Add a new flag XDefaultSignatures to enable just the signatures on the default method...

[ghc-hetmet.git] / compiler / parser / Parser.y.pp

diff --git a/compiler/parser/Parser.y.pp b/compiler/parser/Parser.y.pp
index bfadfba..e009071 100644 (file)
--- a/compiler/parser/Parser.y.pp
+++ b/compiler/parser/Parser.y.pp
@@ -721,6 +721,11 @@ decl_cls  :: { Located (OrdList (LHsDecl RdrName)) }
 decl_cls  : at_decl_cls                        { LL (unitOL (L1 (TyClD (unLoc $1)))) }
          | decl                        { $1 }
 
+         -- A 'default' signature used with the generic-programming extension
+          | 'default' infixexp '::' sigtypedoc
+                    {% do { (TypeSig l ty) <- checkValSig $2 $4
+                          ; return (LL $ unitOL (LL $ SigD (GenericSig l ty))) } }
+
 decls_cls :: { Located (OrdList (LHsDecl RdrName)) }   -- Reversed
          : decls_cls ';' decl_cls      { LL (unLoc $1 `appOL` unLoc $3) }
          | decls_cls ';'               { LL (unLoc $1) }
@@ -1232,9 +1237,11 @@ gdrh :: { LGRHS RdrName }
        : '|' guardquals '=' exp        { sL (comb2 $1 $>) $ GRHS (unLoc $2) $4 }
 
 sigdecl :: { Located (OrdList (LHsDecl RdrName)) }
-       : infixexp '::' sigtypedoc      {% do s <- checkValSig $1 $3 
-                                        ; return (LL $ unitOL (LL $ SigD s)) }
-               -- See Note [Declaration/signature overlap] for why we need infixexp here
+        : 
+       -- See Note [Declaration/signature overlap] for why we need infixexp here
+         infixexp '::' sigtypedoc
+                        {% do s <- checkValSig $1 $3 
+                        ; return (LL $ unitOL (LL $ SigD s)) }
        | var ',' sig_vars '::' sigtypedoc
                                { LL $ toOL [ LL $ SigD (TypeSig n $5) | n <- $1 : unLoc $3 ] }
        | infix prec ops        { LL $ toOL [ LL $ SigD (FixSig (FixitySig n (Fixity $2 (unLoc $1))))