Tweak ... generation

[ghc-hetmet.git] / compiler / hsSyn / HsExpr.lhs

diff --git a/compiler/hsSyn/HsExpr.lhs b/compiler/hsSyn/HsExpr.lhs
index 2be1ee6..11b4df3 100644 (file)
--- a/compiler/hsSyn/HsExpr.lhs
+++ b/compiler/hsSyn/HsExpr.lhs
@@ -22,6 +22,7 @@ import HsBinds
 import Var
 import Name
 import BasicTypes
+import DataCon
 import SrcLoc
 import Outputable      
 import FastString
@@ -158,9 +159,11 @@ data HsExpr id
        -- Record update
   | RecordUpd  (LHsExpr id)
                (HsRecordBinds id)
-               PostTcType              -- Type of *input* record
-               PostTcType              -- Type of *result* record (may differ from
-                                       --      type of input record)
+               [DataCon]               -- Filled in by the type checker to the *non-empty*
+                                       -- list of DataCons that have all the upd'd fields
+               [PostTcType]            -- Argument types of *input* record type
+               [PostTcType]            --              and  *output* record type
+       -- For a type family, the arg types are of the *instance* tycon, not the family tycon
 
   | ExprWithTySig                      -- e :: type
                (LHsExpr id)
@@ -228,6 +231,7 @@ data HsExpr id
 
   | HsTick 
      Int                               -- module-local tick number
+     [id]                               -- variables in scope
      (LHsExpr id)                      -- sub-expression
 
   | HsBinTick
@@ -274,17 +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)
 
@@ -374,12 +391,12 @@ 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
 
-ppr_expr (RecordUpd aexp rbinds _ _)
+ppr_expr (RecordUpd aexp rbinds _ _ _)
   = pp_rbinds (pprParendExpr aexp) rbinds
 
 ppr_expr (ExprWithTySig expr sig)
@@ -399,7 +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
@@ -410,8 +427,8 @@ ppr_expr (HsBracketOut e ps) = ppr e $$ ptext SLIT("pending") <+> ppr ps
 ppr_expr (HsProc pat (L _ (HsCmdTop cmd _ _ _)))
   = hsep [ptext SLIT("proc"), ppr pat, ptext SLIT("->"), ppr cmd]
 
-ppr_expr (HsTick tickId exp)
-  = hcat [ptext SLIT("tick<"), ppr tickId,ptext SLIT(">("), ppr exp,ptext SLIT(")")]
+ppr_expr (HsTick tickId vars exp)
+  = hcat [ptext SLIT("tick<"), ppr tickId,ptext SLIT(">("), hsep (map pprHsVar vars), ppr exp,ptext SLIT(")")]
 ppr_expr (HsBinTick tickIdTrue tickIdFalse exp)
   = hcat [ptext SLIT("bintick<"), 
          ppr tickIdTrue,
@@ -466,9 +483,8 @@ pprParendExpr expr
        -- I think that is usually (always?) right
     in
     case unLoc expr of
-      HsLit l          -> ppr l
-      HsOverLit l      -> ppr l
-                       
+      HsLit l          -> pp_as_was
+      HsOverLit l      -> pp_as_was
       HsVar _          -> pp_as_was
       HsIPVar _                -> pp_as_was
       ExplicitList _ _  -> pp_as_was
@@ -478,6 +494,15 @@ pprParendExpr expr
       HsBracket _      -> pp_as_was
       HsBracketOut _ []        -> 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}
 
 %************************************************************************
@@ -669,11 +694,9 @@ 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