X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FdeSugar%2FDsUtils.lhs;h=9d787add263e25e9e29d67c6391bdeb66e244b5f;hb=806ab6331b967d6176b8790a0b1b551ec0e8e2b6;hp=3f340911e70336da6365ce9b400c83084b1f71ea;hpb=2eb04ca0f8d0ec72b417cddc60672c696b4a3daa;p=ghc-hetmet.git

diff --git a/compiler/deSugar/DsUtils.lhs b/compiler/deSugar/DsUtils.lhs
index 3f34091..9d787ad 100644
--- a/compiler/deSugar/DsUtils.lhs
+++ b/compiler/deSugar/DsUtils.lhs
@@ -8,6 +8,13 @@ Utilities for desugaring
 This module exports some utility functions of no great interest.
 
 \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 DsUtils (
 	EquationInfo(..), 
 	firstPat, shiftEqns,
@@ -18,7 +25,7 @@ module DsUtils (
 	cantFailMatchResult, alwaysFailMatchResult,
 	extractMatchResult, combineMatchResults, 
 	adjustMatchResult,  adjustMatchResultDs,
-	mkCoLetMatchResult, mkGuardedMatchResult, 
+	mkCoLetMatchResult, mkViewMatchResult, mkGuardedMatchResult, 
 	matchCanFail, mkEvalMatchResult,
 	mkCoPrimCaseMatchResult, mkCoAlgCaseMatchResult,
 	wrapBind, wrapBinds,
@@ -312,6 +319,12 @@ seqVar var body = Case (Var var) var (exprType body)
 mkCoLetMatchResult :: CoreBind -> MatchResult -> MatchResult
 mkCoLetMatchResult bind = adjustMatchResult (mkDsLet bind)
 
+-- (mkViewMatchResult var' viewExpr var mr) makes the expression
+-- let var' = viewExpr var in mr
+mkViewMatchResult :: Id -> CoreExpr -> Id -> MatchResult -> MatchResult
+mkViewMatchResult var' viewExpr var = 
+    adjustMatchResult (mkDsLet (NonRec var' (mkDsApp viewExpr (Var var))))
+
 mkEvalMatchResult :: Id -> Type -> MatchResult -> MatchResult
 mkEvalMatchResult var ty
   = adjustMatchResult (\e -> Case (Var var) var ty [(DEFAULT, [], e)])