+module Main where
+import System
+import Char
+import List
+import IO
+import System.Environment
+import System.Console.GetOpt
+import System.Exit
+
+
+-- search for definitions of things
+-- we do this by looking for the following patterns:
+-- data XXX = ... giving a datatype location
+-- newtype XXX = ... giving a newtype location
+-- bla :: ... giving a function location
+--
+-- by doing it this way, we avoid picking up local definitions
+-- (whether this is good or not is a matter for debate)
+--
+
+-- We generate both CTAGS and ETAGS format tags files
+-- The former is for use in most sensible editors, while EMACS uses ETAGS
+
+
+main :: IO ()
+main = do
+ progName <- getProgName
+ args <- getArgs
+ let usageString = "Usage: " ++ progName ++ " [OPTION...] [files...]"
+ let (modes, filenames, errs) = getOpt Permute options args
+ if errs /= [] || elem Help modes || filenames == []
+ then do
+ putStr $ unlines errs
+ putStr $ usageInfo usageString options
+ exitWith (ExitFailure 1)
+ else return ()
+ let mode = getMode modes
+ filedata <- mapM findthings filenames
+ if mode == BothTags || mode == CTags
+ then do
+ ctagsfile <- openFile "tags" WriteMode
+ writectagsfile ctagsfile filedata
+ hClose ctagsfile
+ else return ()
+ if mode == BothTags || mode == ETags
+ then do
+ etagsfile <- openFile "TAGS" WriteMode
+ writeetagsfile etagsfile filedata
+ hClose etagsfile
+ else return ()
+
+-- | getMode takes a list of modes and extract the mode with the
+-- highest precedence. These are as follows: Both, CTags, ETags
+-- The default case is Both.
+getMode :: [Mode] -> Mode
+getMode [] = BothTags
+getMode [x] = x
+getMode (x:xs) = max x (getMode xs)
+
+
+data Mode = ETags | CTags | BothTags | Help deriving (Ord, Eq, Show)
+
+options :: [OptDescr Mode]
+options = [ Option "c" ["ctags"]
+ (NoArg CTags) "generate CTAGS file (ctags)"
+ , Option "e" ["etags"]
+ (NoArg ETags) "generate ETAGS file (etags)"
+ , Option "b" ["both"]
+ (NoArg BothTags) ("generate both CTAGS and ETAGS")
+ , Option "h" ["help"] (NoArg Help) "This help"
+ ]
+
+type FileName = String
+
+type ThingName = String
+
+-- The position of a token or definition
+data Pos = Pos
+ FileName -- file name
+ Int -- line number
+ Int -- token number
+ String -- string that makes up that line
+ deriving Show
+
+-- A definition we have found
+data FoundThing = FoundThing ThingName Pos
+ deriving Show
+
+-- Data we have obtained from a file
+data FileData = FileData FileName [FoundThing]
+
+data Token = Token String Pos
+ deriving Show
+
+
+-- stuff for dealing with ctags output format
+
+writectagsfile :: Handle -> [FileData] -> IO ()
+writectagsfile ctagsfile filedata = do
+ let things = concat $ map getfoundthings filedata
+ mapM_ (\x -> hPutStrLn ctagsfile $ dumpthing x) things
+
+getfoundthings :: FileData -> [FoundThing]
+getfoundthings (FileData filename things) = things
+
+dumpthing :: FoundThing -> String
+dumpthing (FoundThing name (Pos filename line _ _)) =
+ name ++ "\t" ++ filename ++ "\t" ++ (show $ line + 1)
+
+
+-- stuff for dealing with etags output format
+
+writeetagsfile :: Handle -> [FileData] -> IO ()
+writeetagsfile etagsfile filedata = do
+ mapM_ (\x -> hPutStr etagsfile $ e_dumpfiledata x) filedata
+
+e_dumpfiledata :: FileData -> String
+e_dumpfiledata (FileData filename things) =
+ "\x0c\n" ++ filename ++ "," ++ (show thingslength) ++ "\n" ++ thingsdump
+ where
+ thingsdump = concat $ map e_dumpthing things
+ thingslength = length thingsdump
+
+e_dumpthing :: FoundThing -> String
+e_dumpthing (FoundThing name (Pos filename line token fullline)) =
+ (concat $ take (token + 1) $ spacedwords fullline)
+ ++ "\x7f" ++ (show line) ++ "," ++ (show $ line+1) ++ "\n"
+
+
+-- like "words", but keeping the whitespace, and so letting us build
+-- accurate prefixes
+
+spacedwords :: String -> [String]
+spacedwords [] = []
+spacedwords xs = (blanks ++ wordchars):(spacedwords rest2)
+ where
+ (blanks,rest) = span Char.isSpace xs
+ (wordchars,rest2) = span (\x -> not $ Char.isSpace x) rest
+
+
+-- Find the definitions in a file
+
+findthings :: FileName -> IO FileData
+findthings filename = do
+ text <- readFile filename
+ evaluate text -- forces evaluation of text
+ -- too many files were being opened otherwise since
+ -- readFile is lazy
+ let aslines = lines text
+ let wordlines = map words aslines
+ let noslcoms = map stripslcomments wordlines
+ let tokens = concat $ zipWith3 (withline filename) noslcoms
+ aslines [0 ..]
+ let nocoms = stripblockcomments tokens
+ return $ FileData filename $ findstuff nocoms
+ where evaluate [] = return ()
+ evaluate (c:cs) = c `seq` evaluate cs
+
+-- Create tokens from words, by recording their line number
+-- and which token they are through that line
+
+withline :: FileName -> [String] -> String -> Int -> [Token]
+withline filename words fullline i =
+ zipWith (\w t -> Token w (Pos filename i t fullline)) words $ [0 ..]
+
+-- comments stripping
+
+stripslcomments :: [String] -> [String]
+stripslcomments ("--":xs) = []
+stripslcomments (x:xs) = x : stripslcomments xs
+stripslcomments [] = []
+
+stripblockcomments :: [Token] -> [Token]
+stripblockcomments ((Token "\\end{code}" _):xs) = afterlitend xs
+stripblockcomments ((Token "{-" _):xs) = afterblockcomend xs
+stripblockcomments (x:xs) = x:stripblockcomments xs
+stripblockcomments [] = []
+
+afterlitend2 :: [Token] -> [Token]
+afterlitend2 (x:xs) = afterlitend xs
+afterlitend2 [] = []
+
+afterlitend :: [Token] -> [Token]
+afterlitend ((Token "\\begin{code}" _):xs) = xs
+afterlitend (x:xs) = afterlitend xs
+afterlitend [] = []
+
+afterblockcomend :: [Token] -> [Token]
+afterblockcomend ((Token token _):xs) | contains "-}" token = xs
+ | otherwise = afterblockcomend xs
+afterblockcomend [] = []
+
+
+-- does one string contain another string
+
+contains :: Eq a => [a] -> [a] -> Bool
+contains sub full = any (isPrefixOf sub) $ tails full
+
+ints :: Int -> [Int]
+ints i = i:(ints $ i+1)
+
+
+-- actually pick up definitions
+
+findstuff :: [Token] -> [FoundThing]
+findstuff ((Token "data" _):(Token name pos):xs) =
+ FoundThing name pos : (getcons xs) ++ (findstuff xs)
+findstuff ((Token "newtype" _):(Token name pos):xs) =
+ FoundThing name pos : findstuff xs
+findstuff ((Token "type" _):(Token name pos):xs) =
+ FoundThing name pos : findstuff xs
+findstuff ((Token name pos):(Token "::" _):xs) =
+ FoundThing name pos : findstuff xs
+findstuff (x:xs) = findstuff xs
+findstuff [] = []
+
+
+-- get the constructor definitions, knowing that a datatype has just started
+
+getcons :: [Token] -> [FoundThing]
+getcons ((Token "=" _):(Token name pos):xs) =
+ FoundThing name pos : getcons2 xs
+getcons (x:xs) = getcons xs
+getcons [] = []
+
+
+getcons2 ((Token "=" _):xs) = []
+getcons2 ((Token "|" _):(Token name pos):xs) =
+ FoundThing name pos : getcons2 xs
+getcons2 (x:xs) = getcons2 xs
+getcons2 [] = []
+