GF/src is now for 2.9, and the new sources are in src-3.0 - keep it this way until the release of GF 3

src-3.0/GF/Infra/CheckM.hs

@@ -0,0 +1,89 @@
+----------------------------------------------------------------------
+-- |
+-- 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,
+	       checkError, checkCond, checkWarn, checkUpdate, checkInContext,
+	       checkUpdates, checkReset, checkResets, checkGetContext, 
+	       checkLookup, checkStart, checkErr, checkVal, checkIn, 
+	       prtFail
+	      ) where
+
+import GF.Data.Operations
+import GF.Grammar.Grammar
+import GF.Infra.Ident
+import GF.Grammar.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