[project @ 2000-05-13 00:20:57 by lewie]

[ghc-hetmet.git] / ghc / compiler / typecheck / TcForeign.lhs

diff --git a/ghc/compiler/typecheck/TcForeign.lhs b/ghc/compiler/typecheck/TcForeign.lhs
index 8ea02f7..e814e06 100644 (file)
--- a/ghc/compiler/typecheck/TcForeign.lhs
+++ b/ghc/compiler/typecheck/TcForeign.lhs
@@ -20,7 +20,7 @@ module TcForeign
 #include "HsVersions.h"
 
 import HsSyn           ( HsDecl(..), ForeignDecl(..), HsExpr(..),
-                         ExtName(..), isDynamic, MonoBinds(..),
+                         ExtName(Dynamic), isDynamicExtName, MonoBinds(..),
                          OutPat(..), ForKind(..)
                        )
 import RnHsSyn         ( RenamedHsDecl, RenamedForeignDecl )
@@ -41,11 +41,8 @@ import Name          ( nameOccName )
 import Type            ( splitFunTys
                        , splitTyConApp_maybe
                        , splitForAllTys
-                       , splitRhoTy
-                       , isForAllTy
-                       , mkForAllTys
                        )
-
+import PprType         ( {- instance Outputable Type -} )
 import TysWiredIn      ( isFFIArgumentTy, isFFIResultTy, 
                          isFFIExternalTy, isAddrTy
                        )
@@ -82,7 +79,7 @@ isForeignImport (ForeignDecl _ k _ dyn _ _) =
 
 -- exports a binding
 isForeignExport :: ForeignDecl name -> Bool
-isForeignExport (ForeignDecl _ FoExport _ ext_nm _ _) = not (isDynamic ext_nm)
+isForeignExport (ForeignDecl _ FoExport _ ext_nm _ _) = not (isDynamicExtName ext_nm)
 isForeignExport _                                    = False
 
 \end{code}
@@ -117,7 +114,7 @@ tcFImport fo@(ForeignDecl nm FoLabel hs_ty ext_nm cconv src_loc) =
    let i = (mkVanillaId nm sig_ty) in
    returnTc (i, (ForeignDecl i FoLabel undefined ext_nm cconv src_loc))
 
-tcFImport fo@(ForeignDecl nm imp_exp hs_ty ext_nm cconv src_loc) =
+tcFImport fo@(ForeignDecl nm imp_exp@(FoImport isUnsafe) hs_ty ext_nm cconv src_loc) =
    tcAddSrcLoc src_loc              $
    tcAddErrCtxt (foreignDeclCtxt fo) $
 
@@ -131,7 +128,7 @@ tcFImport fo@(ForeignDecl nm imp_exp hs_ty ext_nm cconv src_loc) =
    in
    case splitFunTys t_ty of
      (arg_tys, res_ty) ->
-        checkForeignImport (isDynamic ext_nm) ty arg_tys res_ty `thenTc_`
+        checkForeignImport (isDynamicExtName ext_nm) (not isUnsafe) ty arg_tys res_ty `thenTc_`
        let i = (mkVanillaId nm ty) in
        returnTc (i, (ForeignDecl i imp_exp undefined ext_nm cconv src_loc))
 
@@ -168,62 +165,62 @@ tcFExport fo@(ForeignDecl nm imp_exp hs_ty ext_nm cconv src_loc) =
 
 
 \begin{code}
-checkForeignImport :: Bool -> Type -> [Type] -> Type -> TcM s ()
-checkForeignImport is_dynamic ty args res
+checkForeignImport :: Bool -> Bool -> Type -> [Type] -> Type -> TcM s ()
+checkForeignImport is_dynamic is_safe ty args res
  | is_dynamic =
     -- * first arg has got to be an Addr
    case args of
      []     -> check False (illegalForeignTyErr True{-Arg-} ty)
      (x:xs) ->
         check (isAddrTy x) (illegalForeignTyErr True{-Arg-} ty) `thenTc_`
-        mapTc (checkForeignArg isFFIArgumentTy) xs             `thenTc_`
-       checkForeignRes (isFFIResultTy) res
+        mapTc (checkForeignArg (isFFIArgumentTy is_safe)) xs   `thenTc_`
+       checkForeignRes True {-NonIO ok-} isFFIResultTy res
  | otherwise =
-     mapTc (checkForeignArg isFFIArgumentTy) args              `thenTc_`
-     checkForeignRes (isFFIResultTy) res
+     mapTc (checkForeignArg (isFFIArgumentTy is_safe)) args     `thenTc_`
+     checkForeignRes True {-NonIO ok-} isFFIResultTy res
 
 checkForeignExport :: Bool -> Type -> [Type] -> Type -> TcM s ()
 checkForeignExport is_dynamic ty args res
  | is_dynamic = 
     -- * the first (and only!) arg has got to be a function type
-    -- * result type is an Addr
+    --   and it must return IO t
+    -- * result type is an Addr or IO Addr
    case args of
      [arg]  ->
        case splitFunTys arg of
           (arg_tys, res_ty) -> 
-               mapTc (checkForeignArg isFFIExternalTy) arg_tys `thenTc_`
-               checkForeignRes (isFFIResultTy) res_ty          `thenTc_`
-               checkForeignRes (isAddrTy) res
+               mapTc (checkForeignArg isFFIExternalTy) arg_tys         `thenTc_`
+               checkForeignRes True  {-NonIO ok-} isFFIResultTy res_ty `thenTc_`
+               checkForeignRes False {-Must be IO-} isAddrTy      res
      _      -> check False (illegalForeignTyErr True{-Arg-} ty)
  | otherwise =
      mapTc (checkForeignArg isFFIExternalTy) args              `thenTc_`
-     checkForeignRes (isFFIResultTy) res
+     checkForeignRes True {-NonIO ok-} isFFIResultTy res
  
-check :: Bool -> Message -> TcM s ()
-check True _      = returnTc ()
-check _    the_err = addErrTc the_err `thenNF_Tc_` returnTc ()
-
 checkForeignArg :: (Type -> Bool) -> Type -> TcM s ()
 checkForeignArg pred ty = check (pred ty) (illegalForeignTyErr True{-Arg-} ty)
 
 -- Check that the type has the form 
 --    (IO t) or (t) , and that t satisfies the given predicate.
 --
-checkForeignRes :: (Type -> Bool) -> Type -> TcM s ()
-checkForeignRes pred_res_ty ty =
+checkForeignRes :: Bool -> (Type -> Bool) -> Type -> TcM s ()
+checkForeignRes non_io_result_ok pred_res_ty ty =
  case (splitTyConApp_maybe ty) of
     Just (io, [res_ty]) 
         | (getUnique io) == ioTyConKey && pred_res_ty res_ty 
        -> returnTc ()
     _   
-        | pred_res_ty ty -> returnTc ()
-       | otherwise      -> check False (illegalForeignTyErr False{-Res-} ty)
-
+        -> check (non_io_result_ok && pred_res_ty ty) 
+                (illegalForeignTyErr False{-Res-} ty)
 \end{code}
 
 Warnings
 
 \begin{code}
+check :: Bool -> Message -> TcM s ()
+check True _      = returnTc ()
+check _    the_err = addErrTc the_err `thenNF_Tc_` returnTc ()
+
 illegalForeignTyErr isArg ty
   = hang (hsep [ptext SLIT("Unacceptable"), arg_or_res, ptext SLIT("type in foreign declaration:")])
         4 (hsep [ppr ty])
@@ -235,5 +232,4 @@ illegalForeignTyErr isArg ty
 foreignDeclCtxt fo = 
  hang (ptext SLIT("When checking declaration:"))
   4   (ppr fo)
-
 \end{code}