#include "HsVersions.h"
-import Match ( matchWrapper, matchSimply )
-import MatchLit ( dsLit )
+import Match ( matchWrapper, matchSimply, matchSinglePat )
+import MatchLit ( dsLit, dsOverLit )
import DsBinds ( dsHsNestedBinds )
import DsGRHSs ( dsGuarded )
import DsListComp ( dsListComp, dsPArrComp )
import DsUtils ( mkErrorAppDs, mkStringExpr, mkConsExpr, mkNilExpr,
- mkCoreTupTy, selectSimpleMatchVarL,
- dsReboundNames, lookupReboundName )
+ extractMatchResult, cantFailMatchResult, matchCanFail,
+ mkCoreTupTy, selectSimpleMatchVarL, lookupEvidence )
import DsArrows ( dsProcExpr )
import DsMonad
-- Sigh. This is a pain.
import TcType ( tcSplitAppTy, tcSplitFunTys, tcTyConAppTyCon, tcTyConAppArgs,
- tcTyConAppArgs, isUnLiftedType, Type, mkAppTy, tcEqType )
+ tcTyConAppArgs, isUnLiftedType, Type, mkAppTy )
import Type ( funArgTy, splitFunTys, isUnboxedTupleType, mkFunTy )
import CoreSyn
import CoreUtils ( exprType, mkIfThenElse, bindNonRec )
import CostCentre ( mkUserCC )
-import Id ( Id, idType, idName )
+import Id ( Id, idType, idName, isDataConWorkId_maybe )
import PrelInfo ( rEC_CON_ERROR_ID, iRREFUT_PAT_ERROR_ID )
import DataCon ( DataCon, dataConWrapId, dataConFieldLabels, dataConInstOrigArgTys )
import DataCon ( isVanillaDataCon )
mfixName )
import SrcLoc ( Located(..), unLoc, getLoc, noLoc )
import Util ( zipEqual, zipWithEqual )
+import Maybe ( fromJust )
import Bag ( bagToList )
import Outputable
import FastString
dsExpr (HsPar e) = dsLExpr e
dsExpr (ExprWithTySigOut e _) = dsLExpr e
-dsExpr (HsVar var) = returnDs (Var var)
-dsExpr (HsIPVar ip) = returnDs (Var (ipNameName ip))
-dsExpr (HsLit lit) = dsLit lit
--- HsOverLit has been gotten rid of by the type checker
+dsExpr (HsVar var) = returnDs (Var var)
+dsExpr (HsIPVar ip) = returnDs (Var (ipNameName ip))
+dsExpr (HsLit lit) = dsLit lit
+dsExpr (HsOverLit lit) = dsOverLit lit
+
+dsExpr (NegApp expr neg_expr)
+ = do { core_expr <- dsLExpr expr
+ ; core_neg <- dsExpr neg_expr
+ ; return (core_neg `App` core_expr) }
dsExpr expr@(HsLam a_Match)
= matchWrapper LambdaExpr a_Match `thenDs` \ (binders, matching_code) ->
-- We need the `ListComp' form to use `deListComp' (rather than the "do" form)
-- because the interpretation of `stmts' depends on what sort of thing it is.
--
-dsExpr (HsDo ListComp stmts _ result_ty)
+dsExpr (HsDo ListComp stmts body result_ty)
= -- Special case for list comprehensions
- dsListComp stmts elt_ty
+ dsListComp stmts body elt_ty
where
[elt_ty] = tcTyConAppArgs result_ty
-dsExpr (HsDo do_or_lc stmts ids result_ty)
- | isDoExpr do_or_lc
- = dsDo do_or_lc stmts ids result_ty
+dsExpr (HsDo DoExpr stmts body result_ty)
+ = dsDo stmts body result_ty
+
+dsExpr (HsDo (MDoExpr tbl) stmts body result_ty)
+ = dsMDo tbl stmts body result_ty
-dsExpr (HsDo PArrComp stmts _ result_ty)
+dsExpr (HsDo PArrComp stmts body result_ty)
= -- Special case for array comprehensions
- dsPArrComp (map unLoc stmts) elt_ty
+ dsPArrComp (map unLoc stmts) body elt_ty
where
[elt_ty] = tcTyConAppArgs result_ty
returnDs (mkConApp (tupleCon boxity (length expr_list))
(map (Type . exprType) core_exprs ++ core_exprs))
-dsExpr (ArithSeqOut expr (From from))
- = dsLExpr expr `thenDs` \ expr2 ->
- dsLExpr from `thenDs` \ from2 ->
+dsExpr (ArithSeq expr (From from))
+ = dsExpr expr `thenDs` \ expr2 ->
+ dsLExpr from `thenDs` \ from2 ->
returnDs (App expr2 from2)
-dsExpr (ArithSeqOut expr (FromTo from two))
- = dsLExpr expr `thenDs` \ expr2 ->
- dsLExpr from `thenDs` \ from2 ->
+dsExpr (ArithSeq expr (FromTo from two))
+ = dsExpr expr `thenDs` \ expr2 ->
+ dsLExpr from `thenDs` \ from2 ->
dsLExpr two `thenDs` \ two2 ->
returnDs (mkApps expr2 [from2, two2])
-dsExpr (ArithSeqOut expr (FromThen from thn))
- = dsLExpr expr `thenDs` \ expr2 ->
- dsLExpr from `thenDs` \ from2 ->
+dsExpr (ArithSeq expr (FromThen from thn))
+ = dsExpr expr `thenDs` \ expr2 ->
+ dsLExpr from `thenDs` \ from2 ->
dsLExpr thn `thenDs` \ thn2 ->
returnDs (mkApps expr2 [from2, thn2])
-dsExpr (ArithSeqOut expr (FromThenTo from thn two))
- = dsLExpr expr `thenDs` \ expr2 ->
- dsLExpr from `thenDs` \ from2 ->
+dsExpr (ArithSeq expr (FromThenTo from thn two))
+ = dsExpr expr `thenDs` \ expr2 ->
+ dsLExpr from `thenDs` \ from2 ->
dsLExpr thn `thenDs` \ thn2 ->
dsLExpr two `thenDs` \ two2 ->
returnDs (mkApps expr2 [from2, thn2, two2])
-dsExpr (PArrSeqOut expr (FromTo from two))
- = dsLExpr expr `thenDs` \ expr2 ->
- dsLExpr from `thenDs` \ from2 ->
+dsExpr (PArrSeq expr (FromTo from two))
+ = dsExpr expr `thenDs` \ expr2 ->
+ dsLExpr from `thenDs` \ from2 ->
dsLExpr two `thenDs` \ two2 ->
returnDs (mkApps expr2 [from2, two2])
-dsExpr (PArrSeqOut expr (FromThenTo from thn two))
- = dsLExpr expr `thenDs` \ expr2 ->
- dsLExpr from `thenDs` \ from2 ->
+dsExpr (PArrSeq expr (FromThenTo from thn two))
+ = dsExpr expr `thenDs` \ expr2 ->
+ dsLExpr from `thenDs` \ from2 ->
dsLExpr thn `thenDs` \ thn2 ->
dsLExpr two `thenDs` \ two2 ->
returnDs (mkApps expr2 [from2, thn2, two2])
-dsExpr (PArrSeqOut expr _)
+dsExpr (PArrSeq expr _)
= panic "DsExpr.dsExpr: Infinite parallel array!"
-- the parser shouldn't have generated it and the renamer and typechecker
-- shouldn't have let it through
constructor @C@, setting all of @C@'s fields to bottom.
\begin{code}
-dsExpr (RecordConOut data_con con_expr rbinds)
- = dsLExpr con_expr `thenDs` \ con_expr' ->
+dsExpr (RecordCon (L _ data_con_id) con_expr rbinds)
+ = dsExpr con_expr `thenDs` \ con_expr' ->
let
(arg_tys, _) = tcSplitFunTys (exprType con_expr')
-- A newtype in the corner should be opaque;
[] -> mkErrorAppDs rEC_CON_ERROR_ID arg_ty (showSDoc (ppr lbl))
unlabelled_bottom arg_ty = mkErrorAppDs rEC_CON_ERROR_ID arg_ty ""
- labels = dataConFieldLabels data_con
+ labels = dataConFieldLabels (fromJust (isDataConWorkId_maybe data_con_id))
+ -- The data_con_id is guaranteed to be the work id of the constructor
in
(if null labels
dictionaries.
\begin{code}
-dsExpr (RecordUpdOut record_expr record_in_ty record_out_ty [])
+dsExpr (RecordUpd record_expr [] record_in_ty record_out_ty)
= dsLExpr record_expr
-dsExpr expr@(RecordUpdOut record_expr record_in_ty record_out_ty rbinds)
+dsExpr expr@(RecordUpd record_expr rbinds record_in_ty record_out_ty)
= dsLExpr record_expr `thenDs` \ record_expr' ->
-- Desugar the rbinds, and generate let-bindings if
#ifdef DEBUG
-- HsSyn constructs that just shouldn't be here:
dsExpr (ExprWithTySig _ _) = panic "dsExpr:ExprWithTySig"
-dsExpr (ArithSeqIn _) = panic "dsExpr:ArithSeqIn"
-dsExpr (PArrSeqIn _) = panic "dsExpr:PArrSeqIn"
#endif
\end{code}
Haskell 98 report:
\begin{code}
-dsDo :: HsStmtContext Name
- -> [LStmt Id]
- -> ReboundNames Id -- id for: [return,fail,>>=,>>] and possibly mfixName
- -> Type -- Element type; the whole expression has type (m t)
+dsDo :: [LStmt Id]
+ -> LHsExpr Id
+ -> Type -- Type of the whole expression
-> DsM CoreExpr
-dsDo do_or_lc stmts ids result_ty
- = dsReboundNames ids `thenDs` \ (meth_binds, ds_meths) ->
- let
- fail_id = lookupReboundName ds_meths failMName
- bind_id = lookupReboundName ds_meths bindMName
- then_id = lookupReboundName ds_meths thenMName
-
- (m_ty, b_ty) = tcSplitAppTy result_ty -- result_ty must be of the form (m b)
-
- -- For ExprStmt, see the comments near HsExpr.Stmt about
- -- exactly what ExprStmts mean!
- --
- -- In dsDo we can only see DoStmt and ListComp (no guards)
-
- go [ResultStmt expr] = dsLExpr expr
-
-
- go (ExprStmt expr a_ty : stmts)
- = dsLExpr expr `thenDs` \ expr2 ->
- go stmts `thenDs` \ rest ->
- returnDs (mkApps then_id [Type a_ty, Type b_ty, expr2, rest])
-
- go (LetStmt binds : stmts)
- = go stmts `thenDs` \ rest ->
- dsLet binds rest
-
- go (BindStmt pat expr : stmts)
- = go stmts `thenDs` \ body ->
- dsLExpr expr `thenDs` \ rhs ->
- mkStringExpr (mk_msg (getLoc pat)) `thenDs` \ core_msg ->
- let
- -- In a do expression, pattern-match failure just calls
- -- the monadic 'fail' rather than throwing an exception
- fail_expr = mkApps fail_id [Type b_ty, core_msg]
- a_ty = hsPatType pat
- in
- selectSimpleMatchVarL pat `thenDs` \ var ->
- matchSimply (Var var) (StmtCtxt do_or_lc) pat
- body fail_expr `thenDs` \ match_code ->
- returnDs (mkApps bind_id [Type a_ty, Type b_ty, rhs, Lam var match_code])
-
- go (RecStmt rec_stmts later_vars rec_vars rec_rets : stmts)
- = go (bind_stmt : stmts)
- where
- bind_stmt = dsRecStmt m_ty ds_meths rec_stmts later_vars rec_vars rec_rets
-
- in
- go (map unLoc stmts) `thenDs` \ stmts_code ->
- returnDs (foldr Let stmts_code meth_binds)
-
+dsDo stmts body result_ty
+ = go (map unLoc stmts)
where
- mk_msg locn = "Pattern match failure in do expression at " ++ showSDoc (ppr locn)
+ go [] = dsLExpr body
+
+ go (ExprStmt rhs then_expr _ : stmts)
+ = do { rhs2 <- dsLExpr rhs
+ ; then_expr2 <- dsExpr then_expr
+ ; rest <- go stmts
+ ; returnDs (mkApps then_expr2 [rhs2, rest]) }
+
+ go (LetStmt binds : stmts)
+ = do { rest <- go stmts
+ ; dsLet binds rest }
+
+ go (BindStmt pat rhs bind_op fail_op : stmts)
+ = do { body <- go stmts
+ ; var <- selectSimpleMatchVarL pat
+ ; match <- matchSinglePat (Var var) (StmtCtxt DoExpr) pat
+ result_ty (cantFailMatchResult body)
+ ; match_code <- handle_failure pat match fail_op
+ ; rhs' <- dsLExpr rhs
+ ; bind_op' <- dsExpr bind_op
+ ; returnDs (mkApps bind_op' [rhs', Lam var match_code]) }
+
+ -- In a do expression, pattern-match failure just calls
+ -- the monadic 'fail' rather than throwing an exception
+ handle_failure pat match fail_op
+ | matchCanFail match
+ = do { fail_op' <- dsExpr fail_op
+ ; fail_msg <- mkStringExpr (mk_fail_msg pat)
+ ; extractMatchResult match (App fail_op' fail_msg) }
+ | otherwise
+ = extractMatchResult match (error "It can't fail")
+
+mk_fail_msg pat = "Pattern match failure in do expression at " ++
+ showSDoc (ppr (getLoc pat))
\end{code}
Translation for RecStmt's:
return (v1,..vn))
\begin{code}
-dsRecStmt :: Type -- Monad type constructor :: * -> *
- -> [(Name,Id)] -- Rebound Ids
- -> [LStmt Id]
- -> [Id] -> [Id] -> [LHsExpr Id]
- -> Stmt Id
-dsRecStmt m_ty ds_meths stmts later_vars rec_vars rec_rets
- = ASSERT( length rec_vars > 0 )
- ASSERT( length rec_vars == length rec_rets )
- BindStmt (mk_tup_pat later_pats) mfix_app
- where
- -- Remove any vars from later_vars that already in rec_vars
- -- NB that having the same name is not enough; they must have
- -- the same type. See Note [RecStmt] in HsExpr.
- trimmed_laters = filter not_in_rec later_vars
- not_in_rec lv = null [ v | let lv_type = idType lv
- , v <- rec_vars
- , v == lv
- , lv_type `tcEqType` idType v ]
+dsMDo :: PostTcTable
+ -> [LStmt Id]
+ -> LHsExpr Id
+ -> Type -- Type of the whole expression
+ -> DsM CoreExpr
+
+dsMDo tbl stmts body result_ty
+ = go (map unLoc stmts)
+ where
+ (m_ty, b_ty) = tcSplitAppTy result_ty -- result_ty must be of the form (m b)
+ mfix_id = lookupEvidence tbl mfixName
+ return_id = lookupEvidence tbl returnMName
+ bind_id = lookupEvidence tbl bindMName
+ then_id = lookupEvidence tbl thenMName
+ fail_id = lookupEvidence tbl failMName
+ ctxt = MDoExpr tbl
+
+ go [] = dsLExpr body
+
+ go (LetStmt binds : stmts)
+ = do { rest <- go stmts
+ ; dsLet binds rest }
+
+ go (ExprStmt rhs _ rhs_ty : stmts)
+ = do { rhs2 <- dsLExpr rhs
+ ; rest <- go stmts
+ ; returnDs (mkApps (Var then_id) [Type rhs_ty, Type b_ty, rhs2, rest]) }
+
+ go (BindStmt pat rhs _ _ : stmts)
+ = do { body <- go stmts
+ ; var <- selectSimpleMatchVarL pat
+ ; match <- matchSinglePat (Var var) (StmtCtxt ctxt) pat
+ result_ty (cantFailMatchResult body)
+ ; fail_msg <- mkStringExpr (mk_fail_msg pat)
+ ; let fail_expr = mkApps (Var fail_id) [Type b_ty, fail_msg]
+ ; match_code <- extractMatchResult match fail_expr
+
+ ; rhs' <- dsLExpr rhs
+ ; returnDs (mkApps (Var bind_id) [Type (hsPatType pat), Type b_ty,
+ rhs', Lam var match_code]) }
+
+ go (RecStmt rec_stmts later_ids rec_ids rec_rets binds : stmts)
+ = ASSERT( length rec_ids > 0 )
+ ASSERT( length rec_ids == length rec_rets )
+ go (new_bind_stmt : let_stmt : stmts)
+ where
+ new_bind_stmt = mkBindStmt (mk_tup_pat later_pats) mfix_app
+ let_stmt = LetStmt [HsBindGroup binds [] Recursive]
+
+ -- Remove the later_ids that appear (without fancy coercions)
+ -- in rec_rets, because there's no need to knot-tie them separately
+ -- See Note [RecStmt] in HsExpr
+ later_ids' = filter (`notElem` mono_rec_ids) later_ids
+ mono_rec_ids = [ id | HsVar id <- rec_rets ]
+
mfix_app = nlHsApp (noLoc $ TyApp (nlHsVar mfix_id) [tup_ty]) mfix_arg
mfix_arg = noLoc $ HsLam (MatchGroup [mkSimpleMatch [mfix_pat] body]
(mkFunTy tup_ty body_ty))
- -- The rec_tup_pat must bind the rec_vars only; remember that the
+ -- The rec_tup_pat must bind the rec_ids only; remember that the
-- trimmed_laters may share the same Names
-- Meanwhile, the later_pats must bind the later_vars
- rec_tup_pats = map mk_wild_pat trimmed_laters ++ map nlVarPat rec_vars
- later_pats = map nlVarPat trimmed_laters ++ map mk_later_pat rec_vars
- rets = map nlHsVar trimmed_laters ++ rec_rets
+ rec_tup_pats = map mk_wild_pat later_ids' ++ map nlVarPat rec_ids
+ later_pats = map nlVarPat later_ids' ++ map mk_later_pat rec_ids
+ rets = map nlHsVar later_ids' ++ map noLoc rec_rets
mfix_pat = noLoc $ LazyPat $ mk_tup_pat rec_tup_pats
- body = noLoc $ HsDo DoExpr (stmts ++ [return_stmt])
- [(n, HsVar id) | (n,id) <- ds_meths] -- A bit of a hack
- body_ty
+ body = noLoc $ HsDo ctxt rec_stmts return_app body_ty
body_ty = mkAppTy m_ty tup_ty
- tup_ty = mkCoreTupTy (map idType (trimmed_laters ++ rec_vars))
+ tup_ty = mkCoreTupTy (map idType (later_ids' ++ rec_ids))
-- mkCoreTupTy deals with singleton case
- Var return_id = lookupReboundName ds_meths returnMName
- Var mfix_id = lookupReboundName ds_meths mfixName
-
- return_stmt = noLoc $ ResultStmt return_app
return_app = nlHsApp (noLoc $ TyApp (nlHsVar return_id) [tup_ty])
(mk_ret_tup rets)
mk_wild_pat v = noLoc $ WildPat $ idType v
mk_later_pat :: Id -> LPat Id
- mk_later_pat v | v `elem` trimmed_laters = mk_wild_pat v
- | otherwise = nlVarPat v
+ mk_later_pat v | v `elem` later_ids' = mk_wild_pat v
+ | otherwise = nlVarPat v
mk_tup_pat :: [LPat Id] -> LPat Id
mk_tup_pat [p] = p
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