilerLanguages      = hugsLanguages,
          compilerExtensions     = hugsLanguageExtensions
        }
        compPlatform = Nothing
    return (comp, compPlatform, conf'')
  
    where
      hugsProgram' = hugsProgram { programFindVersion = getVersion }
  
  getVersion :: Verbosity -> FilePath -> IO (Maybe Version)
  getVersion verbosity hugsPath = do
    (output, _err, exit) <- rawSystemStdInOut verbosity hugsPath []
                                Nothing Nothing
                                (Just (":quit", False)) False
    if exit == ExitSuccess
      then return $! findVersion output
      else return Nothing
  
    where
      findVersion output = do
        (monthStr, yearStr) <- selectWords output
        year  <- convertYear yearStr
        month <- convertMonth monthStr
        return (Version [year, month] [])
  
      selectWords output =
        case [ (month, year)
             | [_,_,"Version:", month, year,_] <- map words (lines output) ] of
          [(month, year)] -> Just (month, year)
          _               -> Nothing
      convertYear year = case reads year of
        [(y, [])] | y >= 1999 && y < 2020 -> Just y
        _                                 -> Nothing
      convertMonth month = lookup month (zip months [1..])
      months = [ "January", "February", "March", "April", "May", "June", "July"
               , "August", "September", "October", "November", "December" ]
  
  hugsLanguages :: [(Language, Flag)]
  hugsLanguages = [(Haskell98, "")] --default is 98 mode
  
  -- | The flags for the supported extensions
  hugsLanguageExtensions :: [(Extension, Flag)]
  hugsLanguageExtensions =
      let doFlag (f, (enable, disable)) = [(EnableExtension  f, enable),
                                           (DisableExtension f, disable)]
          alwaysOn = ("", ""{- wrong -})
          ext98 = ("-98", ""{- wrong -})
      in concatMap doFlag
      [(OverlappingInstances       , ("+o",  "-o"))
      ,(IncoherentInstances        , ("+oO", "-O"))
      ,(HereDocuments              , ("+H",  "-H"))
      ,(TypeSynonymInstances       , ext98)
      ,(RecursiveDo                , ext98)
      ,(ParallelListComp           , ext98)
      ,(MultiParamTypeClasses      , ext98)
      ,(FunctionalDependencies     , ext98)
      ,(Rank2Types                 , ext98)
      ,(PolymorphicComponents      , ext98)
      ,(ExistentialQuantification  , ext98)
      ,(ScopedTypeVariables        , ext98)
      ,(ImplicitParams             , ext98)
      ,(ExtensibleRecords          , ext98)
      ,(RestrictedTypeSynonyms     , ext98)
      ,(FlexibleContexts           , ext98)
      ,(FlexibleInstances          , ext98)
      ,(ForeignFunctionInterface   , alwaysOn)
      ,(EmptyDataDecls             , alwaysOn)
      ,(CPP                        , alwaysOn)
      ]
  
  getInstalledPackages :: Verbosity -> PackageDBStack -> ProgramConfiguration
                       -> IO PackageIndex
  getInstalledPackages verbosity packagedbs conf = do
    homedir       <- getHomeDirectory
    (hugsProg, _) <- requireProgram verbosity hugsProgram conf
    let hugsbindir = takeDirectory (programPath hugsProg)
        hugslibdir = takeDirectory hugsbindir </> "lib" </> "hugs"
        dbdirs = nub (concatMap (packageDbPaths homedir hugslibdir) packagedbs)
    indexes  <- mapM getIndividualDBPackages dbdirs
    return $! mconcat indexes
  
    where
      getIndividualDBPackages :: FilePath -> IO PackageIndex
      getIndividualDBPackages dbdir = do
        pkgdirs <- getPackageDbDirs dbdir
        pkgs    <- sequence [ getInstalledPackage pkgname pkgdir
                            | (pkgname, pkgdir) <- pkgdirs ]
        let pkgs' = map setInstalledPackageId (catMaybes pkgs)
        return (PackageIndex.fromList pkgs')
  
  packageDbPaths :: FilePath -> FilePath -> PackageDB -> [FilePath]
  packageDbPaths home hugslibdir db = case db of
    GlobalPackageDB        -> [ hugslibdir </> "packages"
                              , "/usr/local/lib/hugs/packages" ]
    UserPackageDB          -> [ home </> "lib/hugs/packages" ]
    SpecificPackageDB path -> [ path ]
  
  getPackageDbDirs :: FilePath -> IO [(PackageName, FilePath)]
  getPackageDbDirs dbdir = do
    dbexists <- doesDirectoryExist dbdir
    if not dbexists
      then return []
      else do
        entries  <- getDirectoryContents dbdir
        pkgdirs  <- sequence
          [ do pkgdirExists <- doesDirectoryExist pkgdir
               return (pkgname, pkgdir, pkgdirExists)
          | (entry, Just pkgname) <- [ (entry, simpleParse entry)
                                     | entry <- entries ]
          , let pkgdir = dbdir </> entry ]
        return [ (pkgname, pkgdir) | (pkgname, pkgdir, True) <- pkgdirs ]
  
  getInstalledPackage :: PackageName -> FilePath -> IO (Maybe InstalledPackageInfo)
  getInstalledPackage pkgname pkgdir = do
    let pkgconfFile = pkgdir </> "package.conf"
    pkgconfExists <- doesFileExist pkgconfFile
  
    let pathsModule = pkgdir </> ("Paths_" ++ display pkgname)  <.> "hs"
    pathsModuleExists <- doesFileExist pathsModule
  
    case () of
      _ | pkgconfExists     -> getFullInstalledPackageInfo pkgname pkgconfFile
        | pathsModuleExists -> getPhonyInstalledPackageInfo pkgname pathsModule
        | otherwise         -> return Nothing
  
  getFullInstalledPackageInfo :: PackageName -> FilePath
                              -> IO (Maybe InstalledPackageInfo)
  getFullInstalledPackageInfo pkgname pkgconfFile =
    withUTF8FileContents pkgconfFile $ \contents ->
      case parseInstalledPackageInfo contents of
        ParseOk _ pkginfo | packageName pkginfo == pkgname
                          -> return (Just pkginfo)
        _                 -> return Nothing
  
  -- | This is a backup option for existing versions of Hugs which do not supply
  -- proper installed package info files for the bundled libs. Instead we look
  -- for the Paths_pkgname.hs file and extract the package version from that.
  -- We don't know any other details for such packages, in particular we pretend
  -- that they have no dependencies.
  --
  getPhonyInstalledPackageInfo :: PackageName -> FilePath
                               -> IO (Maybe InstalledPackageInfo)
  getPhonyInstalledPackageInfo pkgname pathsModule = do
    content <- readFile pathsModule
    case extractVersion content of
      Nothing      -> return Nothing
      Just version -> return (Just pkginfo)
        where
          pkgid   = PackageIdentifier pkgname version
          pkginfo = emptyInstalledPackageInfo { sourcePackageId = pkgid }
    where
      -- search through the Paths_pkgname.hs file, looking for a line like:
      --
      -- > version = Version {versionBranch = [2,0], versionTags = []}
      --
      -- and parse it using 'Read'. Yes we are that evil.
      --
      extractVersion content =
        case [ version
             | ("version":"=":rest) <- map words (lines content)
             , (version, []) <- reads (concat rest) ] of
          [version] -> Just version
          _         -> Nothing
  
  -- Older installed package info files did not have the installedPackageId
  -- field, so if it is missing then we fill it as the source package ID.
  setInstalledPackageId :: InstalledPackageInfo -> InstalledPackageInfo
  setInstalledPackageId pkginfo@InstalledPackageInfo {
                          installedPackageId = InstalledPackageId "",
                          sourcePackageId    = pkgid
                        }
                      = pkginfo {
                          --TODO use a proper named function for the conversion
                          -- from source package id to installed package id
                          installedPackageId = InstalledPackageId (display pkgid)
                        }
  setInstalledPackageId pkginfo = pkginfo
  
  -- -----------------------------------------------------------------------------
  -- Building
  
  -- |Building a package for Hugs.
  buildLib :: Verbosity -> PackageDescription -> LocalBuildInfo
                        -> Library            -> ComponentLocalBuildInfo -> IO ()
  buildLib verbosity pkg_descr lbi lib _clbi = do
      let pref = scratchDir lbi
      createDirectoryIfMissingVerbose verbosity True pref
      copyFileVerbose verbosity (autogenModulesDir lbi </> paths_modulename)
                                (pref </> paths_modulename)
      compileBuildInfo verbosity pref [] (libModules lib) (libBuildInfo lib) lbi
    where
      paths_modulename = ModuleName.toFilePath (autogenModuleName pkg_descr)
                           <.> ".hs"
      --TODO: switch to using autogenModulesDir as a search dir, rather than
      --      always copying the file over.
  
  -- |Building an executable for Hugs.
  buildExe :: Verbosity -> PackageDescription -> LocalBuildInfo
                        -> Executable         -> ComponentLocalBuildInfo -> IO ()
  buildExe verbosity pkg_descr lbi
    exe@Executable {modulePath=mainPath, buildInfo=bi} _clbi = do
      let pref = scratchDir lbi
      createDirectoryIfMissingVerbose verbosity True pref
      
      let destDir = pref </> "programs"
      let exeMods = otherModules bi
      srcMainFile <- findFile (hsSourceDirs bi) mainPath
      let exeDir = destDir </> exeName exe
      let destMainFile = exeDir </> hugsMainFilename exe
      copyModule verbosity (EnableExtension CPP `elem` allExtensions bi) bi lbi srcMainFile destMainFile
      let destPathsFile = exeDir </> paths_modulename
      copyFileVerbose verbosity (autogenModulesDir lbi </> paths_modulename)
                                destPathsFile
      compileBuildInfo verbosity exeDir 
        (maybe [] (hsSourceDirs . libBuildInfo) (library pkg_descr)) exeMods bi lbi
      compileFiles verbosity bi lbi exeDir [destMainFile, destPathsFile]
  
    where
      paths_modulename = ModuleName.toFilePath (autogenModuleName pkg_descr)
                           <.> ".hs"
  
  compileBuildInfo :: Verbosity
                   -> FilePath -- ^output directory
                   -> [FilePath] -- ^library source dirs, if building exes
                   -> [ModuleName] -- ^Modules
                   -> BuildInfo
                   -> LocalBuildInfo
                   -> IO ()
  --TODO: should not be using mLibSrcDirs at all
  compileBuildInfo verbosity destDir mLibSrcDirs mods bi lbi = do
      -- Pass 1: copy or cpp files from build directory to scratch directory
      let useCpp = EnableExtension CPP `elem` allExtensions bi
      let srcDir = buildDir lbi
          srcDirs = nub $ srcDir : hsSourceDirs bi ++ mLibSrcDirs
      info verbosity $ "Source directories: " ++ show srcDirs
      flip mapM_ mods $ \ m -> do
          fs <- findFileWithExtension suffixes srcDirs (ModuleName.toFilePath m)
          case fs of
            Nothing ->
              die ("can't find source for module " ++ display m)
            Just srcFile -> do
              let ext = takeExtension srcFile
              copyModule verbosity useCpp bi lbi srcFile
                  (destDir </> ModuleName.toFilePath m <.> ext)
      -- Pass 2: compile foreign stubs in scratch directory
      stubsFileLists <- fmap catMaybes $ sequence
        [ findFileWithExtension suffixes [destDir] (ModuleName.toFilePath modu)
        | modu <- mods]
      compileFiles verbosity bi lbi destDir stubsFileLists
  
  suffixes :: [String]
  suffixes = ["hs", "lhs"]
  
  -- Copy or cpp a file from the source directory to the build directory.
  copyModule :: Verbosity -> Bool -> BuildInfo -> LocalBuildInfo -> FilePath -> FilePath -> IO ()
  copyModule verbosity cppAll bi lbi srcFile destFile = do
      createDirectoryIfMissingVerbose verbosity True (takeDirectory destFile)
      (exts, opts, _) <- getOptionsFromSource srcFile
      let ghcOpts = [ op | (GHC, ops) <- opts, op <- ops ]
      if cppAll || EnableExtension CPP `elem` exts || "-cpp" `elem` ghcOpts then do
          runSimplePreProcessor (ppCpp bi lbi) srcFile destFile verbosity
          return ()
        else
          copyFileVerbose verbosity srcFile destFile
  
  compileFiles :: Verbosity -> BuildInfo -> LocalBuildInfo -> FilePath -> [FilePath] -> IO ()
  compileFiles verbosity bi lbi modDir fileList = do
      ffiFileList <- filterM testFFI fileList
      unless (null ffiFileList) $ do
          notice verbosity "Compiling FFI stubs"
          mapM_ (compileFFI verbosity bi lbi modDir) ffiFileList
  
  -- Only compile FFI stubs for a file if it contains some FFI stuff
  testFFI :: FilePath -> IO Bool
  testFFI file =
    withHaskellFile file $ \inp ->
      return $! "foreign" `elem` symbols (stripComments False inp)
  
  compileFFI :: Verbosity -> BuildInfo -> LocalBuildInfo -> FilePath -> FilePath -> IO ()
  compileFFI verbosity bi lbi modDir file = do
      (_, opts, file_incs) <- getOptionsFromSource file
      let ghcOpts = [ op | (GHC, ops) <- opts, op <- ops ]
      let pkg_incs = ["\"" ++ inc ++ "\"" | inc <- includes bi]
      let incs = nub (sort (file_incs ++ includeOpts ghcOpts ++ pkg_incs))
      let pathFlag = "-P" ++ modDir ++ [searchPathSeparator]
      let hugsArgs = "-98" : pathFlag : map ("-i" ++) incs
      cfiles <- getCFiles file
      let cArgs =
              ["-I" ++ dir | dir <- includeDirs bi] ++
              ccOptions bi ++
              cfiles ++
              ["-L" ++ dir | dir <- extraLibDirs bi] ++
              ldOptions bi ++
              ["-l" ++ lib | lib <- extraLibs bi] ++
              concat [["-framework", f] | f <- frameworks bi]
      rawSystemProgramConf verbosity ffihugsProgram (withPrograms lbi)
        (hugsArgs ++ file : cArgs)
  
  includeOpts :: [String] -> [String]
  includeOpts [] = []
  includeOpts ("-#include" : arg : opts) = arg : includeOpts opts
  includeOpts (_ : opts) = includeOpts opts
  
  -- get C file names from CFILES pragmas throughout the source file
  getCFiles :: FilePath -> IO [String]
  getCFiles file =
    withHaskellFile file $ \inp ->
      let cfiles =
            [ normalise cfile
            | "{-#" : "CFILES" : rest <- map words
                                       $ lines
                                       $ stripComments True inp
            , last rest == "#-}"
            , cfile <- init rest]
       in seq (length cfiles) (return cfiles)
  
  -- List of terminal symbols in a source file.
  symbols :: String -> [String]
  symbols cs = case lex cs of
      (sym, cs'):_ | not (null sym) -> sym : symbols cs'
      _ -> []
  
  -- Get the non-literate source of a Haskell module.
  withHaskellFile :: FilePath -> (String -> IO a) -> IO a
  withHaskellFile file action =
      withUTF8FileContents file $ \text ->
          if ".lhs" `isSuffixOf` file
            then either action die (unlit file text)
            else action text
  
  -- ------------------------------------------------------------
  -- * options in source files
  -- ------------------------------------------------------------
  
  -- |Read the initial part of a source file, before any Haskell code,
  -- and return the contents of any LANGUAGE, OPTIONS and INCLUDE pragmas.
  getOptionsFromSource
      :: FilePath
      -> IO ([Extension],                 -- LANGUAGE pragma, if any
             [(CompilerFlavor,[String])], -- OPTIONS_FOO pragmas
             [String]                     -- INCLUDE pragmas
            )
  getOptionsFromSource file =
      withHaskellFile file $
          (return $!)
        . foldr appendOptions ([],[],[]) . map getOptions
        . takeWhileJust . map getPragma
        . filter textLine . map (dropWhile isSpace) . lines
        . stripComments True
  
    where textLine [] = False
          textLine ('#':_) = False
          textLine _ = True
  
          getPragma :: String -> Maybe [String]
          getPragma line = case words line of
              ("{-#" : rest) | last rest == "#-}" -> Just (init rest)
              _ -> Nothing
  
          getOptions ("OPTIONS":opts) = ([], [(GHC, opts)], [])
          getOptions ("OPTIONS_GHC":opts) = ([], [(GHC, opts)], [])
          getOptions ("OPTIONS_NHC98":opts) = ([], [(NHC, opts)], [])
          getOptions ("OPTIONS_HUGS":opts) = ([], [(Hugs, opts)], [])
          getOptions ("LANGUAGE":ws) = (mapMaybe readExtension ws, [], [])
            where readExtension :: String -> Maybe Extension
                  readExtension w = case reads w of
                      [(ext, "")] -> Just ext
                      [(ext, ",")] -> Just ext
                      _ -> Nothing
          getOptions ("INCLUDE":ws) = ([], [], ws)
          getOptions _ = ([], [], [])
  
          appendOptions (exts, opts, incs) (exts', opts', incs')
            = (exts++exts', opts++opts', incs++incs')
  
  -- takeWhileJust f = map fromJust . takeWhile isJust
  takeWhileJust :: [Maybe a] -> [a]
  takeWhileJust (Just x:xs) = x : takeWhileJust xs
  takeWhileJust _ = []
  
  -- |Strip comments from Haskell source.
  stripComments
      :: Bool     -- ^ preserve pragmas?
      -> String   -- ^ input source text
      -> String
  stripComments keepPragmas = stripCommentsLevel 0
    where stripCommentsLevel :: Int -> String -> String
          stripCommentsLevel 0 ('"':cs) = '"':copyString cs
          stripCommentsLevel 0 ('-':'-':cs) =     -- FIX: symbols like -->
              stripCommentsLevel 0 (dropWhile (/= '\n') cs)
          stripCommentsLevel 0 ('{':'-':'#':cs)
            | keepPragmas = '{' : '-' : '#' : copyPragma cs
          stripCommentsLevel n ('{':'-':cs) = stripCommentsLevel (n+1) cs
          stripCommentsLevel 0 (c:cs) = c : stripCommentsLevel 0 cs
          stripCommentsLevel n ('-':'}':cs) = stripCommentsLevel (n-1) cs
          stripCommentsLevel n (_:cs) = stripCommentsLevel n cs
          stripCommentsLevel _ [] = []
  
          copyString ('\\':c:cs) = '\\' : c : copyString cs
          copyString ('"':cs) = '"' : stripCommentsLevel 0 cs
          copyString (c:cs) = c : copyString cs
          copyString [] = []
  
          copyPragma ('#':'-':'}':cs) = '#' : '-' : '}' : stripCommentsLevel 0 cs
          copyPragma (c:cs) = c : copyPragma cs
          copyPragma [] = []
  
  -- -----------------------------------------------------------------------------
  -- |Install for Hugs.
  -- For install, copy-prefix = prefix, but for copy they're different.
  -- The library goes in \<copy-prefix>\/lib\/hugs\/packages\/\<pkgname>
  -- (i.e. \<prefix>\/lib\/hugs\/packages\/\<pkgname> on the target system).
  -- Each executable goes in \<copy-prefix>\/lib\/hugs\/programs\/\<exename>
  -- (i.e. \<prefix>\/lib\/hugs\/programs\/\<exename> on the target system)
  -- with a script \<copy-prefix>\/bin\/\<exename> pointing at
  -- \<prefix>\/lib\/hugs\/programs\/\<exename>.
  install
      :: Verbosity -- ^verbosity
      -> LocalBuildInfo
      -> FilePath  -- ^Library install location
      -> FilePath  -- ^Program install location
      -> FilePath  -- ^Executable install location
      -> FilePath  -- ^Program location on target system
      -> FilePath  -- ^Build location
      -> (FilePath,FilePath)  -- ^Executable (prefix,suffix)
      -> PackageDescription
      -> IO ()
  --FIXME: this script should be generated at build time, just installed at this stage
  install verbosity lbi libDir installProgDir binDir targetProgDir buildPref (progprefix,progsuffix) pkg_descr = do
      removeDirectoryRecursive libDir `catchIO` \_ -> return ()
      withLib pkg_descr $ \ lib ->
        findModuleFiles [buildPref] hugsInstallSuffixes (libModules lib)
          >>= installOrdinaryFiles verbosity libDir
      let buildProgDir = buildPref </> "programs"
      when (any (buildable . buildInfo) (executables pkg_descr)) $
          createDirectoryIfMissingVerbose verbosity True binDir
      withExe pkg_descr $ \ exe -> do
          let bi = buildInfo exe
          let theBuildDir = buildProgDir </> exeName exe
          let installDir = installProgDir </> exeName exe
          let targetDir = targetProgDir </> exeName exe
          removeDirectoryRecursive installDir `catchIO` \_ -> return ()
          findModuleFiles [theBuildDir] hugsInstallSuffixes
                          (ModuleName.main : autogenModuleName pkg_descr
                                           : otherModules (buildInfo exe))
            >>= installOrdinaryFiles verbosity installDir
          let targetName = "\"" ++ (targetDir </> hugsMainFilename exe) ++ "\""
          let hugsOptions = hcOptions Hugs (buildInfo exe)
                         ++ languageToFlags (compiler lbi) (defaultLanguage bi)
                         ++ extensionsToFlags (compiler lbi) (allExtensions bi)
              --TODO: also need to consider options, extensions etc of deps
              --      see ticket #43
          let baseExeFile = progprefix ++ (exeName exe) ++ progsuffix
          let exeFile = case buildOS of
                            Windows -> binDir </> baseExeFile <.> ".bat"
                            _       -> binDir </> baseExeFile
          let script = case buildOS of
                           Windows ->
                               let args = hugsOptions ++ [targetName, "%*"]
                               in unlines ["@echo off",
                                           unwords ("runhugs" : args)]
                           _ ->
                               let args = hugsOptions ++ [targetName, "\"$@\""]
                               in unlines ["#! /bin/sh",
                                           unwords ("runhugs" : args)]
          writeFileAtomic exeFile (BS.Char8.pack script)
          setFileExecutable exeFile
  
  hugsInstallSuffixes :: [String]
  hugsInstallSuffixes = [".hs", ".lhs", dllExtension]
  
  -- |Filename used by Hugs for the main module of an executable.
  -- This is a simple filename, so that Hugs will look for any auxiliary
  -- modules it uses relative to the directory it's in.
  hugsMainFilename :: Executable -> FilePath
  hugsMainFilename exe = "Main" <.> ext
    where ext = takeExtension (modulePath exe)
  
  -- -----------------------------------------------------------------------------
  -- Registering
  
  registerPackage
    :: Verbosity
    -> InstalledPackageInfo
    -> PackageDescription
    -> LocalBuildInfo
    -> Bool
    -> PackageDBStack
    -> IO ()
  registerPackage verbosity installedPkgInfo pkg lbi inplace _packageDbs = do
    --TODO: prefer to have it based on the packageDbs, but how do we know
    -- the package subdir based on the name? the user can set crazy libsubdir
    let installDirs = absoluteInstallDirs pkg lbi NoCopyDest
        pkgdir  | inplace   = buildDir lbi
                | otherwise = libdir installDirs
    createDirectoryIfMissingVerbose verbosity True pkgdir
    writeUTF8File (pkgdir </> "package.conf")
                  (showInstalledPackageInfo installedPkgInfo)
  