X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;ds=sidebyside;f=compiler%2FhsSyn%2FHsPat.lhs;h=e87a6a27b446ba774fc223b3923dcb6fceffb5d8;hb=a1895147d4d0480f65535c99488ba25873e97bff;hp=84eadb77946b21e84bad43e09ed8bbf089fd9a5e;hpb=7707c269e935f3e433839cccca96b36ca44048ca;p=ghc-hetmet.git

diff --git a/compiler/hsSyn/HsPat.lhs b/compiler/hsSyn/HsPat.lhs
index 84eadb7..e87a6a2 100644
--- a/compiler/hsSyn/HsPat.lhs
+++ b/compiler/hsSyn/HsPat.lhs
@@ -25,7 +25,7 @@ module HsPat (
 
 	isBangHsBind, hsPatNeedsParens,
 	patsAreAllCons, isConPat, isSigPat, isWildPat,
-	patsAreAllLits,	isLitPat, isIrrefutableHsPat
+	patsAreAllLits,	isLitPat, isIrrefutableHsPat, hasViewPat
     ) where
 
 import {-# SOURCE #-} HsExpr		(SyntaxExpr, LHsExpr, pprLExpr)
@@ -369,6 +369,34 @@ patterns are treated specially, of course.
 
 The 1.3 report defines what ``irrefutable'' and ``failure-free'' patterns are.
 \begin{code}
+hasViewPat :: LPat id -> Bool
+hasViewPat (L _ p) = go p where
+  go (WildPat _)             = False
+  go (VarPat _)              = False
+  go (VarPatOut _ _)         = False
+  go (LazyPat p)             = hasViewPat p
+  go (AsPat _ p)             = hasViewPat p
+  go (ParPat p)              = hasViewPat p
+  go (BangPat p)             = hasViewPat p
+  go (ListPat p _)           = any hasViewPat p
+  go (TuplePat p _ _)        = any hasViewPat p
+  go (PArrPat p _)           = any hasViewPat p
+  go (ConPatIn _ p)          = go' p
+  go (ConPatOut _ _ _ _ p _) = go' p
+  go (ViewPat _ _ _)         = True
+  go (QuasiQuotePat _)       = False
+  go (LitPat _)              = False
+  go (NPat _ _ _)            = False
+  go (NPlusKPat _ _ _ _)     = False
+  go (TypePat _)             = False
+  go (SigPatIn p _)          = hasViewPat p
+  go (SigPatOut p _)         = hasViewPat p
+  go (CoPat _ _ _)           = False
+  go' p = case p of
+    PrefixCon ps              -> any hasViewPat ps
+    RecCon (HsRecFields fs _) -> any (hasViewPat . hsRecFieldArg) fs
+    InfixCon p1 p2            -> hasViewPat p1 || hasViewPat p2
+
 isWildPat :: Pat id -> Bool
 isWildPat (WildPat _) = True
 isWildPat _           = False