{-# OPTIONS -cpp #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Distribution.ParseUtils
-- Copyright   :  (c) The University of Glasgow 2004
-- 
-- Maintainer  :  libraries@haskell.org
-- Stability   :  alpha
-- Portability :  portable
--
-- Utilities for parsing PackageDescription and InstalledPackageInfo.


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-- This module is meant to be local-only to Distribution...

-- #hide
module Distribution.ParseUtils (
        LineNo, PError(..), PWarning, locatedErrorMsg, syntaxError, warning,
	runP, ParseResult(..), catchParseError, parseFail,
	Field(..), fName, lineNo,
	FieldDescr(..), readFields,
	parseFilePathQ, parseTokenQ,
	parseModuleNameQ, parseDependency, parsePkgconfigDependency,
        parseOptVersion, parsePackageNameQ, parseVersionRangeQ,
	parseTestedWithQ, parseLicenseQ, parseExtensionQ, 
	parseSepList, parseCommaList, parseOptCommaList,
	showFilePath, showToken, showTestedWith, showDependency, showFreeText,
	field, simpleField, listField, commaListField, optsField, liftField,
	parseReadS, parseReadSQ, parseQuoted,
  ) where

import Distribution.Compiler (CompilerFlavor)
import Distribution.License
import Distribution.Version
import Distribution.Package	( parsePackageName )
import Distribution.Compat.ReadP as ReadP hiding (get)
import Language.Haskell.Extension (Extension)

import Text.PrettyPrint.HughesPJ hiding (braces)
import Data.Char        (isSpace, isUpper, toLower, isAlphaNum)
import Data.Maybe	( fromMaybe)
import Data.List        (intersperse)

#ifdef DEBUG
import Test.HUnit (Test(..), assertBool, Assertion, runTestTT, Counts, assertEqual)
import IO
import System.Environment ( getArgs )
import Control.Monad ( zipWithM_ )
#endif

-- -----------------------------------------------------------------------------

type LineNo = Int

data PError = AmbigousParse String LineNo
            | NoParse String LineNo
            | TabsError LineNo
            | FromString String (Maybe LineNo)
        deriving Show

type PWarning = String

data ParseResult a = ParseFailed PError | ParseOk [PWarning] a
        deriving Show

instance Monad ParseResult where
	return x = ParseOk [] x
	ParseFailed err >>= _ = ParseFailed err
	ParseOk ws x >>= f = case f x of
	                       ParseFailed err -> ParseFailed err
			       ParseOk ws' x' -> ParseOk (ws'++ws) x'
	fail s = ParseFailed (FromString s Nothing)

catchParseError :: ParseResult a -> (PError -> ParseResult a)
                -> ParseResult a
p@(ParseOk _ _) `catchParseError` _ = p
ParseFailed e `catchParseError` k   = k e

parseFail :: PError -> ParseResult a
parseFail = ParseFailed

runP :: LineNo -> String -> ReadP a a -> String -> ParseResult a
runP line fieldname p s =
  case [ x | (x,"") <- results ] of
    [a] -> ParseOk [] a
    []  -> case [ x | (x,ys) <- results, all isSpace ys ] of
             [a] -> ParseOk [] a
             []  -> ParseFailed (NoParse fieldname line)
             _   -> ParseFailed (AmbigousParse fieldname line)
    _   -> ParseFailed (AmbigousParse fieldname line)
  where results = readP_to_S p s

locatedErrorMsg :: PError -> (Maybe LineNo, String)
locatedErrorMsg (AmbigousParse f n) = (Just n, "Ambiguous parse in field '"++f++"'")
locatedErrorMsg (NoParse f n)       = (Just n, "Parse of field '"++f++"' failed: ")
locatedErrorMsg (TabsError n)       = (Just n, "Tab used as indentation.")
locatedErrorMsg (FromString s n)    = (n, s)

syntaxError :: LineNo -> String -> ParseResult a
syntaxError n s = ParseFailed $ FromString s (Just n)

tabsError :: LineNo -> ParseResult a
tabsError ln = ParseFailed $ TabsError ln

warning :: String -> ParseResult ()
warning s = ParseOk [s] ()

-- | Field descriptor.  The parameter @a@ parameterizes over where the field's
--   value is stored in.
data FieldDescr a 
  = FieldDescr 
      { fieldName     :: String
      , fieldGet      :: a -> Doc
      , fieldSet      :: LineNo -> String -> a -> ParseResult a
        -- ^ @fieldSet n str x@ Parses the field value from the given input
        -- string @str@ and stores the result in @x@ if the parse was
        -- successful.  Otherwise, reports an error on line number @n@.
      }

field :: String -> (a -> Doc) -> (ReadP a a) -> FieldDescr a
field name showF readF = 
  FieldDescr name showF (\line val _st -> runP line name readF val)

-- Lift a field descriptor storing into an 'a' to a field descriptor storing
-- into a 'b'.
liftField :: (b -> a) -> (a -> b -> b) -> FieldDescr a -> FieldDescr b
liftField get set (FieldDescr name showF parseF)
 = FieldDescr name (\b -> showF (get b))
	(\line str b -> do
	    a <- parseF line str (get b)
	    return (set a b))

-- Parser combinator for simple fields.  Takes a field name, a pretty printer,
-- a parser function, an accessor, and a setter, returns a FieldDescr over the
-- compoid structure.
simpleField :: String -> (a -> Doc) -> (ReadP a a)
            -> (b -> a) -> (a -> b -> b) -> FieldDescr b
simpleField name showF readF get set
  = liftField get set $ field name showF readF

commaListField :: String -> (a -> Doc) -> (ReadP [a] a)
		 -> (b -> [a]) -> ([a] -> b -> b) -> FieldDescr b
commaListField name showF readF get set = 
  liftField get set $ 
    field name (fsep . punctuate comma . map showF) (parseCommaList readF)

listField :: String -> (a -> Doc) -> (ReadP [a] a)
		 -> (b -> [a]) -> ([a] -> b -> b) -> FieldDescr b
listField name showF readF get set = 
  liftField get set $ 
    field name (fsep . map showF) (parseOptCommaList readF)

optsField :: String -> CompilerFlavor -> (b -> [(CompilerFlavor,[String])]) -> ([(CompilerFlavor,[String])] -> b -> b) -> FieldDescr b
optsField name flavor get set = 
   liftField (fromMaybe [] . lookup flavor . get) 
	     (\opts b -> set (update flavor opts (get b)) b) $
	field name (hsep . map text)
		   (sepBy parseTokenQ' (munch1 isSpace))
  where
        update f opts [] = [(f,opts)]
	update f opts ((f',opts'):rest)
           | f == f'   = (f, opts ++ opts') : rest
           | otherwise = (f',opts') : update f opts rest

------------------------------------------------------------------------------

-- The data type for our three syntactic categories 
data Field 
    = F LineNo String String
      -- ^ A regular @<property>: <value>@ field
    | Section LineNo String String [Field]
      -- ^ A section with a name and possible parameter.  The syntactic
      -- structure is:
      -- 
      -- @
      --   <sectionname> <arg> {
      --     <field>*
      --   }
      -- @
    | IfBlock LineNo String [Field] [Field]
      -- ^ A conditional block with an optional else branch:
      --
      -- @
      --  if <condition> {
      --    <field>*
      --  } else {
      --    <field>*
      --  }
      -- @
      deriving (Show
               ,Eq)   -- for testing

lineNo :: Field -> LineNo
lineNo (F n _ _) = n
lineNo (Section n _ _ _) = n
lineNo (IfBlock n _ _ _) = n

fName :: Field -> String
fName (F _ n _) = n
fName (Section _ n _ _) = n
fName _ = error "fname: not a field or section"

readFields :: String -> ParseResult [Field]
readFields input = 
      ifelse
  =<< mapM (mkField 0)
  =<< mkTree (tokenise input)

  where tokenise = concatMap tokeniseLine
                 . trimLines
                 . lines
                 . normaliseLineEndings
                 -- TODO: should decode UTF8

-- attach line number and determine indentation
trimLines :: [String] -> [(LineNo, Indent, HasTabs, String)]
trimLines ls = [ (lineno, indent, hastabs, (trimTrailing l'))
               | (lineno, l) <- zip [1..] ls
               , let (sps, l') = span isSpace l
                     indent    = length sps
                     hastabs   = '\t' `elem` sps
               , validLine l' ]
  where validLine ('-':'-':_) = False      -- Comment
        validLine []          = False      -- blank line
        validLine _           = True

-- | We parse generically based on indent level and braces '{' '}'. To do that
-- we split into lines and then '{' '}' tokens and other spans within a line.
data Token = 
       -- | The 'Line' token is for bits that /start/ a line, eg:
       --
       -- > "\n  blah blah { blah"
       --
       -- tokenises to:
       -- 
       -- > [Line n 2 False "blah blah", OpenBracket, Span n "blah"]
       --
       -- so lines are the only ones that can have nested layout, since they
       -- have a known indentation level.
       --
       -- eg: we can't have this:
       --
       -- > if ... {
       -- > } else
       -- >     other
       --
       -- because other cannot nest under else, since else doesn't start a line
       -- so cannot have nested layout. It'd have to be:
       --
       -- > if ... {
       -- > }
       -- >   else
       -- >     other
       --
       -- but that's not so common, people would normally use layout or
       -- brackets not both in a single @if else@ construct.
       -- 
       -- > if ... { foo : bar }
       -- > else
       -- >    other
       -- 
       -- this is ok
       Line LineNo Indent HasTabs String
     | Span LineNo                String  -- ^ span in a line, following brackets
     | OpenBracket LineNo | CloseBracket LineNo

type Indent = Int
type HasTabs = Bool

-- | Tokenise a single line, splitting on '{' '}' and the spans inbetween.
-- Also trims leading & trailing space on those spans within the line.
tokeniseLine :: (LineNo, Indent, HasTabs, String) -> [Token]
tokeniseLine (n0, i, t, l) = case split n0 l of
                            (Span _ l':ss) -> Line n0 i t l' :ss
                            cs              -> cs
  where split _ "" = []
        split n s  = case span (\c -> c /='}' && c /= '{') s of
          ("", '{' : s') ->             OpenBracket  n : split n s'
          (w , '{' : s') -> mkspan n w (OpenBracket  n : split n s')
          ("", '}' : s') ->             CloseBracket n : split n s'
          (w , '}' : s') -> mkspan n w (CloseBracket n : split n s') 
          (w ,        _) -> mkspan n w []

        mkspan n s ss | null s'   =             ss
                      | otherwise = Span n s' : ss
          where s' = trimTrailing (trimLeading s)

trimLeading, trimTrailing :: String -> String
trimLeading  = dropWhile isSpace
trimTrailing = reverse . dropWhile isSpace . reverse


-- | Fix different systems silly line ending conventions
normaliseLineEndings :: String -> String
normaliseLineEndings [] = []
normaliseLineEndings ('\r':'\n':s) = '\n' : normaliseLineEndings s -- windows
normaliseLineEndings ('\r':s)      = '\n' : normaliseLineEndings s -- old osx
normaliseLineEndings (  c :s)      =   c  : normaliseLineEndings s

type SyntaxTree = Tree (LineNo, HasTabs, String)

-- | Parse the stream of tokens into a tree of them, based on indent \/ layout
mkTree :: [Token] -> ParseResult [SyntaxTree]
mkTree toks =
  layout 0 [] toks >>= \(trees, trailing) -> case trailing of
    []               -> return trees
    OpenBracket  n:_ -> syntaxError n "mismatched backets, unexpected {"
    CloseBracket n:_ -> syntaxError n "mismatched backets, unexpected }"
    -- the following two should never happen:
    Span n     l  :_ -> syntaxError n $ "unexpected span: " ++ show l
    Line n _ _ l  :_ -> syntaxError n $ "unexpected line: " ++ show l


-- | Parse the stream of tokens into a tree of them, based on indent
-- This parse state expect to be in a layout context, though possibly
-- nested within a braces context so we may still encounter closing braces.
layout :: Indent       -- ^ indent level of the parent\/previous line
       -> [SyntaxTree] -- ^ accumulating param, trees in this level
       -> [Token]      -- ^ remaining tokens
       -> ParseResult ([SyntaxTree], [Token])
                       -- ^ collected trees on this level and trailing tokens
layout _ a []                               = return (reverse a, [])
layout i a (s@(Line _ i' _ _):ss) | i' < i  = return (reverse a, s:ss)
layout i a (Line n _ t l:OpenBracket n':ss) = do
    (sub, ss') <- braces n' [] ss
    layout i (Node (n,t,l) sub:a) ss'

layout i a (Span n     l:OpenBracket n':ss) = do
    (sub, ss') <- braces n' [] ss
    layout i (Node (n,False,l) sub:a) ss'

-- look ahead to see if following lines are more indented, giving a sub-tree
layout i a (Line n i' t l:ss) = do
    lookahead <- layout (i'+1) [] ss
    case lookahead of
        ([], _)   -> layout i (Node (n,t,l) [] :a) ss
        (ts, ss') -> layout i (Node (n,t,l) ts :a) ss'

layout _ _ (   OpenBracket  n :_)  = syntaxError n $ "unexpected '{'"
layout _ a (s@(CloseBracket _):ss) = return (reverse a, s:ss)
layout _ _ (   Span n l       : _) = syntaxError n $ "unexpected span: "
                                                  ++ show l

-- | Parse the stream of tokens into a tree of them, based on explicit braces
-- This parse state expects to find a closing bracket.
braces :: LineNo       -- ^ line of the '{', used for error messages
       -> [SyntaxTree] -- ^ accumulating param, trees in this level
       -> [Token]      -- ^ remaining tokens
       -> ParseResult ([SyntaxTree],[Token])
                       -- ^ collected trees on this level and trailing tokens
braces m a (Line n _ t l:OpenBracket n':ss) = do
    (sub, ss') <- braces n' [] ss
    braces m (Node (n,t,l) sub:a) ss'

braces m a (Span n     l:OpenBracket n':ss) = do 
    (sub, ss') <- braces n' [] ss
    braces m (Node (n,False,l) sub:a) ss'

braces m a (Line n i t l:ss) = do
    lookahead <- layout (i+1) [] ss
    case lookahead of
        ([], _)   -> braces m (Node (n,t,l) [] :a) ss
        (ts, ss') -> braces m (Node (n,t,l) ts :a) ss'

braces m a (Span n       l:ss) = braces m (Node (n,False,l) []:a) ss
braces _ a (CloseBracket _:ss) = return (reverse a, ss)
braces n _ []                  = syntaxError n $ "opening brace '{'"
                              ++ "has no matching closing brace '}'"
braces _ _ (OpenBracket  n:_)  = syntaxError n "unexpected '{'"

-- | Convert the parse tree into the Field AST
-- Also check for dodgy uses of tabs in indentation.
mkField :: Int -> SyntaxTree -> ParseResult Field
mkField d (Node (n,t,_) _) | d >= 1 && t = tabsError n
mkField d (Node (n,_,l) ts) = case span (\c -> isAlphaNum c || c == '-') l of
  ([], _)       -> syntaxError n $ "unrecognised field or section: " ++ show l
  (name, rest)  -> case trimLeading rest of
    (':':rest') -> do let followingLines = concatMap flatten ts
                          tabs = not (null [()| (_,True,_) <- followingLines ])
                      if tabs && d >= 1
                        then tabsError n
                        else return $ F n (map toLower name)
                                          (fieldValue rest' followingLines) 
    rest'       -> do ts' <- mapM (mkField (d+1)) ts
                      return (Section n (map toLower name) rest' ts')
    where fieldValue firstLine followingLines =
            let firstLine' = trimLeading firstLine
                followingLines' = map (\(_,_,s) -> stripDot s) followingLines
                allLines | null firstLine' =              followingLines'
                         | otherwise       = firstLine' : followingLines'
             in (concat . intersperse "\n") allLines
          stripDot "." = ""
          stripDot s   = s

-- | Convert if/then/else 'Section's to 'IfBlock's
ifelse :: [Field] -> ParseResult [Field]
ifelse [] = return []
ifelse (Section n "if"   cond thenpart
       :Section _ "else" as   elsepart:fs)
       | null cond     = syntaxError n "'if' with missing condition"
       | null thenpart = syntaxError n "'then' branch of 'if' is empty"
       | not (null as) = syntaxError n "'else' takes no arguments"
       | null elsepart = syntaxError n "'else' branch of 'if' is empty"
       | otherwise     = do tp  <- ifelse thenpart
                            ep  <- ifelse elsepart
                            fs' <- ifelse fs
                            return (IfBlock n cond tp ep:fs')
ifelse (Section n "if"   cond thenpart:fs)
       | null cond     = syntaxError n "'if' with missing condition"
       | null thenpart = syntaxError n "'then' branch of 'if' is empty"
       | otherwise     = do tp  <- ifelse thenpart
                            fs' <- ifelse fs
                            return (IfBlock n cond tp []:fs')
ifelse (Section n "else" _ _:_) = syntaxError n "stray 'else' with no preceding 'if'"
ifelse (Section n s a fs':fs) = do fs''  <- ifelse fs'
                                   fs''' <- ifelse fs
                                   return (Section n s a fs'' : fs''')
ifelse (f:fs) = do fs' <- ifelse fs 
                   return (f : fs')

------------------------------------------------------------------------------

-- |parse a module name
parseModuleNameQ :: ReadP r String
parseModuleNameQ = parseQuoted modu <++ modu
 where modu = do 
	  c <- satisfy isUpper
	  cs <- munch (\x -> isAlphaNum x || x `elem` "_'.")
	  return (c:cs)

parseFilePathQ :: ReadP r FilePath
parseFilePathQ = parseTokenQ 
  -- removed until normalise is no longer broken, was:
  --   liftM normalise parseTokenQ

parseReadS :: Read a => ReadP r a
parseReadS = readS_to_P reads

parseDependency :: ReadP r Dependency
parseDependency = do name <- parsePackageNameQ
                     skipSpaces
                     ver <- parseVersionRangeQ <++ return AnyVersion
                     skipSpaces
                     return $ Dependency name ver

-- pkg-config allows versions and other letters in package names, 
-- eg "gtk+-2.0" is a valid pkg-config package _name_.
-- It then has a package version number like 2.10.13
parsePkgconfigDependency :: ReadP r Dependency
parsePkgconfigDependency = do name <- munch1 (\c -> isAlphaNum c || c `elem` "+-._")
                              skipSpaces
                              ver <- parseVersionRangeQ <++ return AnyVersion
                              skipSpaces
                              return $ Dependency name ver

parsePackageNameQ :: ReadP r String
parsePackageNameQ = parseQuoted parsePackageName <++ parsePackageName 

parseVersionRangeQ :: ReadP r VersionRange
parseVersionRangeQ = parseQuoted parseVersionRange <++ parseVersionRange

parseOptVersion :: ReadP r Version
parseOptVersion = parseQuoted ver <++ ver
  where ver = parseVersion <++ return noVersion
	noVersion = Version{ versionBranch=[], versionTags=[] }

parseTestedWithQ :: ReadP r (CompilerFlavor,VersionRange)
parseTestedWithQ = parseQuoted tw <++ tw
  where tw = do compiler <- parseReadS
		skipSpaces
		version <- parseVersionRange <++ return AnyVersion
		skipSpaces
		return (compiler,version)

parseLicenseQ :: ReadP r License
parseLicenseQ = parseQuoted parseReadS <++ parseReadS

-- urgh, we can't define optQuotes :: ReadP r a -> ReadP r a
-- because the "compat" version of ReadP isn't quite powerful enough.  In
-- particular, the type of <++ is ReadP r r -> ReadP r a -> ReadP r a
-- Hence the trick above to make 'lic' polymorphic.

parseExtensionQ :: ReadP r Extension
parseExtensionQ = parseQuoted parseReadS <++ parseReadS

-- | Parse something optionally wrapped in quotes.
parseReadSQ :: Read a => ReadP r a
parseReadSQ = parseQuoted parseReadS <++ parseReadS

parseTokenQ :: ReadP r String
parseTokenQ = parseReadS <++ munch1 (\x -> not (isSpace x) && x /= ',')

parseTokenQ' :: ReadP r String
parseTokenQ' = parseReadS <++ munch1 (\x -> not (isSpace x))

parseSepList :: ReadP r b
	     -> ReadP r a -- ^The parser for the stuff between commas
             -> ReadP r [a]
parseSepList sepr p = sepBy p separator
    where separator = skipSpaces >> sepr >> skipSpaces

parseCommaList :: ReadP r a -- ^The parser for the stuff between commas
               -> ReadP r [a]
parseCommaList = parseSepList (ReadP.char ',')

parseOptCommaList :: ReadP r a -- ^The parser for the stuff between commas
                  -> ReadP r [a]
parseOptCommaList = parseSepList (optional (ReadP.char ','))

parseQuoted :: ReadP r a -> ReadP r a
parseQuoted p = between (ReadP.char '"') (ReadP.char '"') p

-- --------------------------------------------
-- ** Pretty printing

showFilePath :: FilePath -> Doc
showFilePath = showToken

showToken :: String -> Doc
showToken str
 | not (any dodgy str) &&
   not (null str)       = text str
 | otherwise            = text (show str)
  where dodgy c = isSpace c || c == ','

showTestedWith :: (CompilerFlavor,VersionRange) -> Doc
showTestedWith (compiler,version) = text (show compiler ++ " " ++ showVersionRange version)

showDependency :: Dependency -> Doc
showDependency (Dependency name ver) = text name <+> text (showVersionRange ver)

-- | Pretty-print free-format text, ensuring that it is vertically aligned,
-- and with blank lines replaced by dots for correct re-parsing.
showFreeText :: String -> Doc
showFreeText s = vcat [text (if null l then "." else l) | l <- lines s]

-- --------------------------------------------
-- ** Tree bits

-- Data.Tree was not present in ghc-6.2, and we only need these bits:

data Tree a = Node a (Forest a)
type Forest a = [Tree a]

flatten :: Tree a -> [a]
flatten t = squish t []
  where squish (Node x ts) xs = x:foldr squish xs ts

------------------------------------------------------------------------------
-- TESTING

#ifdef DEBUG
test_readFields = case 
                    readFields testFile 
                  of
                    ParseOk _ x -> x == expectedResult
                    _ -> False
  where 
    testFile = unlines $
          [ "Cabal-version: 3"
          , ""
          , "Description: This is a test file   "
          , "  with a description longer than two lines.  "
          , "if os(windows) {"
          , "  License:  You may not use this software"
          , "    ."
          , "    If you do use this software you will be seeked and destroyed."
          , "}"
          , "if os(linux) {"
          , "  Main-is:  foo1  "
          , "}"
          , ""
          , "if os(vista) {"
          , "  executable RootKit {"
          , "    Main-is: DRMManager.hs"
          , "  }"
          , "} else {"
          , "  executable VistaRemoteAccess {"
          , "    Main-is: VCtrl"
          , "}}"
          , ""
          , "executable Foo-bar {"
          , "  Main-is: Foo.hs"
          , "}"
          ]
    expectedResult = 
          [ F 1 "cabal-version" "3"
          , F 3 "description" 
                  "This is a test file\nwith a description longer than two lines."
          , IfBlock 5 "os(windows) " 
              [ F 6 "license" 
                      "You may not use this software\n\nIf you do use this software you will be seeked and destroyed."
              ]
              []
          , IfBlock 10 "os(linux) " 
              [ F 11 "main-is" "foo1" ] 
              [ ]
          , IfBlock 14 "os(vista) " 
              [ Section 15 "executable" "RootKit " 
                [ F 16 "main-is" "DRMManager.hs"]
              ] 
              [ Section 19 "executable" "VistaRemoteAccess "
                 [F 20 "main-is" "VCtrl"]
              ]
          , Section 23 "executable" "Foo-bar " 
              [F 24 "main-is" "Foo.hs"]
          ]

test_readFieldsCompat' = case test_readFieldsCompat of
                           ParseOk _ fs -> mapM_ (putStrLn . show) fs
                           x -> putStrLn $ "Failed: " ++ show x
test_readFieldsCompat = readFields testPkgDesc
  where 
    testPkgDesc = unlines [
        "-- Required",
        "Name: Cabal",
        "Version: 0.1.1.1.1-rain",
        "License: LGPL",
        "License-File: foo",
        "Copyright: Free Text String",
        "Cabal-version: >1.1.1",
        "-- Optional - may be in source?",
        "Author: Happy Haskell Hacker",
        "Homepage: http://www.haskell.org/foo",
        "Package-url: http://www.haskell.org/foo",
        "Synopsis: a nice package!",
        "Description: a really nice package!",
        "Category: tools",
        "buildable: True",
        "CC-OPTIONS: -g -o",
        "LD-OPTIONS: -BStatic -dn",
        "Frameworks: foo",
        "Tested-with: GHC",
        "Stability: Free Text String",
        "Build-Depends: haskell-src, HUnit>=1.0.0-rain",
        "Other-Modules: Distribution.Package, Distribution.Version,",
        "                Distribution.Simple.GHCPackageConfig",
        "Other-files: file1, file2",
        "Extra-Tmp-Files:    file1, file2",
        "C-Sources: not/even/rain.c, such/small/hands",
        "HS-Source-Dirs: src, src2",
        "Exposed-Modules: Distribution.Void, Foo.Bar",
        "Extensions: OverlappingInstances, TypeSynonymInstances",
        "Extra-Libraries: libfoo, bar, bang",
        "Extra-Lib-Dirs: \"/usr/local/libs\"",
        "Include-Dirs: your/slightest, look/will",
        "Includes: /easily/unclose, /me, \"funky, path\\\\name\"",
        "Install-Includes: /easily/unclose, /me, \"funky, path\\\\name\"",
        "GHC-Options: -fTH -fglasgow-exts",
        "Hugs-Options: +TH",
        "Nhc-Options: ",
        "Jhc-Options: ",
        "",
        "-- Next is an executable",
        "Executable: somescript",
        "Main-is: SomeFile.hs",
        "Other-Modules: Foo1, Util, Main",
        "HS-Source-Dir: scripts",
        "Extensions: OverlappingInstances",
        "GHC-Options: ",
        "Hugs-Options: ",
        "Nhc-Options: ",
        "Jhc-Options: "
        ]
{-
test' = do h <- openFile "../Cabal.cabal" ReadMode
           s <- hGetContents h
           let r = readFields s
           case r of
             ParseOk _ fs -> mapM_ (putStrLn . show) fs
             x -> putStrLn $ "Failed: " ++ show x
           putStrLn "==================="
           mapM_ (putStrLn . show) $
                 merge . zip [1..] . lines $ s
           hClose h
-}

-- ghc -DDEBUG --make Distribution/ParseUtils.hs -o test

main :: IO ()
main = do
  inputFiles <- getArgs
  ok <- mapM checkResult inputFiles

  zipWithM_ summary inputFiles ok
  putStrLn $ show (length (filter not ok)) ++ " out of " ++ show (length ok) ++ " failed"

  where summary f True  = return ()
        summary f False = putStrLn $ f  ++ " failed :-("

checkResult :: FilePath -> IO Bool
checkResult inputFile = do
  file <- readFile inputFile
  case readFields file of
    ParseOk _ result -> do
       hPutStrLn stderr $ inputFile ++ " parses ok :-)"
       return True
    ParseFailed err -> do
       hPutStrLn stderr $ inputFile ++ " parse failed:"
       hPutStrLn stderr $ show err
       return False

-- 
#endif