X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FhsSyn%2FHsExpr.lhs;h=44d9b436c3bd8adca739a2ea071cb68410e7dd1f;hb=fd7f8e936e50b3ee589efc36ac2fc54cc6c05300;hp=e56eeac7cc017ad862c33f523c38d69f69f50124;hpb=ff8e1d01524b48e028b09e2b04b2e5303cb6d95f;p=ghc-hetmet.git

diff --git a/compiler/hsSyn/HsExpr.lhs b/compiler/hsSyn/HsExpr.lhs
index e56eeac..44d9b43 100644
--- a/compiler/hsSyn/HsExpr.lhs
+++ b/compiler/hsSyn/HsExpr.lhs
@@ -278,17 +278,30 @@ instance OutputableBndr id => Outputable (HsExpr id) where
 \end{code}
 
 \begin{code}
--- pprExpr and pprLExpr call pprDeeper; 
+-----------------------
+-- pprExpr, pprLExpr, pprBinds call pprDeeper; 
 -- the underscore versions do not
-pprExpr :: OutputableBndr id => HsExpr id -> SDoc
-pprExpr  e = pprDeeper (ppr_expr e)
-
 pprLExpr :: OutputableBndr id => LHsExpr id -> SDoc
-pprLExpr e = pprDeeper (ppr_expr (unLoc e))
+pprLExpr (L _ e) = pprExpr e
+
+pprExpr :: OutputableBndr id => HsExpr id -> SDoc
+pprExpr e | isAtomicHsExpr e || isQuietHsExpr e =            ppr_expr e
+          | otherwise                           = pprDeeper (ppr_expr e)
+
+isQuietHsExpr :: HsExpr id -> Bool
+-- Parentheses do display something, but it gives little info and
+-- if we go deeper when we go inside them then we get ugly things
+-- like (...)
+isQuietHsExpr (HsPar _) = True
+-- applications don't display anything themselves
+isQuietHsExpr (HsApp _ _) = True
+isQuietHsExpr (OpApp _ _ _ _) = True
+isQuietHsExpr _ = False
 
 pprBinds :: OutputableBndr id => HsLocalBinds id -> SDoc
 pprBinds b = pprDeeper (ppr b)
 
+-----------------------
 ppr_lexpr :: OutputableBndr id => LHsExpr id -> SDoc
 ppr_lexpr e = ppr_expr (unLoc e)
 
@@ -378,7 +391,7 @@ ppr_expr (ExplicitPArr _ exprs)
   = pa_brackets (pprDeeperList fsep (punctuate comma (map ppr_lexpr exprs)))
 
 ppr_expr (ExplicitTuple exprs boxity)
-  = tupleParens boxity (pprDeeperList sep (punctuate comma (map ppr_lexpr exprs)))
+  = tupleParens boxity (sep (punctuate comma (map ppr_lexpr exprs)))
 
 ppr_expr (RecordCon con_id con_expr rbinds)
   = pp_rbinds (ppr con_id) rbinds
@@ -403,7 +416,7 @@ ppr_expr (EAsPat v e) = ppr v <> char '@' <> pprParendExpr e
 ppr_expr (HsSCC lbl expr)
   = sep [ ptext SLIT("_scc_") <+> doubleQuotes (ftext lbl), pprParendExpr expr ]
 
-ppr_expr (HsWrap co_fn e) = pprHsWrapper (ppr_expr e) co_fn
+ppr_expr (HsWrap co_fn e) = pprHsWrapper (pprExpr e) co_fn
 ppr_expr (HsType id)	    = ppr id
 
 ppr_expr (HsSpliceE s)       = pprSplice s
@@ -470,18 +483,28 @@ pprParendExpr expr
 	-- I think that is usually (always?) right
     in
     case unLoc expr of
-      HsLit l		-> ppr l
-      HsOverLit l 	-> ppr l
-			
-      HsVar _		-> pp_as_was
-      HsIPVar _		-> pp_as_was
-      ExplicitList _ _  -> pp_as_was
-      ExplicitPArr _ _  -> pp_as_was
-      ExplicitTuple _ _	-> pp_as_was
-      HsPar _		-> pp_as_was
-      HsBracket _	-> pp_as_was
-      HsBracketOut _ []	-> pp_as_was
-      _			-> parens pp_as_was
+      HsLit l		   -> pp_as_was
+      HsOverLit l 	   -> pp_as_was
+      HsVar _		   -> pp_as_was
+      HsIPVar _		   -> pp_as_was
+      ExplicitList _ _     -> pp_as_was
+      ExplicitPArr _ _     -> pp_as_was
+      ExplicitTuple _ _	   -> pp_as_was
+      HsPar _		   -> pp_as_was
+      HsBracket _	   -> pp_as_was
+      HsBracketOut _ []	   -> pp_as_was
+      HsDo sc _ _ _
+       | isListCompExpr sc -> pp_as_was
+      _			   -> parens pp_as_was
+
+isAtomicHsExpr :: HsExpr id -> Bool	-- A single token
+isAtomicHsExpr (HsVar {})     = True
+isAtomicHsExpr (HsLit {})     = True
+isAtomicHsExpr (HsOverLit {}) = True
+isAtomicHsExpr (HsIPVar {})   = True
+isAtomicHsExpr (HsWrap _ e)   = isAtomicHsExpr e
+isAtomicHsExpr (HsPar e)      = isAtomicHsExpr (unLoc e)
+isAtomicHsExpr e	      = False
 \end{code}
 
 %************************************************************************
@@ -673,11 +696,9 @@ pprMatch ctxt (Match pats maybe_ty grhss)
 
 pprGRHSs :: OutputableBndr id => HsMatchContext id -> GRHSs id -> SDoc
 pprGRHSs ctxt (GRHSs grhss binds)
-  = pprDeeper
-    (vcat (map (pprGRHS ctxt . unLoc) grhss)
-      $$
-     if isEmptyLocalBinds binds then empty
-     else text "where" $$ nest 4 (pprBinds binds))
+  = vcat (map (pprGRHS ctxt . unLoc) grhss)
+ $$ if isEmptyLocalBinds binds then empty
+                               else text "where" $$ nest 4 (pprBinds binds)
 
 pprGRHS :: OutputableBndr id => HsMatchContext id -> GRHS id -> SDoc
 
@@ -917,7 +938,12 @@ data HsStmtContext id
 isDoExpr :: HsStmtContext id -> Bool
 isDoExpr DoExpr      = True
 isDoExpr (MDoExpr _) = True
-isDoExpr other       = False
+isDoExpr _           = False
+
+isListCompExpr :: HsStmtContext id -> Bool
+isListCompExpr ListComp = True
+isListCompExpr PArrComp = True
+isListCompExpr _        = False
 \end{code}
 
 \begin{code}