Refactor the parsing of data type declarations

This is a minor change to the parser that tidies it up a bit,
and allows us to parse

	data T :: *
        data S :: * -> *

just like

	data T
	data S a

diff --git a/compiler/parser/Parser.y.pp b/compiler/parser/Parser.y.pp
index f051726..6dbb49e 100644 (file)
--- a/compiler/parser/Parser.y.pp
+++ b/compiler/parser/Parser.y.pp
@@ -611,10 +611,10 @@ ty_decl :: { LTyClDecl RdrName }
 
           -- ordinary GADT declaration
         | data_or_newtype tycl_hdr opt_kind_sig 
 
           -- ordinary GADT declaration
         | data_or_newtype tycl_hdr opt_kind_sig 

-                'where' gadt_constrlist
+                gadt_constrlist

                 deriving
                {% mkTyData (comb4 $1 $2 $4 $5) (unLoc $1) False $2 
                 deriving
                {% mkTyData (comb4 $1 $2 $4 $5) (unLoc $1) False $2 

-                            (unLoc $3) (reverse (unLoc $5)) (unLoc $6) }
+                            (unLoc $3) (unLoc $4) (unLoc $5) }

                                   -- We need the location on tycl_hdr in case 
                                   -- constrs and deriving are both empty
 
                                   -- We need the location on tycl_hdr in case 
                                   -- constrs and deriving are both empty
 

@@ -629,10 +629,10 @@ ty_decl :: { LTyClDecl RdrName }
 
           -- GADT instance declaration
         | data_or_newtype 'instance' tycl_hdr opt_kind_sig 
 
           -- GADT instance declaration
         | data_or_newtype 'instance' tycl_hdr opt_kind_sig 

-                'where' gadt_constrlist
+                gadt_constrlist

                 deriving
                 deriving

-               {% mkTyData (comb4 $1 $3 $6 $7) (unLoc $1) True $3
-                           (unLoc $4) (reverse (unLoc $6)) (unLoc $7) }
+               {% mkTyData (comb4 $1 $3 $5 $6) (unLoc $1) True $3
+                           (unLoc $4) (unLoc $5) (unLoc $6) }

 
 -- Associated type family declarations
 --
 
 -- Associated type family declarations
 --

@@ -676,10 +676,10 @@ at_decl_inst :: { LTyClDecl RdrName }
 
         -- GADT instance declaration
         | data_or_newtype tycl_hdr opt_kind_sig 
 
         -- GADT instance declaration
         | data_or_newtype tycl_hdr opt_kind_sig 

-                'where' gadt_constrlist
+                gadt_constrlist

                 deriving
                 deriving

-               {% mkTyData (comb4 $1 $2 $5 $6) (unLoc $1) True $2 
-                           (unLoc $3) (reverse (unLoc $5)) (unLoc $6) }
+               {% mkTyData (comb4 $1 $2 $4 $5) (unLoc $1) True $2 
+                           (unLoc $3) (unLoc $4) (unLoc $5) }

 
 data_or_newtype :: { Located NewOrData }
        : 'data'        { L1 DataType }
 
 data_or_newtype :: { Located NewOrData }
        : 'data'        { L1 DataType }

@@ -1079,14 +1079,15 @@ akind   :: { Located Kind }
 -----------------------------------------------------------------------------
 -- Datatype declarations
 
 -----------------------------------------------------------------------------
 -- Datatype declarations
 

-gadt_constrlist :: { Located [LConDecl RdrName] }
-       : '{'            gadt_constrs '}'       { LL (unLoc $2) }
-       |     vocurly    gadt_constrs close     { $2 }
+gadt_constrlist :: { Located [LConDecl RdrName] }      -- Returned in order
+       : 'where' '{'        gadt_constrs '}'      { L (comb2 $1 $3) (unLoc $3) }
+       | 'where' vocurly    gadt_constrs close    { L (comb2 $1 $3) (unLoc $3) }
+       | {- empty -}                              { noLoc [] }

 
 gadt_constrs :: { Located [LConDecl RdrName] }
 
 gadt_constrs :: { Located [LConDecl RdrName] }

-        : gadt_constrs ';' gadt_constr  { sL (comb2 $1 (head $3)) ($3 ++ unLoc $1) }
-        | gadt_constrs ';'             { $1 }
-        | gadt_constr                   { sL (getLoc (head $1)) $1 } 
+        : gadt_constr ';' gadt_constrs  { L (comb2 (head $1) $3) ($1 ++ unLoc $3) }
+        | gadt_constr                   { L (getLoc (head $1)) $1 }
+        | {- empty -}                  { noLoc [] }

 
 -- We allow the following forms:
 --     C :: Eq a => a -> T a
 
 -- We allow the following forms:
 --     C :: Eq a => a -> T a

@@ -1094,7 +1095,7 @@ gadt_constrs :: { Located [LConDecl RdrName] }
 --     D { x,y :: a } :: T a
 --     forall a. Eq a => D { x,y :: a } :: T a
 
 --     D { x,y :: a } :: T a
 --     forall a. Eq a => D { x,y :: a } :: T a
 

-gadt_constr :: { [LConDecl RdrName] }
+gadt_constr :: { [LConDecl RdrName] }  -- Returns a list because of:   C,D :: ty

         : con_list '::' sigtype
                 { map (sL (comb2 $1 $3)) (mkGadtDecl (unLoc $1) $3) } 
 
         : con_list '::' sigtype
                 { map (sL (comb2 $1 $3)) (mkGadtDecl (unLoc $1) $3) } 
 

@@ -1104,8 +1105,7 @@ gadt_constr :: { [LConDecl RdrName] }
                       ; return [cd] } }
 
 constrs :: { Located [LConDecl RdrName] }
                       ; return [cd] } }
 
 constrs :: { Located [LConDecl RdrName] }

-        : {- empty; a GHC extension -}  { noLoc [] }
-        | maybe_docnext '=' constrs1    { L (comb2 $2 $3) (addConDocs (unLoc $3) $1) }
+        : maybe_docnext '=' constrs1    { L (comb2 $2 $3) (addConDocs (unLoc $3) $1) }

 
 constrs1 :: { Located [LConDecl RdrName] }
        : constrs1 maybe_docnext '|' maybe_docprev constr { LL (addConDoc $5 $2 : addConDocFirst (unLoc $1) $4) }
 
 constrs1 :: { Located [LConDecl RdrName] }
        : constrs1 maybe_docnext '|' maybe_docprev constr { LL (addConDoc $5 $2 : addConDocFirst (unLoc $1) $4) }