content: {-# LANGUAGE DeriveDataTypeable #-}
  {-# LANGUAGE DeriveGeneric #-}
  
  -----------------------------------------------------------------------------
  -- |
  -- Module      :  Distribution.Compiler
  -- Copyright   :  Isaac Jones 2003-2004
  -- License     :  BSD3
  --
  -- Maintainer  :  cabal-devel@haskell.org
  -- Portability :  portable
  --
  -- This has an enumeration of the various compilers that Cabal knows about. It
  -- also specifies the default compiler. Sadly you'll often see code that does
  -- case analysis on this compiler flavour enumeration like:
  --
  -- > case compilerFlavor comp of
  -- >   GHC -> GHC.getInstalledPackages verbosity packageDb progdb
  -- >   JHC -> JHC.getInstalledPackages verbosity packageDb progdb
  --
  -- Obviously it would be better to use the proper 'Compiler' abstraction
  -- because that would keep all the compiler-specific code together.
  -- Unfortunately we cannot make this change yet without breaking the
  -- 'UserHooks' api, which would break all custom @Setup.hs@ files, so for the
  -- moment we just have to live with this deficiency. If you're interested, see
  -- ticket #57.
  
  module Distribution.Compiler (
    -- * Compiler flavor
    CompilerFlavor(..),
    buildCompilerId,
    buildCompilerFlavor,
    defaultCompilerFlavor,
    parseCompilerFlavorCompat,
    classifyCompilerFlavor,
  
    -- * Compiler id
    CompilerId(..),
  
    -- * Compiler info
    CompilerInfo(..),
    unknownCompilerInfo,
    AbiTag(..), abiTagString
    ) where
  
  import Prelude ()
  import Distribution.Compat.Prelude
  
  import Language.Haskell.Extension
  
  import Distribution.Version (Version, mkVersion', nullVersion)
  
  import qualified System.Info (compilerName, compilerVersion)
  import Distribution.Text (Text(..), display)
  import qualified Distribution.Compat.ReadP as Parse
  import qualified Text.PrettyPrint as Disp
  
  data CompilerFlavor =
    GHC | GHCJS | NHC | YHC | Hugs | HBC | Helium | JHC | LHC | UHC
    | Eta
    | HaskellSuite String -- string is the id of the actual compiler
    | OtherCompiler String
    deriving (Generic, Show, Read, Eq, Ord, Typeable, Data)
  
  instance Binary CompilerFlavor
  
  knownCompilerFlavors :: [CompilerFlavor]
  knownCompilerFlavors = [GHC, GHCJS, Eta, NHC, YHC, Hugs, HBC, Helium, JHC, LHC, UHC]
  
  instance Text CompilerFlavor where
    disp (OtherCompiler name) = Disp.text name
    disp (HaskellSuite name)  = Disp.text name
    disp NHC                  = Disp.text "nhc98"
    disp other                = Disp.text (lowercase (show other))
  
    parse = do
      comp <- Parse.munch1 isAlphaNum
      when (all isDigit comp) Parse.pfail
      return (classifyCompilerFlavor comp)
  
  classifyCompilerFlavor :: String -> CompilerFlavor
  classifyCompilerFlavor s =
    fromMaybe (OtherCompiler s) $ lookup (lowercase s) compilerMap
    where
      compilerMap = [ (display compiler, compiler)
                    | compiler <- knownCompilerFlavors ]
  
  
  --TODO: In some future release, remove 'parseCompilerFlavorCompat' and use
  -- ordinary 'parse'. Also add ("nhc", NHC) to the above 'compilerMap'.
  
  -- | Like 'classifyCompilerFlavor' but compatible with the old ReadS parser.
  --
  -- It is compatible in the sense that it accepts only the same strings,
  -- eg "GHC" but not "ghc". However other strings get mapped to 'OtherCompiler'.
  -- The point of this is that we do not allow extra valid values that would
  -- upset older Cabal versions that had a stricter parser however we cope with
  -- new values more gracefully so that we'll be able to introduce new value in
  -- future without breaking things so much.
  --
  parseCompilerFlavorCompat :: Parse.ReadP r CompilerFlavor
  parseCompilerFlavorCompat = do
    comp <- Parse.munch1 isAlphaNum
    when (all isDigit comp) Parse.pfail
    case lookup comp compilerMap of
      Just compiler -> return compiler
      Nothing       -> return (OtherCompiler comp)
    where
      compilerMap = [ (show compiler, compiler)
                    | compiler <- knownCompilerFlavors
                    , compiler /= YHC ]
  
  buildCompilerFlavor :: CompilerFlavor
  buildCompilerFlavor = classifyCompilerFlavor System.Info.compilerName
  
  buildCompilerVersion :: Version
  buildCompilerVersion = mkVersion' System.Info.compilerVersion
  
  buildCompilerId :: CompilerId
  buildCompilerId = CompilerId buildCompilerFlavor buildCompilerVersion
  
  -- | The default compiler flavour to pick when compiling stuff. This defaults
  -- to the compiler used to build the Cabal lib.
  --
  -- However if it's not a recognised compiler then it's 'Nothing' and the user
  -- will have to specify which compiler they want.
  --
  defaultCompilerFlavor :: Maybe CompilerFlavor
  defaultCompilerFlavor = Just Eta
  
  -- ------------------------------------------------------------
  -- * Compiler Id
  -- ------------------------------------------------------------
  
  data CompilerId = CompilerId CompilerFlavor Version
    deriving (Eq, Generic, Ord, Read, Show)
  
  instance Binary CompilerId
  
  instance Text CompilerId where
    disp (CompilerId f v)
      | v == nullVersion = disp f
      | otherwise        = disp f <<>> Disp.char '-' <<>> disp v
  
    parse = do
      flavour <- parse
      version <- (Parse.char '-' >> parse) Parse.<++ return nullVersion
      return (CompilerId flavour version)
  
  lowercase :: String -> String
  lowercase = map toLower
  
  -- ------------------------------------------------------------
  -- * Compiler Info
  -- ------------------------------------------------------------
  
  -- | Compiler information used for resolving configurations. Some
  --   fields can be set to Nothing to indicate that the information is
  --   unknown.
  
  data CompilerInfo = CompilerInfo {
           compilerInfoId         :: CompilerId,
           -- ^ Compiler flavour and version.
           compilerInfoAbiTag     :: AbiTag,
           -- ^ Tag for distinguishing incompatible ABI's on the same
           -- architecture/os.
           compilerInfoCompat     :: Maybe [CompilerId],
           -- ^ Other implementations that this compiler claims to be
           -- compatible with, if known.
           compilerInfoLanguages  :: Maybe [Language],
           -- ^ Supported language standards, if known.
           compilerInfoExtensions :: Maybe [Extension]
           -- ^ Supported extensions, if known.
       }
       deriving (Generic, Show, Read)
  
  instance Binary CompilerInfo
  
  data AbiTag
    = NoAbiTag
    | AbiTag String
    deriving (Eq, Generic, Show, Read)
  
  instance Binary AbiTag
  
  instance Text AbiTag where
    disp NoAbiTag     = Disp.empty
    disp (AbiTag tag) = Disp.text tag
  
    parse = do
      tag <- Parse.munch (\c -> isAlphaNum c || c == '_')
      if null tag then return NoAbiTag else return (AbiTag tag)
  
  abiTagString :: AbiTag -> String
  abiTagString NoAbiTag     = ""
  abiTagString (AbiTag tag) = tag
  
  -- | Make a CompilerInfo of which only the known information is its CompilerId,
  --   its AbiTag and that it does not claim to be compatible with other
  --   compiler id's.
  unknownCompilerInfo :: CompilerId -> AbiTag -> CompilerInfo
  unknownCompilerInfo compilerId abiTag =
    CompilerInfo compilerId abiTag (Just []) Nothing Nothing
  