1 -----------------------------------------------------------------------------
3 -- | Parsing the top of a Haskell source file to get its module name,
4 -- imports and options.
6 -- (c) Simon Marlow 2005
9 -----------------------------------------------------------------------------
11 module HeaderInfo ( getImports
12 , mkPrelImports -- used by the renamer too
13 , getOptionsFromFile, getOptions
15 checkProcessArgsResult ) where
17 #include "HsVersions.h"
21 import Parser ( parseHeader )
35 import Bag ( emptyBag, listToBag, unitBag )
41 import System.IO.Unsafe
44 ------------------------------------------------------------------------------
46 -- | Parse the imports of a source file.
48 -- Throws a 'SourceError' if parsing fails.
49 getImports :: DynFlags
50 -> StringBuffer -- ^ Parse this.
51 -> FilePath -- ^ Filename the buffer came from. Used for
52 -- reporting parse error locations.
53 -> FilePath -- ^ The original source filename (used for locations
54 -- in the function result)
55 -> IO ([Located (ImportDecl RdrName)], [Located (ImportDecl RdrName)], Located ModuleName)
56 -- ^ The source imports, normal imports, and the module name.
57 getImports dflags buf filename source_filename = do
58 let loc = mkSrcLoc (mkFastString filename) 1 1
59 case unP parseHeader (mkPState dflags buf loc) of
60 PFailed span err -> parseError span err
61 POk pst rdr_module -> do
62 let _ms@(_warns, errs) = getMessages pst
63 -- don't log warnings: they'll be reported when we parse the file
64 -- for real. See #2500.
67 if errorsFound dflags ms
68 then throwIO $ mkSrcErr errs
71 L _ (HsModule mb_mod _ imps _ _ _) ->
73 main_loc = mkSrcLoc (mkFastString source_filename) 1 1
74 mod = mb_mod `orElse` L (srcLocSpan main_loc) mAIN_NAME
75 (src_idecls, ord_idecls) = partition (ideclSource.unLoc) imps
77 -- GHC.Prim doesn't exist physically, so don't go looking for it.
78 ordinary_imps = filter ((/= moduleName gHC_PRIM) . unLoc . ideclName . unLoc)
81 implicit_prelude = xopt Opt_ImplicitPrelude dflags
82 implicit_imports = mkPrelImports (unLoc mod) implicit_prelude imps
84 return (src_idecls, implicit_imports ++ ordinary_imps, mod)
86 mkPrelImports :: ModuleName -> Bool -> [LImportDecl RdrName]
87 -> [LImportDecl RdrName]
88 -- Consruct the implicit declaration "import Prelude" (or not)
90 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
91 -- because the former doesn't even look at Prelude.hi for instance
92 -- declarations, whereas the latter does.
93 mkPrelImports this_mod implicit_prelude import_decls
94 | this_mod == pRELUDE_NAME
95 || explicit_prelude_import
96 || not implicit_prelude
98 | otherwise = [preludeImportDecl]
100 explicit_prelude_import
101 = notNull [ () | L _ (ImportDecl mod Nothing _ _ _ _) <- import_decls,
102 unLoc mod == pRELUDE_NAME ]
104 preludeImportDecl :: LImportDecl RdrName
107 ImportDecl (L loc pRELUDE_NAME)
108 Nothing {- no specific package -}
109 False {- Not a boot interface -}
110 False {- Not qualified -}
111 Nothing {- No "as" -}
112 Nothing {- No import list -}
114 loc = mkGeneralSrcSpan (fsLit "Implicit import declaration")
116 parseError :: SrcSpan -> Message -> IO a
117 parseError span err = throwOneError $ mkPlainErrMsg span err
119 --------------------------------------------------------------
121 --------------------------------------------------------------
123 -- | Parse OPTIONS and LANGUAGE pragmas of the source file.
125 -- Throws a 'SourceError' if flag parsing fails (including unsupported flags.)
126 getOptionsFromFile :: DynFlags
127 -> FilePath -- ^ Input file
128 -> IO [Located String] -- ^ Parsed options, if any.
129 getOptionsFromFile dflags filename
131 (openBinaryFile filename ReadMode)
134 opts <- fmap getOptions' $ lazyGetToks dflags filename handle
135 seqList opts $ return opts)
138 -- blockSize = 17 -- for testing :-)
141 lazyGetToks :: DynFlags -> FilePath -> Handle -> IO [Located Token]
142 lazyGetToks dflags filename handle = do
143 buf <- hGetStringBufferBlock handle blockSize
144 unsafeInterleaveIO $ lazyLexBuf handle (pragState dflags buf loc) False
146 loc = mkSrcLoc (mkFastString filename) 1 1
148 lazyLexBuf :: Handle -> PState -> Bool -> IO [Located Token]
149 lazyLexBuf handle state eof = do
150 case unP (lexer return) state of
152 -- pprTrace "lazyLexBuf" (text (show (buffer state'))) (return ())
153 if atEnd (buffer state') && not eof
154 -- if this token reached the end of the buffer, and we haven't
155 -- necessarily read up to the end of the file, then the token might
156 -- be truncated, so read some more of the file and lex it again.
157 then getMore handle state
159 L _ ITeof -> return [t]
160 _other -> do rest <- lazyLexBuf handle state' eof
162 _ | not eof -> getMore handle state
163 | otherwise -> return [L (last_loc state) ITeof]
164 -- parser assumes an ITeof sentinel at the end
166 getMore :: Handle -> PState -> IO [Located Token]
167 getMore handle state = do
168 -- pprTrace "getMore" (text (show (buffer state))) (return ())
169 nextbuf <- hGetStringBufferBlock handle blockSize
170 if (len nextbuf == 0) then lazyLexBuf handle state True else do
171 newbuf <- appendStringBuffers (buffer state) nextbuf
172 unsafeInterleaveIO $ lazyLexBuf handle state{buffer=newbuf} False
175 getToks :: DynFlags -> FilePath -> StringBuffer -> [Located Token]
176 getToks dflags filename buf = lexAll (pragState dflags buf loc)
178 loc = mkSrcLoc (mkFastString filename) 1 1
180 lexAll state = case unP (lexer return) state of
181 POk _ t@(L _ ITeof) -> [t]
182 POk state' t -> t : lexAll state'
183 _ -> [L (last_loc state) ITeof]
186 -- | Parse OPTIONS and LANGUAGE pragmas of the source file.
188 -- Throws a 'SourceError' if flag parsing fails (including unsupported flags.)
189 getOptions :: DynFlags
190 -> StringBuffer -- ^ Input Buffer
191 -> FilePath -- ^ Source filename. Used for location info.
192 -> [Located String] -- ^ Parsed options.
193 getOptions dflags buf filename
194 = getOptions' (getToks dflags filename buf)
196 -- The token parser is written manually because Happy can't
197 -- return a partial result when it encounters a lexer error.
198 -- We want to extract options before the buffer is passed through
199 -- CPP, so we can't use the same trick as 'getImports'.
200 getOptions' :: [Located Token] -- Input buffer
201 -> [Located String] -- Options.
205 getToken (L _loc tok) = tok
206 getLoc (L loc _tok) = loc
208 parseToks (open:close:xs)
209 | IToptions_prag str <- getToken open
210 , ITclose_prag <- getToken close
211 = map (L (getLoc open)) (words str) ++
213 parseToks (open:close:xs)
214 | ITinclude_prag str <- getToken open
215 , ITclose_prag <- getToken close
216 = map (L (getLoc open)) ["-#include",removeSpaces str] ++
218 parseToks (open:close:xs)
219 | ITdocOptions str <- getToken open
220 , ITclose_prag <- getToken close
221 = map (L (getLoc open)) ["-haddock-opts", removeSpaces str]
224 | ITdocOptionsOld str <- getToken open
225 = map (L (getLoc open)) ["-haddock-opts", removeSpaces str]
228 | ITlanguage_prag <- getToken open
231 | ITdocCommentNext _ <- getToken x
234 parseLanguage (L loc (ITconid fs):rest)
235 = checkExtension (L loc fs) :
237 (L _loc ITcomma):more -> parseLanguage more
238 (L _loc ITclose_prag):more -> parseToks more
239 (L loc _):_ -> languagePragParseError loc
240 [] -> panic "getOptions'.parseLanguage(1) went past eof token"
241 parseLanguage (tok:_)
242 = languagePragParseError (getLoc tok)
244 = panic "getOptions'.parseLanguage(2) went past eof token"
246 -----------------------------------------------------------------------------
248 -- | Complain about non-dynamic flags in OPTIONS pragmas.
250 -- Throws a 'SourceError' if the input list is non-empty claiming that the
251 -- input flags are unknown.
252 checkProcessArgsResult :: MonadIO m => [Located String] -> m ()
253 checkProcessArgsResult flags
254 = when (notNull flags) $
255 liftIO $ throwIO $ mkSrcErr $ listToBag $ map mkMsg flags
256 where mkMsg (L loc flag)
257 = mkPlainErrMsg loc $
258 (text "unknown flag in {-# OPTIONS_GHC #-} pragma:" <+>
261 -----------------------------------------------------------------------------
263 checkExtension :: Located FastString -> Located String
264 checkExtension (L l ext)
265 -- Checks if a given extension is valid, and if so returns
266 -- its corresponding flag. Otherwise it throws an exception.
267 = let ext' = unpackFS ext in
268 if ext' `elem` supportedLanguagesAndExtensions
269 then L l ("-X"++ext')
270 else unsupportedExtnError l ext'
272 languagePragParseError :: SrcSpan -> a
273 languagePragParseError loc =
274 throw $ mkSrcErr $ unitBag $
276 vcat [ text "Cannot parse LANGUAGE pragma"
277 , text "Expecting comma-separated list of language options,"
278 , text "each starting with a capital letter"
279 , nest 2 (text "E.g. {-# LANGUAGE RecordPuns, Generics #-}") ])
281 unsupportedExtnError :: SrcSpan -> String -> a
282 unsupportedExtnError loc unsup =
283 throw $ mkSrcErr $ unitBag $
285 text "Unsupported extension: " <> text unsup $$
286 if null suggestions then empty else text "Perhaps you meant" <+> quotedListWithOr (map text suggestions)
288 suggestions = fuzzyMatch unsup supportedLanguagesAndExtensions
291 optionsErrorMsgs :: [String] -> [Located String] -> FilePath -> Messages
292 optionsErrorMsgs unhandled_flags flags_lines _filename
293 = (emptyBag, listToBag (map mkMsg unhandled_flags_lines))
294 where unhandled_flags_lines = [ L l f | f <- unhandled_flags,
295 L l f' <- flags_lines, f == f' ]
296 mkMsg (L flagSpan flag) =
297 ErrUtils.mkPlainErrMsg flagSpan $
298 text "unknown flag in {-# OPTIONS_GHC #-} pragma:" <+> text flag