content: {-# LANGUAGE CPP #-}
  {-# LANGUAGE DeriveDataTypeable #-}
  {-# LANGUAGE FlexibleContexts #-}
  {-# LANGUAGE RankNTypes #-}
  {-# LANGUAGE ScopedTypeVariables #-}
  -----------------------------------------------------------------------------
  -- |
  -- Module      :  Distribution.PackageDescription.Parse
  -- Copyright   :  Isaac Jones 2003-2005
  -- License     :  BSD3
  --
  -- Maintainer  :  cabal-devel@haskell.org
  -- Portability :  portable
  --
  -- This defined parsers and partial pretty printers for the @.cabal@ format.
  -- Some of the complexity in this module is due to the fact that we have to be
  -- backwards compatible with old @.cabal@ files, so there's code to translate
  -- into the newer structure.
  
  module Distribution.PackageDescription.Parse (
          -- * Package descriptions
          readGenericPackageDescription,
          parseGenericPackageDescription,
  
          -- ** Deprecated names
          readPackageDescription,
          parsePackageDescription,
  
          -- ** Parsing
          ParseResult(..),
          FieldDescr(..),
          LineNo,
  
          -- ** Private, but needed for pretty-printer
          TestSuiteStanza(..),
          BenchmarkStanza(..),
  
          -- ** Supplementary build information
          readHookedBuildInfo,
          parseHookedBuildInfo,
  
          pkgDescrFieldDescrs,
          libFieldDescrs,
          foreignLibFieldDescrs,
          executableFieldDescrs,
          binfoFieldDescrs,
          sourceRepoFieldDescrs,
          testSuiteFieldDescrs,
          benchmarkFieldDescrs,
          flagFieldDescrs
    ) where
  
  import Prelude ()
  import Distribution.Compat.Prelude
  
  import Distribution.Types.Dependency
  import Distribution.Types.ForeignLib
  import Distribution.Types.ForeignLibType
  import Distribution.Types.UnqualComponentName
  import Distribution.Types.CondTree
  import Distribution.Types.PackageId
  import Distribution.ParseUtils hiding (parseFields)
  import Distribution.PackageDescription
  import Distribution.PackageDescription.Utils
  import Distribution.Package
  import Distribution.ModuleName
  import Distribution.Version
  import Distribution.Verbosity
  import Distribution.Compiler
  import Distribution.PackageDescription.Configuration
  import Distribution.Simple.Utils
  import Distribution.Text
  import Distribution.Compat.ReadP hiding (get)
  
  import Data.List        (partition, (\\))
  import System.Directory (doesFileExist)
  import Control.Monad    (mapM)
  
  import Text.PrettyPrint
         (vcat, ($$), (<+>), text, render,
          comma, fsep, nest, ($+$), punctuate)
  
  
  -- -----------------------------------------------------------------------------
  -- The PackageDescription type
  
  pkgDescrFieldDescrs :: [FieldDescr PackageDescription]
  pkgDescrFieldDescrs =
      [ simpleField "name"
             disp                   parse
             packageName            (\name pkg -> pkg{package=(package pkg){pkgName=name}})
   , simpleField "version"
             disp                   parse
             packageVersion         (\ver pkg -> pkg{package=(package pkg){pkgVersion=ver}})
   , simpleField "cabal-version"
             (either disp disp)     (liftM Left parse +++ liftM Right parse)
             specVersionRaw         (\v pkg -> pkg{specVersionRaw=v})
   , simpleField "build-type"
             (maybe mempty disp)  (fmap Just parse)
             buildType              (\t pkg -> pkg{buildType=t})
   , simpleField "license"
             disp                   parseLicenseQ
             license                (\l pkg -> pkg{license=l})
     -- We have both 'license-file' and 'license-files' fields.
     -- Rather than declaring license-file to be deprecated, we will continue
     -- to allow both. The 'license-file' will continue to only allow single
     -- tokens, while 'license-files' allows multiple. On pretty-printing, we
     -- will use 'license-file' if there's just one, and use 'license-files'
     -- otherwise.
   , simpleField "license-file"
             showFilePath           parseFilePathQ
             (\pkg -> case licenseFiles pkg of
                        [x] -> x
                        _   -> "")
             (\l pkg -> pkg{licenseFiles=licenseFiles pkg ++ [l]})
   , listField "license-files"
             showFilePath           parseFilePathQ
             (\pkg -> case licenseFiles pkg of
                        [_] -> []
                        xs  -> xs)
             (\ls pkg -> pkg{licenseFiles=ls})
   , simpleField "copyright"
             showFreeText           parseFreeText
             copyright              (\val pkg -> pkg{copyright=val})
   , simpleField "maintainer"
             showFreeText           parseFreeText
             maintainer             (\val pkg -> pkg{maintainer=val})
   , simpleField "stability"
             showFreeText           parseFreeText
             stability              (\val pkg -> pkg{stability=val})
   , simpleField "homepage"
             showFreeText           parseFreeText
             homepage               (\val pkg -> pkg{homepage=val})
   , simpleField "package-url"
             showFreeText           parseFreeText
             pkgUrl                 (\val pkg -> pkg{pkgUrl=val})
   , simpleField "bug-reports"
             showFreeText           parseFreeText
             bugReports             (\val pkg -> pkg{bugReports=val})
   , simpleField "synopsis"
             showFreeText           parseFreeText
             synopsis               (\val pkg -> pkg{synopsis=val})
   , simpleField "description"
             showFreeText           parseFreeText
             description            (\val pkg -> pkg{description=val})
   , simpleField "category"
             showFreeText           parseFreeText
             category               (\val pkg -> pkg{category=val})
   , simpleField "author"
             showFreeText           parseFreeText
             author                 (\val pkg -> pkg{author=val})
   , listField "tested-with"
             showTestedWith         parseTestedWithQ
             testedWith             (\val pkg -> pkg{testedWith=val})
   , listFieldWithSep vcat "data-files"
             showFilePath           parseFilePathQ
             dataFiles              (\val pkg -> pkg{dataFiles=val})
   , simpleField "data-dir"
             showFilePath           parseFilePathQ
             dataDir                (\val pkg -> pkg{dataDir=val})
   , listFieldWithSep vcat "extra-source-files"
             showFilePath    parseFilePathQ
             extraSrcFiles          (\val pkg -> pkg{extraSrcFiles=val})
   , listFieldWithSep vcat "extra-tmp-files"
             showFilePath       parseFilePathQ
             extraTmpFiles          (\val pkg -> pkg{extraTmpFiles=val})
   , listFieldWithSep vcat "extra-doc-files"
             showFilePath    parseFilePathQ
             extraDocFiles          (\val pkg -> pkg{extraDocFiles=val})
   ]
  
  -- | Store any fields beginning with "x-" in the customFields field of
  --   a PackageDescription.  All other fields will generate a warning.
  storeXFieldsPD :: UnrecFieldParser PackageDescription
  storeXFieldsPD (f@('x':'-':_),val) pkg =
    Just pkg{ customFieldsPD =
                 customFieldsPD pkg ++ [(f,val)]}
  storeXFieldsPD _ _ = Nothing
  
  -- ---------------------------------------------------------------------------
  -- The Library type
  
  libFieldDescrs :: [FieldDescr Library]
  libFieldDescrs =
    [ listFieldWithSep vcat "exposed-modules" disp parseModuleNameQ
        exposedModules (\mods lib -> lib{exposedModules=mods})
  
    , commaListFieldWithSep vcat "reexported-modules" disp parse
        reexportedModules (\mods lib -> lib{reexportedModules=mods})
  
    , listFieldWithSep vcat "signatures" disp parseModuleNameQ
        signatures (\mods lib -> lib{signatures=mods})
  
    , boolField "exposed"
        libExposed     (\val lib -> lib{libExposed=val})
    ] ++ map biToLib binfoFieldDescrs
    where biToLib = liftField libBuildInfo (\bi lib -> lib{libBuildInfo=bi})
  
  storeXFieldsLib :: UnrecFieldParser Library
  storeXFieldsLib (f@('x':'-':_), val) l@(Library { libBuildInfo = bi }) =
      Just $ l {libBuildInfo =
                   bi{ customFieldsBI = customFieldsBI bi ++ [(f,val)]}}
  storeXFieldsLib _ _ = Nothing
  
  -- ---------------------------------------------------------------------------
  -- Foreign libraries
  
  foreignLibFieldDescrs :: [FieldDescr ForeignLib]
  foreignLibFieldDescrs =
    [ simpleField "type"
        disp                   parse
        foreignLibType         (\x flib -> flib { foreignLibType = x })
    , listField "options"
        disp                   parse
        foreignLibOptions      (\x flib -> flib { foreignLibOptions = x })
    , simpleField "lib-version-info"
        (maybe mempty disp)    (fmap Just parse)
        foreignLibVersionInfo  (\x flib -> flib { foreignLibVersionInfo = x })
    , simpleField "lib-version-linux"
        (maybe mempty disp)    (fmap Just parse)
        foreignLibVersionLinux (\x flib -> flib { foreignLibVersionLinux = x })
    , listField "mod-def-file"
        showFilePath           parseFilePathQ
        foreignLibModDefFile   (\x flib -> flib { foreignLibModDefFile = x })
    ]
    ++ map biToFLib binfoFieldDescrs
    where biToFLib = liftField foreignLibBuildInfo $ \bi flib ->
            flib { foreignLibBuildInfo = bi }
  
  storeXFieldsForeignLib :: UnrecFieldParser ForeignLib
  storeXFieldsForeignLib (f@('x':'-':_), val)
                          l@(ForeignLib { foreignLibBuildInfo = bi }) =
      Just $ l { foreignLibBuildInfo = bi {
                     customFieldsBI = (f,val):customFieldsBI bi
                   }
               }
  storeXFieldsForeignLib _ _ = Nothing
  
  -- ---------------------------------------------------------------------------
  -- The Executable type
  
  
  executableFieldDescrs :: [FieldDescr Executable]
  executableFieldDescrs =
    [ simpleField "main-is"
                             showFilePath       parseFilePathQ
                             modulePath         (\xs    exe -> exe{modulePath=xs})
    ]
    ++ map biToExe binfoFieldDescrs
    where biToExe = liftField buildInfo (\bi exe -> exe{buildInfo=bi})
  
  storeXFieldsExe :: UnrecFieldParser Executable
  storeXFieldsExe (f@('x':'-':_), val) e@(Executable { buildInfo = bi }) =
      Just $ e {buildInfo = bi{ customFieldsBI = (f,val):customFieldsBI bi}}
  storeXFieldsExe _ _ = Nothing
  
  -- ---------------------------------------------------------------------------
  -- The TestSuite type
  
  -- | An intermediate type just used for parsing the test-suite stanza.
  -- After validation it is converted into the proper 'TestSuite' type.
  data TestSuiteStanza = TestSuiteStanza {
         testStanzaTestType   :: Maybe TestType,
         testStanzaMainIs     :: Maybe FilePath,
         testStanzaTestModule :: Maybe ModuleName,
         testStanzaBuildInfo  :: BuildInfo
       }
  
  emptyTestStanza :: TestSuiteStanza
  emptyTestStanza = TestSuiteStanza Nothing Nothing Nothing mempty
  
  testSuiteFieldDescrs :: [FieldDescr TestSuiteStanza]
  testSuiteFieldDescrs =
      [ simpleField "type"
          (maybe mempty disp) (fmap Just parse)
          testStanzaTestType    (\x suite -> suite { testStanzaTestType = x })
      , simpleField "main-is"
          (maybe mempty showFilePath)  (fmap Just parseFilePathQ)
          testStanzaMainIs      (\x suite -> suite { testStanzaMainIs = x })
      , simpleField "test-module"
          (maybe mempty disp) (fmap Just parseModuleNameQ)
          testStanzaTestModule  (\x suite -> suite { testStanzaTestModule = x })
      ]
      ++ map biToTest binfoFieldDescrs
    where
      biToTest = liftField testStanzaBuildInfo
                           (\bi suite -> suite { testStanzaBuildInfo = bi })
  
  storeXFieldsTest :: UnrecFieldParser TestSuiteStanza
  storeXFieldsTest (f@('x':'-':_), val) t@(TestSuiteStanza { testStanzaBuildInfo = bi }) =
      Just $ t {testStanzaBuildInfo = bi{ customFieldsBI = (f,val):customFieldsBI bi}}
  storeXFieldsTest _ _ = Nothing
  
  validateTestSuite :: LineNo -> TestSuiteStanza -> ParseResult TestSuite
  validateTestSuite line stanza =
      case testStanzaTestType stanza of
        Nothing -> return $
          emptyTestSuite { testBuildInfo = testStanzaBuildInfo stanza }
  
        Just tt@(TestTypeUnknown _ _) ->
          return emptyTestSuite {
            testInterface = TestSuiteUnsupported tt,
            testBuildInfo = testStanzaBuildInfo stanza
          }
  
        Just tt | tt `notElem` knownTestTypes ->
          return emptyTestSuite {
            testInterface = TestSuiteUnsupported tt,
            testBuildInfo = testStanzaBuildInfo stanza
          }
  
        Just tt@(TestTypeExe ver) ->
          case testStanzaMainIs stanza of
            Nothing   -> syntaxError line (missingField "main-is" tt)
            Just file -> do
              when (isJust (testStanzaTestModule stanza)) $
                warning (extraField "test-module" tt)
              return emptyTestSuite {
                testInterface = TestSuiteExeV10 ver file,
                testBuildInfo = testStanzaBuildInfo stanza
              }
  
        Just tt@(TestTypeLib ver) ->
          case testStanzaTestModule stanza of
            Nothing      -> syntaxError line (missingField "test-module" tt)
            Just module_ -> do
              when (isJust (testStanzaMainIs stanza)) $
                warning (extraField "main-is" tt)
              return emptyTestSuite {
                testInterface = TestSuiteLibV09 ver module_,
                testBuildInfo = testStanzaBuildInfo stanza
              }
  
    where
      missingField name tt = "The '" ++ name ++ "' field is required for the "
                          ++ display tt ++ " test suite type."
  
      extraField   name tt = "The '" ++ name ++ "' field is not used for the '"
                          ++ display tt ++ "' test suite type."
  
  
  -- ---------------------------------------------------------------------------
  -- The Benchmark type
  
  -- | An intermediate type just used for parsing the benchmark stanza.
  -- After validation it is converted into the proper 'Benchmark' type.
  data BenchmarkStanza = BenchmarkStanza {
         benchmarkStanzaBenchmarkType   :: Maybe BenchmarkType,
         benchmarkStanzaMainIs          :: Maybe FilePath,
         benchmarkStanzaBenchmarkModule :: Maybe ModuleName,
         benchmarkStanzaBuildInfo       :: BuildInfo
       }
  
  emptyBenchmarkStanza :: BenchmarkStanza
  emptyBenchmarkStanza = BenchmarkStanza Nothing Nothing Nothing mempty
  
  benchmarkFieldDescrs :: [FieldDescr BenchmarkStanza]
  benchmarkFieldDescrs =
      [ simpleField "type"
          (maybe mempty disp)    (fmap Just parse)
          benchmarkStanzaBenchmarkType
          (\x suite -> suite { benchmarkStanzaBenchmarkType = x })
      , simpleField "main-is"
          (maybe mempty showFilePath)  (fmap Just parseFilePathQ)
          benchmarkStanzaMainIs
          (\x suite -> suite { benchmarkStanzaMainIs = x })
      ]
      ++ map biToBenchmark binfoFieldDescrs
    where
      biToBenchmark = liftField benchmarkStanzaBuildInfo
                      (\bi suite -> suite { benchmarkStanzaBuildInfo = bi })
  
  storeXFieldsBenchmark :: UnrecFieldParser BenchmarkStanza
  storeXFieldsBenchmark (f@('x':'-':_), val)
      t@(BenchmarkStanza { benchmarkStanzaBuildInfo = bi }) =
          Just $ t {benchmarkStanzaBuildInfo =
                         bi{ customFieldsBI = (f,val):customFieldsBI bi}}
  storeXFieldsBenchmark _ _ = Nothing
  
  validateBenchmark :: LineNo -> BenchmarkStanza -> ParseResult Benchmark
  validateBenchmark line stanza =
      case benchmarkStanzaBenchmarkType stanza of
        Nothing -> return $
          emptyBenchmark { benchmarkBuildInfo = benchmarkStanzaBuildInfo stanza }
  
        Just tt@(BenchmarkTypeUnknown _ _) ->
          return emptyBenchmark {
            benchmarkInterface = BenchmarkUnsupported tt,
            benchmarkBuildInfo = benchmarkStanzaBuildInfo stanza
          }
  
        Just tt | tt `notElem` knownBenchmarkTypes ->
          return emptyBenchmark {
            benchmarkInterface = BenchmarkUnsupported tt,
            benchmarkBuildInfo = benchmarkStanzaBuildInfo stanza
          }
  
        Just tt@(BenchmarkTypeExe ver) ->
          case benchmarkStanzaMainIs stanza of
            Nothing   -> syntaxError line (missingField "main-is" tt)
            Just file -> do
              when (isJust (benchmarkStanzaBenchmarkModule stanza)) $
                warning (extraField "benchmark-module" tt)
              return emptyBenchmark {
                benchmarkInterface = BenchmarkExeV10 ver file,
                benchmarkBuildInfo = benchmarkStanzaBuildInfo stanza
              }
  
    where
      missingField name tt = "The '" ++ name ++ "' field is required for the "
                          ++ display tt ++ " benchmark type."
  
      extraField   name tt = "The '" ++ name ++ "' field is not used for the '"
                          ++ display tt ++ "' benchmark type."
  
  -- ---------------------------------------------------------------------------
  -- The BuildInfo type
  
  binfoFieldDescrs :: [FieldDescr BuildInfo]
  binfoFieldDescrs =
   [ boolField "buildable"
             buildable          (\val binfo -> binfo{buildable=val})
   , commaListField  "build-tools"
             disp               parse
             buildTools         (\xs  binfo -> binfo{buildTools=xs})
   , commaListField  "build-tool-depends"
             disp               parse
             buildToolDepends   (\xs  binfo -> binfo{buildToolDepends=xs})
   , commaListFieldWithSep vcat "build-depends"
             disp                   parse
             targetBuildDepends (\xs binfo -> binfo{targetBuildDepends=xs})
   , commaListFieldWithSep vcat "mixins"
             disp                   parse
             mixins   (\xs binfo -> binfo{mixins=xs})
   , spaceListField "cpp-options"
             showToken          parseTokenQ'
             cppOptions          (\val binfo -> binfo{cppOptions=val})
   , spaceListField "cc-options"
             showToken          parseTokenQ'
             ccOptions          (\val binfo -> binfo{ccOptions=val})
   , spaceListField "ld-options"
             showToken          parseTokenQ'
             ldOptions          (\val binfo -> binfo{ldOptions=val})
   , commaListField  "pkgconfig-depends"
             disp               parse
             pkgconfigDepends   (\xs  binfo -> binfo{pkgconfigDepends=xs})
   , listField "frameworks"
             showToken          parseTokenQ
             frameworks         (\val binfo -> binfo{frameworks=val})
   , listField "extra-framework-dirs"
             showToken          parseFilePathQ
             extraFrameworkDirs (\val binfo -> binfo{extraFrameworkDirs=val})
   , listFieldWithSep vcat "maven-repos"
             showToken          parseTokenQ
             frameworks         (\paths binfo -> binfo{frameworks=paths})
   , listFieldWithSep vcat "c-sources"
             showFilePath       parseFilePathQ
             cSources           (\paths binfo -> binfo{cSources=paths})
   , listFieldWithSep vcat "js-sources"
             showFilePath       parseFilePathQ
             jsSources          (\paths binfo -> binfo{jsSources=paths})
   , listFieldWithSep vcat "java-sources"
             showFilePath       parseFilePathQ
             javaSources        (\paths binfo -> binfo{javaSources=paths})
   , commaListFieldWithSep vcat "maven-depends"
             showToken          parseTokenQ
             extraLibs          (\xs    binfo -> binfo{extraLibs=xs})
   , simpleField "default-language"
             (maybe mempty disp) (option Nothing (fmap Just parseLanguageQ))
             defaultLanguage    (\lang  binfo -> binfo{defaultLanguage=lang})
   , listField   "other-languages"
             disp               parseLanguageQ
             otherLanguages     (\langs binfo -> binfo{otherLanguages=langs})
   , listField   "default-extensions"
             disp               parseExtensionQ
             defaultExtensions  (\exts  binfo -> binfo{defaultExtensions=exts})
   , listField   "other-extensions"
             disp               parseExtensionQ
             otherExtensions    (\exts  binfo -> binfo{otherExtensions=exts})
   , listField   "extensions"
             disp               parseExtensionQ
             oldExtensions      (\exts  binfo -> binfo{oldExtensions=exts})
  
   , listFieldWithSep vcat "extra-libraries"
             showToken          parseTokenQ
             extraLibs          (\xs    binfo -> binfo{extraLibs=xs})
   , listFieldWithSep vcat "extra-ghci-libraries"
             showToken          parseTokenQ
             extraGHCiLibs      (\xs    binfo -> binfo{extraGHCiLibs=xs})
   , listField   "extra-lib-dirs"
             showFilePath       parseFilePathQ
             extraLibDirs       (\xs    binfo -> binfo{extraLibDirs=xs})
   , listFieldWithSep vcat "includes"
             showFilePath       parseFilePathQ
             includes           (\paths binfo -> binfo{includes=paths})
   , listFieldWithSep vcat "install-includes"
             showFilePath       parseFilePathQ
             installIncludes    (\paths binfo -> binfo{installIncludes=paths})
   , listField   "include-dirs"
             showFilePath       parseFilePathQ
             includeDirs        (\paths binfo -> binfo{includeDirs=paths})
   , listField   "hs-source-dirs"
             showFilePath       parseFilePathQ
             hsSourceDirs       (\paths binfo -> binfo{hsSourceDirs=paths})
   , listFieldWithSep vcat "other-modules"
             disp               parseModuleNameQ
             otherModules       (\val binfo -> binfo{otherModules=val})
   , listFieldWithSep vcat "autogen-modules"
             disp               parseModuleNameQ
             autogenModules       (\val binfo -> binfo{autogenModules=val})
   , optsField   "ghc-prof-options" GHC
             profOptions        (\val binfo -> binfo{profOptions=val})
   , optsField   "ghcjs-prof-options" GHCJS
             profOptions        (\val binfo -> binfo{profOptions=val})
   , optsField   "ghc-shared-options" GHC
             sharedOptions      (\val binfo -> binfo{sharedOptions=val})
   , optsField   "ghcjs-shared-options" GHCJS
             sharedOptions      (\val binfo -> binfo{sharedOptions=val})
   , optsField   "eta-shared-options" Eta
              sharedOptions      (\val binfo -> binfo{sharedOptions=val})
   , optsField   "ghc-options"  GHC
             options            (\path  binfo -> binfo{options=path})
   , optsField   "ghcjs-options" GHCJS
             options            (\path  binfo -> binfo{options=path})
   , optsField   "eta-options" Eta
             options            (\path  binfo -> binfo{options=path})
   , optsField   "jhc-options"  JHC
             options            (\path  binfo -> binfo{options=path})
  
   -- NOTE: Hugs and NHC are not supported anymore, but these fields are kept
   -- around for backwards compatibility.
   , optsField   "hugs-options" Hugs
             options            (const id)
   , optsField   "nhc98-options" NHC
             options            (const id)
   ]
  
  storeXFieldsBI :: UnrecFieldParser BuildInfo
  storeXFieldsBI (f@('x':'-':_),val) bi = Just bi{ customFieldsBI = (f,val):customFieldsBI bi }
  storeXFieldsBI _ _ = Nothing
  
  ------------------------------------------------------------------------------
  
  flagFieldDescrs :: [FieldDescr Flag]
  flagFieldDescrs =
      [ simpleField "description"
          showFreeText     parseFreeText
          flagDescription  (\val fl -> fl{ flagDescription = val })
      , boolField "default"
          flagDefault      (\val fl -> fl{ flagDefault = val })
      , boolField "manual"
          flagManual       (\val fl -> fl{ flagManual = val })
      ]
  
  ------------------------------------------------------------------------------
  
  sourceRepoFieldDescrs :: [FieldDescr SourceRepo]
  sourceRepoFieldDescrs =
      [ simpleField "type"
          (maybe mempty disp)         (fmap Just parse)
          repoType                   (\val repo -> repo { repoType = val })
      , simpleField "location"
          (maybe mempty showFreeText) (fmap Just parseFreeText)
          repoLocation               (\val repo -> repo { repoLocation = val })
      , simpleField "module"
          (maybe mempty showToken)    (fmap Just parseTokenQ)
          repoModule                 (\val repo -> repo { repoModule = val })
      , simpleField "branch"
          (maybe mempty showToken)    (fmap Just parseTokenQ)
          repoBranch                 (\val repo -> repo { repoBranch = val })
      , simpleField "tag"
          (maybe mempty showToken)    (fmap Just parseTokenQ)
          repoTag                    (\val repo -> repo { repoTag = val })
      , simpleField "commit"
          (maybe mempty showToken)    (fmap Just parseTokenQ)
          repoCommit                  (\val repo -> repo { repoCommit = val })
      , simpleField "subdir"
          (maybe mempty showFilePath) (fmap Just parseFilePathQ)
          repoSubdir                 (\val repo -> repo { repoSubdir = val })
      ]
  
  ------------------------------------------------------------------------------
  
  setupBInfoFieldDescrs :: [FieldDescr SetupBuildInfo]
  setupBInfoFieldDescrs =
      [ commaListFieldWithSep vcat "setup-depends"
          disp         parse
          setupDepends (\xs binfo -> binfo{setupDepends=xs})
      ]
  
  -- ---------------------------------------------------------------
  -- Parsing
  
  -- | Given a parser and a filename, return the parse of the file,
  -- after checking if the file exists.
  readAndParseFile :: (FilePath -> (String -> IO a) -> IO a)
                   -> (String -> ParseResult a)
                   -> Verbosity
                   -> FilePath -> IO a
  readAndParseFile withFileContents' parser verbosity fpath = do
    exists <- doesFileExist fpath
    unless exists $
      die' verbosity $
        "Error Parsing: file \"" ++ fpath ++ "\" doesn't exist. Cannot continue."
    withFileContents' fpath $ \str -> case parser str of
      ParseFailed e -> do
          let (line, message) = locatedErrorMsg e
          dieWithLocation' verbosity fpath line message
      ParseOk warnings x -> do
          traverse_ (warn verbosity . showPWarning fpath) $ reverse warnings
          return x
  
  readHookedBuildInfo :: Verbosity -> FilePath -> IO HookedBuildInfo
  readHookedBuildInfo =
      readAndParseFile withFileContents parseHookedBuildInfo
  
  readPackageDescription :: Verbosity -> FilePath -> IO GenericPackageDescription
  readPackageDescription = readGenericPackageDescription
  {-# DEPRECATED readPackageDescription "Use readGenericPackageDescription, old name is missleading." #-}
  
  -- | Parse the given package file.
  readGenericPackageDescription :: Verbosity -> FilePath -> IO GenericPackageDescription
  readGenericPackageDescription =
      readAndParseFile withUTF8FileContents parseGenericPackageDescription
  
  stanzas :: [Field] -> [[Field]]
  stanzas [] = []
  stanzas (f:fields) = (f:this) : stanzas rest
    where
      (this, rest) = break isStanzaHeader fields
  
  isStanzaHeader :: Field -> Bool
  isStanzaHeader (F _ f _) = f == "executable"
  isStanzaHeader _ = False
  
  ------------------------------------------------------------------------------
  
  
  mapSimpleFields :: (Field -> ParseResult Field) -> [Field]
                  -> ParseResult [Field]
  mapSimpleFields f = traverse walk
    where
      walk fld@F{} = f fld
      walk (IfBlock l c fs1 fs2) = do
        fs1' <- traverse walk fs1
        fs2' <- traverse walk fs2
        return (IfBlock l c fs1' fs2')
      walk (Section ln n l fs1) = do
        fs1' <-  traverse walk fs1
        return (Section ln n l fs1')
  
  -- prop_isMapM fs = mapSimpleFields return fs == return fs
  
  
  -- names of fields that represents dependencies
  -- TODO: maybe build-tools should go here too?
  constraintFieldNames :: [String]
  constraintFieldNames = ["build-depends"]
  
  -- Possible refactoring would be to have modifiers be explicit about what
  -- they add and define an accessor that specifies what the dependencies
  -- are.  This way we would completely reuse the parsing knowledge from the
  -- field descriptor.
  parseConstraint :: Field -> ParseResult [Dependency]
  parseConstraint (F l n v)
      | n `elem` constraintFieldNames = runP l n (parseCommaList parse) v
  parseConstraint f = userBug $ "Constraint was expected (got: " ++ show f ++ ")"
  
  {-
  headerFieldNames :: [String]
  headerFieldNames = filter (\n -> not (n `elem` constraintFieldNames))
                   . map fieldName $ pkgDescrFieldDescrs
  -}
  
  libFieldNames :: [String]
  libFieldNames = map fieldName libFieldDescrs
                  ++ buildInfoNames ++ constraintFieldNames
  
  -- exeFieldNames :: [String]
  -- exeFieldNames = map fieldName executableFieldDescrs
  --                 ++ buildInfoNames
  
  buildInfoNames :: [String]
  buildInfoNames = map fieldName binfoFieldDescrs
                  ++ map fst deprecatedFieldsBuildInfo
  
  -- A minimal implementation of the StateT monad transformer to avoid depending
  -- on the 'mtl' package.
  newtype StT s m a = StT { runStT :: s -> m (a,s) }
  
  instance Functor f => Functor (StT s f) where
      fmap g (StT f) = StT $ fmap (first g)  . f
  
  #if __GLASGOW_HASKELL__ >= 710
  instance (Monad m) => Applicative (StT s m) where
  #else
  instance (Monad m, Functor m) => Applicative (StT s m) where
  #endif
      pure a = StT (\s -> return (a,s))
      (<*>) = ap
  
  
  instance Monad m => Monad (StT s m) where
  #if __GLASGOW_HASKELL__ < 710
      return a = StT (\s -> return (a,s))
  #endif
      StT f >>= g = StT $ \s -> do
                          (a,s') <- f s
                          runStT (g a) s'
  
  getSt :: Monad m => StT s m s
  getSt = StT $ \s -> return (s, s)
  
  modify :: Monad m => (s -> s) -> StT s m ()
  modify f = StT $ \s -> return ((),f s)
  
  lift :: Monad m => m a -> StT s m a
  lift m = StT $ \s -> m >>= \a -> return (a,s)
  
  evalStT :: Monad m => StT s m a -> s -> m a
  evalStT st s = liftM fst $ runStT st s
  
  -- Our monad for parsing a list/tree of fields.
  --
  -- The state represents the remaining fields to be processed.
  type PM a = StT [Field] ParseResult a
  
  
  
  -- return look-ahead field or nothing if we're at the end of the file
  peekField :: PM (Maybe Field)
  peekField = liftM listToMaybe getSt
  
  -- Unconditionally discard the first field in our state.  Will error when it
  -- reaches end of file.  (Yes, that's evil.)
  skipField :: PM ()
  skipField = modify tail
  
  --FIXME: this should take a ByteString, not a String. We have to be able to
  -- decode UTF8 and handle the BOM.
  
  parsePackageDescription :: String -> ParseResult GenericPackageDescription
  parsePackageDescription = parseGenericPackageDescription
  {-# DEPRECATED parsePackageDescription "Use parseGenericPackageDescription, old name is missleading" #-}
  
  -- | Parses the given file into a 'GenericPackageDescription'.
  --
  -- In Cabal 1.2 the syntax for package descriptions was changed to a format
  -- with sections and possibly indented property descriptions.
  parseGenericPackageDescription :: String -> ParseResult GenericPackageDescription
  parseGenericPackageDescription file = do
  
      -- This function is quite complex because it needs to be able to parse
      -- both pre-Cabal-1.2 and post-Cabal-1.2 files.  Additionally, it contains
      -- a lot of parser-related noise since we do not want to depend on Parsec.
      --
      -- If we detect an pre-1.2 file we implicitly convert it to post-1.2
      -- style.  See 'sectionizeFields' below for details about the conversion.
  
      fields0 <- readFields file `catchParseError` \err ->
                   let tabs = findIndentTabs file in
                   case err of
                     -- In case of a TabsError report them all at once.
                     TabsError tabLineNo -> reportTabsError
                     -- but only report the ones including and following
                     -- the one that caused the actual error
                                              [ t | t@(lineNo',_) <- tabs
                                                  , lineNo' >= tabLineNo ]
                     _ -> parseFail err
  
      let cabalVersionNeeded =
            head $ [ minVersionBound versionRange
                   | Just versionRange <- [ simpleParse v
                                          | F _ "cabal-version" v <- fields0 ] ]
                ++ [mkVersion [0]]
          minVersionBound versionRange =
            case asVersionIntervals versionRange of
              []                            -> mkVersion [0]
              ((LowerBound version _, _):_) -> version
  
      handleFutureVersionParseFailure cabalVersionNeeded $ do
  
        let sf = sectionizeFields fields0  -- ensure 1.2 format
  
          -- figure out and warn about deprecated stuff (warnings are collected
          -- inside our parsing monad)
        fields <- mapSimpleFields deprecField sf
  
          -- Our parsing monad takes the not-yet-parsed fields as its state.
          -- After each successful parse we remove the field from the state
          -- ('skipField') and move on to the next one.
          --
          -- Things are complicated a bit, because fields take a tree-like
          -- structure -- they can be sections or "if"/"else" conditionals.
  
        flip evalStT fields $ do
  
            -- The header consists of all simple fields up to the first section
            -- (flag, library, executable).
          header_fields <- getHeader []
  
            -- Parses just the header fields and stores them in a
            -- 'PackageDescription'.  Note that our final result is a
            -- 'GenericPackageDescription'; for pragmatic reasons we just store
            -- the partially filled-out 'PackageDescription' inside the
            -- 'GenericPackageDescription'.
          pkg <- lift $ parseFields pkgDescrFieldDescrs
                                    storeXFieldsPD
                                    emptyPackageDescription
                                    header_fields
  
            -- 'getBody' assumes that the remaining fields only consist of
            -- flags, lib and exe sections.
          (repos, flags, mcsetup, mlib, sub_libs, flibs, exes, tests, bms) <- getBody pkg
          warnIfRest  -- warn if getBody did not parse up to the last field.
            -- warn about using old/new syntax with wrong cabal-version:
          maybeWarnCabalVersion (not $ oldSyntax fields0) pkg
          checkForUndefinedFlags flags mlib sub_libs exes tests
          return $ GenericPackageDescription
                     pkg { sourceRepos = repos, setupBuildInfo = mcsetup }
                     flags mlib sub_libs flibs exes tests bms
  
    where
      oldSyntax = all isSimpleField
      reportTabsError tabs =
          syntaxError (fst (head tabs)) $
            "Do not use tabs for indentation (use spaces instead)\n"
            ++ "  Tabs were used at (line,column): " ++ show tabs
  
      maybeWarnCabalVersion newsyntax pkg
        | newsyntax && specVersion pkg < mkVersion [1,2]
        = lift $ warning $
               "A package using section syntax must specify at least\n"
            ++ "'cabal-version: >= 1.2'."
  
      maybeWarnCabalVersion newsyntax pkg
        | not newsyntax && specVersion pkg >= mkVersion [1,2]
        = lift $ warning $
               "A package using 'cabal-version: "
            ++ displaySpecVersion (specVersionRaw pkg)
            ++ "' must use section syntax. See the Cabal user guide for details."
        where
          displaySpecVersion (Left version)       = display version
          displaySpecVersion (Right versionRange) =
            case asVersionIntervals versionRange of
              [] {- impossible -}           -> display versionRange
              ((LowerBound version _, _):_) -> display (orLaterVersion version)
  
      maybeWarnCabalVersion _ _ = return ()
  
  
      -- In Eta, we don't really care about the version of the cabal-version field
      -- as we are not concerned with Cabal's backward compatibility.
      handleFutureVersionParseFailure cabalVersionNeeded parseBody = parseBody
          `catchParseError` \parseError -> case parseError of
          TabsError _   -> parseFail parseError
          _ | versionOk -> parseFail parseError
            | otherwise -> fail message
        where versionOk = cabalVersionNeeded <= cabalVersion
              message   = "This package requires at least Cabal version "
                       ++ display cabalVersionNeeded
  
      -- "Sectionize" an old-style Cabal file.  A sectionized file has:
      --
      --  * all global fields at the beginning, followed by
      --
      --  * all flag declarations, followed by
      --
      --  * an optional library section, and an arbitrary number of executable
      --    sections (in any order).
      --
      -- The current implementation just gathers all library-specific fields
      -- in a library section and wraps all executable stanzas in an executable
      -- section.
      sectionizeFields :: [Field] -> [Field]
      sectionizeFields fs
        | oldSyntax fs =
            let
              -- "build-depends" is a local field now.  To be backwards
              -- compatible, we still allow it as a global field in old-style
              -- package description files and translate it to a local field by
              -- adding it to every non-empty section
              (hdr0, exes0) = break ((=="executable") . fName) fs
              (hdr, libfs0) = partition (not . (`elem` libFieldNames) . fName) hdr0
  
              (deps, libfs) = partition ((== "build-depends") . fName)
                                         libfs0
  
              exes = unfoldr toExe exes0
              toExe [] = Nothing
              toExe (F l e n : r)
                | e == "executable" =
                    let (efs, r') = break ((=="executable") . fName) r
                    in Just (Section l "executable" n (deps ++ efs), r')
              toExe _ = cabalBug "unexpected input to 'toExe'"
            in
              hdr ++
             (if null libfs then []
              else [Section (lineNo (head libfs)) "library" "" (deps ++ libfs)])
              ++ exes
        | otherwise = fs
  
      isSimpleField F{} = True
      isSimpleField _ = False
  
      -- warn if there's something at the end of the file
      warnIfRest :: PM ()
      warnIfRest = do
        s <- getSt
        case s of
          [] -> return ()
          _ -> lift $ warning "Ignoring trailing declarations."  -- add line no.
  
      -- all simple fields at the beginning of the file are (considered) header
      -- fields
      getHeader :: [Field] -> PM [Field]
      getHeader acc = peekField >>= \mf -> case mf of
          Just f@F{} -> skipField >> getHeader (f:acc)
          _ -> return (reverse acc)
  
      --
      -- body ::= { repo | flag | library | sub library | foreign library
      --          | executable | test | bench }+
      --
      -- The body consists of an optional sequence of declarations of flags and
      -- an arbitrary number of components
      --
      -- TODO: This method is long due for a rewrite to use a accumulator
      -- data type, or perhaps some more general way of balling the
      -- components up.
      getBody :: PackageDescription
              -> PM ([SourceRepo], [Flag]
                    ,Maybe SetupBuildInfo
                    ,(Maybe (CondTree ConfVar [Dependency] Library))
                    ,[(UnqualComponentName, CondTree ConfVar [Dependency] Library)]
                    ,[(UnqualComponentName, CondTree ConfVar [Dependency] ForeignLib)]
                    ,[(UnqualComponentName, CondTree ConfVar [Dependency] Executable)]
                    ,[(UnqualComponentName, CondTree ConfVar [Dependency] TestSuite)]
                    ,[(UnqualComponentName, CondTree ConfVar [Dependency] Benchmark)])
      getBody pkg = peekField >>= \mf -> case mf of
        Just (Section line_no sec_type sec_label sec_fields)
          | sec_type == "executable" -> do
              when (null sec_label) $ lift $ syntaxError line_no
                "'executable' needs one argument (the executable's name)"
              exename <- lift $ runP line_no "executable" parseTokenQ sec_label
              flds <- collectFields parseExeFields sec_fields
              skipField
              (repos, flags, csetup, mlib, sub_libs, flibs, exes, tests, bms) <- getBody pkg
              return (repos, flags, csetup, mlib, sub_libs, flibs, (mkUnqualComponentName exename, flds): exes, tests, bms)
  
          | sec_type == "foreign-library" -> do
              when (null sec_label) $ lift $ syntaxError line_no
                "'foreign-library' needs one argument (the library's name)"
              libname <- lift $ runP line_no "foreign-library" parseTokenQ sec_label
              flds <- collectFields parseForeignLibFields sec_fields
  
              -- Check that a valid foreign library type has been chosen. A type
              -- field may be given inside a conditional block, so we must check
              -- for that before complaining that a type field has not been given.
              -- The foreign library must always have a valid type, so we need to
              -- check both the 'then' and 'else' blocks, though the blocks need
              -- not have the same type.
              let hasType ts = foreignLibType ts /= foreignLibType mempty
              if onAllBranches hasType flds
                  then do
                      skipField
                      (repos, flags, csetup, mlib, sub_libs, flibs, exes, tests, bms) <- getBody pkg
                      return (repos, flags, csetup, mlib, sub_libs, (mkUnqualComponentName libname, flds):flibs, exes, tests, bms)
                  else lift $ syntaxError line_no $
                           "Foreign library \"" ++ libname
                        ++ "\" is missing required field \"type\" or the field "
                        ++ "is not present in all conditional branches. The "
                        ++ "available test types are: "
                        ++ intercalate ", " (map display knownForeignLibTypes)
  
          | sec_type == "test-suite" -> do
              when (null sec_label) $ lift $ syntaxError line_no
                  "'test-suite' needs one argument (the test suite's name)"
              testname <- lift $ runP line_no "test" parseTokenQ sec_label
              flds <- collectFields (parseTestFields line_no) sec_fields
  
              -- Check that a valid test suite type has been chosen. A type field
              -- may be given inside a conditional block, so we must check for
              -- that before complaining that a type field has not been given. The
              -- test suite must always have a valid type, so we need to check
              -- both the 'then' and 'else' blocks, though the blocks need not
              -- have the same type.
              let hasType ts = testInterface ts /= testInterface mempty
              if onAllBranches hasType flds
                  then do
                      skipField
                      (repos, flags, csetup, mlib, sub_libs, flibs, exes, tests, bms) <- getBody pkg
                      return (repos, flags, csetup, mlib, sub_libs, flibs, exes,
                              (mkUnqualComponentName testname, flds) : tests, bms)
                  else lift $ syntaxError line_no $
                           "Test suite \"" ++ testname
                        ++ "\" is missing required field \"type\" or the field "
                        ++ "is not present in all conditional branches. The "
                        ++ "available test types are: "
                        ++ intercalate ", " (map display knownTestTypes)
  
          | sec_type == "benchmark" -> do
              when (null sec_label) $ lift $ syntaxError line_no
                  "'benchmark' needs one argument (the benchmark's name)"
              benchname <- lift $ runP line_no "benchmark" parseTokenQ sec_label
              flds <- collectFields (parseBenchmarkFields line_no) sec_fields
  
              -- Check that a valid benchmark type has been chosen. A type field
              -- may be given inside a conditional block, so we must check for
              -- that before complaining that a type field has not been given. The
              -- benchmark must always have a valid type, so we need to check both
              -- the 'then' and 'else' blocks, though the blocks need not have the
              -- same type.
              let hasType ts = benchmarkInterface ts /= benchmarkInterface mempty
              if onAllBranches hasType flds
                  then do
                      skipField
                      (repos, flags, csetup, mlib, sub_libs, flibs, exes, tests, bms) <- getBody pkg
                      return (repos, flags, csetup, mlib, sub_libs, flibs, exes,
                              tests, (mkUnqualComponentName benchname, flds) : bms)
                  else lift $ syntaxError line_no $
                           "Benchmark \"" ++ benchname
                        ++ "\" is missing required field \"type\" or the field "
                        ++ "is not present in all conditional branches. The "
                        ++ "available benchmark types are: "
                        ++ intercalate ", " (map display knownBenchmarkTypes)
  
          | sec_type == "library" -> do
              mb_libname <- if null sec_label
                              then return Nothing
                              -- TODO: relax this parsing so that scoping is handled
                              -- correctly
                              else fmap Just . lift
                                    $ runP line_no "library" parseTokenQ sec_label
              flds <- collectFields parseLibFields sec_fields
              skipField
              (repos, flags, csetup, mlib, sub_libs, flibs, exes, tests, bms) <- getBody pkg
              case mb_libname of
                  Just libname ->
                      return (repos, flags, csetup, mlib, (mkUnqualComponentName libname, flds) : sub_libs, flibs, exes, tests, bms)
                  Nothing -> do
                      when (isJust mlib) $ lift $ syntaxError line_no
                        "There can only be one (public) library section in a package description."
                      return (repos, flags, csetup, Just flds, sub_libs, flibs, exes, tests, bms)
  
          | sec_type == "flag" -> do
              when (null sec_label) $ lift $
                syntaxError line_no "'flag' needs one argument (the flag's name)"
              flag <- lift $ parseFields
                      flagFieldDescrs
                      warnUnrec
                      (emptyFlag (mkFlagName (lowercase sec_label)))
                      sec_fields
              skipField
              (repos, flags, csetup, mlib, sub_libs, flibs, exes, tests, bms) <- getBody pkg
              return (repos, flag:flags, csetup, mlib, sub_libs, flibs, exes, tests, bms)
  
          | sec_type == "source-repository" -> do
              when (null sec_label) $ lift $ syntaxError line_no $
                   "'source-repository' needs one argument, "
                ++ "the repo kind which is usually 'head' or 'this'"
              kind <- case simpleParse sec_label of
                Just kind -> return kind
                Nothing   -> lift $ syntaxError line_no $
                               "could not parse repo kind: " ++ sec_label
              repo <- lift $ parseFields
                      sourceRepoFieldDescrs
                      warnUnrec
                      (emptySourceRepo kind)
                      sec_fields
              skipField
              (repos, flags, csetup, mlib, sub_libs, flibs, exes, tests, bms) <- getBody pkg
              return (repo:repos, flags, csetup, mlib, sub_libs, flibs, exes, tests, bms)
  
          | sec_type == "custom-setup" -> do
              unless (null sec_label) $ lift $
                syntaxError line_no "'setup' expects no argument"
              _flds <- lift $ parseFields
                               setupBInfoFieldDescrs
                               warnUnrec
                               mempty
                               sec_fields
              skipField
              (repos, flags, csetup0, mlib, sub_libs, flibs, exes, tests, bms) <- getBody pkg
              when (isJust csetup0) $ lift $ syntaxError line_no
                "There can only be one 'custom-setup' section in a package description."
              -- TODO: Replace this once Custom setups are supported.
              return (repos, flags, Nothing, mlib, sub_libs, flibs, exes, tests, bms)
  
          | otherwise -> do
              lift $ warning $ "Ignoring unknown section type: " ++ sec_type
              skipField
              getBody pkg
        Just f@(F {}) -> do
              _ <- lift $ syntaxError (lineNo f) $
                "Plain fields are not allowed in between stanzas: " ++ show f
              skipField
              getBody pkg
        Just f@(IfBlock {}) -> do
              _ <- lift $ syntaxError (lineNo f) $
                "If-blocks are not allowed in between stanzas: " ++ show f
              skipField
              getBody pkg
        Nothing -> return ([], [], Nothing, Nothing, [], [], [], [], [])
  
      -- Extracts all fields in a block and returns a 'CondTree'.
      --
      -- We have to recurse down into conditionals and we treat fields that
      -- describe dependencies specially.
      collectFields :: ([Field] -> PM a) -> [Field]
                    -> PM (CondTree ConfVar [Dependency] a)
      collectFields parser allflds = do
  
          let simplFlds = [ F l n v | F l n v <- allflds ]
              condFlds = [ f | f@IfBlock{} <- allflds ]
              sections = [ s | s@Section{} <- allflds ]
  
          traverse_
              (\(Section l n _ _) -> lift . warning $
                  "Unexpected section '" ++ n ++ "' on line " ++ show l)
              sections
  
          a <- parser simplFlds
  
          -- Dependencies must be treated specially: when we
          -- parse into a CondTree, not only do we parse them into
          -- the targetBuildDepends/etc field inside the
          -- PackageDescription, but we also have to put the
          -- combined dependencies into CondTree.
          --
          -- This information is, in principle, redundant, but
          -- putting it here makes it easier for the constraint
          -- solver to pick a flag assignment which supports
          -- all of the dependencies (because it only has
          -- to check the CondTree, rather than grovel everywhere
          -- inside the conditional bits).
          deps <- liftM concat
                . traverse (lift . parseConstraint)
                . filter isConstraint
                $ simplFlds
  
          ifs <- traverse processIfs condFlds
  
          return (CondNode a deps ifs)
        where
          isConstraint (F _ n _) = n `elem` constraintFieldNames
          isConstraint _ = False
  
          processIfs (IfBlock l c t e) = do
              cnd <- lift $ runP l "if" parseCondition c
              t' <- collectFields parser t
              e' <- case e of
                     [] -> return Nothing
                     es -> do fs <- collectFields parser es
                              return (Just fs)
              return (CondBranch cnd t' e')
          processIfs _ = cabalBug "processIfs called with wrong field type"
  
      parseLibFields :: [Field] -> PM Library
      parseLibFields = lift . parseFields libFieldDescrs storeXFieldsLib emptyLibrary
  
      -- Note: we don't parse the "executable" field here, hence the tail hack.
      parseExeFields :: [Field] -> PM Executable
      parseExeFields = lift . parseFields executableFieldDescrs
                                          storeXFieldsExe emptyExecutable
  
      parseForeignLibFields :: [Field] -> PM ForeignLib
      parseForeignLibFields =
          lift . parseFields foreignLibFieldDescrs
                             storeXFieldsForeignLib
                             emptyForeignLib
  
      parseTestFields :: LineNo -> [Field] -> PM TestSuite
      parseTestFields line fields = do
          x <- lift $ parseFields testSuiteFieldDescrs storeXFieldsTest
                                  emptyTestStanza fields
          lift $ validateTestSuite line x
  
      parseBenchmarkFields :: LineNo -> [Field] -> PM Benchmark
      parseBenchmarkFields line fields = do
          x <- lift $ parseFields benchmarkFieldDescrs storeXFieldsBenchmark
                                  emptyBenchmarkStanza fields
          lift $ validateBenchmark line x
  
      checkForUndefinedFlags ::
          [Flag] ->
          Maybe (CondTree ConfVar [Dependency] Library) ->
          [(UnqualComponentName, CondTree ConfVar [Dependency] Library)] ->
          [(UnqualComponentName, CondTree ConfVar [Dependency] Executable)] ->
          [(UnqualComponentName, CondTree ConfVar [Dependency] TestSuite)] ->
          PM ()
      checkForUndefinedFlags flags mlib sub_libs exes tests = do
          let definedFlags = map flagName flags
          traverse_ (checkCondTreeFlags definedFlags) (maybeToList mlib)
          traverse_ (checkCondTreeFlags definedFlags . snd) sub_libs
          traverse_ (checkCondTreeFlags definedFlags . snd) exes
          traverse_ (checkCondTreeFlags definedFlags . snd) tests
  
      checkCondTreeFlags :: [FlagName] -> CondTree ConfVar c a -> PM ()
      checkCondTreeFlags definedFlags ct = do
          let fv = nub $ freeVars ct
          unless (all (`elem` definedFlags) fv) $
              fail $ "These flags are used without having been defined: "
                  ++ intercalate ", " [ unFlagName fn | fn <- fv \\ definedFlags ]
  
  -- Check that a property holds on all branches of a condition tree
  onAllBranches :: forall v c a. Monoid a => (a -> Bool) -> CondTree v c a -> Bool
  onAllBranches p = go mempty
    where
      -- If the current level of the tree satisfies the property, then we are
      -- done. If not, then one of the conditional branches below the current node
      -- must satisfy it. Each node may have multiple immediate children; we only
      -- one need one to satisfy the property because the configure step uses
      -- 'mappend' to join together the results of flag resolution.
      go :: a -> CondTree v c a -> Bool
      go acc ct = let acc' = acc `mappend` condTreeData ct
                  in p acc' || any (goBranch acc') (condTreeComponents ct)
  
      -- Both the 'true' and the 'false' block must satisfy the property.
      goBranch :: a -> CondBranch v c a -> Bool
      goBranch _   (CondBranch _ _ Nothing) = False
      goBranch acc (CondBranch _ t (Just e))  = go acc t && go acc e
  
  -- | Parse a list of fields, given a list of field descriptions,
  --   a structure to accumulate the parsed fields, and a function
  --   that can decide what to do with fields which don't match any
  --   of the field descriptions.
  parseFields :: [FieldDescr a]      -- ^ descriptions of fields we know how to
                                     --   parse
              -> UnrecFieldParser a  -- ^ possibly do something with
                                     --   unrecognized fields
              -> a                   -- ^ accumulator
              -> [Field]             -- ^ fields to be parsed
              -> ParseResult a
  parseFields descrs unrec ini fields =
      do (a, unknowns) <- foldM (parseField descrs unrec) (ini, []) fields
         unless (null unknowns) $ warning $ render $
           text "Unknown fields:" <+>
                commaSep (map (\(l,u) -> u ++ " (line " ++ show l ++ ")")
                              (reverse unknowns))
           $+$
           text "Fields allowed in this section:" $$
             nest 4 (commaSep $ map fieldName descrs)
         return a
    where
      commaSep = fsep . punctuate comma . map text
  
  parseField :: [FieldDescr a]     -- ^ list of parseable fields
             -> UnrecFieldParser a -- ^ possibly do something with
                                   --   unrecognized fields
             -> (a,[(Int,String)]) -- ^ accumulated result and warnings
             -> Field              -- ^ the field to be parsed
             -> ParseResult (a, [(Int,String)])
  parseField (FieldDescr name _ parser : fields) unrec (a, us) (F line f val)
    | name == f = parser line val a >>= \a' -> return (a',us)
    | otherwise = parseField fields unrec (a,us) (F line f val)
  parseField [] unrec (a,us) (F l f val) = return $
    case unrec (f,val) a of        -- no fields matched, see if the 'unrec'
      Just a' -> (a',us)           -- function wants to do anything with it
      Nothing -> (a, (l,f):us)
  parseField _ _ _ _ = cabalBug "'parseField' called on a non-field"
  
  deprecatedFields :: [(String,String)]
  deprecatedFields =
      deprecatedFieldsPkgDescr ++ deprecatedFieldsBuildInfo
  
  deprecatedFieldsPkgDescr :: [(String,String)]
  deprecatedFieldsPkgDescr = [ ("other-files", "extra-source-files") ]
  
  deprecatedFieldsBuildInfo :: [(String,String)]
  deprecatedFieldsBuildInfo = [ ("hs-source-dir","hs-source-dirs") ]
  
  -- Handle deprecated fields
  deprecField :: Field -> ParseResult Field
  deprecField (F line fld val) = do
    fld' <- case lookup fld deprecatedFields of
              Nothing -> return fld
              Just newName -> do
                warning $ "The field \"" ++ fld
                        ++ "\" is deprecated, please use \"" ++ newName ++ "\""
                return newName
    return (F line fld' val)
  deprecField _ = cabalBug "'deprecField' called on a non-field"
  
  
  parseHookedBuildInfo :: String -> ParseResult HookedBuildInfo
  parseHookedBuildInfo inp = do
    fields <- readFields inp
    let ss@(mLibFields:exes) = stanzas fields
    mLib <- parseLib mLibFields
    biExes <- mapM parseExe (maybe ss (const exes) mLib)
    return (mLib, biExes)
    where
      parseLib :: [Field] -> ParseResult (Maybe BuildInfo)
      parseLib (bi@(F _ inFieldName _:_))
          | lowercase inFieldName /= "executable" = liftM Just (parseBI bi)
      parseLib _ = return Nothing
  
      parseExe :: [Field] -> ParseResult (UnqualComponentName, BuildInfo)
      parseExe (F line inFieldName mName:bi)
          | lowercase inFieldName == "executable"
              = do bis <- parseBI bi
                   return (mkUnqualComponentName mName, bis)
          | otherwise = syntaxError line "expecting 'executable' at top of stanza"
      parseExe (_:_) = cabalBug "`parseExe' called on a non-field"
      parseExe [] = syntaxError 0 "error in parsing buildinfo file. Expected executable stanza"
  
      parseBI st = parseFields binfoFieldDescrs storeXFieldsBI emptyBuildInfo st
  
  -- replace all tabs used as indentation with whitespace, also return where
  -- tabs were found
  findIndentTabs :: String -> [(Int,Int)]
  findIndentTabs = concatMap checkLine
                 . zip [1..]
                 . lines
      where
        checkLine (lineno, l) =
            let (indent, _content) = span isSpace l
                tabCols = map fst . filter ((== '\t') . snd) . zip [0..]
                addLineNo = map (\col -> (lineno,col))
            in addLineNo (tabCols indent)
  
  --test_findIndentTabs = findIndentTabs $ unlines $
  --    [ "foo", "  bar", " \t baz", "\t  biz\t", "\t\t \t mib" ]
  