New syntax for stand-alone deriving. Implemented fully.

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

diff --git a/compiler/parser/Parser.y.pp b/compiler/parser/Parser.y.pp
index 0fd1b4d..a72b47b 100644 (file)
--- a/compiler/parser/Parser.y.pp
+++ b/compiler/parser/Parser.y.pp
@@ -159,6 +159,7 @@ incorrect.
  'deriving'    { L _ ITderiving }
  'do'          { L _ ITdo }
  'else'        { L _ ITelse }
+ 'for'                 { L _ ITfor }
  'hiding'      { L _ IThiding }
  'if'          { L _ ITif }
  'import'      { L _ ITimport }
@@ -455,9 +456,8 @@ topdecl :: { OrdList (LHsDecl RdrName) }
        : cl_decl                       { unitOL (L1 (TyClD (unLoc $1))) }
        | ty_decl                       { unitOL (L1 (TyClD (unLoc $1))) }
        | 'instance' inst_type where
-               { let (binds, sigs, ats) = cvBindsAndSigs (unLoc $3)
-                 in unitOL (L (comb3 $1 $2 $3) 
-                           (InstD (InstDecl $2 binds sigs ats))) }
+               { let (binds,sigs) = cvBindsAndSigs (unLoc $3)
+                 in unitOL (L (comb3 $1 $2 $3) (InstD (InstDecl $2 binds sigs))) }
        | 'default' '(' comma_types0 ')'        { unitOL (LL $ DefD (DefaultDecl $3)) }
        | 'foreign' fdecl                       { unitOL (LL (unLoc $2)) }
        | '{-# DEPRECATED' deprecations '#-}'   { $2 }
@@ -663,6 +663,16 @@ tycl_hdr :: { Located (LHsContext RdrName,
        | type                          {% checkTyClHdr (noLoc []) $1 >>= return.L1 }
 
 -----------------------------------------------------------------------------
+-- Stand-alone deriving
+
+-- Glasgow extension: stand-alone deriving declarations
+stand_alone_deriving :: { LDerivDecl RdrName }
+       : 'deriving' qtycon            'for' qtycon  {% do { p <- checkInstType (fmap HsTyVar $2)
+                                                          ; checkDerivDecl (LL (DerivDecl p $4)) } }
+
+        | 'deriving' '(' inst_type ')' 'for' qtycon  {% checkDerivDecl (LL (DerivDecl $3 $6)) }
+
+-----------------------------------------------------------------------------
 -- Nested declarations
 
 -- Type declaration or value declaration