%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[DsExpr]{Matching expressions (Exprs)}
\begin{code}
-#include "HsVersions.h"
+module DsExpr ( dsExpr, dsLet ) where
-module DsExpr ( dsExpr ) where
+#include "HsVersions.h"
-IMP_Ubiq()
-IMPORT_DELOOPER(DsLoop) -- partly to get dsBinds, partly to chk dsExpr
import HsSyn ( failureFreePat,
HsExpr(..), OutPat(..), HsLit(..), ArithSeqInfo(..),
- Stmt(..), Match(..), Qual, HsBinds, PolyType,
- GRHSsAndBinds
+ Stmt(..), StmtCtxt(..), Match(..), HsBinds(..), MonoBinds(..),
)
-import TcHsSyn ( TypecheckedHsExpr(..), TypecheckedHsBinds(..),
- TypecheckedRecordBinds(..), TypecheckedPat(..),
- TypecheckedStmt(..)
+import TcHsSyn ( TypecheckedHsExpr, TypecheckedHsBinds,
+ TypecheckedStmt,
+ maybeBoxedPrimType
+
)
import CoreSyn
import DsMonad
+import DsBinds ( dsMonoBinds )
+import DsGRHSs ( dsGuarded )
import DsCCall ( dsCCall )
-import DsHsSyn ( outPatType )
import DsListComp ( dsListComp )
-import DsUtils ( mkAppDs, mkConDs, mkPrimDs, dsExprToAtom,
- mkErrorAppDs, showForErr, EquationInfo,
- MatchResult
- )
-import Match ( matchWrapper )
+import DsUtils ( mkErrorAppDs )
+import Match ( matchWrapper, matchSimply )
-import CoreUnfold ( UnfoldingDetails(..), UnfoldingGuidance(..),
- FormSummary )
-import CoreUtils ( coreExprType, substCoreExpr, argToExpr,
- mkCoreIfThenElse, unTagBinders )
+import CoreUtils ( coreExprType )
import CostCentre ( mkUserCC )
-import FieldLabel ( fieldLabelType, FieldLabel )
-import Id ( mkTupleCon, idType, nullIdEnv, addOneToIdEnv,
- getIdUnfolding, dataConArgTys, dataConFieldLabels,
- recordSelectorFieldLabel
- )
-import Literal ( mkMachInt, Literal(..) )
-import MagicUFs ( MagicUnfoldingFun )
-import Name ( Name{--O only-} )
-import PprStyle ( PprStyle(..) )
-import PprType ( GenType )
-import PrelVals ( rEC_CON_ERROR_ID, rEC_UPD_ERROR_ID, voidId )
-import Pretty ( ppShow, ppBesides, ppPStr, ppStr )
-import TyCon ( isDataTyCon, isNewTyCon )
-import Type ( splitSigmaTy, splitFunTy, typePrimRep,
- getAppDataTyConExpandingDicts, getAppTyCon, applyTy,
- maybeBoxedPrimType
+import FieldLabel ( FieldLabel )
+import Id ( Id, idType, recordSelectorFieldLabel )
+import Const ( Con(..) )
+import DataCon ( DataCon, dataConId, dataConTyCon, dataConArgTys, dataConFieldLabels )
+import Const ( mkMachInt, Literal(..) )
+import PrelVals ( rEC_CON_ERROR_ID, rEC_UPD_ERROR_ID, iRREFUT_PAT_ERROR_ID )
+import TyCon ( isNewTyCon )
+import DataCon ( isExistentialDataCon )
+import Type ( splitFunTys, mkTyConApp,
+ splitAlgTyConApp, splitTyConApp_maybe,
+ splitAppTy, isUnLiftedType, Type
)
-import TysWiredIn ( mkTupleTy, voidTy, nilDataCon, consDataCon,
- charDataCon, charTy
+import TysWiredIn ( tupleCon, unboxedTupleCon,
+ consDataCon, listTyCon, mkListTy,
+ charDataCon, charTy, stringTy
)
-import TyVar ( nullTyVarEnv, addOneToTyVarEnv, GenTyVar{-instance Eq-} )
-import Usage ( UVar(..) )
-import Util ( zipEqual, pprError, panic, assertPanic )
-
-mk_nil_con ty = mkCon nilDataCon [] [ty] [] -- micro utility...
+import BasicTypes ( RecFlag(..) )
+import Maybes ( maybeToBool )
+import Util ( zipEqual, zipWithEqual )
+import Outputable
\end{code}
-The funny business to do with variables is that we look them up in the
-Id-to-Id and Id-to-Id maps that the monadery is carrying
-around; if we get hits, we use the value accordingly.
+
+%************************************************************************
+%* *
+\subsection{dsLet}
+%* *
+%************************************************************************
+
+@dsLet@ is a match-result transformer, taking the MatchResult for the body
+and transforming it into one for the let-bindings enclosing the body.
+
+This may seem a bit odd, but (source) let bindings can contain unboxed
+binds like
+
+ C x# = e
+
+This must be transformed to a case expression and, if the type has
+more than one constructor, may fail.
+
+\begin{code}
+dsLet :: TypecheckedHsBinds -> CoreExpr -> DsM CoreExpr
+
+dsLet EmptyBinds body
+ = returnDs body
+
+dsLet (ThenBinds b1 b2) body
+ = dsLet b2 body `thenDs` \ body' ->
+ dsLet b1 body'
+
+-- Special case for bindings which bind unlifted variables
+dsLet (MonoBind (AbsBinds [] [] binder_triples bind) sigs is_rec) body
+ | or [isUnLiftedType (idType g) | (_, g, l) <- binder_triples]
+ = ASSERT (case is_rec of {NonRecursive -> True; other -> False})
+ putSrcLocDs loc $
+ dsGuarded grhss `thenDs` \ rhs ->
+ let
+ body' = foldr bind body binder_triples
+ bind (tyvars, g, l) body = ASSERT( null tyvars )
+ bindNonRec g (Var l) body
+ in
+ mkErrorAppDs iRREFUT_PAT_ERROR_ID result_ty (showSDoc (ppr pat)) `thenDs` \ error_expr ->
+ matchSimply rhs PatBindMatch pat body' error_expr
+ where
+ PatMonoBind pat grhss loc = bind
+ result_ty = coreExprType body
+
+-- Ordinary case for bindings
+dsLet (MonoBind binds sigs is_rec) body
+ = dsMonoBinds False binds [] `thenDs` \ prs ->
+ case is_rec of
+ Recursive -> returnDs (Let (Rec prs) body)
+ NonRecursive -> returnDs (foldr mk_let body prs)
+ where
+ mk_let (bndr,rhs) body = Let (NonRec bndr rhs) body
+\end{code}
%************************************************************************
%* *
\begin{code}
dsExpr :: TypecheckedHsExpr -> DsM CoreExpr
-dsExpr (HsVar var) = dsApp (HsVar var) []
+dsExpr e@(HsVar var) = returnDs (Var var)
\end{code}
%************************************************************************
\begin{code}
dsExpr (HsLitOut (HsString s) _)
| _NULL_ s
- = returnDs (mk_nil_con charTy)
+ = returnDs (mkNilExpr charTy)
| _LENGTH_ s == 1
= let
- the_char = mkCon charDataCon [] [] [LitArg (MachChar (_HEAD_ s))]
- the_nil = mk_nil_con charTy
+ the_char = mkConApp charDataCon [mkLit (MachChar (_HEAD_ s))]
+ the_nil = mkNilExpr charTy
+ the_cons = mkConApp consDataCon [Type charTy, the_char, the_nil]
in
- mkConDs consDataCon [charTy] [the_char, the_nil]
+ returnDs the_cons
+
-- "_" => build (\ c n -> c 'c' n) -- LATER
-- the Core-to-STG pass will wrap it in an application of "unpackCStringId".
dsExpr (HsLitOut (HsString str) _)
- = returnDs (Lit (NoRepStr str))
+ = returnDs (mkLit (NoRepStr str stringTy))
-dsExpr (HsLitOut (HsLitLit s) ty)
- = returnDs ( mkCon data_con [] [] [LitArg (MachLitLit s kind)] )
+dsExpr (HsLitOut (HsLitLit str) ty)
+ = returnDs ( mkConApp data_con [mkLit (MachLitLit str prim_ty)] )
where
- (data_con, kind)
+ (data_con, prim_ty)
= case (maybeBoxedPrimType ty) of
- Just (boxing_data_con, prim_ty)
- -> (boxing_data_con, typePrimRep prim_ty)
+ Just (boxing_data_con, prim_ty) -> (boxing_data_con, prim_ty)
Nothing
- -> pprError "ERROR: ``literal-literal'' not a single-constructor type: "
- (ppBesides [ppPStr s, ppStr "; type: ", ppr PprDebug ty])
+ -> pprPanic "ERROR: ``literal-literal'' not a single-constructor type: "
+ (hcat [ptext str, text "; type: ", ppr ty])
dsExpr (HsLitOut (HsInt i) ty)
- = returnDs (Lit (NoRepInteger i ty))
+ = returnDs (mkLit (NoRepInteger i ty))
dsExpr (HsLitOut (HsFrac r) ty)
- = returnDs (Lit (NoRepRational r ty))
+ = returnDs (mkLit (NoRepRational r ty))
-- others where we know what to do:
dsExpr (HsLitOut (HsIntPrim i) _)
- = if (i >= toInteger minInt && i <= toInteger maxInt) then
- returnDs (Lit (mkMachInt i))
- else
- error ("ERROR: Int constant " ++ show i ++ out_of_range_msg)
+ | (i >= toInteger minInt && i <= toInteger maxInt)
+ = returnDs (mkLit (mkMachInt i))
+ | otherwise
+ = error ("ERROR: Int constant " ++ show i ++ out_of_range_msg)
dsExpr (HsLitOut (HsFloatPrim f) _)
- = returnDs (Lit (MachFloat f))
+ = returnDs (mkLit (MachFloat f))
-- ToDo: range checking needed!
dsExpr (HsLitOut (HsDoublePrim d) _)
- = returnDs (Lit (MachDouble d))
+ = returnDs (mkLit (MachDouble d))
-- ToDo: range checking needed!
dsExpr (HsLitOut (HsChar c) _)
- = returnDs ( mkCon charDataCon [] [] [LitArg (MachChar c)] )
+ = returnDs ( mkConApp charDataCon [mkLit (MachChar c)] )
dsExpr (HsLitOut (HsCharPrim c) _)
- = returnDs (Lit (MachChar c))
+ = returnDs (mkLit (MachChar c))
dsExpr (HsLitOut (HsStringPrim s) _)
- = returnDs (Lit (MachStr s))
+ = returnDs (mkLit (MachStr s))
-- end of literals magic. --
dsExpr expr@(HsLam a_Match)
= matchWrapper LambdaMatch [a_Match] "lambda" `thenDs` \ (binders, matching_code) ->
- returnDs ( mkValLam binders matching_code )
+ returnDs (mkLams binders matching_code)
+
+dsExpr expr@(HsApp fun arg)
+ = dsExpr fun `thenDs` \ core_fun ->
+ dsExpr arg `thenDs` \ core_arg ->
+ returnDs (core_fun `App` core_arg)
-dsExpr expr@(HsApp e1 e2) = dsApp expr []
-dsExpr expr@(OpApp e1 op e2) = dsApp expr []
\end{code}
Operator sections. At first it looks as if we can convert
will sort it out.
\begin{code}
+dsExpr (OpApp e1 op _ e2)
+ = dsExpr op `thenDs` \ core_op ->
+ -- for the type of y, we need the type of op's 2nd argument
+ let
+ (x_ty:y_ty:_, _) = splitFunTys (coreExprType core_op)
+ in
+ dsExpr e1 `thenDs` \ x_core ->
+ dsExpr e2 `thenDs` \ y_core ->
+ returnDs (mkApps core_op [x_core, y_core])
+
dsExpr (SectionL expr op)
- = dsExpr op `thenDs` \ core_op ->
- dsExpr expr `thenDs` \ core_expr ->
- dsExprToAtom core_expr $ \ y_atom ->
-
- -- for the type of x, we need the type of op's 2nd argument
+ = dsExpr op `thenDs` \ core_op ->
+ -- for the type of y, we need the type of op's 2nd argument
let
- x_ty = case (splitSigmaTy (coreExprType core_op)) of { (_, _, tau_ty) ->
- case (splitFunTy tau_ty) of {
- ((_:arg2_ty:_), _) -> arg2_ty;
- _ -> panic "dsExpr:SectionL:arg 2 ty" }}
+ (x_ty:y_ty:_, _) = splitFunTys (coreExprType core_op)
in
- newSysLocalDs x_ty `thenDs` \ x_id ->
- returnDs (mkValLam [x_id] (core_op `App` y_atom `App` VarArg x_id))
+ dsExpr expr `thenDs` \ x_core ->
+ newSysLocalDs x_ty `thenDs` \ x_id ->
+ newSysLocalDs y_ty `thenDs` \ y_id ->
+
+ returnDs (bindNonRec x_id x_core $
+ Lam y_id (mkApps core_op [Var x_id, Var y_id]))
-- dsExpr (SectionR op expr) -- \ x -> op x expr
dsExpr (SectionR op expr)
= dsExpr op `thenDs` \ core_op ->
- dsExpr expr `thenDs` \ core_expr ->
- dsExprToAtom core_expr $ \ y_atom ->
-
- -- for the type of x, we need the type of op's 1st argument
+ -- for the type of x, we need the type of op's 2nd argument
let
- x_ty = case (splitSigmaTy (coreExprType core_op)) of { (_, _, tau_ty) ->
- case (splitFunTy tau_ty) of {
- ((arg1_ty:_), _) -> arg1_ty;
- _ -> panic "dsExpr:SectionR:arg 1 ty" }}
+ (x_ty:y_ty:_, _) = splitFunTys (coreExprType core_op)
in
- newSysLocalDs x_ty `thenDs` \ x_id ->
- returnDs (mkValLam [x_id] (core_op `App` VarArg x_id `App` y_atom))
+ dsExpr expr `thenDs` \ y_core ->
+ newSysLocalDs x_ty `thenDs` \ x_id ->
+ newSysLocalDs y_ty `thenDs` \ y_id ->
+
+ returnDs (bindNonRec y_id y_core $
+ Lam x_id (mkApps core_op [Var x_id, Var y_id]))
dsExpr (CCall label args may_gc is_asm result_ty)
= mapDs dsExpr args `thenDs` \ core_args ->
dsExpr (HsSCC cc expr)
= dsExpr expr `thenDs` \ core_expr ->
getModuleAndGroupDs `thenDs` \ (mod_name, group_name) ->
- returnDs ( SCC (mkUserCC cc mod_name group_name) core_expr)
+ returnDs (Note (SCC (mkUserCC cc mod_name group_name)) core_expr)
-dsExpr expr@(HsCase discrim matches src_loc)
- = putSrcLocDs src_loc $
+-- special case to handle unboxed tuple patterns
+
+dsExpr (HsCase discrim matches@[PatMatch (TuplePat ps boxed) (GRHSMatch rhs)]
+ src_loc)
+ | all var_pat ps
+ = putSrcLocDs src_loc $
dsExpr discrim `thenDs` \ core_discrim ->
matchWrapper CaseMatch matches "case" `thenDs` \ ([discrim_var], matching_code) ->
- returnDs ( mkCoLetAny (NonRec discrim_var core_discrim) matching_code )
+ case matching_code of
+ Case (Var x) bndr alts | x == discrim_var ->
+ returnDs (Case core_discrim bndr alts)
+ _ -> panic ("dsExpr: tuple pattern:\n" ++ showSDoc (ppr matching_code))
-dsExpr (ListComp expr quals)
- = dsExpr expr `thenDs` \ core_expr ->
- dsListComp core_expr quals
-
-dsExpr (HsLet binds expr)
- = dsBinds binds `thenDs` \ core_binds ->
- dsExpr expr `thenDs` \ core_expr ->
- returnDs ( mkCoLetsAny core_binds core_expr )
-
-dsExpr (HsDoOut stmts then_id zero_id src_loc)
+dsExpr (HsCase discrim matches src_loc)
= putSrcLocDs src_loc $
- dsDo then_id zero_id stmts
+ dsExpr discrim `thenDs` \ core_discrim ->
+ matchWrapper CaseMatch matches "case" `thenDs` \ ([discrim_var], matching_code) ->
+ returnDs (bindNonRec discrim_var core_discrim matching_code)
+
+dsExpr (HsLet binds body)
+ = dsExpr body `thenDs` \ body' ->
+ dsLet binds body'
+
+dsExpr (HsDoOut do_or_lc stmts return_id then_id zero_id result_ty src_loc)
+ | maybeToBool maybe_list_comp
+ = -- Special case for list comprehensions
+ putSrcLocDs src_loc $
+ dsListComp stmts elt_ty
+
+ | otherwise
+ = putSrcLocDs src_loc $
+ dsDo do_or_lc stmts return_id then_id zero_id result_ty
+ where
+ maybe_list_comp
+ = case (do_or_lc, splitTyConApp_maybe result_ty) of
+ (ListComp, Just (tycon, [elt_ty]))
+ | tycon == listTyCon
+ -> Just elt_ty
+ other -> Nothing
+ -- We need the ListComp form to use deListComp (rather than the "do" form)
+ -- because the "return" in a do block is a call to "PrelBase.return", and
+ -- not a ReturnStmt. Only the ListComp form has ReturnStmts
+
+ Just elt_ty = maybe_list_comp
dsExpr (HsIf guard_expr then_expr else_expr src_loc)
= putSrcLocDs src_loc $
dsExpr guard_expr `thenDs` \ core_guard ->
dsExpr then_expr `thenDs` \ core_then ->
dsExpr else_expr `thenDs` \ core_else ->
- returnDs (mkCoreIfThenElse core_guard core_then core_else)
+ returnDs (mkIfThenElse core_guard core_then core_else)
\end{code}
\begin{code}
dsExpr (TyLam tyvars expr)
= dsExpr expr `thenDs` \ core_expr ->
- returnDs (mkTyLam tyvars core_expr)
+ returnDs (mkLams tyvars core_expr)
-dsExpr expr@(TyApp e tys) = dsApp expr []
+dsExpr (TyApp expr tys)
+ = dsExpr expr `thenDs` \ core_expr ->
+ returnDs (mkTyApps core_expr tys)
\end{code}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
dsExpr (ExplicitListOut ty xs)
- = case xs of
- [] -> returnDs (mk_nil_con ty)
- (y:ys) ->
- dsExpr y `thenDs` \ core_hd ->
- dsExpr (ExplicitListOut ty ys) `thenDs` \ core_tl ->
- mkConDs consDataCon [ty] [core_hd, core_tl]
-
-dsExpr (ExplicitTuple expr_list)
- = mapDs dsExpr expr_list `thenDs` \ core_exprs ->
- mkConDs (mkTupleCon (length expr_list))
- (map coreExprType core_exprs)
- core_exprs
-
--- Two cases, one for ordinary constructors and one for newtype constructors
-dsExpr (HsCon con tys args)
- | isDataTyCon tycon -- The usual datatype case
- = mapDs dsExpr args `thenDs` \ args_exprs ->
- mkConDs con tys args_exprs
-
- | otherwise -- The newtype case
- = ASSERT( isNewTyCon tycon )
- ASSERT( null rest_args )
- dsExpr first_arg `thenDs` \ arg_expr ->
- returnDs (Coerce (CoerceIn con) result_ty arg_expr)
+ = go xs
+ where
+ list_ty = mkListTy ty
+
+ go [] = returnDs (mkNilExpr ty)
+ go (x:xs) = dsExpr x `thenDs` \ core_x ->
+ go xs `thenDs` \ core_xs ->
+ returnDs (mkConApp consDataCon [Type ty, core_x, core_xs])
+dsExpr (ExplicitTuple expr_list boxed)
+ = mapDs dsExpr expr_list `thenDs` \ core_exprs ->
+ returnDs (mkConApp ((if boxed
+ then tupleCon
+ else unboxedTupleCon) (length expr_list))
+ (map (Type . coreExprType) core_exprs ++ core_exprs))
+
+dsExpr (HsCon con_id [ty] [arg])
+ | isNewTyCon tycon
+ = dsExpr arg `thenDs` \ arg' ->
+ returnDs (Note (Coerce result_ty (coreExprType arg')) arg')
where
- (first_arg:rest_args) = args
- (args_tys, result_ty) = splitFunTy (foldl applyTy (idType con) tys)
- (tycon,_) = getAppTyCon result_ty
+ result_ty = mkTyConApp tycon [ty]
+ tycon = dataConTyCon con_id
+
+dsExpr (HsCon con_id tys args)
+ = mapDs dsExpr args `thenDs` \ args2 ->
+ returnDs (mkConApp con_id (map Type tys ++ args2))
dsExpr (ArithSeqOut expr (From from))
= dsExpr expr `thenDs` \ expr2 ->
dsExpr from `thenDs` \ from2 ->
- mkAppDs expr2 [] [from2]
+ returnDs (App expr2 from2)
dsExpr (ArithSeqOut expr (FromTo from two))
= dsExpr expr `thenDs` \ expr2 ->
dsExpr from `thenDs` \ from2 ->
dsExpr two `thenDs` \ two2 ->
- mkAppDs expr2 [] [from2, two2]
+ returnDs (mkApps expr2 [from2, two2])
dsExpr (ArithSeqOut expr (FromThen from thn))
= dsExpr expr `thenDs` \ expr2 ->
dsExpr from `thenDs` \ from2 ->
dsExpr thn `thenDs` \ thn2 ->
- mkAppDs expr2 [] [from2, thn2]
+ returnDs (mkApps expr2 [from2, thn2])
dsExpr (ArithSeqOut expr (FromThenTo from thn two))
= dsExpr expr `thenDs` \ expr2 ->
dsExpr from `thenDs` \ from2 ->
dsExpr thn `thenDs` \ thn2 ->
dsExpr two `thenDs` \ two2 ->
- mkAppDs expr2 [] [from2, thn2, two2]
+ returnDs (mkApps expr2 [from2, thn2, two2])
\end{code}
Record construction and update
\begin{code}
-dsExpr (RecordCon con_expr rbinds)
+dsExpr (RecordConOut data_con con_expr rbinds)
= dsExpr con_expr `thenDs` \ con_expr' ->
let
- con_id = get_con con_expr'
- (arg_tys, _) = splitFunTy (coreExprType con_expr')
+ (arg_tys, _) = splitFunTys (coreExprType con_expr')
mk_arg (arg_ty, lbl)
= case [rhs | (sel_id,rhs,_) <- rbinds,
lbl == recordSelectorFieldLabel sel_id] of
(rhs:rhss) -> ASSERT( null rhss )
dsExpr rhs
- [] -> mkErrorAppDs rEC_CON_ERROR_ID arg_ty (showForErr lbl)
+ [] -> mkErrorAppDs rEC_CON_ERROR_ID arg_ty (showSDoc (ppr lbl))
in
- mapDs mk_arg (zipEqual "dsExpr:RecordCon" arg_tys (dataConFieldLabels con_id)) `thenDs` \ con_args ->
- mkAppDs con_expr' [] con_args
- where
- -- "con_expr'" is simply an application of the constructor Id
- -- to types and (perhaps) dictionaries. This gets the constructor...
- get_con (Var con) = con
- get_con (App fun _) = get_con fun
+ mapDs mk_arg (zipEqual "dsExpr:RecordCon" arg_tys (dataConFieldLabels data_con)) `thenDs` \ con_args ->
+ returnDs (mkApps con_expr' con_args)
\end{code}
Record update is a little harder. Suppose we have the decl:
dictionaries.
\begin{code}
-dsExpr (RecordUpdOut record_expr dicts rbinds)
- = dsExpr record_expr `thenDs` \ record_expr' ->
+dsExpr (RecordUpdOut record_expr record_out_ty dicts rbinds)
+ = dsExpr record_expr `thenDs` \ record_expr' ->
-- Desugar the rbinds, and generate let-bindings if
-- necessary so that we don't lose sharing
- dsRbinds rbinds $ \ rbinds' ->
+
+ let
+ ds_rbind (sel_id, rhs, pun_flag)
+ = dsExpr rhs `thenDs` \ rhs' ->
+ returnDs (recordSelectorFieldLabel sel_id, rhs')
+ in
+ mapDs ds_rbind rbinds `thenDs` \ rbinds' ->
let
- record_ty = coreExprType record_expr'
- (tycon, inst_tys, cons) = _trace "DsExpr.getAppDataTyConExpandingDicts" $
- getAppDataTyConExpandingDicts record_ty
- cons_to_upd = filter has_all_fields cons
+ record_in_ty = coreExprType record_expr'
+ (tycon, in_inst_tys, cons) = splitAlgTyConApp record_in_ty
+ (_, out_inst_tys, _) = splitAlgTyConApp record_out_ty
+ cons_to_upd = filter has_all_fields cons
-- initial_args are passed to every constructor
- initial_args = map TyArg inst_tys ++ map VarArg dicts
+ initial_args = map Type out_inst_tys ++ map Var dicts
- mk_val_arg (field, arg_id)
- = case [arg | (f, arg) <- rbinds',
- field == recordSelectorFieldLabel f] of
- (arg:args) -> ASSERT(null args)
- arg
- [] -> VarArg arg_id
+ mk_val_arg field old_arg_id
+ = case [rhs | (f, rhs) <- rbinds', field == f] of
+ (rhs:rest) -> ASSERT(null rest) rhs
+ [] -> Var old_arg_id
mk_alt con
- = newSysLocalsDs (dataConArgTys con inst_tys) `thenDs` \ arg_ids ->
+ = newSysLocalsDs (dataConArgTys con in_inst_tys) `thenDs` \ arg_ids ->
let
- val_args = map mk_val_arg (zipEqual "dsExpr:RecordUpd" (dataConFieldLabels con) arg_ids)
+ val_args = zipWithEqual "dsExpr:RecordUpd" mk_val_arg
+ (dataConFieldLabels con) arg_ids
+ rhs = mkApps (mkApps (Var (dataConId con)) initial_args) val_args
in
- returnDs (con, arg_ids, mkGenApp (mkGenApp (Var con) initial_args) val_args)
+ returnDs (DataCon con, arg_ids, rhs)
mk_default
| length cons_to_upd == length cons
- = returnDs NoDefault
+ = returnDs []
| otherwise
- = newSysLocalDs record_ty `thenDs` \ deflt_id ->
- mkErrorAppDs rEC_UPD_ERROR_ID record_ty "" `thenDs` \ err ->
- returnDs (BindDefault deflt_id err)
+ = mkErrorAppDs rEC_UPD_ERROR_ID record_out_ty "" `thenDs` \ err ->
+ returnDs [(DEFAULT, [], err)]
in
+ -- Record stuff doesn't work for existentials
+ ASSERT( all (not . isExistentialDataCon) cons )
+
+ newSysLocalDs record_in_ty `thenDs` \ case_bndr ->
mapDs mk_alt cons_to_upd `thenDs` \ alts ->
mk_default `thenDs` \ deflt ->
- returnDs (Case record_expr' (AlgAlts alts deflt))
-
+ returnDs (Case record_expr' case_bndr (alts ++ deflt))
where
- has_all_fields :: Id -> Bool
+ has_all_fields :: DataCon -> Bool
has_all_fields con_id
= all ok rbinds
where
\begin{code}
dsExpr (DictLam dictvars expr)
= dsExpr expr `thenDs` \ core_expr ->
- returnDs( mkValLam dictvars core_expr )
+ returnDs (mkLams dictvars core_expr)
------------------
-dsExpr expr@(DictApp e dicts) -- becomes a curried application
- = dsApp expr []
+dsExpr (DictApp expr dicts) -- becomes a curried application
+ = dsExpr expr `thenDs` \ core_expr ->
+ returnDs (foldl (\f d -> f `App` (Var d)) core_expr dicts)
\end{code}
-@SingleDicts@ become @Locals@; @Dicts@ turn into tuples, unless
-of length 0 or 1.
-@ClassDictLam dictvars methods expr@ is ``the opposite'':
-\begin{verbatim}
-\ x -> case x of ( dictvars-and-methods-tuple ) -> expr
-\end{verbatim}
\begin{code}
-dsExpr (SingleDict dict) -- just a local
- = lookupEnvWithDefaultDs dict (Var dict)
-
-dsExpr (Dictionary dicts methods)
- = -- hey, these things may have been substituted away...
- zipWithDs lookupEnvWithDefaultDs
- dicts_and_methods dicts_and_methods_exprs
- `thenDs` \ core_d_and_ms ->
-
- (case num_of_d_and_ms of
- 0 -> returnDs (Var voidId)
- 1 -> returnDs (head core_d_and_ms) -- just a single Id
-
- _ -> -- tuple 'em up
- mkConDs (mkTupleCon num_of_d_and_ms)
- (map coreExprType core_d_and_ms)
- core_d_and_ms
- )
- where
- dicts_and_methods = dicts ++ methods
- dicts_and_methods_exprs = map Var dicts_and_methods
- num_of_d_and_ms = length dicts_and_methods
-
-dsExpr (ClassDictLam dicts methods expr)
- = dsExpr expr `thenDs` \ core_expr ->
- case num_of_d_and_ms of
- 0 -> newSysLocalDs voidTy `thenDs` \ new_x ->
- returnDs (mkValLam [new_x] core_expr)
-
- 1 -> -- no untupling
- returnDs (mkValLam dicts_and_methods core_expr)
-
- _ -> -- untuple it
- newSysLocalDs tuple_ty `thenDs` \ new_x ->
- returnDs (
- Lam (ValBinder new_x)
- (Case (Var new_x)
- (AlgAlts
- [(tuple_con, dicts_and_methods, core_expr)]
- NoDefault)))
- where
- num_of_d_and_ms = length dicts + length methods
- dicts_and_methods = dicts ++ methods
- tuple_ty = mkTupleTy num_of_d_and_ms (map idType dicts_and_methods)
- tuple_con = mkTupleCon num_of_d_and_ms
#ifdef DEBUG
-- HsSyn constructs that just shouldn't be here:
-dsExpr (HsDo _ _) = panic "dsExpr:HsDo"
+dsExpr (HsDo _ _ _) = panic "dsExpr:HsDo"
dsExpr (ExplicitList _) = panic "dsExpr:ExplicitList"
dsExpr (ExprWithTySig _ _) = panic "dsExpr:ExprWithTySig"
dsExpr (ArithSeqIn _) = panic "dsExpr:ArithSeqIn"
%--------------------------------------------------------------------
-@(dsApp e [t_1,..,t_n, e_1,..,e_n])@ returns something with the same
-value as:
-\begin{verbatim}
-e t_1 ... t_n e_1 .. e_n
-\end{verbatim}
-
-We're doing all this so we can saturate constructors (as painlessly as
-possible).
+Basically does the translation given in the Haskell~1.3 report:
\begin{code}
-type DsCoreArg = GenCoreArg CoreExpr{-NB!-} TyVar UVar
-
-dsApp :: TypecheckedHsExpr -- expr to desugar
- -> [DsCoreArg] -- accumulated ty/val args: NB:
- -> DsM CoreExpr -- final result
-
-dsApp (HsApp e1 e2) args
- = dsExpr e2 `thenDs` \ core_e2 ->
- dsApp e1 (VarArg core_e2 : args)
-
-dsApp (OpApp e1 op e2) args
- = dsExpr e1 `thenDs` \ core_e1 ->
- dsExpr e2 `thenDs` \ core_e2 ->
- dsApp op (VarArg core_e1 : VarArg core_e2 : args)
-
-dsApp (DictApp expr dicts) args
- = -- now, those dicts may have been substituted away...
- zipWithDs lookupEnvWithDefaultDs dicts (map Var dicts)
- `thenDs` \ core_dicts ->
- dsApp expr (map VarArg core_dicts ++ args)
-
-dsApp (TyApp expr tys) args
- = dsApp expr (map TyArg tys ++ args)
-
--- we might should look out for SectionLs, etc., here, but we don't
-
-dsApp (HsVar v) args
- = lookupEnvDs v `thenDs` \ maybe_expr ->
- case maybe_expr of
- Just expr -> apply_to_args expr args
-
- Nothing -> -- we're only saturating constructors and PrimOps
- case getIdUnfolding v of
- GenForm _ the_unfolding EssentialUnfolding
- -> do_unfold nullTyVarEnv nullIdEnv (unTagBinders the_unfolding) args
-
- _ -> apply_to_args (Var v) args
-
-
-dsApp anything_else args
- = dsExpr anything_else `thenDs` \ core_expr ->
- apply_to_args core_expr args
-
--- a DsM version of mkGenApp:
-apply_to_args :: CoreExpr -> [DsCoreArg] -> DsM CoreExpr
+dsDo :: StmtCtxt
+ -> [TypecheckedStmt]
+ -> Id -- id for: return m
+ -> Id -- id for: (>>=) m
+ -> Id -- id for: zero m
+ -> Type -- Element type; the whole expression has type (m t)
+ -> DsM CoreExpr
-apply_to_args fun args
+dsDo do_or_lc stmts return_id then_id zero_id result_ty
= let
- (ty_args, val_args) = foldr sep ([],[]) args
+ (_, b_ty) = splitAppTy result_ty -- result_ty must be of the form (m b)
+
+ go [ReturnStmt expr]
+ = dsExpr expr `thenDs` \ expr2 ->
+ returnDs (mkApps (Var return_id) [Type b_ty, expr2])
+
+ go (GuardStmt expr locn : stmts)
+ = do_expr expr locn `thenDs` \ expr2 ->
+ go stmts `thenDs` \ rest ->
+ returnDs (mkIfThenElse expr2 rest (App (Var zero_id) (Type b_ty)))
+
+ go (ExprStmt expr locn : stmts)
+ = do_expr expr locn `thenDs` \ expr2 ->
+ let
+ (_, a_ty) = splitAppTy (coreExprType expr2) -- Must be of form (m a)
+ in
+ if null stmts then
+ returnDs expr2
+ else
+ go stmts `thenDs` \ rest ->
+ newSysLocalDs a_ty `thenDs` \ ignored_result_id ->
+ returnDs (mkApps (Var then_id) [Type a_ty, Type b_ty, expr2,
+ Lam ignored_result_id rest])
+
+ go (LetStmt binds : stmts )
+ = go stmts `thenDs` \ rest ->
+ dsLet binds rest
+
+ go (BindStmt pat expr locn : stmts)
+ = putSrcLocDs locn $
+ dsExpr expr `thenDs` \ expr2 ->
+ let
+ (_, a_ty) = splitAppTy (coreExprType expr2) -- Must be of form (m a)
+ zero_expr = TyApp (HsVar zero_id) [b_ty]
+ main_match = PatMatch pat (SimpleMatch (
+ HsDoOut do_or_lc stmts return_id then_id zero_id result_ty locn))
+ the_matches
+ = if failureFreePat pat
+ then [main_match]
+ else [main_match, PatMatch (WildPat a_ty) (SimpleMatch zero_expr)]
+ in
+ matchWrapper DoBindMatch the_matches match_msg
+ `thenDs` \ (binders, matching_code) ->
+ returnDs (mkApps (Var then_id) [Type a_ty, Type b_ty, expr2,
+ mkLams binders matching_code])
in
- mkAppDs fun ty_args val_args
- where
- sep a@(LitArg l) (tys,vals) = (tys, (Lit l):vals)
- sep a@(VarArg e) (tys,vals) = (tys, e:vals)
- sep a@(TyArg ty) (tys,vals) = (ty:tys, vals)
- sep a@(UsageArg _) _ = panic "DsExpr:apply_to_args:UsageArg"
-\end{code}
-
-
-\begin{code}
-dsRbinds :: TypecheckedRecordBinds -- The field bindings supplied
- -> ([(Id, CoreArg)] -> DsM CoreExpr) -- A continuation taking the field
- -- bindings with atomic rhss
- -> DsM CoreExpr -- The result of the continuation,
- -- wrapped in suitable Lets
-
-dsRbinds [] continue_with
- = continue_with []
-
-dsRbinds ((sel_id, rhs, pun_flag) : rbinds) continue_with
- = dsExpr rhs `thenDs` \ rhs' ->
- dsExprToAtom rhs' $ \ rhs_atom ->
- dsRbinds rbinds $ \ rbinds' ->
- continue_with ((sel_id, rhs_atom) : rbinds')
-\end{code}
-
-\begin{code}
-do_unfold ty_env val_env (Lam (TyBinder tyvar) body) (TyArg ty : args)
- = do_unfold (addOneToTyVarEnv ty_env tyvar ty) val_env body args
-
-do_unfold ty_env val_env (Lam (ValBinder binder) body) (VarArg expr : args)
- = dsExprToAtom expr $ \ arg_atom ->
- do_unfold ty_env
- (addOneToIdEnv val_env binder (argToExpr arg_atom))
- body args
+ go stmts
-do_unfold ty_env val_env body args
- = -- Clone the remaining part of the template
- uniqSMtoDsM (substCoreExpr val_env ty_env body) `thenDs` \ body' ->
+ where
+ do_expr expr locn = putSrcLocDs locn (dsExpr expr)
- -- Apply result to remaining arguments
- apply_to_args body' args
+ match_msg = case do_or_lc of
+ DoStmt -> "`do' statement"
+ ListComp -> "comprehension"
\end{code}
-Basically does the translation given in the Haskell~1.3 report:
\begin{code}
-dsDo :: Id -- id for: (>>=) m
- -> Id -- id for: zero m
- -> [TypecheckedStmt]
- -> DsM CoreExpr
-
-dsDo then_id zero_id (stmt:stmts)
- = case stmt of
- ExprStmt expr locn -> ASSERT( null stmts ) do_expr expr locn
-
- ExprStmtOut expr locn a b ->
- do_expr expr locn `thenDs` \ expr2 ->
- ds_rest `thenDs` \ rest ->
- dsApp (HsVar then_id) [TyArg a, TyArg b, VarArg expr2, VarArg rest]
-
- LetStmt binds ->
- dsBinds binds `thenDs` \ binds2 ->
- ds_rest `thenDs` \ rest ->
- returnDs (mkCoLetsAny binds2 rest)
-
- BindStmtOut pat expr locn a b ->
- do_expr expr locn `thenDs` \ expr2 ->
- let
- zero_expr = TyApp (HsVar zero_id) [b]
- main_match
- = PatMatch pat (SimpleMatch (HsDoOut stmts then_id zero_id locn))
- the_matches
- = if failureFreePat pat
- then [main_match]
- else [main_match, PatMatch (WildPat a) (SimpleMatch zero_expr)]
- in
- matchWrapper DoBindMatch the_matches "`do' statement"
- `thenDs` \ (binders, matching_code) ->
- dsApp (HsVar then_id) [TyArg a, TyArg b,
- VarArg expr2, VarArg (mkValLam binders matching_code)]
- where
- ds_rest = dsDo then_id zero_id stmts
- do_expr expr locn = putSrcLocDs locn (dsExpr expr)
-
-#ifdef DEBUG
-dsDo then_expr zero_expr [] = panic "dsDo:[]"
-#endif
+var_pat (WildPat _) = True
+var_pat (VarPat _) = True
+var_pat _ = False
\end{code}
+
projects / ghc-hetmet.git / blobdiff