Commit dcc8f0a8 authored by twanvl's avatar twanvl

Monadify deSugar/DsListComp: use do, return, applicative, standard monad functions

parent aee37b14
......@@ -75,7 +75,7 @@ dsListComp lquals body elt_ty = do
result <- dfListComp c n quals body
build_id <- dsLookupGlobalId buildName
returnDs (Var build_id `App` Type elt_ty `App` mkLams [n_tyvar, c, n] result)
return (Var build_id `App` Type elt_ty `App` mkLams [n_tyvar, c, n] result)
where
-- We must test for ParStmt anywhere, not just at the head, because an extension
......@@ -247,7 +247,7 @@ deListComp :: [Stmt Id] -> LHsExpr Id -> CoreExpr -> DsM CoreExpr
deListComp (ParStmt stmtss_w_bndrs : quals) body list
= do
exps_and_qual_tys <- mappM dsInnerListComp stmtss_w_bndrs
exps_and_qual_tys <- mapM dsInnerListComp stmtss_w_bndrs
let (exps, qual_tys) = unzip exps_and_qual_tys
(zip_fn, zip_rhs) <- mkZipBind qual_tys
......@@ -260,23 +260,23 @@ deListComp (ParStmt stmtss_w_bndrs : quals) body list
bndrs_s = map snd stmtss_w_bndrs
-- pat is the pattern ((x1,..,xn), (y1,..,ym)) in the example above
pat = mkBigLHsPatTup pats
pat = mkBigLHsPatTup pats
pats = map mkBigLHsVarPatTup bndrs_s
-- Last: the one to return
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)
deListComp [] body list = do -- Figure 7.4, SLPJ, p 135, rule C above
core_body <- dsLExpr body
return (mkConsExpr (exprType core_body) core_body list)
-- Non-last: must be a guard
deListComp (ExprStmt guard _ _ : quals) body list -- rule B above
= dsLExpr guard `thenDs` \ core_guard ->
deListComp quals body list `thenDs` \ core_rest ->
returnDs (mkIfThenElse core_guard core_rest list)
deListComp (ExprStmt guard _ _ : quals) body list = do -- rule B above
core_guard <- dsLExpr guard
core_rest <- deListComp quals body list
return (mkIfThenElse core_guard core_rest list)
-- [e | let B, qs] = let B in [e | qs]
deListComp (LetStmt binds : quals) body list
= deListComp quals body list `thenDs` \ core_rest ->
deListComp (LetStmt binds : quals) body list = do
core_rest <- deListComp quals body list
dsLocalBinds binds core_rest
deListComp (stmt@(TransformStmt _ _ _) : quals) body list = do
......@@ -287,8 +287,8 @@ deListComp (stmt@(GroupStmt _ _) : quals) body list = do
(inner_list_expr, pat) <- dsGroupStmt stmt
deBindComp pat inner_list_expr quals body list
deListComp (BindStmt pat list1 _ _ : quals) body core_list2 -- rule A' above
= dsLExpr list1 `thenDs` \ core_list1 ->
deListComp (BindStmt pat list1 _ _ : quals) body core_list2 = do -- rule A' above
core_list1 <- dsLExpr list1
deBindComp pat core_list1 quals body core_list2
\end{code}
......@@ -350,19 +350,19 @@ dfListComp :: Id -> Id -- 'c' and 'n'
-> DsM CoreExpr
-- Last: the one to return
dfListComp c_id n_id [] body
= dsLExpr body `thenDs` \ core_body ->
returnDs (mkApps (Var c_id) [core_body, Var n_id])
dfListComp c_id n_id [] body = do
core_body <- dsLExpr body
return (mkApps (Var c_id) [core_body, Var n_id])
-- Non-last: must be a guard
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) body
-- new in 1.3, local bindings
= dfListComp c_id n_id quals body `thenDs` \ core_rest ->
dfListComp c_id n_id (ExprStmt guard _ _ : quals) body = do
core_guard <- dsLExpr guard
core_rest <- dfListComp c_id n_id quals body
return (mkIfThenElse core_guard core_rest (Var n_id))
dfListComp c_id n_id (LetStmt binds : quals) body = do
-- new in 1.3, local bindings
core_rest <- dfListComp c_id n_id quals body
dsLocalBinds binds core_rest
dfListComp c_id n_id (stmt@(TransformStmt _ _ _) : quals) body = do
......@@ -430,9 +430,9 @@ mkZipBind :: [Type] -> DsM (Id, CoreExpr)
-- (a2:as'2) -> (a1, a2) : zip as'1 as'2)]
mkZipBind elt_tys = do
ass <- mappM newSysLocalDs elt_list_tys
as' <- mappM newSysLocalDs elt_tys
as's <- mappM newSysLocalDs elt_list_tys
ass <- mapM newSysLocalDs elt_list_tys
as' <- mapM newSysLocalDs elt_tys
as's <- mapM newSysLocalDs elt_list_tys
zip_fn <- newSysLocalDs zip_fn_ty
......@@ -470,8 +470,8 @@ mkUnzipBind elt_tys = do
ax <- newSysLocalDs elt_tuple_ty
axs <- newSysLocalDs elt_list_tuple_ty
ys <- newSysLocalDs elt_tuple_list_ty
xs <- mappM newSysLocalDs elt_tys
xss <- mappM newSysLocalDs elt_list_tys
xs <- mapM newSysLocalDs elt_tys
xss <- mapM newSysLocalDs elt_list_tys
unzip_fn <- newSysLocalDs unzip_fn_ty
......@@ -523,12 +523,10 @@ dsPArrComp :: [Stmt Id]
-> DsM CoreExpr
dsPArrComp [ParStmt qss] body _ = -- parallel comprehension
dePArrParComp qss body
dsPArrComp qs body _ = -- no ParStmt in `qs'
dsLookupGlobalId singletonPName `thenDs` \sglP ->
let unitArray = mkApps (Var sglP) [Type unitTy,
mkCoreTup []]
in
dePArrComp qs body (mkLHsPatTup []) unitArray
dsPArrComp qs body _ = do -- no ParStmt in `qs'
sglP <- dsLookupGlobalId singletonPName
let unitArray = mkApps (Var sglP) [Type unitTy, mkCoreTup []]
dePArrComp qs body (mkLHsPatTup []) unitArray
......@@ -542,22 +540,19 @@ dePArrComp :: [Stmt Id]
--
-- <<[:e' | :]>> pa ea = mapP (\pa -> e') ea
--
dePArrComp [] e' pa cea =
dsLookupGlobalId mapPName `thenDs` \mapP ->
let ty = parrElemType cea
in
deLambda ty pa e' `thenDs` \(clam,
ty'e') ->
returnDs $ mkApps (Var mapP) [Type ty, Type ty'e', clam, cea]
dePArrComp [] e' pa cea = do
mapP <- dsLookupGlobalId mapPName
let ty = parrElemType cea
(clam, ty'e') <- deLambda ty pa e'
return $ mkApps (Var mapP) [Type ty, Type ty'e', clam, cea]
--
-- <<[:e' | b, qs:]>> pa ea = <<[:e' | qs:]>> pa (filterP (\pa -> b) ea)
--
dePArrComp (ExprStmt b _ _ : qs) body pa cea =
dsLookupGlobalId filterPName `thenDs` \filterP ->
let ty = parrElemType cea
in
deLambda ty pa b `thenDs` \(clam,_) ->
dePArrComp qs body pa (mkApps (Var filterP) [Type ty, clam, cea])
dePArrComp (ExprStmt b _ _ : qs) body pa cea = do
filterP <- dsLookupGlobalId filterPName
let ty = parrElemType cea
(clam,_) <- deLambda ty pa b
dePArrComp qs body pa (mkApps (Var filterP) [Type ty, clam, cea])
--
-- <<[:e' | p <- e, qs:]>> pa ea =
......@@ -572,27 +567,24 @@ dePArrComp (ExprStmt b _ _ : qs) body pa cea =
-- in
-- <<[:e' | qs:]>> (pa, p) (crossMapP ea ef)
--
dePArrComp (BindStmt p e _ _ : qs) body pa cea =
dsLookupGlobalId filterPName `thenDs` \filterP ->
dsLookupGlobalId crossMapPName `thenDs` \crossMapP ->
dsLExpr e `thenDs` \ce ->
let ety'cea = parrElemType cea
ety'ce = parrElemType ce
false = Var falseDataConId
true = Var trueDataConId
in
newSysLocalDs ety'ce `thenDs` \v ->
matchSimply (Var v) (StmtCtxt PArrComp) p true false `thenDs` \pred ->
let cef | isIrrefutableHsPat p = ce
| otherwise = mkApps (Var filterP) [Type ety'ce, mkLams [v] pred, ce]
in
mkLambda ety'cea pa cef `thenDs` \(clam,
_ ) ->
let ety'cef = ety'ce -- filter doesn't change the element type
pa' = mkLHsPatTup [pa, p]
in
dePArrComp qs body pa' (mkApps (Var crossMapP)
[Type ety'cea, Type ety'cef, cea, clam])
dePArrComp (BindStmt p e _ _ : qs) body pa cea = do
filterP <- dsLookupGlobalId filterPName
crossMapP <- dsLookupGlobalId crossMapPName
ce <- dsLExpr e
let ety'cea = parrElemType cea
ety'ce = parrElemType ce
false = Var falseDataConId
true = Var trueDataConId
v <- newSysLocalDs ety'ce
pred <- matchSimply (Var v) (StmtCtxt PArrComp) p true false
let cef | isIrrefutableHsPat p = ce
| otherwise = mkApps (Var filterP) [Type ety'ce, mkLams [v] pred, ce]
(clam, _) <- mkLambda ety'cea pa cef
let ety'cef = ety'ce -- filter doesn't change the element type
pa' = mkLHsPatTup [pa, p]
dePArrComp qs body pa' (mkApps (Var crossMapP)
[Type ety'cea, Type ety'cef, cea, clam])
--
-- <<[:e' | let ds, qs:]>> pa ea =
-- <<[:e' | qs:]>> (pa, (x_1, ..., x_n))
......@@ -600,26 +592,23 @@ dePArrComp (BindStmt p e _ _ : qs) body pa cea =
-- where
-- {x_1, ..., x_n} = DV (ds) -- Defined Variables
--
dePArrComp (LetStmt ds : qs) body pa cea =
dsLookupGlobalId mapPName `thenDs` \mapP ->
let xs = map unLoc (collectLocalBinders ds)
ty'cea = parrElemType cea
in
newSysLocalDs ty'cea `thenDs` \v ->
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]
errTy = exprType projBody
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' = mkLHsPatTup [pa, mkLHsPatTup (map nlVarPat xs)]
proj = mkLams [v] ccase
in
dePArrComp qs body pa' (mkApps (Var mapP)
[Type ty'cea, Type errTy, proj, cea])
dePArrComp (LetStmt ds : qs) body pa cea = do
mapP <- dsLookupGlobalId mapPName
let xs = map unLoc (collectLocalBinders ds)
ty'cea = parrElemType cea
v <- newSysLocalDs ty'cea
clet <- dsLocalBinds ds (mkCoreTup (map Var xs))
let'v <- newSysLocalDs (exprType clet)
let projBody = mkDsLet (NonRec let'v clet) $
mkCoreTup [Var v, Var let'v]
errTy = exprType projBody
errMsg = "DsListComp.dePArrComp: internal error!"
cerr <- mkErrorAppDs pAT_ERROR_ID errTy errMsg
ccase <- matchSimply (Var v) (StmtCtxt PArrComp) pa projBody cerr
let pa' = mkLHsPatTup [pa, mkLHsPatTup (map nlVarPat xs)]
proj = mkLams [v] ccase
dePArrComp qs body pa' (mkApps (Var mapP)
[Type ty'cea, Type errTy, proj, cea])
--
-- The parser guarantees that parallel comprehensions can only appear as
-- singeltons qualifier lists, which we already special case in the caller.
......@@ -634,31 +623,27 @@ dePArrComp (ParStmt _ : _) _ _ _ =
-- where
-- {x_1, ..., x_n} = DV (qs)
--
dePArrParComp qss body =
deParStmt qss `thenDs` \(pQss,
ceQss) ->
dePArrComp [] body pQss ceQss
dePArrParComp qss body = do
(pQss, ceQss) <- deParStmt qss
dePArrComp [] body pQss ceQss
where
deParStmt [] =
-- empty parallel statement lists have no source representation
panic "DsListComp.dePArrComp: Empty parallel list comprehension"
deParStmt ((qs, xs):qss) = -- first statement
deParStmt ((qs, xs):qss) = do -- first statement
let res_expr = mkLHsVarTup xs
in
dsPArrComp (map unLoc qs) res_expr undefined `thenDs` \cqs ->
cqs <- dsPArrComp (map unLoc qs) res_expr undefined
parStmts qss (mkLHsVarPatTup xs) cqs
---
parStmts [] pa cea = return (pa, cea)
parStmts ((qs, xs):qss) pa cea = -- subsequent statements (zip'ed)
dsLookupGlobalId zipPName `thenDs` \zipP ->
parStmts ((qs, xs):qss) pa cea = do -- subsequent statements (zip'ed)
zipP <- dsLookupGlobalId zipPName
let pa' = mkLHsPatTup [pa, mkLHsVarPatTup xs]
ty'cea = parrElemType cea
res_expr = mkLHsVarTup xs
in
dsPArrComp (map unLoc qs) res_expr undefined `thenDs` \cqs ->
ty'cea = parrElemType cea
res_expr = mkLHsVarTup xs
cqs <- dsPArrComp (map unLoc qs) res_expr undefined
let ty'cqs = parrElemType cqs
cea' = mkApps (Var zipP) [Type ty'cea, Type ty'cqs, cea, cqs]
in
cea' = mkApps (Var zipP) [Type ty'cea, Type ty'cqs, cea, cqs]
parStmts qss pa' cea'
-- generate Core corresponding to `\p -> e'
......@@ -668,8 +653,7 @@ deLambda :: Type -- type of the argument
-> LHsExpr Id -- body
-> DsM (CoreExpr, Type)
deLambda ty p e =
dsLExpr e `thenDs` \ce ->
mkLambda ty p ce
mkLambda ty p =<< dsLExpr e
-- generate Core for a lambda pattern match, where the body is already in Core
--
......@@ -677,14 +661,13 @@ mkLambda :: Type -- type of the argument
-> LPat Id -- argument pattern
-> CoreExpr -- desugared body
-> DsM (CoreExpr, Type)
mkLambda ty p ce =
newSysLocalDs ty `thenDs` \v ->
let errMsg = "DsListComp.deLambda: internal error!"
ce'ty = exprType ce
in
mkErrorAppDs pAT_ERROR_ID ce'ty errMsg `thenDs` \cerr ->
matchSimply (Var v) (StmtCtxt PArrComp) p ce cerr `thenDs` \res ->
returnDs (mkLams [v] res, ce'ty)
mkLambda ty p ce = do
v <- newSysLocalDs ty
let errMsg = do "DsListComp.deLambda: internal error!"
ce'ty = exprType ce
cerr <- mkErrorAppDs pAT_ERROR_ID ce'ty errMsg
res <- matchSimply (Var v) (StmtCtxt PArrComp) p ce cerr
return (mkLams [v] res, ce'ty)
-- obtain the element type of the parallel array produced by the given Core
-- expression
......
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