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|
----------------------------------------------------------------------
-- |
-- Module : Tokenize
-- Maintainer : AR
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/09/29 13:20:08 $
-- > CVS $Author: aarne $
-- > CVS $Revision: 1.14 $
--
-- lexers = tokenizers, to prepare input for GF grammars. AR 4\/1\/2002.
-- an entry for each is included in 'Custom.customTokenizer'
-----------------------------------------------------------------------------
module GF.UseGrammar.Tokenize ( tokWords,
tokLits,
tokVars,
lexHaskell,
lexHaskellLiteral,
lexHaskellVar,
lexText,
lexTextVar,
lexC2M, lexC2M',
lexTextLiteral,
lexIgnore,
wordsLits
) where
import GF.Data.Operations
---- import UseGrammar (isLiteral,identC)
import GF.CF.CFIdent
import Data.Char
-- lexers = tokenizers, to prepare input for GF grammars. AR 4/1/2002
-- an entry for each is included in Custom.customTokenizer
-- | just words
tokWords :: String -> [CFTok]
tokWords = map tS . words
tokLits :: String -> [CFTok]
tokLits = map mkCFTok . mergeStr . wordsLits where
mergeStr ss = case ss of
w@(c:cs):rest | elem c "\'\"" && c /= last w -> getStr [w] rest
w :rest -> w : mergeStr rest
[] -> []
getStr v ss = case ss of
w@(_:_):rest | elem (last w) "\'\"" -> (unwords (reverse (w:v))) : mergeStr rest
w :rest -> getStr (w:v) rest
[] -> reverse v
tokVars :: String -> [CFTok]
tokVars = map mkCFTokVar . wordsLits
isFloat s = case s of
c:cs | isDigit c -> isFloat cs
'.':cs@(_:_) -> all isDigit cs
_ -> False
isString s = case s of
c:cs@(_:_) -> (c == '\'' && d == '\'') || (c == '"' && d == '"') where d = last cs
_ -> False
mkCFTok :: String -> CFTok
mkCFTok s = case s of
'"' :cs@(_:_) | last cs == '"' -> tL $ init cs
'\'':cs@(_:_) | last cs == '\'' -> tL $ init cs --- 's Gravenhage
_:_ | isFloat s -> tF s
_:_ | all isDigit s -> tI s
_ -> tS s
mkCFTokVar :: String -> CFTok
mkCFTokVar s = case s of
'?':_:_ -> tM s --- "?" --- compat with prCF
'x':'_':_ -> tV s
'x':[] -> tV s
'$':xs@(_:_) -> if last s == '$' then tV (init xs) else tS s
_ -> tS s
mkTokVars :: (String -> [CFTok]) -> String -> [CFTok]
mkTokVars tok = map tv . tok where
tv (TS s) = mkCFTokVar s
tv t = t
mkLit :: String -> CFTok
mkLit s
| isFloat s = tF s
| all isDigit s = tI s
| otherwise = tL s
-- obsolete
mkTL :: String -> CFTok
mkTL s
| isFloat s = tF s
| all isDigit s = tI s
| otherwise = tL ("'" ++ s ++ "'")
-- | Haskell lexer, usable for much code
lexHaskell :: String -> [CFTok]
lexHaskell ss = case lex ss of
[(w@(_:_),ws)] -> tS w : lexHaskell ws
_ -> []
-- | somewhat shaky text lexer
lexText :: String -> [CFTok]
lexText = uncap . lx where
lx s = case s of
'?':'?':cs -> tS "??" : lx cs
p : cs | isMPunct p -> tS [p] : uncap (lx cs)
p : cs | isPunct p -> tS [p] : lx cs
s : cs | isSpace s -> lx cs
_ : _ -> getWord s
_ -> []
getWord s = tS w : lx ws where (w,ws) = span isNotSpec s
isMPunct c = elem c ".!?"
isPunct c = elem c ",:;()\""
isNotSpec c = not (isMPunct c || isPunct c || isSpace c)
uncap (TS (c:cs) : ws) = tC (c:cs) : ws
uncap s = s
-- | lexer for C--, a mini variant of C
lexC2M :: String -> [CFTok]
lexC2M = lexC2M' False
lexC2M' :: Bool -> String -> [CFTok]
lexC2M' isHigherOrder s = case s of
'#':cs -> lexC $ dropWhile (/='\n') cs
'/':'*':cs -> lexC $ dropComment cs
c:cs | isSpace c -> lexC cs
c:cs | isAlpha c -> getId s
c:cs | isDigit c -> getLit s
c:d:cs | isSymb [c,d] -> tS [c,d] : lexC cs
c:cs | isSymb [c] -> tS [c] : lexC cs
_ -> [] --- covers end of file and unknown characters
where
lexC = lexC2M' isHigherOrder
getId s = mkT i : lexC cs where (i,cs) = span isIdChar s
getLit s = tI i : lexC cs where (i,cs) = span isDigit s ---- Float!
isIdChar c = isAlpha c || isDigit c || elem c "'_"
isSymb = reservedAnsiCSymbol
dropComment s = case s of
'*':'/':cs -> cs
_:cs -> dropComment cs
_ -> []
mkT i = if (isRes i) then (tS i) else
if isHigherOrder then (tV i) else (tL ("'" ++ i ++ "'"))
isRes = reservedAnsiC
reservedAnsiCSymbol s = case lookupTree show s ansiCtree of
Ok True -> True
_ -> False
reservedAnsiC s = case lookupTree show s ansiCtree of
Ok False -> True
_ -> False
-- | for an efficient lexer: precompile this!
ansiCtree = buildTree $ [(s,True) | s <- reservedAnsiCSymbols] ++
[(s,False) | s <- reservedAnsiCWords]
reservedAnsiCSymbols = words $
"<<= >>= << >> ++ -- == <= >= *= += -= %= /= &= ^= |= " ++
"^ { } = , ; + * - ( ) < > & % ! ~"
reservedAnsiCWords = words $
"auto break case char const continue default " ++
"do double else enum extern float for goto if int " ++
"long register return short signed sizeof static struct switch typedef " ++
"union unsigned void volatile while " ++
"main printin putchar" --- these are not ansi-C
-- | turn unknown tokens into string literals; not recursively for literals 123, 'foo'
unknown2string :: (String -> Bool) -> [CFTok] -> [CFTok]
unknown2string isKnown = map mkOne where
mkOne t@(TS s)
| isKnown s = t
| isFloat s = tF s
| all isDigit s = tI s
| otherwise = tL s
mkOne t@(TC s) = if isKnown s then t else mkLit s
mkOne t = t
unknown2var :: (String -> Bool) -> [CFTok] -> [CFTok]
unknown2var isKnown = map mkOne where
mkOne t@(TS "??") = if isKnown "??" then t else tM "??"
mkOne t@(TS s)
| isKnown s = t
| isFloat s = tF s
| isString s = tL (init (tail s))
| all isDigit s = tI s
| otherwise = tV s
mkOne t@(TC s) = if isKnown s then t else tV s
mkOne t = t
lexTextLiteral, lexHaskellLiteral, lexHaskellVar :: (String -> Bool) -> String -> [CFTok]
lexTextLiteral isKnown = unknown2string (eitherUpper isKnown) . lexText
lexHaskellLiteral isKnown = unknown2string isKnown . lexHaskell
lexHaskellVar isKnown = unknown2var isKnown . lexHaskell
lexTextVar isKnown = unknown2var (eitherUpper isKnown) . lexText
eitherUpper isKnown w@(c:cs) = isKnown (toLower c : cs) || isKnown (toUpper c : cs)
eitherUpper isKnown w = isKnown w
-- ignore unknown tokens (e.g. keyword spotting)
lexIgnore :: (String -> Bool) -> [CFTok] -> [CFTok]
lexIgnore isKnown = concatMap mkOne where
mkOne t@(TS s)
| isKnown s = [t]
| otherwise = []
mkOne t = [t]
|
