\section[DsExpr]{Matching expressions (Exprs)}
\begin{code}
-module DsExpr ( dsExpr, dsLet, dsLit ) where
+module DsExpr ( dsExpr, dsLExpr, dsLet, dsLit ) where
#include "HsVersions.h"
import Match ( matchWrapper, matchSimply )
import MatchLit ( dsLit )
-import DsBinds ( dsMonoBinds, AutoScc(..) )
+import DsBinds ( dsHsBinds, AutoScc(..) )
import DsGRHSs ( dsGuarded )
-import DsCCall ( dsCCall )
import DsListComp ( dsListComp, dsPArrComp )
-import DsUtils ( mkErrorAppDs, mkStringLit, mkConsExpr, mkNilExpr, selectMatchVar )
+import DsUtils ( mkErrorAppDs, mkStringLit, mkConsExpr, mkNilExpr,
+ mkCoreTupTy, selectMatchVarL,
+ dsReboundNames, lookupReboundName )
+import DsArrows ( dsProcExpr )
import DsMonad
#ifdef GHCI
-- Template Haskell stuff iff bootstrapped
-import DsMeta ( dsBracket, dsReify )
+import DsMeta ( dsBracket )
#endif
-import HsSyn ( HsExpr(..), Pat(..), ArithSeqInfo(..),
- Stmt(..), HsMatchContext(..), HsStmtContext(..),
- Match(..), HsBinds(..), MonoBinds(..), HsConDetails(..),
- mkSimpleMatch, isDoExpr
- )
-import TcHsSyn ( TypecheckedHsExpr, TypecheckedHsBinds, TypecheckedStmt, hsPatType )
+import HsSyn
+import TcHsSyn ( hsPatType )
-- NB: The desugarer, which straddles the source and Core worlds, sometimes
-- needs to see source types (newtypes etc), and sometimes not
import DataCon ( isExistentialDataCon )
import Name ( Name )
import TyCon ( tyConDataCons )
-import TysWiredIn ( tupleCon, mkTupleTy )
+import TysWiredIn ( tupleCon )
import BasicTypes ( RecFlag(..), Boxity(..), ipNameName )
-import PrelNames ( toPName )
-import SrcLoc ( noSrcLoc )
+import PrelNames ( toPName,
+ returnMName, bindMName, thenMName, failMName,
+ mfixName )
+import SrcLoc ( Located(..), unLoc, getLoc, noLoc )
import Util ( zipEqual, zipWithEqual )
+import Bag ( bagToList )
import Outputable
import FastString
\end{code}
more than one constructor, may fail.
\begin{code}
-dsLet :: TypecheckedHsBinds -> CoreExpr -> DsM CoreExpr
+dsLet :: [HsBindGroup Id] -> CoreExpr -> DsM CoreExpr
+dsLet groups body = foldlDs dsBindGroup body (reverse groups)
-dsLet EmptyBinds body
- = returnDs body
-
-dsLet (ThenBinds b1 b2) body
- = dsLet b2 body `thenDs` \ body' ->
- dsLet b1 body'
-
-dsLet (IPBinds binds is_with) body
+dsBindGroup :: CoreExpr -> HsBindGroup Id -> DsM CoreExpr
+dsBindGroup body (HsIPBinds binds)
= foldlDs dsIPBind body binds
where
- dsIPBind body (n, e)
- = dsExpr e `thenDs` \ e' ->
+ dsIPBind body (L _ (IPBind n e))
+ = dsLExpr e `thenDs` \ e' ->
returnDs (Let (NonRec (ipNameName n) e') body)
-- Special case for bindings which bind unlifted variables
-- We need to do a case right away, rather than building
-- a tuple and doing selections.
-- Silently ignore INLINE pragmas...
-dsLet bind@(MonoBind (AbsBinds [] [] exports inlines binds) sigs is_rec) body
- | or [isUnLiftedType (idType g) | (_, g, l) <- exports]
+dsBindGroup body bind@(HsBindGroup hsbinds sigs is_rec)
+ | [L _ (AbsBinds [] [] exports inlines binds)] <- bagToList hsbinds,
+ or [isUnLiftedType (idType g) | (_, g, l) <- exports]
= ASSERT (case is_rec of {NonRecursive -> True; other -> False})
-- Unlifted bindings are always non-recursive
-- and are always a Fun or Pat monobind
-- ToDo: in some bizarre case it's conceivable that there
-- could be dict binds in the 'binds'. (See the notes
-- below. Then pattern-match would fail. Urk.)
- case binds of
- FunMonoBind fun _ matches loc
- -> putSrcLocDs loc $
+ let
+ body_w_exports = foldr bind_export body exports
+ bind_export (tvs, g, l) body = ASSERT( null tvs )
+ bindNonRec g (Var l) body
+
+ mk_error_app pat = mkErrorAppDs iRREFUT_PAT_ERROR_ID
+ (exprType body)
+ (showSDoc (ppr pat))
+ in
+ case bagToList binds of
+ [L loc (FunBind (L _ fun) _ matches)]
+ -> putSrcSpanDs loc $
matchWrapper (FunRhs (idName fun)) matches `thenDs` \ (args, rhs) ->
ASSERT( null args ) -- Functions aren't lifted
returnDs (bindNonRec fun rhs body_w_exports)
- PatMonoBind pat grhss loc
- -> putSrcLocDs loc $
+ [L loc (PatBind pat grhss)]
+ -> putSrcSpanDs loc $
dsGuarded grhss `thenDs` \ rhs ->
mk_error_app pat `thenDs` \ error_expr ->
matchSimply rhs PatBindRhs pat body_w_exports error_expr
other -> pprPanic "dsLet: unlifted" (ppr bind $$ ppr body)
- where
- body_w_exports = foldr bind_export body exports
- bind_export (tvs, g, l) body = ASSERT( null tvs )
- bindNonRec g (Var l) body
-
- mk_error_app pat = mkErrorAppDs iRREFUT_PAT_ERROR_ID
- (exprType body)
- (showSDoc (ppr pat))
-- Ordinary case for bindings
-dsLet (MonoBind binds sigs is_rec) body
- = dsMonoBinds NoSccs binds [] `thenDs` \ prs ->
+dsBindGroup body (HsBindGroup binds sigs is_rec)
+ = dsHsBinds NoSccs binds [] `thenDs` \ prs ->
returnDs (Let (Rec prs) body)
-- Use a Rec regardless of is_rec.
- -- Why? Because it allows the MonoBinds to be all
+ -- Why? Because it allows the binds to be all
-- mixed up, which is what happens in one rare case
-- Namely, for an AbsBind with no tyvars and no dicts,
-- but which does have dictionary bindings.
%************************************************************************
\begin{code}
-dsExpr :: TypecheckedHsExpr -> DsM CoreExpr
+dsLExpr :: LHsExpr Id -> DsM CoreExpr
+dsLExpr (L loc e) = putSrcSpanDs loc $ dsExpr e
+
+dsExpr :: HsExpr Id -> DsM CoreExpr
-dsExpr (HsPar x) = dsExpr x
+dsExpr (HsPar x) = dsLExpr x
dsExpr (HsVar var) = returnDs (Var var)
dsExpr (HsIPVar ip) = returnDs (Var (ipNameName ip))
dsExpr (HsLit lit) = dsLit lit
returnDs (mkLams binders matching_code)
dsExpr expr@(HsApp fun arg)
- = dsExpr fun `thenDs` \ core_fun ->
- dsExpr arg `thenDs` \ core_arg ->
+ = dsLExpr fun `thenDs` \ core_fun ->
+ dsLExpr arg `thenDs` \ core_arg ->
returnDs (core_fun `App` core_arg)
\end{code}
\begin{code}
dsExpr (OpApp e1 op _ e2)
- = dsExpr op `thenDs` \ core_op ->
+ = dsLExpr op `thenDs` \ core_op ->
-- for the type of y, we need the type of op's 2nd argument
- dsExpr e1 `thenDs` \ x_core ->
- dsExpr e2 `thenDs` \ y_core ->
+ dsLExpr e1 `thenDs` \ x_core ->
+ dsLExpr e2 `thenDs` \ y_core ->
returnDs (mkApps core_op [x_core, y_core])
dsExpr (SectionL expr op)
- = dsExpr op `thenDs` \ core_op ->
+ = dsLExpr op `thenDs` \ core_op ->
-- for the type of y, we need the type of op's 2nd argument
let
(x_ty:y_ty:_, _) = splitFunTys (exprType core_op)
-- Must look through an implicit-parameter type;
-- newtype impossible; hence Type.splitFunTys
in
- dsExpr expr `thenDs` \ x_core ->
+ dsLExpr 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
+-- dsLExpr (SectionR op expr) -- \ x -> op x expr
dsExpr (SectionR op expr)
- = dsExpr op `thenDs` \ core_op ->
+ = dsLExpr op `thenDs` \ core_op ->
-- for the type of x, we need the type of op's 2nd argument
let
(x_ty:y_ty:_, _) = splitFunTys (exprType core_op)
-- See comment with SectionL
in
- dsExpr expr `thenDs` \ y_core ->
+ dsLExpr 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 (HsCCall lbl args may_gc is_asm result_ty)
- = mapDs dsExpr args `thenDs` \ core_args ->
- dsCCall lbl core_args may_gc is_asm result_ty
- -- dsCCall does all the unboxification, etc.
-
dsExpr (HsSCC cc expr)
- = dsExpr expr `thenDs` \ core_expr ->
+ = dsLExpr expr `thenDs` \ core_expr ->
getModuleDs `thenDs` \ mod_name ->
returnDs (Note (SCC (mkUserCC cc mod_name)) core_expr)
-- hdaume: core annotation
dsExpr (HsCoreAnn fs expr)
- = dsExpr expr `thenDs` \ core_expr ->
+ = dsLExpr expr `thenDs` \ core_expr ->
returnDs (Note (CoreNote $ unpackFS fs) core_expr)
-- special case to handle unboxed tuple patterns.
-dsExpr (HsCase discrim matches src_loc)
+dsExpr (HsCase discrim matches)
| all ubx_tuple_match matches
- = putSrcLocDs src_loc $
- dsExpr discrim `thenDs` \ core_discrim ->
+ = dsLExpr discrim `thenDs` \ core_discrim ->
matchWrapper CaseAlt matches `thenDs` \ ([discrim_var], 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))
+ _ -> panic ("dsLExpr: tuple pattern:\n" ++ showSDoc (ppr matching_code))
where
- ubx_tuple_match (Match [TuplePat ps Unboxed] _ _) = True
+ ubx_tuple_match (L _ (Match [L _ (TuplePat _ Unboxed)] _ _)) = True
ubx_tuple_match _ = False
-dsExpr (HsCase discrim matches src_loc)
- = putSrcLocDs src_loc $
- dsExpr discrim `thenDs` \ core_discrim ->
+dsExpr (HsCase discrim matches)
+ = dsLExpr discrim `thenDs` \ core_discrim ->
matchWrapper CaseAlt matches `thenDs` \ ([discrim_var], matching_code) ->
returnDs (bindNonRec discrim_var core_discrim matching_code)
dsExpr (HsLet binds body)
- = dsExpr body `thenDs` \ body' ->
+ = dsLExpr body `thenDs` \ body' ->
dsLet binds body'
-- 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 src_loc)
+dsExpr (HsDo ListComp stmts _ result_ty)
= -- Special case for list comprehensions
- putSrcLocDs src_loc $
dsListComp stmts elt_ty
where
(_, [elt_ty]) = tcSplitTyConApp result_ty
-dsExpr (HsDo do_or_lc stmts ids result_ty src_loc)
+dsExpr (HsDo do_or_lc stmts ids result_ty)
| isDoExpr do_or_lc
- = putSrcLocDs src_loc $
- dsDo do_or_lc stmts ids result_ty
+ = dsDo do_or_lc stmts ids result_ty
-dsExpr (HsDo PArrComp stmts _ result_ty src_loc)
+dsExpr (HsDo PArrComp stmts _ result_ty)
= -- Special case for array comprehensions
- putSrcLocDs src_loc $
- dsPArrComp stmts elt_ty
+ dsPArrComp (map unLoc stmts) elt_ty
where
(_, [elt_ty]) = tcSplitTyConApp result_ty
-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 ->
+dsExpr (HsIf guard_expr then_expr else_expr)
+ = dsLExpr guard_expr `thenDs` \ core_guard ->
+ dsLExpr then_expr `thenDs` \ core_then ->
+ dsLExpr else_expr `thenDs` \ core_else ->
returnDs (mkIfThenElse core_guard core_then core_else)
\end{code}
% ~~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
dsExpr (TyLam tyvars expr)
- = dsExpr expr `thenDs` \ core_expr ->
+ = dsLExpr expr `thenDs` \ core_expr ->
returnDs (mkLams tyvars core_expr)
dsExpr (TyApp expr tys)
- = dsExpr expr `thenDs` \ core_expr ->
+ = dsLExpr expr `thenDs` \ core_expr ->
returnDs (mkTyApps core_expr tys)
\end{code}
= go xs
where
go [] = returnDs (mkNilExpr ty)
- go (x:xs) = dsExpr x `thenDs` \ core_x ->
+ go (x:xs) = dsLExpr x `thenDs` \ core_x ->
go xs `thenDs` \ core_xs ->
returnDs (mkConsExpr ty core_x core_xs)
returnDs (mkApps (Var toP) [Type ty, coreList])
dsExpr (ExplicitTuple expr_list boxity)
- = mapDs dsExpr expr_list `thenDs` \ core_exprs ->
+ = mappM dsLExpr expr_list `thenDs` \ core_exprs ->
returnDs (mkConApp (tupleCon boxity (length expr_list))
(map (Type . exprType) core_exprs ++ core_exprs))
dsExpr (ArithSeqOut expr (From from))
- = dsExpr expr `thenDs` \ expr2 ->
- dsExpr from `thenDs` \ from2 ->
+ = dsLExpr expr `thenDs` \ expr2 ->
+ dsLExpr from `thenDs` \ from2 ->
returnDs (App expr2 from2)
dsExpr (ArithSeqOut expr (FromTo from two))
- = dsExpr expr `thenDs` \ expr2 ->
- dsExpr from `thenDs` \ from2 ->
- dsExpr two `thenDs` \ two2 ->
+ = dsLExpr expr `thenDs` \ expr2 ->
+ dsLExpr from `thenDs` \ from2 ->
+ dsLExpr two `thenDs` \ two2 ->
returnDs (mkApps expr2 [from2, two2])
dsExpr (ArithSeqOut expr (FromThen from thn))
- = dsExpr expr `thenDs` \ expr2 ->
- dsExpr from `thenDs` \ from2 ->
- dsExpr thn `thenDs` \ thn2 ->
+ = dsLExpr expr `thenDs` \ expr2 ->
+ dsLExpr from `thenDs` \ from2 ->
+ dsLExpr thn `thenDs` \ 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 ->
+ = dsLExpr 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))
- = dsExpr expr `thenDs` \ expr2 ->
- dsExpr from `thenDs` \ from2 ->
- dsExpr two `thenDs` \ two2 ->
+ = dsLExpr expr `thenDs` \ expr2 ->
+ dsLExpr from `thenDs` \ from2 ->
+ dsLExpr two `thenDs` \ two2 ->
returnDs (mkApps expr2 [from2, two2])
dsExpr (PArrSeqOut expr (FromThenTo from thn two))
- = dsExpr expr `thenDs` \ expr2 ->
- dsExpr from `thenDs` \ from2 ->
- dsExpr thn `thenDs` \ thn2 ->
- dsExpr two `thenDs` \ two2 ->
+ = dsLExpr expr `thenDs` \ expr2 ->
+ dsLExpr from `thenDs` \ from2 ->
+ dsLExpr thn `thenDs` \ thn2 ->
+ dsLExpr two `thenDs` \ two2 ->
returnDs (mkApps expr2 [from2, thn2, two2])
dsExpr (PArrSeqOut expr _)
\begin{code}
dsExpr (RecordConOut data_con con_expr rbinds)
- = dsExpr con_expr `thenDs` \ con_expr' ->
+ = dsLExpr con_expr `thenDs` \ con_expr' ->
let
(arg_tys, _) = tcSplitFunTys (exprType con_expr')
-- A newtype in the corner should be opaque;
-- hence TcType.tcSplitFunTys
mk_arg (arg_ty, lbl)
- = case [rhs | (sel_id,rhs) <- rbinds,
+ = case [rhs | (L _ sel_id, rhs) <- rbinds,
lbl == recordSelectorFieldLabel sel_id] of
(rhs:rhss) -> ASSERT( null rhss )
- dsExpr rhs
+ dsLExpr rhs
[] -> mkErrorAppDs rEC_CON_ERROR_ID arg_ty (showSDoc (ppr lbl))
unlabelled_bottom arg_ty = mkErrorAppDs rEC_CON_ERROR_ID arg_ty ""
in
(if null labels
- then mapDs unlabelled_bottom arg_tys
- else mapDs mk_arg (zipEqual "dsExpr:RecordCon" arg_tys labels))
+ then mappM unlabelled_bottom arg_tys
+ else mappM mk_arg (zipEqual "dsExpr:RecordCon" arg_tys labels))
`thenDs` \ con_args ->
returnDs (mkApps con_expr' con_args)
\begin{code}
dsExpr (RecordUpdOut record_expr record_in_ty record_out_ty [])
- = dsExpr record_expr
+ = dsLExpr record_expr
dsExpr expr@(RecordUpdOut record_expr record_in_ty record_out_ty rbinds)
- = getSrcLocDs `thenDs` \ src_loc ->
- dsExpr record_expr `thenDs` \ record_expr' ->
+ = dsLExpr record_expr `thenDs` \ record_expr' ->
-- Desugar the rbinds, and generate let-bindings if
-- necessary so that we don't lose sharing
out_inst_tys = tcTyConAppArgs record_out_ty -- Newtype opaque
mk_val_arg field old_arg_id
- = case [rhs | (sel_id, rhs) <- rbinds,
+ = case [rhs | (L _ sel_id, rhs) <- rbinds,
field == recordSelectorFieldLabel sel_id] of
(rhs:rest) -> ASSERT(null rest) rhs
- [] -> HsVar old_arg_id
+ [] -> nlHsVar old_arg_id
mk_alt con
= newSysLocalsDs (dataConInstOrigArgTys con in_inst_tys) `thenDs` \ arg_ids ->
let
val_args = zipWithEqual "dsExpr:RecordUpd" mk_val_arg
(dataConFieldLabels con) arg_ids
- rhs = foldl HsApp (TyApp (HsVar (dataConWrapId con)) out_inst_tys)
- val_args
+ rhs = foldl (\a b -> nlHsApp a b)
+ (noLoc $ TyApp (nlHsVar (dataConWrapId con))
+ out_inst_tys)
+ val_args
in
- returnDs (mkSimpleMatch [ConPatOut con (PrefixCon (map VarPat arg_ids)) record_in_ty [] []]
+ returnDs (mkSimpleMatch [noLoc $ ConPatOut con (PrefixCon (map nlVarPat arg_ids)) record_in_ty [] []]
rhs
- record_out_ty
- src_loc)
+ record_out_ty)
in
-- Record stuff doesn't work for existentials
-- The type checker checks for this, but we need
-- and the right hand sides with applications of the wrapper Id
-- so that everything works when we are doing fancy unboxing on the
-- constructor aguments.
- mapDs mk_alt cons_to_upd `thenDs` \ alts ->
+ mappM mk_alt cons_to_upd `thenDs` \ alts ->
matchWrapper RecUpd alts `thenDs` \ ([discrim_var], matching_code) ->
returnDs (bindNonRec discrim_var record_expr' matching_code)
where
updated_fields :: [FieldLabel]
- updated_fields = [recordSelectorFieldLabel sel_id | (sel_id,_) <- rbinds]
+ updated_fields = [ recordSelectorFieldLabel sel_id
+ | (L _ sel_id,_) <- rbinds]
-- Get the type constructor from the first field label,
-- so that we are sure it'll have all its DataCons
complicated; reminiscent of fully-applied constructors.
\begin{code}
dsExpr (DictLam dictvars expr)
- = dsExpr expr `thenDs` \ core_expr ->
+ = dsLExpr expr `thenDs` \ core_expr ->
returnDs (mkLams dictvars core_expr)
------------------
dsExpr (DictApp expr dicts) -- becomes a curried application
- = dsExpr expr `thenDs` \ core_expr ->
+ = dsLExpr expr `thenDs` \ core_expr ->
returnDs (foldl (\f d -> f `App` (Var d)) core_expr dicts)
\end{code}
#ifdef GHCI /* Only if bootstrapping */
dsExpr (HsBracketOut x ps) = dsBracket x ps
-dsExpr (HsReify r) = dsReify r
-dsExpr (HsSplice n e _) = pprPanic "dsExpr:splice" (ppr e)
+dsExpr (HsSpliceE s) = pprPanic "dsExpr:splice" (ppr s)
#endif
+-- Arrow notation extension
+dsExpr (HsProc pat cmd) = dsProcExpr pat cmd
\end{code}
%--------------------------------------------------------------------
-Basically does the translation given in the Haskell~1.3 report:
+Desugar 'do' and 'mdo' expressions (NOT list comprehensions, they're
+handled in DsListComp). Basically does the translation given in the
+Haskell 98 report:
\begin{code}
dsDo :: HsStmtContext Name
- -> [TypecheckedStmt]
- -> [Id] -- id for: [return,fail,>>=,>>] and possibly mfixName
- -> Type -- Element type; the whole expression has type (m t)
+ -> [LStmt Id]
+ -> ReboundNames Id -- id for: [return,fail,>>=,>>] and possibly mfixName
+ -> Type -- Element type; the whole expression has type (m t)
-> DsM CoreExpr
dsDo do_or_lc stmts ids result_ty
- = let
- (return_id : fail_id : bind_id : then_id : _) = ids
+ = dsReboundNames ids `thenDs` \ (meth_binds, ds_meths) ->
+ let
+ return_id = lookupReboundName ds_meths returnMName
+ 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)
- is_do = isDoExpr do_or_lc -- True for both MDo and Do
-- 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 locn]
- | is_do = do_expr expr locn
- | otherwise = do_expr expr locn `thenDs` \ expr2 ->
- returnDs (mkApps (Var return_id) [Type b_ty, expr2])
+ go [ResultStmt expr] = dsLExpr expr
- go (ExprStmt expr a_ty locn : stmts)
- | is_do -- Do expression
- = do_expr expr locn `thenDs` \ expr2 ->
- go stmts `thenDs` \ rest ->
- returnDs (mkApps (Var then_id) [Type a_ty, Type b_ty, expr2, rest])
- | otherwise -- List comprehension
- = do_expr expr locn `thenDs` \ expr2 ->
- go stmts `thenDs` \ rest ->
- let
- msg = "Pattern match failure in do expression, " ++ showSDoc (ppr locn)
- in
- mkStringLit msg `thenDs` \ core_msg ->
- returnDs (mkIfThenElse expr2 rest
- (App (App (Var fail_id) (Type b_ty)) core_msg))
+ 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 (LetStmt binds : stmts)
= go stmts `thenDs` \ rest ->
dsLet binds rest
- go (BindStmt pat expr locn : stmts)
+ go (BindStmt pat expr : stmts)
= go stmts `thenDs` \ body ->
- putSrcLocDs locn $ -- Rest is associated with this location
- dsExpr expr `thenDs` \ rhs ->
- mkStringLit (mk_msg locn) `thenDs` \ core_msg ->
+ dsLExpr expr `thenDs` \ rhs ->
+ mkStringLit (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 (Var fail_id) [Type b_ty, core_msg]
+ fail_expr = mkApps fail_id [Type b_ty, core_msg]
a_ty = hsPatType pat
in
- selectMatchVar pat `thenDs` \ var ->
+ selectMatchVarL pat `thenDs` \ var ->
matchSimply (Var var) (StmtCtxt do_or_lc) pat
body fail_expr `thenDs` \ match_code ->
- returnDs (mkApps (Var bind_id) [Type a_ty, Type b_ty, rhs, Lam var match_code])
+ returnDs (mkApps bind_id [Type a_ty, Type b_ty, rhs, Lam var match_code])
- go (RecStmt rec_vars rec_stmts rec_rets : stmts)
+ go (RecStmt rec_stmts later_vars rec_vars rec_rets : stmts)
= go (bind_stmt : stmts)
where
- bind_stmt = dsRecStmt m_ty ids rec_vars rec_stmts rec_rets
+ bind_stmt = dsRecStmt m_ty ds_meths rec_stmts later_vars rec_vars rec_rets
in
- go stmts
+ go (map unLoc stmts) `thenDs` \ stmts_code ->
+ returnDs (foldr Let stmts_code meth_binds)
where
- do_expr expr locn = putSrcLocDs locn (dsExpr expr)
mk_msg locn = "Pattern match failure in do expression at " ++ showSDoc (ppr locn)
\end{code}
\begin{code}
dsRecStmt :: Type -- Monad type constructor :: * -> *
- -> [Id] -- Ids for: [return,fail,>>=,>>,mfix]
- -> [Id] -> [TypecheckedStmt] -> [TypecheckedHsExpr] -- Guts of the RecStmt
- -> TypecheckedStmt
-dsRecStmt m_ty ids@[return_id, _, _, _, mfix_id] vars stmts rets
+ -> [(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 vars == length rets )
- BindStmt tup_pat mfix_app noSrcLoc
+ BindStmt tup_pat mfix_app
where
- (var1:rest) = vars -- Always at least one
- (ret1:_) = rets
- one_var = null rest
+ vars@(var1:rest) = later_vars ++ rec_vars -- Always at least one
+ rets@(ret1:_) = map nlHsVar later_vars ++ rec_rets
+ one_var = null rest
- mfix_app = HsApp (TyApp (HsVar mfix_id) [tup_ty]) mfix_arg
- mfix_arg = HsLam (mkSimpleMatch [tup_pat] body tup_ty noSrcLoc)
+ mfix_app = nlHsApp (noLoc $ TyApp (nlHsVar mfix_id) [tup_ty]) mfix_arg
+ mfix_arg = noLoc $ HsLam (mkSimpleMatch [tup_pat] body tup_ty)
tup_expr | one_var = ret1
- | otherwise = ExplicitTuple rets Boxed
- tup_ty | one_var = idType var1
- | otherwise = mkTupleTy Boxed (length vars) (map idType vars)
- tup_pat | one_var = VarPat var1
- | otherwise = LazyPat (TuplePat (map VarPat vars) Boxed)
-
- body = HsDo DoExpr (stmts ++ [return_stmt])
- ids -- Don't need the mfix, but it does no harm
+ | otherwise = noLoc $ ExplicitTuple rets Boxed
+ tup_ty = mkCoreTupTy (map idType vars)
+ -- Deals with singleton case
+ tup_pat | one_var = nlVarPat var1
+ | otherwise = noLoc $ LazyPat (noLoc $ TuplePat (map nlVarPat vars) Boxed)
+
+ body = noLoc $ HsDo DoExpr (stmts ++ [return_stmt])
+ [(n, nlHsVar id) | (n,id) <- ds_meths] -- A bit of a hack
(mkAppTy m_ty tup_ty)
- noSrcLoc
- return_stmt = ResultStmt return_app noSrcLoc
- return_app = HsApp (TyApp (HsVar return_id) [tup_ty]) tup_expr
+ 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]) tup_expr
\end{code}
projects / ghc-hetmet.git / blobdiff