Kind sig for toplevel family decls is optional

Mon Sep 18 19:13:47 EDT 2006  Manuel M T Chakravarty <chak@cse.unsw.edu.au>
  * Kind sig for toplevel family decls is optional
  Sat Aug 26 19:03:50 EDT 2006  Manuel M T Chakravarty <chak@cse.unsw.edu.au>
    * Kind sig for toplevel family decls is optional
    - Kind sigs are still compulsory for AT family decls.  Changing this is more
      tricky, as AT decls don't have the family keyword and hence look like empty
      data decls.  That impacts reduce/reduce conflicts and/or the criteria for
      checking whether a TyData variant is a family signature.
    - Also removed iso from the syntax (it's still in the lexer in case we want to
      resurrect it).

diff --git a/compiler/parser/Parser.y.pp b/compiler/parser/Parser.y.pp
index 3fb6cb1..c650a7c 100644 (file)
--- a/compiler/parser/Parser.y.pp
+++ b/compiler/parser/Parser.y.pp
@@ -502,13 +502,16 @@ ty_decl :: { LTyClDecl RdrName }
                       } }
 
            -- type family declarations
-        | 'type' 'family' opt_iso type '::' kind
+        | 'type' 'family' type opt_kind_sig 
                -- Note the use of type for the head; this allows
                -- infix type constructors to be declared
                --
-               {% do { (tc, tvs, _) <- checkSynHdr $4 False
-                     ; return (L (comb3 $1 $4 $6) 
-                                 (TyFunction tc tvs $3 (unLoc $6)))
+               {% do { (tc, tvs, _) <- checkSynHdr $3 False
+                     ; let kind = case unLoc $4 of
+                                    Nothing -> liftedTypeKind
+                                    Just ki -> ki
+                     ; return (L (comb3 $1 $3 $4) 
+                                 (TyFunction tc tvs False kind))
                      } }
 
            -- type instance declarations
@@ -540,17 +543,20 @@ ty_decl :: { LTyClDecl RdrName }
                       ; checkTyVars tparms    -- can have type pats
                      ; return $
                          L (comb4 $1 $2 $4 $5)
-                           (mkTyData (unLoc $1) (ctxt, tc, tvs, Nothing) $3
-                             (reverse (unLoc $5)) (unLoc $6)) } }
+                           (mkTyData (unLoc $1) (ctxt, tc, tvs, Nothing) 
+                             (unLoc $3) (reverse (unLoc $5)) (unLoc $6)) } }
 
           -- data/newtype family
-        | data_or_newtype 'family' tycl_hdr '::' kind
+        | data_or_newtype 'family' tycl_hdr opt_kind_sig
                {% do { let {(ctxt, tc, tvs, tparms) = unLoc $3}
                       ; checkTyVars tparms    -- no type pattern
+                     ; let kind = case unLoc $4 of
+                                    Nothing -> liftedTypeKind
+                                    Just ki -> ki
                      ; return $
-                         L (comb3 $1 $2 $5)
+                         L (comb3 $1 $2 $4)
                            (mkTyData (unLoc $1) (ctxt, tc, tvs, Nothing) 
-                             (Just (unLoc $5)) [] Nothing) } }
+                             (Just kind) [] Nothing) } }
 
           -- data/newtype instance declaration
        | data_or_newtype 'instance' tycl_hdr constrs deriving
@@ -572,31 +578,32 @@ ty_decl :: { LTyClDecl RdrName }
                      ; return $
                          L (comb4 $1 $3 $6 $7)
                            (mkTyData (unLoc $1) (ctxt, tc, tvs, Just tparms) 
-                              $4 (reverse (unLoc $6)) (unLoc $7)) } }
+                              (unLoc $4) (reverse (unLoc $6)) (unLoc $7)) } }
 
 -- Associate type declarations
 --
 at_decl :: { LTyClDecl RdrName }
            -- type family declarations
-        : 'type' opt_iso type '::' kind
+        : 'type' type opt_kind_sig
                -- Note the use of type for the head; this allows
                -- infix type constructors to be declared
                --
-               {% do { (tc, tvs, _) <- checkSynHdr $3 False
-                     ; return (L (comb3 $1 $3 $5) 
-                                 (TyFunction tc tvs $2 (unLoc $5)))
+               {% do { (tc, tvs, _) <- checkSynHdr $2 False
+                     ; let kind = case unLoc $3 of
+                                    Nothing -> liftedTypeKind
+                                    Just ki -> ki
+                     ; return (L (comb3 $1 $2 $3) 
+                                 (TyFunction tc tvs False kind))
                      } }
 
            -- type instance declarations
-        | 'type' opt_iso type '=' ctype
+        | 'type' type '=' ctype
                -- Note the use of type for the head; this allows
                -- infix type constructors and type patterns
                --
-               {% do { when $2 $ 
-                         parseError (comb2 $1 $>) "Misplaced iso keyword"
-                     ; (tc, tvs, typats) <- checkSynHdr $3 True
-                     ; return (L (comb2 $1 $5) 
-                                 (TySynonym tc tvs (Just typats) $5)) 
+               {% do { (tc, tvs, typats) <- checkSynHdr $2 True
+                     ; return (L (comb2 $1 $4) 
+                                 (TySynonym tc tvs (Just typats) $4)) 
                       } }
 
           -- data/newtype family
@@ -628,7 +635,7 @@ at_decl :: { LTyClDecl RdrName }
                      ; return $
                          L (comb4 $1 $2 $5 $6)
                            (mkTyData (unLoc $1) (ctxt, tc, tvs, Just tparms) 
-                            $3 (reverse (unLoc $5)) (unLoc $6)) } }
+                            (unLoc $3) (reverse (unLoc $5)) (unLoc $6)) } }
 
 opt_iso :: { Bool }
        :       { False }
@@ -638,9 +645,9 @@ data_or_newtype :: { Located NewOrData }
        : 'data'        { L1 DataType }
        | 'newtype'     { L1 NewType }
 
-opt_kind_sig :: { Maybe Kind }
-       :                               { Nothing }
-       | '::' kind                     { Just (unLoc $2) }
+opt_kind_sig :: { Located (Maybe Kind) }
+       :                               { noLoc Nothing }
+       | '::' kind                     { LL (Just (unLoc $2)) }
 
 -- tycl_hdr parses the header of a class or data type decl,
 -- which takes the form