More refactorings

curry-frontend.cabal

@@ -71,8 +71,8 @@ Executable cymake
     , Env.Arity
     , Env.Eval
     , Env.Import
+    , Env.Interfaces
     , Env.Label
-    , Env.Module
     , Env.NestEnv
     , Env.OldScopeEnv
     , Env.OpPrec

src/Base/CurryTypes.lhs

@@ -44,7 +44,7 @@ order of type variables in the left hand side of a type declaration.
 > toType' tvs (CS.ConstructorType tc tys) =
 >   TypeConstructor tc (map (toType' tvs) tys)
 > toType' tvs (CS.VariableType tv) =
->   maybe (internalError ("toType " ++ show tv)) TypeVariable (Map.lookup tv tvs)
+>   maybe (internalError $ "toType " ++ show tv) TypeVariable (Map.lookup tv tvs)
 > toType' tvs (CS.TupleType tys)
 >   | null tys = TypeConstructor (qualify unitId) []
 >   | otherwise = TypeConstructor (qualify (tupleId (length tys'))) tys'

src/Base/ErrorMessages.hs

+module Base.ErrorMessages where
+
+import Data.List (intercalate)
+
+import Curry.Base.Ident
+
+errCyclicImport :: [ModuleIdent] -> String
+errCyclicImport []  = error "Base.ErrorMessages.errCyclicImport: empty list"
+errCyclicImport [m] = "Recursive import for module " ++ moduleName m
+errCyclicImport ms  = "Cylic import dependency between modules "
+                      ++ intercalate ", " inits ++ " and " ++ lastm
+  where
+  (inits, lastm)         = splitLast $ map moduleName ms
+  splitLast []           = error "Base.ErrorMessages.splitLast: empty list"
+  splitLast (x : [])     = ([]  , x)
+  splitLast (x : y : ys) = (x : xs, z) where (xs, z) = splitLast (y : ys)
+
+errMissingFile :: FilePath -> String
+errMissingFile f = "Missing file \"" ++ f ++ "\""
+
+errFileModuleMismatch :: FilePath -> ModuleIdent -> String
+errFileModuleMismatch f m =  "File name '" ++ f
+  ++ "' does not match module name '" ++ moduleName m ++ "'"
+
+errModuleFileMismatch :: ModuleIdent -> String
+errModuleFileMismatch mid = "module \"" ++ moduleName mid
+  ++ "\" must be in a file \"" ++ moduleName mid ++ ".(l)curry\""
+
+errWrongInterface :: ModuleIdent -> ModuleIdent -> String
+errWrongInterface m m' =
+  "Expected interface for " ++ show m ++ " but found " ++ show m'
+  ++ show (moduleQualifiers m, moduleQualifiers m')
+
+errWrongModule :: ModuleIdent -> ModuleIdent -> String
+errWrongModule m m' =
+  "Expected module for " ++ show m ++ " but found " ++ show m'
+  ++ show (moduleQualifiers m, moduleQualifiers m')
+
+errInterfaceNotFound :: ModuleIdent -> String
+errInterfaceNotFound m = "Interface for module " ++ moduleName m ++ " not found"
+
+errInterfaceModuleMismatch :: ModuleIdent -> ModuleIdent -> String
+errInterfaceModuleMismatch mi mm =
+  "Interface " ++ show mi ++ " does not match module " ++ show mm

src/Base/Subst.lhs

@@ -14,8 +14,8 @@ marked with a boolean flag (see below).
 
 > module Base.Subst
 >   ( Subst (..), IntSubst (..), idSubst, substToList, bindSubst, unbindSubst
->   , compose,  substVar', isubstVar, restrictSubstTo
->   )where
+>   , compose, substVar', isubstVar, restrictSubstTo
+>   ) where
 
 > import qualified Data.Map as Map
 

src/Base/TypeSubst.lhs

@@ -9,7 +9,9 @@
 This module implements substitutions on types.
 \begin{verbatim}
 
-> module Base.TypeSubst (module Base.TypeSubst, idSubst, bindSubst, compose) where
+> module Base.TypeSubst
+>   ( module Base.TypeSubst, idSubst, bindSubst, compose
+>   ) where
 
 > import Data.List (nub)
 > import Data.Maybe (fromJust, isJust)

src/Base/Typing.lhs

@@ -19,7 +19,7 @@
 > import Base.Messages (internalError)
 > import Base.Types
 > import Base.TypeSubst
-> import Base.Utils
+> import Base.Utils (foldr2)
 
 > import Env.TopEnv
 > import Env.Value (ValueEnv, ValueInfo (..), lookupValue, qualLookupValue)

src/Base/Utils.lhs

@@ -11,8 +11,7 @@ commonly used in the compiler, but not implemented in the Haskell
 \begin{verbatim}
 
 > module Base.Utils
->   ( fst3, snd3, thd3, apFst3, apSnd3, apThd3, curry3, uncurry3
->   , (++!), foldl2, foldr2, mapAccumM, findDouble
+>   ( thd3, (++!), foldr2, mapAccumM, findDouble
 >   ) where
 
 > infixr 5 ++!
@@ -24,29 +23,29 @@ triples. We provide projection, (un-)currying, and mapping for triples
 here.
 \begin{verbatim}
 
-> fst3 :: (a, b, c) -> a
-> fst3 (x, _, _) = x
+fst3 :: (a, b, c) -> a
+fst3 (x, _, _) = x
 
-> snd3 :: (a, b, c) -> b
-> snd3 (_, y, _) = y
+snd3 :: (a, b, c) -> b
+snd3 (_, y, _) = y
 
 > thd3 :: (a, b, c) -> c
 > thd3 (_, _, z) = z
 
-> apFst3 :: (a -> d) -> (a, b, c) -> (d, b, c)
-> apFst3 f (x, y, z) = (f x, y, z)
+apFst3 :: (a -> d) -> (a, b, c) -> (d, b, c)
+apFst3 f (x, y, z) = (f x, y, z)
 
-> apSnd3 :: (b -> d) -> (a, b, c) -> (a, d, c)
-> apSnd3 f (x, y, z) = (x, f y, z)
+apSnd3 :: (b -> d) -> (a, b, c) -> (a, d, c)
+apSnd3 f (x, y, z) = (x, f y, z)
 
-> apThd3 :: (c -> d) -> (a, b, c) -> (a, b, d)
-> apThd3 f (x, y, z) = (x, y, f z)
+apThd3 :: (c -> d) -> (a, b, c) -> (a, b, d)
+apThd3 f (x, y, z) = (x, y, f z)
 
-> curry3 :: ((a, b, c) -> d) -> a -> b -> c -> d
-> curry3 f x y z = f (x, y, z)
+curry3 :: ((a, b, c) -> d) -> a -> b -> c -> d
+curry3 f x y z = f (x, y, z)
 
-> uncurry3 :: (a -> b -> c -> d) -> (a, b, c) -> d
-> uncurry3 f (x, y, z) = f x y z
+uncurry3 :: (a -> b -> c -> d) -> (a, b, c) -> d
+uncurry3 f (x, y, z) = f x y z
 
 \end{verbatim}
 \paragraph{Lists}
@@ -79,10 +78,10 @@ Fold operations with two arguments lists can be defined using
 definitions are unfolded for efficiency reasons.
 \begin{verbatim}
 
-> foldl2 :: (a -> b -> c -> a) -> a -> [b] -> [c] -> a
-> foldl2 _ z []       _        = z
-> foldl2 _ z _        []       = z
-> foldl2 f z (x : xs) (y : ys) = foldl2 f (f z x y) xs ys
+foldl2 :: (a -> b -> c -> a) -> a -> [b] -> [c] -> a
+foldl2 _ z []       _        = z
+foldl2 _ z _        []       = z
+foldl2 f z (x : xs) (y : ys) = foldl2 f (f z x y) xs ys
 
 > foldr2 :: (a -> b -> c -> c) -> c -> [a] -> [b] -> c
 > foldr2 _ z []       _        = z

src/Check/TypeCheck.lhs

@@ -41,7 +41,7 @@ type annotation is present.
 > import Base.SCC
 > import Base.Types
 > import Base.TypeSubst
-> import Base.Utils
+> import Base.Utils (foldr2)
 
 > import Env.TopEnv
 > import Env.TypeConstructors (TCEnv, TypeInfo (..), bindTypeInfo, qualLookupTC)

src/Check/WarnCheck.hs

@@ -211,7 +211,7 @@ checkExpression mid (Tuple _ exprs)
 checkExpression mid (List _ exprs)
   = foldM' (checkExpression mid ) exprs
 checkExpression mid (ListCompr _ expr stmts) = withScope $ do
-  foldM' (CheckMment mid ) stmts
+  foldM' (checkStatement mid) stmts
   checkExpression mid expr
   idents' <- returnUnrefVars
   when (not $ null idents') $ foldM' genWarning' $ map unrefVar idents'
@@ -249,7 +249,7 @@ checkExpression mid  (Let decls expr) = withScope $ do
   idents' <- returnUnrefVars
   when (not $ null idents') $ foldM' genWarning' $ map unrefVar idents'
 checkExpression mid  (Do stmts expr) = withScope $ do
-  foldM' (CheckMment mid ) stmts
+  foldM' (checkStatement mid ) stmts
   checkExpression mid  expr
   idents' <- returnUnrefVars
   when (not $ null idents') $ foldM' genWarning' $ map unrefVar idents'
@@ -269,15 +269,15 @@ checkExpression mid (RecordUpdate fields expr) = do
 checkExpression _ _  = checked
 
 --
-CheckMment :: ModuleIdent -> Statement -> CheckM ()
-CheckMment mid (StmtExpr _ expr)
+checkStatement :: ModuleIdent -> Statement -> CheckM ()
+checkStatement mid (StmtExpr _ expr)
    = checkExpression mid expr
-CheckMment mid (StmtDecl decls) = do
+checkStatement mid (StmtDecl decls) = do
   foldM' checkLocalDecl decls
   foldM' insertDecl decls
   foldM' (checkDecl mid) decls
   checkDeclOccurrences decls
-CheckMment mid (StmtBind _ cterm expr) = do
+checkStatement mid (StmtBind _ cterm expr) = do
   checkConstrTerm mid cterm
   insertConstrTerm False cterm
   checkExpression mid expr
@@ -372,7 +372,7 @@ checkDeclOccurrences decls = checkDO (mkIdent "") Map.empty decls
                             >> checkDO ident env decls')
                   (Map.lookup ident env))
       else checkDO ident env decls'
- checkDO _ env (_ : decls') = checkDO (mkIdent "") env decls'
+  checkDO _ env (_ : decls') = checkDO (mkIdent "") env decls'
 
 
 -- check import declarations for multiply imported modules
@@ -556,7 +556,7 @@ genWarning pos msg
  where warnMsg = Message (Just pos) msg
 
 genWarning' :: (Position, String) -> CheckM ()
-genWarning' = uncury genWarning
+genWarning' = uncurry genWarning
 
 --
 insertVar :: Ident -> CheckM ()

src/CompilerEnv.hs

@@ -5,8 +5,8 @@ import Curry.Base.Ident (ModuleIdent)
 import Env.Arity
 import Env.Eval
 import Env.Import
+import Env.Interfaces
 import Env.Label
-import Env.Module
 import Env.OpPrec
 import Env.TypeConstructors
 import Env.Value
@@ -17,8 +17,8 @@ data CompilerEnv = CompilerEnv
   , arityEnv     :: ArityEnv
   , evalAnnotEnv :: EvalEnv
   , importEnv    :: ImportEnv
+  , interfaceEnv :: InterfaceEnv
   , labelEnv     :: LabelEnv
-  , moduleEnv    :: ModuleEnv
   , opPrecEnv    :: PEnv
   , tyConsEnv    :: TCEnv
   , valueEnv     :: ValueEnv
@@ -30,8 +30,8 @@ initCompilerEnv mid = CompilerEnv
   , arityEnv     = initAEnv
   , evalAnnotEnv = initEEnv
   , importEnv    = initIEnv
+  , interfaceEnv = initInterfaceEnv
   , labelEnv     = initLEnv
-  , moduleEnv    = initMEnv
   , opPrecEnv    = initPEnv
   , tyConsEnv    = initTCEnv
   , valueEnv     = initDCEnv

src/CurryBuilder.hs

@@ -8,7 +8,7 @@
 module CurryBuilder (buildCurry, smake) where
 
 import Control.Monad (liftM)
-import Data.Maybe (catMaybes, fromMaybe, mapMaybe)
+import Data.Maybe (catMaybes, mapMaybe)
 import System.Time (ClockTime)
 
 import Curry.Base.Ident
@@ -16,6 +16,7 @@ import Curry.Files.Filenames
 import Curry.Files.PathUtils ( dropExtension, doesModuleExist, lookupCurryFile
   , getModuleModTime, tryGetModuleModTime)
 
+import Base.ErrorMessages (errMissingFile)
 import Base.Messages (status, abortWith)
 
 import CompilerOpts (Options (..), TargetType (..))
@@ -30,48 +31,45 @@ buildCurry :: Options -> FilePath -> IO ()
 buildCurry opts file = do
   mbFile <- lookupCurryFile (optImportPaths opts) file
   case mbFile of
-    Nothing -> abortWith [missingModule file]
+    Nothing -> abortWith [errMissingFile file]
     Just f  -> do
       (mods, errs) <- flatDeps opts f
       if null errs
         then makeCurry (defaultToFlatCurry opts) mods f
         else abortWith errs
-  where
-    missingModule f      = "Error: missing module \"" ++ f ++ "\""
-    defaultToFlatCurry opt
-      | null $ optTargetTypes opt = opt { optTargetTypes = [FlatCurry] }
-      | otherwise                 = opt
+  where defaultToFlatCurry opt
+          | null $ optTargetTypes opt = opt { optTargetTypes = [FlatCurry] }
+          | otherwise                 = opt
 
 makeCurry :: Options -> [(ModuleIdent, Source)] -> FilePath -> IO ()
 makeCurry opts mods targetFile = mapM_ (compile . snd) mods where
-  compile (Interface _) = return ()
-  compile Unknown       = return ()
   compile (Source file deps) = do
-    flatIntfExists <- doesModuleExist $ flatIntName file
+    interfaceExists <- doesModuleExist $ flatIntName file
     if dropExtension targetFile == dropExtension file
-      then if flatIntfExists && not (optForce opts) && null (optDumps opts)
-              then smake (targetNames file)
-                          (targetFile : mapMaybe flatInterface deps)
-                          (generateFile file)
-                          (skipFile file)
+      then if interfaceExists && not (optForce opts) && null (optDumps opts)
+              then smake (targetNames file) -- dest files
+                         (file : mapMaybe flatInterface deps) -- dep files
+                         (generateFile file) -- action on changed
+                         (skipFile file)     -- action on unchanged
               else generateFile file
-      else if flatIntfExists
-              then smake [flatName' opts file]
-                        (file : mapMaybe flatInterface deps)
-                        (compileFile file)
-                        (skipFile file)
+      else if interfaceExists
+              then smake [flatName' file]
+                         (file : mapMaybe flatInterface deps)
+                         (compileFile file)
+                         (skipFile file)
               else compileFile file
+  compile _ = return ()
 
-  targetNames fn = [ gen fn | (tgt, gen) <- nameGens, tgt `elem` optTargetTypes opts]
+  targetNames fn = [ gen fn | (tgt, gen) <- nameGens
+                   , tgt `elem` optTargetTypes opts]
     where nameGens =
-            [ (FlatCurry            , flatName   )
-            , (ExtendedFlatCurry    , extFlatName)
-            , (FlatXml              , xmlName    )
-            , (AbstractCurry        , acyName    )
-            , (UntypedAbstractCurry , uacyName   )
-            , (Parsed               , \ f -> fromMaybe (sourceRepName f)
-                                                       (optOutput opts))
-            , (FlatXml              , xmlName    )
+            [ (FlatCurry            , flatName     )
+            , (ExtendedFlatCurry    , extFlatName  )
+            , (FlatXml              , xmlName      )
+            , (AbstractCurry        , acyName      )
+            , (UntypedAbstractCurry , uacyName     )
+            , (Parsed               , sourceRepName)
+            , (FlatXml              , xmlName      )
             ]
 
   flatInterface mod1 = case lookup mod1 mods of
@@ -79,25 +77,19 @@ makeCurry opts mods targetFile = mapM_ (compile . snd) mods where
     Just (Interface file) -> Just $ flatIntName file
     _                     -> Nothing
 
+  flatName'
+    | ExtendedFlatCurry `elem` optTargetTypes opts = extFlatName
+    | otherwise                                    = flatName
+
   compileFile f = do
     status opts $ "compiling " ++ f
-    compileModule (compOpts True) f
-
-  skipFile f = status opts $ "skipping " ++ f
+    compileModule (opts { optTargetTypes = [FlatCurry], optDumps = [] }) f
 
   generateFile f = do
     status opts $ "generating " ++ head (targetNames f)
-    compileModule (compOpts False) f
+    compileModule opts f
 
-  compOpts isImport
-    | isImport  = opts { optTargetTypes = [FlatCurry], optDumps = [] }
-    | otherwise = opts
-
-
-flatName' :: Options -> FilePath -> FilePath
-flatName' opts
-  | ExtendedFlatCurry `elem` optTargetTypes opts  = extFlatName
-  | otherwise                                     = flatName
+  skipFile f = status opts $ "skipping " ++ f
 
 {- |A simple make function
 

src/CurryDeps.lhs

@@ -15,18 +15,19 @@ dependencies and to update programs composed of multiple modules.
 \begin{verbatim}
 
 > module CurryDeps
->   ( Source (..), deps, flatDeps, flattenDeps, sourceDeps, moduleDeps ) where
+>   ( Source (..), flatDeps, deps, flattenDeps, sourceDeps, moduleDeps ) where
 
-> import Control.Monad (foldM)
-> import Data.List (intercalate, isSuffixOf, nub)
+> import Control.Monad (foldM, liftM, unless)
+> import Data.List (isSuffixOf, nub)
 > import qualified Data.Map as Map (Map, empty, insert, lookup, toList)
 
 > import Curry.Base.Ident
 > import Curry.Base.MessageMonad
 > import Curry.Files.Filenames
 > import Curry.Files.PathUtils
-> import Curry.Syntax hiding (Interface (..))
+> import Curry.Syntax (Module (..),  Decl (..), parseHeader)
 
+> import Base.ErrorMessages (errCyclicImport, errWrongModule)
 > import Base.SCC (scc)
 > import CompilerOpts (Options (..), Extension (..))
 
@@ -39,34 +40,14 @@ dependencies and to update programs composed of multiple modules.
 > type SourceEnv = Map.Map ModuleIdent Source
 
 > flatDeps :: Options -> FilePath -> IO ([(ModuleIdent, Source)], [String])
-> flatDeps opts fn = do
->   mEnv <- deps implicitPrelude [] libPaths Map.empty fn
->   return $ flattenDeps mEnv
->   where
->     implicitPrelude = NoImplicitPrelude `notElem` optExtensions opts
->     libPaths = optImportPaths opts
-
-> deps :: Bool -> [FilePath] -> [FilePath] -> SourceEnv -> FilePath
->      -> IO SourceEnv
-> deps implicitPrelude paths libPaths mEnv fn
->   | e `elem` sourceExts
->     = sourceDeps implicitPrelude paths libPaths (mkMIdent [r]) mEnv fn
->   | e == icurryExt
->     = return Map.empty
->   | e `elem` objectExts
->     = targetDeps implicitPrelude paths libPaths mEnv r
->   | otherwise
->     = targetDeps implicitPrelude paths libPaths mEnv fn
->   where r = dropExtension fn
->         e = takeExtension fn
-
-> targetDeps :: Bool -> [FilePath] -> [FilePath] -> SourceEnv -> FilePath
->            -> IO SourceEnv
-> targetDeps implicitPrelude paths libraryPaths mEnv fn =
->   lookupFile [""] sourceExts fn >>=
->   maybe (return (Map.insert m Unknown mEnv))
->         (sourceDeps implicitPrelude paths libraryPaths m mEnv)
->   where m = mkMIdent [fn]
+> flatDeps opts fn = flattenDeps `liftM` deps opts [] Map.empty fn
+
+> deps :: Options -> [FilePath] -> SourceEnv -> FilePath -> IO SourceEnv
+> deps opts paths sEnv fn
+>   | ext   ==   icurryExt  = return Map.empty
+>   | ext `elem` sourceExts = sourceDeps opts paths sEnv fn
+>   | otherwise             = targetDeps opts paths sEnv fn
+>   where ext = takeExtension fn
 
 \end{verbatim}
 The following functions are used to lookup files related to a given
@@ -76,13 +57,36 @@ imported modules, the first is used to find source modules, whereas
 the library path is used only for finding matching interface files. As
 the compiler does not distinguish these paths, we actually check for
 interface files in the source paths as well.
-
-Note that the functions \texttt{buildScript} and \texttt{makeDepend}
-already remove all directories that are included in the both search
-paths from the library paths in order to avoid scanning such
-directories more than twice.
 \begin{verbatim}
 
+> sourceDeps :: Options -> [FilePath] -> SourceEnv -> FilePath -> IO SourceEnv
+> sourceDeps opts paths sEnv fn = do
+>   hdr <- (ok . parseHeader fn) `liftM` readModule fn
+>   moduleDeps opts paths sEnv fn hdr
+
+> targetDeps :: Options -> [FilePath] -> SourceEnv -> FilePath -> IO SourceEnv
+> targetDeps opts paths sEnv fn = do
+>   mFile <- lookupFile [""] sourceExts fn
+>   case mFile of
+>     Nothing   -> return $ Map.insert (mkMIdent [fn]) Unknown sEnv
+>     Just file -> sourceDeps opts paths sEnv file
+
+> moduleDeps :: Options -> [FilePath] -> SourceEnv -> FilePath -> Module -> IO SourceEnv
+> moduleDeps opts paths sEnv fn (Module m _ ds) = case Map.lookup m sEnv of
+>     Just  _ -> return sEnv
+>     Nothing -> do
+>       let imps  = imports opts m ds
+>           sEnv' = Map.insert m (Source fn imps) sEnv
+>       foldM (moduleIdentDeps opts paths) sEnv' imps
+
+> -- |Retrieve the imported modules and add the import of the Prelude
+> --  according to the compiler options.
+> imports :: Options -> ModuleIdent -> [Decl] -> [ModuleIdent]
+> imports opts m ds = nub $
+>      [preludeMIdent | m /= preludeMIdent && implicitPrelude]
+>   ++ [m' | ImportDecl _ m' _ _ _ <- ds]
+>   where implicitPrelude = NoImplicitPrelude `notElem` optExtensions opts
+
 \end{verbatim}
 In order to compute the dependency graph, source files for each module
 need to be looked up. When a source module is found, its header is
@@ -92,44 +96,31 @@ is added implicitly to the list of imported modules except for the
 prelude itself. Any errors reported by the parser are ignored.
 \begin{verbatim}
 
-> moduleDeps :: Bool -> [FilePath] -> [FilePath] -> SourceEnv -> ModuleIdent
->            -> IO SourceEnv
-> moduleDeps implicitPrelude paths libraryPaths mEnv m =
->   case Map.lookup m mEnv of
->     Just _  -> return mEnv
->     Nothing -> do
->       mbFn <- lookupModule paths libraryPaths m
->       case mbFn of
->         Just fn
->           | icurryExt `isSuffixOf` fn ->
->               return (Map.insert m (Interface fn) mEnv)
->           | otherwise -> sourceDeps implicitPrelude paths libraryPaths m mEnv fn
->         Nothing -> return (Map.insert m Unknown mEnv)
-
-> sourceDeps :: Bool -> [FilePath] -> [FilePath] -> ModuleIdent -> SourceEnv
->            -> FilePath -> IO SourceEnv
-> sourceDeps implicitPrelude paths libraryPaths m mEnv fn = do
->   s <- readModule fn
->   case fst $ runMsg $ parseHeader fn s of
->     Right (Module m' _ ds) ->
->       let ms = imports implicitPrelude m' ds in
->       foldM (moduleDeps implicitPrelude paths libraryPaths)
->             (Map.insert m (Source fn ms) mEnv) ms
->     Left _ -> return (Map.insert m (Source fn []) mEnv)
-
-> -- |Retrieve the imported modules and add the import of the Prelude
-> --  according to the flag.
-> imports :: Bool -> ModuleIdent -> [Decl] -> [ModuleIdent]
-> imports implicitPrelude m ds = nub $
->      [preludeMIdent | m /= preludeMIdent && implicitPrelude]
->   ++ [m' | ImportDecl _ m' _ _ _ <- ds]
+> moduleIdentDeps :: Options -> [FilePath] -> SourceEnv -> ModuleIdent -> IO SourceEnv
+> moduleIdentDeps opts paths sEnv m = case Map.lookup m sEnv of
+>   Just _  -> return sEnv
+>   Nothing -> do
+>     mFile <- lookupModule paths libraryPaths m
+>     case mFile of
+>       Nothing -> return $ Map.insert m Unknown sEnv
+>       Just fn
+>         | icurryExt `isSuffixOf` fn -> return $ Map.insert m (Interface fn) sEnv
+>         | otherwise                 -> checkModuleHeader fn
+>   where libraryPaths = optImportPaths opts
+>         checkModuleHeader fn = do
+>           hdr@(Module m' _ _) <- (ok . parseHeader fn) `liftM` readModule fn
+>           unless (m == m') $ error $ errWrongModule m m'
+>           moduleDeps opts paths sEnv fn hdr
 
+\end{verbatim}
 If we want to compile the program instead of generating Makefile
 dependencies the environment has to be sorted topologically. Note
 that the dependency graph should not contain any cycles.
+\begin{verbatim}
 
 > flattenDeps :: SourceEnv -> ([(ModuleIdent, Source)], [String])
-> flattenDeps = fdeps . sortDeps where
+> flattenDeps = fdeps . sortDeps
+>   where
 >   sortDeps :: SourceEnv -> [[(ModuleIdent, Source)]]
 >   sortDeps = scc modules imports' . Map.toList
 >
@@ -145,13 +136,6 @@ that the dependency graph should not contain any cycles.
 >   checkdep []    (srcs, errs) = (srcs      , errs      )
 >   checkdep [src] (srcs, errs) = (src : srcs, errs      )
 >   checkdep dep   (srcs, errs) = (srcs      , err : errs)
->     where err = cyclicError (map fst dep)
-
->   cyclicError :: [ModuleIdent] -> String
->   cyclicError ms = "Cylic import dependency between modules " ++
->                    intercalate ", " inits ++ " and " ++ lastm where
->     (inits, lastm)         = splitLast $ map moduleName ms
->     splitLast []           = error "CurryDeps.splitLast: empty list"
->     splitLast (x : [])     = ([]  , x)
->     splitLast (x : y : ys) = (x : xs, z)
->        where (xs, z) = splitLast (y : ys)
+>     where err = errCyclicImport (map fst dep)
+
+\end{verbatim}

src/Env/Module.hs → src/Env/Interfaces.hs

-module Env.Module where
+module Env.Interfaces where
 
 import qualified Data.Map as Map (Map, empty, lookup)
 
 import Curry.Base.Ident (ModuleIdent)
 import Curry.Syntax (IDecl)
 
-type ModuleEnv = Map.Map ModuleIdent [IDecl]
+type InterfaceEnv = Map.Map ModuleIdent [IDecl]
 
-lookupModule :: ModuleIdent -> ModuleEnv -> Maybe [IDecl]
-lookupModule = Map.lookup
+lookupInterface :: ModuleIdent -> InterfaceEnv -> Maybe [IDecl]
+lookupInterface = Map.lookup
 
-initMEnv :: ModuleEnv
-initMEnv = Map.empty
+initInterfaceEnv :: InterfaceEnv
+initInterfaceEnv = Map.empty

src/Frontend.hs

@@ -8,29 +8,27 @@ module Frontend (parse, fullParse, typingParse) where
 import Data.Maybe (mapMaybe)
 import qualified Data.Map as Map (empty)
 import Control.Monad.Writer