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|
----------------------------------------------------------------------
-- |
-- Module : CheckM
-- Maintainer : (Maintainer)
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/02/18 19:21:13 $
-- > CVS $Author: peb $
-- > CVS $Revision: 1.4 $
--
-- (Description of the module)
-----------------------------------------------------------------------------
module CheckM (Check,
checkError, checkCond, checkWarn, checkUpdate, checkInContext,
checkUpdates, checkReset, checkResets, checkGetContext,
checkLookup, checkStart, checkErr, checkVal, checkIn,
prtFail
) where
import Operations
import Grammar
import Ident
import PrGrammar
-- | the strings are non-fatal warnings
type Check a = STM (Context,[String]) a
checkError :: String -> Check a
checkError = raise
checkCond :: String -> Bool -> Check ()
checkCond s b = if b then return () else checkError s
-- | warnings should be reversed in the end
checkWarn :: String -> Check ()
checkWarn s = updateSTM (\ (cont,msg) -> (cont, s:msg))
checkUpdate :: Decl -> Check ()
checkUpdate d = updateSTM (\ (cont,msg) -> (d:cont, msg))
checkInContext :: [Decl] -> Check r -> Check r
checkInContext g ch = do
i <- checkUpdates g
r <- ch
checkResets i
return r
checkUpdates :: [Decl] -> Check Int
checkUpdates ds = mapM checkUpdate ds >> return (length ds)
checkReset :: Check ()
checkReset = checkResets 1
checkResets :: Int -> Check ()
checkResets i = updateSTM (\ (cont,msg) -> (drop i cont, msg))
checkGetContext :: Check Context
checkGetContext = do
(co,_) <- readSTM
return co
checkLookup :: Ident -> Check Type
checkLookup x = do
co <- checkGetContext
checkErr $ maybe (prtBad "unknown variable" x) return $ lookup x co
checkStart :: Check a -> Err (a,(Context,[String]))
checkStart c = appSTM c ([],[])
checkErr :: Err a -> Check a
checkErr e = stm (\s -> do
v <- e
return (v,s)
)
checkVal :: a -> Check a
checkVal v = return v
prtFail :: Print a => String -> a -> Check b
prtFail s t = checkErr $ prtBad s t
checkIn :: String -> Check a -> Check a
checkIn msg c = stm $ \s@(g,ws) -> case appSTM c s of
Bad e -> Bad $ msg ++++ e
Ok (v,(g',ws')) -> Ok (v,(g',ws2)) where
new = take (length ws' - length ws) ws'
ws2 = [msg ++++ w | w <- new] ++ ws
|
