Three improvements to Template Haskell (fixes #3467)

[ghc-hetmet.git] / compiler / parser / RdrHsSyn.lhs

diff --git a/compiler/parser/RdrHsSyn.lhs b/compiler/parser/RdrHsSyn.lhs
index e8d00a2..03ca542 100644 (file)
--- a/compiler/parser/RdrHsSyn.lhs
+++ b/compiler/parser/RdrHsSyn.lhs
@@ -10,7 +10,7 @@ module RdrHsSyn (
  
        mkHsOpApp, 
        mkHsIntegral, mkHsFractional, mkHsIsString,
-       mkHsDo, mkHsSplice,
+       mkHsDo, mkHsSplice, mkTopSpliceDecl,
         mkClassDecl, mkTyData, mkTyFamily, mkTySynonym,
         splitCon, mkInlineSpec,        
        mkRecConstrOrUpdate, -- HsExp -> [HsFieldUpdate] -> P HsExp
@@ -38,7 +38,6 @@ module RdrHsSyn (
        checkTyVars,          -- [LHsType RdrName] -> P ()
        checkKindSigs,        -- [LTyClDecl RdrName] -> P ()
        checkInstType,        -- HsType -> P HsType
-        checkDerivDecl,       -- LDerivDecl RdrName -> P (LDerivDecl RdrName)
        checkPattern,         -- HsExp -> P HsPat
        bang_RDR,
        checkPatterns,        -- SrcLoc -> [HsExp] -> P [HsPat]
@@ -129,7 +128,8 @@ extract_lty (L loc ty) acc
       HsOpTy ty1 (L loc tv) ty2 -> extract_tv loc tv (extract_lty ty1 (extract_lty ty2 acc))
       HsParTy ty                       -> extract_lty ty acc
       HsNumTy _                 -> acc
-      HsSpliceTy _                     -> acc  -- Type splices mention no type variables
+      HsSpliceTy {}            -> acc  -- Type splices mention no type variables
+      HsSpliceTyOut {}                 -> acc  -- Type splices mention no type variables
       HsKindSig ty _            -> extract_lty ty acc
       HsForAllTy _ [] cx ty     -> extract_lctxt cx (extract_lty ty acc)
       HsForAllTy _ tvs cx ty    -> acc ++ (filter ((`notElem` locals) . unLoc) $
@@ -224,6 +224,20 @@ mkTyFamily loc flavour lhs ksig
   = do { (tc, tparams) <- checkTyClHdr lhs
        ; tyvars <- checkTyVars tparams
        ; return (L loc (TyFamily flavour tc tyvars ksig)) }
+
+mkTopSpliceDecl :: LHsExpr RdrName -> HsDecl RdrName
+-- If the user wrote
+--     $(e)
+-- then that's the splice, but if she wrote, say,
+--      f x
+-- then behave as if she'd written
+--      $(f x)
+mkTopSpliceDecl expr
+  = SpliceD (SpliceDecl expr')
+  where
+    expr' = case expr of
+              (L _ (HsSpliceE (HsSplice _ expr))) -> expr
+              _other                              -> expr
 \end{code}
 
 %************************************************************************
@@ -256,7 +270,7 @@ cvBindGroup binding
                                 ValBindsIn mbs sigs
 
 cvBindsAndSigs :: OrdList (LHsDecl RdrName)
-  -> (Bag (LHsBind RdrName), [LSig RdrName], [LTyClDecl RdrName], [LDocDecl RdrName])
+  -> (Bag (LHsBind RdrName), [LSig RdrName], [LTyClDecl RdrName], [LDocDecl])
 -- Input decls contain just value bindings and signatures
 -- and in case of class or instance declarations also
 -- associated type declarations. They might also contain Haddock comments.
@@ -659,15 +673,6 @@ checkPred (L spn ty)
                                                "malformed class assertion"
 
 ---------------------------------------------------------------------------
--- Checking stand-alone deriving declarations
-
-checkDerivDecl :: LDerivDecl RdrName -> P (LDerivDecl RdrName)
-checkDerivDecl d@(L loc _) = 
-    do stDerivOn <- extension standaloneDerivingEnabled
-       if stDerivOn then return d
-        else parseError loc "Illegal stand-alone deriving declaration (use -XStandaloneDeriving)"
-
----------------------------------------------------------------------------
 -- Checking statements in a do-expression
 --     We parse   do { e1 ; e2 ; }
 --     as [ExprStmt e1, ExprStmt e2]