+\subsection{Tidying lit pats}
+%* *
+%************************************************************************
+
+\begin{code}
+tidyLitPat :: HsLit -> TypecheckedPat -> TypecheckedPat
+tidyLitPat (HsChar c) pat = ConPat charDataCon charTy [] [] [LitPat (HsCharPrim c) charPrimTy]
+tidyLitPat lit pat = pat
+
+tidyNPat :: HsLit -> Type -> TypecheckedPat -> TypecheckedPat
+tidyNPat (HsString s) _ pat
+ | _LENGTH_ s <= 1 -- Short string literals only
+ = foldr (\c pat -> ConPat consDataCon stringTy [] [] [mk_char_lit c,pat])
+ (ConPat nilDataCon stringTy [] [] []) (_UNPK_INT_ s)
+ -- The stringTy is the type of the whole pattern, not
+ -- the type to instantiate (:) or [] with!
+ where
+ mk_char_lit c = ConPat charDataCon charTy [] [] [LitPat (HsCharPrim c) charPrimTy]
+
+tidyNPat lit lit_ty default_pat
+ | lit_ty == intTy = ConPat intDataCon lit_ty [] [] [LitPat (mk_int lit) intPrimTy]
+ | lit_ty == floatTy = ConPat floatDataCon lit_ty [] [] [LitPat (mk_float lit) floatPrimTy]
+ | lit_ty == doubleTy = ConPat doubleDataCon lit_ty [] [] [LitPat (mk_double lit) doublePrimTy]
+ | otherwise = default_pat
+
+ where
+ mk_int (HsInteger i) = HsIntPrim i
+
+ mk_float (HsInteger i) = HsFloatPrim (fromInteger i)
+ mk_float (HsRat f _) = HsFloatPrim f
+
+ mk_double (HsInteger i) = HsDoublePrim (fromInteger i)
+ mk_double (HsRat f _) = HsDoublePrim f
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Building lets}
+%* *
+%************************************************************************
+
+Use case, not let for unlifted types. The simplifier will turn some
+back again.
+
+\begin{code}
+mkDsLet :: CoreBind -> CoreExpr -> CoreExpr
+mkDsLet (NonRec bndr rhs) body
+ | isUnLiftedType (idType bndr) = Case rhs bndr [(DEFAULT,[],body)]
+mkDsLet bind body
+ = Let bind body
+
+mkDsLets :: [CoreBind] -> CoreExpr -> CoreExpr
+mkDsLets binds body = foldr mkDsLet body binds
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{ Selecting match variables}