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gf-core/src/GF/Infra/CheckM.hs
2009-09-20 13:47:08 +00:00

108 lines
3.6 KiB
Haskell

----------------------------------------------------------------------
-- |
-- Module : CheckM
-- Maintainer : (Maintainer)
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/04/21 16:22:33 $
-- > CVS $Author: bringert $
-- > CVS $Revision: 1.5 $
--
-- (Description of the module)
-----------------------------------------------------------------------------
module GF.Infra.CheckM
(Check, Message, runCheck,
checkError, checkCond, checkWarn, checkUpdate, checkInContext,
checkUpdates, checkReset, checkResets, checkGetContext,
checkLookup, checkErr, checkIn, checkMap
) where
import GF.Data.Operations
import GF.Infra.Ident
import GF.Grammar.Grammar
import GF.Grammar.Printer
import qualified Data.Map as Map
import Text.PrettyPrint
type Message = Doc
data CheckResult a
= Fail [Message]
| Success a Context [Message]
newtype Check a = Check {unCheck :: Context -> [Message] -> CheckResult a}
instance Monad Check where
return x = Check (\ctxt msgs -> Success x ctxt msgs)
f >>= g = Check (\ctxt msgs -> case unCheck f ctxt msgs of
Success x ctxt msgs -> unCheck (g x) ctxt msgs
Fail msgs -> Fail msgs)
instance ErrorMonad Check where
raise s = checkError (text s)
handle f h = Check (\ctxt msgs -> case unCheck f ctxt msgs of
Success x ctxt msgs -> Success x ctxt msgs
Fail (msg:msgs) -> unCheck (h (render msg)) ctxt msgs)
checkError :: Message -> Check a
checkError msg = Check (\ctxt msgs -> Fail (msg : msgs))
checkCond :: Message -> Bool -> Check ()
checkCond s b = if b then return () else checkError s
-- | warnings should be reversed in the end
checkWarn :: Message -> Check ()
checkWarn msg = Check (\ctxt msgs -> Success () ctxt ((text "Warning:" <+> msg) : msgs))
checkUpdate :: Hypo -> Check ()
checkUpdate d = Check (\ctxt msgs -> Success () (d:ctxt) msgs)
checkInContext :: [Hypo] -> Check r -> Check r
checkInContext g ch = do
i <- checkUpdates g
r <- ch
checkResets i
return r
checkUpdates :: [Hypo] -> Check Int
checkUpdates ds = mapM checkUpdate ds >> return (length ds)
checkReset :: Check ()
checkReset = checkResets 1
checkResets :: Int -> Check ()
checkResets i = Check (\ctxt msgs -> Success () (drop i ctxt) msgs)
checkGetContext :: Check Context
checkGetContext = Check (\ctxt msgs -> Success ctxt ctxt msgs)
checkLookup :: Ident -> Check Type
checkLookup x = do
co <- checkGetContext
case [ty | (b,y,ty) <- co, x == y] of
[] -> checkError (text "unknown variable" <+> ppIdent x)
(ty:_) -> return ty
runCheck :: Check a -> Either [Message] (a,Context,[Message])
runCheck c =
case unCheck c [] [] of
Fail msgs -> Left msgs
Success v ctxt msgs -> Right (v,ctxt,msgs)
checkMap :: (Ord a) => (a -> b -> Check b) -> Map.Map a b -> Check (Map.Map a b)
checkMap f map = do xs <- mapM (\(k,v) -> do v <- f k v
return (k,v)) (Map.toList map)
return (Map.fromAscList xs)
checkErr :: Err a -> Check a
checkErr (Ok x) = return x
checkErr (Bad err) = checkError (text err)
checkIn :: Doc -> Check a -> Check a
checkIn msg c = Check $ \ctxt msgs ->
case unCheck c ctxt [] of
Fail msgs' -> Fail ((msg $$ nest 3 (vcat (reverse msgs'))) : msgs)
Success v ctxt' msgs' | null msgs' -> Success v ctxt' msgs
| otherwise -> Success v ctxt' ((msg $$ nest 3 (vcat (reverse msgs'))) : msgs)