#include "HsVersions.h"
-import {-# SOURCE #-} DsExpr ( dsLExpr, dsLet )
+import {-# SOURCE #-} DsExpr ( dsLExpr, dsLocalBinds )
import BasicTypes ( Boxity(..) )
import HsSyn
import DsMonad -- the monadery used in the desugarer
import DsUtils
-import CmdLineOpts ( DynFlag(..), dopt, opt_RulesOff )
+import DynFlags ( DynFlag(..), dopt )
+import StaticFlags ( opt_RulesOff )
import CoreUtils ( exprType, mkIfThenElse )
import Id ( idType )
import Var ( Id )
\begin{code}
dsListComp :: [LStmt Id]
+ -> LHsExpr Id
-> Type -- Type of list elements
-> DsM CoreExpr
-dsListComp lquals elt_ty
+dsListComp lquals body elt_ty
= getDOptsDs `thenDs` \dflags ->
let
quals = map unLoc lquals
|| isParallelComp quals
-- Foldr-style desugaring can't handle
-- parallel list comprehensions
- then deListComp quals (mkNilExpr elt_ty)
+ then deListComp quals body (mkNilExpr elt_ty)
else -- Foldr/build should be enabled, so desugar
-- into foldrs and builds
c_ty = mkFunTys [elt_ty, n_ty] n_ty
in
newSysLocalsDs [c_ty,n_ty] `thenDs` \ [c, n] ->
- dfListComp c n quals `thenDs` \ result ->
+ dfListComp c n quals body `thenDs` \ result ->
dsLookupGlobalId buildName `thenDs` \ build_id ->
returnDs (Var build_id `App` Type elt_ty
`App` mkLams [n_tyvar, c, n] result)
with the Unboxed variety.
\begin{code}
-deListComp :: [Stmt Id] -> CoreExpr -> DsM CoreExpr
+deListComp :: [Stmt Id] -> LHsExpr Id -> CoreExpr -> DsM CoreExpr
-deListComp (ParStmt stmtss_w_bndrs : quals) list
+deListComp (ParStmt stmtss_w_bndrs : quals) body 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
+ quals body list
where
bndrs_s = map snd stmtss_w_bndrs
qual_tys = map mk_bndrs_tys bndrs_s
do_list_comp (stmts, bndrs)
- = dsListComp (stmts ++ [noLoc $ ResultStmt (mk_hs_tuple_expr bndrs)])
+ = dsListComp stmts (mk_hs_tuple_expr bndrs)
(mk_bndrs_tys bndrs)
mk_bndrs_tys bndrs = mkCoreTupTy (map idType bndrs)
-- Last: the one to return
-deListComp [ResultStmt expr] list -- Figure 7.4, SLPJ, p 135, rule C above
- = dsLExpr expr `thenDs` \ core_expr ->
- returnDs (mkConsExpr (exprType core_expr) core_expr list)
+deListComp [] body list -- Figure 7.4, SLPJ, p 135, rule C above
+ = dsLExpr body `thenDs` \ core_body ->
+ returnDs (mkConsExpr (exprType core_body) core_body list)
-- Non-last: must be a guard
-deListComp (ExprStmt guard ty : quals) list -- rule B above
+deListComp (ExprStmt guard _ _ : quals) body list -- rule B above
= dsLExpr guard `thenDs` \ core_guard ->
- deListComp quals list `thenDs` \ core_rest ->
+ deListComp quals body list `thenDs` \ core_rest ->
returnDs (mkIfThenElse core_guard core_rest list)
-- [e | let B, qs] = let B in [e | qs]
-deListComp (LetStmt binds : quals) list
- = deListComp quals list `thenDs` \ core_rest ->
- dsLet binds core_rest
+deListComp (LetStmt binds : quals) body list
+ = deListComp quals body list `thenDs` \ core_rest ->
+ dsLocalBinds binds core_rest
-deListComp (BindStmt pat list1 : quals) core_list2 -- rule A' above
+deListComp (BindStmt pat list1 _ _ : quals) body core_list2 -- rule A' above
= dsLExpr list1 `thenDs` \ core_list1 ->
- deBindComp pat core_list1 quals core_list2
+ deBindComp pat core_list1 quals body core_list2
\end{code}
\begin{code}
-deBindComp pat core_list1 quals core_list2
+deBindComp pat core_list1 quals body core_list2
= let
u3_ty@u1_ty = exprType core_list1 -- two names, same thing
core_fail = App (Var h) (Var u3)
letrec_body = App (Var h) core_list1
in
- deListComp quals core_fail `thenDs` \ rest_expr ->
+ deListComp quals body core_fail `thenDs` \ rest_expr ->
matchSimply (Var u2) (StmtCtxt ListComp) pat
rest_expr core_fail `thenDs` \ core_match ->
let
rhs = Lam u1 $
- Case (Var u1) u1 [(DataAlt nilDataCon, [], core_list2),
- (DataAlt consDataCon, [u2, u3], core_match)]
+ Case (Var u1) u1 res_ty
+ [(DataAlt nilDataCon, [], core_list2),
+ (DataAlt consDataCon, [u2, u3], core_match)]
+ -- Increasing order of tag
in
returnDs (Let (Rec [(h, rhs)]) letrec_body)
\end{code}
in
returnDs (zip_fn, mkLams ass zip_body)
where
- list_tys = map mkListTy elt_tys
- ret_elt_ty = mkCoreTupTy elt_tys
- zip_fn_ty = mkFunTys list_tys (mkListTy ret_elt_ty)
+ list_tys = map mkListTy elt_tys
+ ret_elt_ty = mkCoreTupTy elt_tys
+ list_ret_ty = mkListTy ret_elt_ty
+ zip_fn_ty = mkFunTys list_tys list_ret_ty
mk_case (as, a', as') rest
- = Case (Var as) as [(DataAlt nilDataCon, [], mkNilExpr ret_elt_ty),
- (DataAlt consDataCon, [a', as'], rest)]
-
+ = Case (Var as) as list_ret_ty
+ [(DataAlt nilDataCon, [], mkNilExpr ret_elt_ty),
+ (DataAlt consDataCon, [a', as'], rest)]
+ -- Increasing order of tag
-- Helper functions that makes an HsTuple only for non-1-sized tuples
mk_hs_tuple_expr :: [Id] -> LHsExpr Id
mk_hs_tuple_expr [] = nlHsVar unitDataConId
\begin{code}
dfListComp :: Id -> Id -- 'c' and 'n'
-> [Stmt Id] -- the rest of the qual's
+ -> LHsExpr Id
-> DsM CoreExpr
-- Last: the one to return
-dfListComp c_id n_id [ResultStmt expr]
- = dsLExpr expr `thenDs` \ core_expr ->
- returnDs (mkApps (Var c_id) [core_expr, Var n_id])
+dfListComp c_id n_id [] body
+ = dsLExpr body `thenDs` \ core_body ->
+ returnDs (mkApps (Var c_id) [core_body, Var n_id])
-- Non-last: must be a guard
-dfListComp c_id n_id (ExprStmt guard ty : quals)
- = dsLExpr guard `thenDs` \ core_guard ->
- dfListComp c_id n_id quals `thenDs` \ core_rest ->
+dfListComp c_id n_id (ExprStmt guard _ _ : quals) body
+ = dsLExpr guard `thenDs` \ core_guard ->
+ dfListComp c_id n_id quals body `thenDs` \ core_rest ->
returnDs (mkIfThenElse core_guard core_rest (Var n_id))
-dfListComp c_id n_id (LetStmt binds : quals)
+dfListComp c_id n_id (LetStmt binds : quals) body
-- new in 1.3, local bindings
- = dfListComp c_id n_id quals `thenDs` \ core_rest ->
- dsLet binds core_rest
+ = dfListComp c_id n_id quals body `thenDs` \ core_rest ->
+ dsLocalBinds binds core_rest
-dfListComp c_id n_id (BindStmt pat list1 : quals)
+dfListComp c_id n_id (BindStmt pat list1 _ _ : quals) body
-- evaluate the two lists
= dsLExpr list1 `thenDs` \ core_list1 ->
newSysLocalsDs [b_ty,x_ty] `thenDs` \ [b,x] ->
-- build rest of the comprehesion
- dfListComp c_id b quals `thenDs` \ core_rest ->
+ dfListComp c_id b quals body `thenDs` \ core_rest ->
-- build the pattern match
- matchSimply (Var x) (StmtCtxt ListComp)
+ matchSimply (Var x) (StmtCtxt ListComp)
pat core_rest (Var b) `thenDs` \ core_expr ->
-- now build the outermost foldr, and return
-- [:e | qss:] = <<[:e | qss:]>> () [:():]
--
dsPArrComp :: [Stmt Id]
+ -> LHsExpr Id
-> Type -- Don't use; called with `undefined' below
-> DsM CoreExpr
-dsPArrComp qs _ =
+dsPArrComp qs body _ =
dsLookupGlobalId replicatePName `thenDs` \repP ->
let unitArray = mkApps (Var repP) [Type unitTy,
mkIntExpr 1,
mkCoreTup []]
in
- dePArrComp qs (noLoc (TuplePat [] Boxed)) unitArray
+ dePArrComp qs body (mkTuplePat []) unitArray
-- the work horse
--
dePArrComp :: [Stmt Id]
+ -> LHsExpr Id
-> LPat Id -- the current generator pattern
-> CoreExpr -- the current generator expression
-> DsM CoreExpr
--
-- <<[:e' | :]>> pa ea = mapP (\pa -> e') ea
--
-dePArrComp [ResultStmt e'] pa cea =
+dePArrComp [] e' pa cea =
dsLookupGlobalId mapPName `thenDs` \mapP ->
let ty = parrElemType cea
in
--
-- <<[:e' | b, qs:]>> pa ea = <<[:e' | qs:]>> pa (filterP (\pa -> b) ea)
--
-dePArrComp (ExprStmt b _ : qs) pa cea =
+dePArrComp (ExprStmt b _ _ : qs) body pa cea =
dsLookupGlobalId filterPName `thenDs` \filterP ->
let ty = parrElemType cea
in
- deLambda ty pa b `thenDs` \(clam,_) ->
- dePArrComp qs pa (mkApps (Var filterP) [Type ty, clam, cea])
+ deLambda ty pa b `thenDs` \(clam,_) ->
+ dePArrComp qs body pa (mkApps (Var filterP) [Type ty, clam, cea])
--
-- <<[:e' | p <- e, qs:]>> pa ea =
-- let ef = filterP (\x -> case x of {p -> True; _ -> False}) e
-- in
-- <<[:e' | qs:]>> (pa, p) (crossP ea ef)
--
-dePArrComp (BindStmt p e : qs) pa cea =
+dePArrComp (BindStmt p e _ _ : qs) body pa cea =
dsLookupGlobalId filterPName `thenDs` \filterP ->
dsLookupGlobalId crossPName `thenDs` \crossP ->
dsLExpr e `thenDs` \ce ->
true = Var trueDataConId
in
newSysLocalDs ty'ce `thenDs` \v ->
- matchSimply (Var v) (StmtCtxt 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' = noLoc (TuplePat [pa, p] Boxed)
+ pa' = mkTuplePat [pa, p]
in
- dePArrComp qs pa' (mkApps (Var crossP) [Type ty'cea, Type ty'cef, cea, cef])
+ dePArrComp qs body pa' (mkApps (Var crossP) [Type ty'cea, Type ty'cef, cea, cef])
--
-- <<[:e' | let ds, qs:]>> pa ea =
-- <<[:e' | qs:]>> (pa, (x_1, ..., x_n))
-- where
-- {x_1, ..., x_n} = DV (ds) -- Defined Variables
--
-dePArrComp (LetStmt ds : qs) pa cea =
+dePArrComp (LetStmt ds : qs) body pa cea =
dsLookupGlobalId mapPName `thenDs` \mapP ->
- let xs = map unLoc (collectGroupBinders ds)
+ let xs = map unLoc (collectLocalBinders ds)
ty'cea = parrElemType cea
in
newSysLocalDs ty'cea `thenDs` \v ->
- dsLet ds (mkCoreTup (map Var xs)) `thenDs` \clet ->
+ dsLocalBinds ds (mkCoreTup (map Var xs)) `thenDs` \clet ->
newSysLocalDs (exprType clet) `thenDs` \let'v ->
let projBody = mkDsLet (NonRec let'v clet) $
mkCoreTup [Var v, Var let'v]
errMsg = "DsListComp.dePArrComp: internal error!"
in
mkErrorAppDs pAT_ERROR_ID errTy errMsg `thenDs` \cerr ->
- matchSimply (Var v) (StmtCtxt PArrComp) pa projBody cerr `thenDs` \ccase ->
- let pa' = noLoc $ TuplePat [pa, noLoc (TuplePat (map nlVarPat xs) Boxed)] Boxed
+ matchSimply (Var v) (StmtCtxt PArrComp) pa projBody cerr`thenDs` \ccase ->
+ let pa' = mkTuplePat [pa, mkTuplePat (map nlVarPat xs)]
proj = mkLams [v] ccase
in
- dePArrComp qs pa' (mkApps (Var mapP) [Type ty'cea, proj, cea])
+ dePArrComp qs body pa' (mkApps (Var mapP) [Type ty'cea, proj, cea])
--
-- <<[:e' | qs | qss:]>> pa ea =
-- <<[:e' | qss:]>> (pa, (x_1, ..., x_n))
-- where
-- {x_1, ..., x_n} = DV (qs)
--
-dePArrComp (ParStmt [] : qss2) pa cea = dePArrComp qss2 pa cea
-dePArrComp (ParStmt ((qs, xs):qss) : qss2) pa cea =
- dsLookupGlobalId zipPName `thenDs` \zipP ->
- let pa' = noLoc $ TuplePat [pa, noLoc (TuplePat (map nlVarPat xs) Boxed)] Boxed
- ty'cea = parrElemType cea
- resStmt = ResultStmt (noLoc $ ExplicitTuple (map nlHsVar xs) Boxed)
- in
- dsPArrComp (map unLoc qs ++ [resStmt]) undefined `thenDs` \cqs ->
- let ty'cqs = parrElemType cqs
- cea' = mkApps (Var zipP) [Type ty'cea, Type ty'cqs, cea, cqs]
+dePArrComp (ParStmt qss : qs) body pa cea =
+ dsLookupGlobalId crossPName `thenDs` \crossP ->
+ deParStmt qss `thenDs` \(pQss,
+ ceQss) ->
+ let ty'cea = parrElemType cea
+ ty'ceQss = parrElemType ceQss
+ pa' = mkTuplePat [pa, pQss]
in
- dePArrComp (ParStmt qss : qss2) pa' cea'
+ dePArrComp qs body pa' (mkApps (Var crossP) [Type ty'cea, Type ty'ceQss,
+ cea, ceQss])
+ where
+ deParStmt [] =
+ -- empty parallel statement lists have not source representation
+ panic "DsListComp.dePArrComp: Empty parallel list comprehension"
+ deParStmt ((qs, xs):qss) = -- first statement
+ let res_expr = mkExplicitTuple (map nlHsVar xs)
+ in
+ dsPArrComp (map unLoc qs) res_expr undefined `thenDs` \cqs ->
+ parStmts qss (mkTuplePat (map nlVarPat xs)) cqs
+ ---
+ parStmts [] pa cea = return (pa, cea)
+ parStmts ((qs, xs):qss) pa cea = -- subsequent statements (zip'ed)
+ dsLookupGlobalId zipPName `thenDs` \zipP ->
+ let pa' = mkTuplePat [pa, mkTuplePat (map nlVarPat xs)]
+ ty'cea = parrElemType cea
+ res_expr = mkExplicitTuple (map nlHsVar xs)
+ in
+ dsPArrComp (map unLoc qs) res_expr undefined `thenDs` \cqs ->
+ let ty'cqs = parrElemType cqs
+ cea' = mkApps (Var zipP) [Type ty'cea, Type ty'cqs, cea, cqs]
+ in
+ parStmts qss pa' cea'
-- generate Core corresponding to `\p -> e'
--
let errTy = exprType ce
errMsg = "DsListComp.deLambda: internal error!"
in
- mkErrorAppDs pAT_ERROR_ID errTy errMsg `thenDs` \cerr ->
+ mkErrorAppDs pAT_ERROR_ID errTy errMsg `thenDs` \cerr ->
matchSimply (Var v) (StmtCtxt PArrComp) p ce cerr `thenDs` \res ->
returnDs (mkLams [v] res, errTy)
Just (tycon, [ty]) | tycon == parrTyCon -> ty
_ -> panic
"DsListComp.parrElemType: not a parallel array type"
+
+-- Smart constructor for source tuple patterns
+--
+mkTuplePat :: [LPat id] -> LPat id
+mkTuplePat [lpat] = lpat
+mkTuplePat lpats = noLoc $ TuplePat lpats Boxed
+
+-- Smart constructor for source tuple expressions
+--
+mkExplicitTuple :: [LHsExpr id] -> LHsExpr id
+mkExplicitTuple [lexp] = lexp
+mkExplicitTuple lexps = noLoc $ ExplicitTuple lexps Boxed
\end{code}