FIX #1677; poor error message for misspelled module declaration
[ghc.git] / compiler / main / HeaderInfo.hs
1 -----------------------------------------------------------------------------
2 --
3 -- Parsing the top of a Haskell source file to get its module name,
4 -- imports and options.
5 --
6 -- (c) Simon Marlow 2005
7 -- (c) Lemmih 2006
8 --
9 -----------------------------------------------------------------------------
10
11 {-# OPTIONS -w #-}
12 -- The above warning supression flag is a temporary kludge.
13 -- While working on this module you are encouraged to remove it and fix
14 -- any warnings in the module. See
15 -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
16 -- for details
17
18 module HeaderInfo ( getImports
19 , getOptionsFromFile, getOptions
20 , optionsErrorMsgs ) where
21
22 #include "HsVersions.h"
23
24 import Parser ( parseHeader )
25 import Lexer
26 import FastString
27 import HsSyn ( ImportDecl(..), HsModule(..) )
28 import Module ( ModuleName, moduleName )
29 import PrelNames ( gHC_PRIM, mAIN_NAME )
30 import StringBuffer ( StringBuffer(..), hGetStringBuffer, hGetStringBufferBlock
31 , appendStringBuffers )
32 import Config
33 import SrcLoc
34 import DynFlags
35 import ErrUtils
36 import Util
37 import Outputable
38 import Pretty ()
39 import Panic
40 import Maybes
41 import Bag ( emptyBag, listToBag )
42
43 import Control.Exception
44 import Control.Monad
45 import System.Exit
46 import System.IO
47 import Data.List
48
49 #if __GLASGOW_HASKELL__ >= 601
50 import System.IO ( openBinaryFile )
51 #else
52 import IOExts ( openFileEx, IOModeEx(..) )
53 #endif
54
55 #if __GLASGOW_HASKELL__ < 601
56 openBinaryFile fp mode = openFileEx fp (BinaryMode mode)
57 #endif
58
59 getImports :: DynFlags -> StringBuffer -> FilePath -> FilePath
60 -> IO ([Located ModuleName], [Located ModuleName], Located ModuleName)
61 getImports dflags buf filename source_filename = do
62 let loc = mkSrcLoc (mkFastString filename) 1 0
63 case unP parseHeader (mkPState buf loc dflags) of
64 PFailed span err -> parseError span err
65 POk pst rdr_module -> do
66 let ms = getMessages pst
67 printErrorsAndWarnings dflags ms
68 when (errorsFound dflags ms) $ exitWith (ExitFailure 1)
69 case rdr_module of
70 L _ (HsModule mb_mod _ imps _ _ _ _ _) ->
71 let
72 main_loc = mkSrcLoc (mkFastString source_filename) 1 0
73 mod = mb_mod `orElse` L (srcLocSpan main_loc) mAIN_NAME
74 (src_idecls, ord_idecls) = partition isSourceIdecl (map unLoc imps)
75 source_imps = map getImpMod src_idecls
76 ordinary_imps = filter ((/= moduleName gHC_PRIM) . unLoc)
77 (map getImpMod ord_idecls)
78 -- GHC.Prim doesn't exist physically, so don't go looking for it.
79 in
80 return (source_imps, ordinary_imps, mod)
81
82 parseError span err = throwDyn $ mkPlainErrMsg span err
83
84 isSourceIdecl (ImportDecl _ s _ _ _) = s
85
86 getImpMod (ImportDecl located_mod _ _ _ _) = located_mod
87
88 --------------------------------------------------------------
89 -- Get options
90 --------------------------------------------------------------
91
92
93 getOptionsFromFile :: FilePath -- input file
94 -> IO [Located String] -- options, if any
95 getOptionsFromFile filename
96 = Control.Exception.bracket
97 (openBinaryFile filename ReadMode)
98 (hClose)
99 (\handle ->
100 do buf <- hGetStringBufferBlock handle blockSize
101 loop handle buf)
102 where blockSize = 1024
103 loop handle buf
104 | len buf == 0 = return []
105 | otherwise
106 = case getOptions' buf filename of
107 (Nothing, opts) -> return opts
108 (Just buf', opts) -> do nextBlock <- hGetStringBufferBlock handle blockSize
109 newBuf <- appendStringBuffers buf' nextBlock
110 if len newBuf == len buf
111 then return opts
112 else do opts' <- loop handle newBuf
113 return (opts++opts')
114
115 getOptions :: StringBuffer -> FilePath -> [Located String]
116 getOptions buf filename
117 = case getOptions' buf filename of
118 (_,opts) -> opts
119
120 -- The token parser is written manually because Happy can't
121 -- return a partial result when it encounters a lexer error.
122 -- We want to extract options before the buffer is passed through
123 -- CPP, so we can't use the same trick as 'getImports'.
124 getOptions' :: StringBuffer -- Input buffer
125 -> FilePath -- Source file. Used for msgs only.
126 -> ( Maybe StringBuffer -- Just => we can use more input
127 , [Located String] -- Options.
128 )
129 getOptions' buf filename
130 = parseToks (lexAll (pragState buf loc))
131 where loc = mkSrcLoc (mkFastString filename) 1 0
132
133 getToken (buf,L _loc tok) = tok
134 getLoc (buf,L loc _tok) = loc
135 getBuf (buf,_tok) = buf
136 combine opts (flag, opts') = (flag, opts++opts')
137 add opt (flag, opts) = (flag, opt:opts)
138
139 parseToks (open:close:xs)
140 | IToptions_prag str <- getToken open
141 , ITclose_prag <- getToken close
142 = map (L (getLoc open)) (words str) `combine`
143 parseToks xs
144 parseToks (open:close:xs)
145 | ITinclude_prag str <- getToken open
146 , ITclose_prag <- getToken close
147 = map (L (getLoc open)) ["-#include",removeSpaces str] `combine`
148 parseToks xs
149 parseToks (open:xs)
150 | ITlanguage_prag <- getToken open
151 = parseLanguage xs
152 -- The last token before EOF could have been truncated.
153 -- We ignore it to be on the safe side.
154 parseToks [tok,eof]
155 | ITeof <- getToken eof
156 = (Just (getBuf tok),[])
157 parseToks (eof:_)
158 | ITeof <- getToken eof
159 = (Just (getBuf eof),[])
160 parseToks _ = (Nothing,[])
161 parseLanguage ((_buf,L loc (ITconid fs)):rest)
162 = checkExtension (L loc fs) `add`
163 case rest of
164 (_,L loc ITcomma):more -> parseLanguage more
165 (_,L loc ITclose_prag):more -> parseToks more
166 (_,L loc _):_ -> languagePragParseError loc
167 parseLanguage (tok:_)
168 = languagePragParseError (getLoc tok)
169 lexToken t = return t
170 lexAll state = case unP (lexer lexToken) state of
171 POk state' t@(L _ ITeof) -> [(buffer state,t)]
172 POk state' t -> (buffer state,t):lexAll state'
173 _ -> [(buffer state,L (last_loc state) ITeof)]
174
175 checkExtension :: Located FastString -> Located String
176 checkExtension (L l ext)
177 -- Checks if a given extension is valid, and if so returns
178 -- its corresponding flag. Otherwise it throws an exception.
179 = let ext' = unpackFS ext in
180 if ext' `elem` supportedLanguages
181 || ext' `elem` (map ("No"++) supportedLanguages)
182 then L l ("-X"++ext')
183 else unsupportedExtnError l ext'
184
185 languagePragParseError loc =
186 pgmError (showSDoc (mkLocMessage loc (
187 text "cannot parse LANGUAGE pragma")))
188
189 unsupportedExtnError loc unsup =
190 pgmError (showSDoc (mkLocMessage loc (
191 text "unsupported extension: " <>
192 text unsup)))
193
194
195 optionsErrorMsgs :: [String] -> [Located String] -> FilePath -> Messages
196 optionsErrorMsgs unhandled_flags flags_lines filename
197 = (emptyBag, listToBag (map mkMsg unhandled_flags_lines))
198 where unhandled_flags_lines = [ L l f | f <- unhandled_flags,
199 L l f' <- flags_lines, f == f' ]
200 mkMsg (L flagSpan flag) =
201 ErrUtils.mkPlainErrMsg flagSpan $
202 text "unknown flag in {-# OPTIONS #-} pragma:" <+> text flag
203