View patterns, record wildcards, and record puns

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

diff --git a/compiler/parser/RdrHsSyn.lhs b/compiler/parser/RdrHsSyn.lhs
index da838dd..6e77dee 100644 (file)
--- a/compiler/parser/RdrHsSyn.lhs
+++ b/compiler/parser/RdrHsSyn.lhs
@@ -4,6 +4,13 @@
 Functions over HsSyn specialised to RdrName.
 
 \begin{code}
+{-# OPTIONS -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
 module RdrHsSyn (
        extractHsTyRdrTyVars, 
        extractHsRhoRdrTyVars, extractGenericPatTyVars,
@@ -413,9 +420,9 @@ checkTyVars tparms = mapM_ chk tparms
          parseError l "Type found where type variable expected"
 
 -- Check whether the type arguments in a type synonym head are simply
--- variables.  If not, we have a type equation of a type function and return
--- all patterns.  If yes, we return 'Nothing' as the third component to
--- indicate a vanilla type synonym.
+-- variables.  If not, we have a type family instance and return all patterns.
+-- If yes, we return 'Nothing' as the third component to indicate a vanilla
+-- type synonym. 
 --
 checkSynHdr :: LHsType RdrName 
            -> Bool                             -- is type instance?
@@ -442,6 +449,7 @@ checkTyClHdr :: LHsContext RdrName -> LHsType RdrName
 -- etc
 -- With associated types, we can also have non-variable parameters; ie,
 --      T Int [a]
+-- or   Int :++: [a]
 -- The unaltered parameter list is returned in the fourth component of the
 -- result.  Eg, for
 --      T Int [a]
@@ -459,7 +467,7 @@ checkTyClHdr (L l cxt) ty
                                     return (L l tc, tvs, acc)
     go l (HsOpTy t1 ltc@(L _ tc) t2) acc
        | isRdrTc tc            = do tvs <- extractTyVars (t1:t2:acc)
-                                    return (ltc, tvs, acc)
+                                    return (ltc, tvs, t1:t2:acc)
     go l (HsParTy ty)    acc    = gol ty acc
     go l (HsAppTy t1 t2) acc    = gol t1 (t2:acc)
     go l other          acc    = 
@@ -645,7 +653,7 @@ checkAPat loc e = case e of
    -- Overloaded numeric patterns (e.g. f 0 x = x)
    -- Negation is recorded separately, so that the literal is zero or +ve
    -- NB. Negative *primitive* literals are already handled by the lexer
-   HsOverLit pos_lit            -> return (mkNPat pos_lit Nothing)
+   HsOverLit pos_lit          -> return (mkNPat pos_lit Nothing)
    NegApp (L _ (HsOverLit pos_lit)) _ 
                        -> return (mkNPat pos_lit (Just noSyntaxExpr))
    
@@ -657,6 +665,8 @@ checkAPat loc e = case e of
 
    ELazyPat e        -> checkLPat e >>= (return . LazyPat)
    EAsPat n e        -> checkLPat e >>= (return . AsPat n)
+   -- view pattern is well-formed if the pattern is
+   EViewPat expr patE -> checkLPat patE >>= (return . (\p -> ViewPat expr p placeHolderType))
    ExprWithTySig e t  -> checkLPat e >>= \e ->
                         -- Pattern signatures are parsed as sigtypes,
                         -- but they aren't explicit forall points.  Hence
@@ -669,7 +679,7 @@ checkAPat loc e = case e of
    
    -- n+k patterns
    OpApp (L nloc (HsVar n)) (L _ (HsVar plus)) _ 
-       (L _ (HsOverLit lit@(HsIntegral _ _)))
+       (L _ (HsOverLit lit@(HsIntegral _ _ _)))
                      | plus == plus_RDR
                      -> return (mkNPlusKPat (L nloc n) lit)