import {-# SOURCE #-} DsExpr ( dsExpr, dsLet )
import BasicTypes ( Boxity(..) )
-import TyCon ( tyConName )
import HsSyn ( Pat(..), HsExpr(..), Stmt(..),
- HsMatchContext(..), HsDoContext(..),
+ HsMatchContext(..), HsStmtContext(..),
collectHsBinders )
import TcHsSyn ( TypecheckedStmt, TypecheckedPat, TypecheckedHsExpr,
hsPatType )
import DsMonad -- the monadery used in the desugarer
import DsUtils
-import CmdLineOpts ( opt_FoldrBuildOn )
+import CmdLineOpts ( DynFlag(..), dopt, opt_RulesOff )
import CoreUtils ( exprType, mkIfThenElse )
import Id ( idType )
import Var ( Id )
import Type ( mkTyVarTy, mkFunTys, mkFunTy, Type,
splitTyConApp_maybe )
import TysPrim ( alphaTyVar )
-import TysWiredIn ( nilDataCon, consDataCon, unitDataConId, unitTy,
- mkListTy, mkTupleTy )
+import TysWiredIn ( nilDataCon, consDataCon, trueDataConId, falseDataConId,
+ unitDataConId, unitTy, mkListTy, parrTyCon )
import Match ( matchSimply )
-import PrelNames ( trueDataConName, falseDataConName, foldrName,
- buildName, replicatePName, mapPName, filterPName,
- zipPName, crossPName, parrTyConName )
+import PrelNames ( foldrName, buildName, replicatePName, mapPName,
+ filterPName, zipPName, crossPName )
import PrelInfo ( pAT_ERROR_ID )
import SrcLoc ( noSrcLoc )
import Panic ( panic )
-> DsM CoreExpr
dsListComp quals elt_ty
- | not opt_FoldrBuildOn -- Be boring
- || isParallelComp quals
- = deListComp quals (mkNilExpr elt_ty)
-
- | otherwise -- foldr/build lives!
- = newTyVarsDs [alphaTyVar] `thenDs` \ [n_tyvar] ->
+ = getDOptsDs `thenDs` \dflags ->
+ if opt_RulesOff || dopt Opt_IgnoreInterfacePragmas dflags
+ -- Either rules are switched off, or we are ignoring what there are;
+ -- Either way foldr/build won't happen, so use the more efficient
+ -- Wadler-style desugaring
+ || isParallelComp quals
+ -- Foldr-style desugaring can't handle
+ -- parallel list comprehensions
+ then deListComp quals (mkNilExpr elt_ty)
+
+ else -- Foldr/build should be enabled, so desugar
+ -- into foldrs and builds
+ newTyVarsDs [alphaTyVar] `thenDs` \ [n_tyvar] ->
let
n_ty = mkTyVarTy n_tyvar
c_ty = mkFunTys [elt_ty, n_ty] n_ty
returnDs (Var build_id `App` Type elt_ty
`App` mkLams [n_tyvar, c, n] result)
- where isParallelComp (ParStmtOut bndrstmtss : _) = True
- isParallelComp _ = False
+ where isParallelComp (ParStmt bndrstmtss : _) = True
+ isParallelComp _ = False
\end{code}
%************************************************************************
where (x1, .., xn) are the variables bound in p1, v1, p2
(y1, .., ym) are the variables bound in q1, v2, q2
-In the translation below, the ParStmtOut branch translates each parallel branch
+In the translation below, the ParStmt branch translates each parallel branch
into a sub-comprehension, and desugars each independently. The resulting lists
are fed to a zip function, we create a binding for all the variables bound in all
the comprehensions, and then we hand things off the the desugarer for bindings.
deListComp :: [TypecheckedStmt] -> CoreExpr -> DsM CoreExpr
-deListComp (ParStmtOut bndrstmtss : quals) list
- = mapDs do_list_comp bndrstmtss `thenDs` \ exps ->
+deListComp (ParStmt stmtss_w_bndrs : quals) list
+ = mappM do_list_comp stmtss_w_bndrs `thenDs` \ exps ->
mkZipBind qual_tys `thenDs` \ (zip_fn, zip_rhs) ->
-- Deal with [e | pat <- zip l1 .. ln] in example above
deBindComp pat (Let (Rec [(zip_fn, zip_rhs)]) (mkApps (Var zip_fn) exps))
quals list
- where -- pat is the pattern ((x1,..,xn), (y1,..,ym)) in the example above
- pat = TuplePat pats Boxed
- pats = map (\(bs,_) -> mk_hs_tuple_pat bs) bndrstmtss
+ where
+ bndrs_s = map snd stmtss_w_bndrs
+
+ -- pat is the pattern ((x1,..,xn), (y1,..,ym)) in the example above
+ pat = TuplePat pats Boxed
+ pats = map mk_hs_tuple_pat bndrs_s
-- Types of (x1,..,xn), (y1,..,yn) etc
- qual_tys = [ mk_bndrs_tys bndrs | (bndrs,_) <- bndrstmtss ]
+ qual_tys = map mk_bndrs_tys bndrs_s
- do_list_comp (bndrs, stmts)
+ do_list_comp (stmts, bndrs)
= dsListComp (stmts ++ [ResultStmt (mk_hs_tuple_expr bndrs) noSrcLoc])
(mk_bndrs_tys bndrs)
- mk_bndrs_tys bndrs = mk_tuple_ty (map idType bndrs)
+ mk_bndrs_tys bndrs = mkCoreTupTy (map idType bndrs)
-- Last: the one to return
deListComp [ResultStmt expr locn] list -- Figure 7.4, SLPJ, p 135, rule C above
letrec_body = App (Var h) core_list1
in
deListComp quals core_fail `thenDs` \ rest_expr ->
- matchSimply (Var u2) (DoCtxt ListComp) pat
+ matchSimply (Var u2) (StmtCtxt ListComp) pat
rest_expr core_fail `thenDs` \ core_match ->
let
rhs = Lam u1 $
-- (a2:as'2) -> (a2,a2) : zip as'1 as'2)]
mkZipBind elt_tys
- = mapDs newSysLocalDs list_tys `thenDs` \ ass ->
- mapDs newSysLocalDs elt_tys `thenDs` \ as' ->
- mapDs newSysLocalDs list_tys `thenDs` \ as's ->
+ = mappM newSysLocalDs list_tys `thenDs` \ ass ->
+ mappM newSysLocalDs elt_tys `thenDs` \ as' ->
+ mappM newSysLocalDs list_tys `thenDs` \ as's ->
newSysLocalDs zip_fn_ty `thenDs` \ zip_fn ->
let
- inner_rhs = mkConsExpr ret_elt_ty (mkTupleExpr as') (mkVarApps (Var zip_fn) as's)
+ inner_rhs = mkConsExpr ret_elt_ty
+ (mkCoreTup (map Var as'))
+ (mkVarApps (Var zip_fn) as's)
zip_body = foldr mk_case inner_rhs (zip3 ass as' as's)
in
returnDs (zip_fn, mkLams ass zip_body)
where
list_tys = map mkListTy elt_tys
- ret_elt_ty = mk_tuple_ty elt_tys
+ ret_elt_ty = mkCoreTupTy elt_tys
zip_fn_ty = mkFunTys list_tys (mkListTy ret_elt_ty)
mk_case (as, a', as') rest
= Case (Var as) as [(DataAlt nilDataCon, [], mkNilExpr ret_elt_ty),
(DataAlt consDataCon, [a', as'], rest)]
--- Helper function
-mk_tuple_ty :: [Type] -> Type
-mk_tuple_ty [ty] = ty
-mk_tuple_ty tys = mkTupleTy Boxed (length tys) tys
-
-- Helper functions that makes an HsTuple only for non-1-sized tuples
mk_hs_tuple_expr :: [Id] -> TypecheckedHsExpr
mk_hs_tuple_expr [] = HsVar unitDataConId
dfListComp c_id b quals `thenDs` \ core_rest ->
-- build the pattern match
- matchSimply (Var x) (DoCtxt ListComp)
+ matchSimply (Var x) (StmtCtxt ListComp)
pat core_rest (Var b) `thenDs` \ core_expr ->
-- now build the outermost foldr, and return
dsLookupGlobalId replicatePName `thenDs` \repP ->
let unitArray = mkApps (Var repP) [Type unitTy,
mkIntExpr 1,
- mkTupleExpr []]
+ mkCoreTup []]
in
dePArrComp qs (TuplePat [] Boxed) unitArray
-- <<[:e' | qs:]>> (pa, p) (crossP ea ef)
--
dePArrComp (BindStmt p e _ : qs) pa cea =
- dsLookupGlobalId falseDataConName `thenDs` \falseId ->
- dsLookupGlobalId trueDataConName `thenDs` \trueId ->
dsLookupGlobalId filterPName `thenDs` \filterP ->
dsLookupGlobalId crossPName `thenDs` \crossP ->
- dsExpr e `thenDs` \ce ->
+ dsExpr e `thenDs` \ce ->
let ty'cea = parrElemType cea
ty'ce = parrElemType ce
- false = Var falseId
- true = Var trueId
+ false = Var falseDataConId
+ true = Var trueDataConId
in
newSysLocalDs ty'ce `thenDs` \v ->
- matchSimply (Var v) (DoCtxt PArrComp) p true false `thenDs` \pred ->
+ matchSimply (Var v) (StmtCtxt PArrComp) p true false `thenDs` \pred ->
let cef = mkApps (Var filterP) [Type ty'ce, mkLams [v] pred, ce]
ty'cef = ty'ce -- filterP preserves the type
pa' = TuplePat [pa, p] Boxed
ty'cea = parrElemType cea
in
newSysLocalDs ty'cea `thenDs` \v ->
- dsLet ds (mkTupleExpr xs) `thenDs` \clet ->
+ dsLet ds (mkCoreTup (map Var xs)) `thenDs` \clet ->
newSysLocalDs (exprType clet) `thenDs` \let'v ->
- let projBody = mkDsLet (NonRec let'v clet) $ mkTupleExpr [v, let'v]
+ let projBody = mkDsLet (NonRec let'v clet) $
+ mkCoreTup [Var v, Var let'v]
errTy = exprType projBody
errMsg = "DsListComp.dePArrComp: internal error!"
in
mkErrorAppDs pAT_ERROR_ID errTy errMsg `thenDs` \cerr ->
- matchSimply (Var v) (DoCtxt PArrComp) pa projBody cerr `thenDs` \ccase ->
+ matchSimply (Var v) (StmtCtxt PArrComp) pa projBody cerr `thenDs` \ccase ->
let pa' = TuplePat [pa, TuplePat (map VarPat xs) Boxed] Boxed
proj = mkLams [v] ccase
in
-- where
-- {x_1, ..., x_n} = DV (qs)
--
-dePArrComp (ParStmtOut [] : qss2) pa cea = dePArrComp qss2 pa cea
-dePArrComp (ParStmtOut ((xs, qs):qss) : qss2) pa cea =
+dePArrComp (ParStmt [] : qss2) pa cea = dePArrComp qss2 pa cea
+dePArrComp (ParStmt ((qs, xs):qss) : qss2) pa cea =
dsLookupGlobalId zipPName `thenDs` \zipP ->
let pa' = TuplePat [pa, TuplePat (map VarPat xs) Boxed] Boxed
ty'cea = parrElemType cea
let ty'cqs = parrElemType cqs
cea' = mkApps (Var zipP) [Type ty'cea, Type ty'cqs, cea, cqs]
in
- dePArrComp (ParStmtOut qss : qss2) pa' cea'
+ dePArrComp (ParStmt qss : qss2) pa' cea'
-- generate Core corresponding to `\p -> e'
--
errMsg = "DsListComp.deLambda: internal error!"
in
mkErrorAppDs pAT_ERROR_ID errTy errMsg `thenDs` \cerr ->
- matchSimply (Var v) (DoCtxt PArrComp) p ce cerr `thenDs` \res ->
+ matchSimply (Var v) (StmtCtxt PArrComp) p ce cerr `thenDs` \res ->
returnDs (mkLams [v] res, errTy)
-- obtain the element type of the parallel array produced by the given Core
parrElemType :: CoreExpr -> Type
parrElemType e =
case splitTyConApp_maybe (exprType e) of
- Just (tycon, [ty]) | tyConName tycon == parrTyConName -> ty
+ Just (tycon, [ty]) | tycon == parrTyCon -> ty
_ -> panic
"DsListComp.parrElemType: not a parallel array type"
\end{code}
projects / ghc-hetmet.git / blobdiff