import HsSyn ( failureFreePat,
HsExpr(..), OutPat(..), HsLit(..), ArithSeqInfo(..),
- Stmt(..), Match(..), Qualifier, HsBinds, HsType, Fixity,
+ Stmt(..), DoOrListComp(..), Match(..), HsBinds, HsType, Fixity,
GRHSsAndBinds
)
import TcHsSyn ( SYN_IE(TypecheckedHsExpr), SYN_IE(TypecheckedHsBinds),
import PrelVals ( rEC_CON_ERROR_ID, rEC_UPD_ERROR_ID, voidId )
import Pretty ( ppShow, ppBesides, ppPStr, ppStr )
import TyCon ( isDataTyCon, isNewTyCon )
-import Type ( splitSigmaTy, splitFunTy, typePrimRep,
- getAppDataTyConExpandingDicts, getAppTyCon, applyTy,
- maybeBoxedPrimType
+import Type ( splitSigmaTy, splitFunTy, typePrimRep,
+ getAppDataTyConExpandingDicts, maybeAppTyCon, getAppTyCon, applyTy,
+ maybeBoxedPrimType, splitAppTy
)
import TysPrim ( voidTy )
-import TysWiredIn ( mkTupleTy, tupleCon, nilDataCon, consDataCon,
+import TysWiredIn ( mkTupleTy, tupleCon, nilDataCon, consDataCon, listTyCon,
charDataCon, charTy
)
import TyVar ( nullTyVarEnv, addOneToTyVarEnv, GenTyVar{-instance Eq-} )
import Usage ( SYN_IE(UVar) )
+import Maybes ( maybeToBool )
import Util ( zipEqual, pprError, panic, assertPanic )
mk_nil_con ty = mkCon nilDataCon [] [ty] [] -- micro utility...
\begin{code}
dsExpr :: TypecheckedHsExpr -> DsM CoreExpr
-dsExpr e@(HsVar var) = dsApp e []
+dsExpr e@(HsVar var) = dsId var
\end{code}
%************************************************************************
matchWrapper CaseMatch matches "case" `thenDs` \ ([discrim_var], matching_code) ->
returnDs ( mkCoLetAny (NonRec discrim_var core_discrim) matching_code )
-dsExpr (ListComp expr quals)
- = dsExpr expr `thenDs` \ core_expr ->
- dsListComp core_expr quals
-
dsExpr (HsLet binds expr)
- = dsBinds False binds `thenDs` \ core_binds ->
+ = dsBinds binds `thenDs` \ core_binds ->
dsExpr expr `thenDs` \ core_expr ->
returnDs ( mkCoLetsAny core_binds core_expr )
-dsExpr (HsDoOut stmts then_id zero_id src_loc)
+dsExpr (HsDoOut do_or_lc stmts return_id then_id zero_id result_ty src_loc)
+ | maybeToBool maybe_list_comp -- Special case for list comprehensions
+ = putSrcLocDs src_loc $
+ dsListComp stmts elt_ty
+
+ | otherwise
= putSrcLocDs src_loc $
- dsDo then_id zero_id stmts
+ dsDo do_or_lc stmts return_id then_id zero_id result_ty
+ where
+ maybe_list_comp = case maybeAppTyCon result_ty of
+ Just (tycon, [elt_ty]) | tycon == listTyCon
+ -> Just elt_ty
+ other -> Nothing
+ Just elt_ty = maybe_list_comp
dsExpr (HsIf guard_expr then_expr else_expr src_loc)
= putSrcLocDs src_loc $
#ifdef DEBUG
-- HsSyn constructs that just shouldn't be here:
-dsExpr (HsDo _ _) = panic "dsExpr:HsDo"
+dsExpr (HsDo _ _ _) = panic "dsExpr:HsDo"
dsExpr (ExplicitList _) = panic "dsExpr:ExplicitList"
dsExpr (ExprWithTySig _ _) = panic "dsExpr:ExprWithTySig"
dsExpr (ArithSeqIn _) = panic "dsExpr:ArithSeqIn"
-- we might should look out for SectionLs, etc., here, but we don't
-dsApp (HsVar v) args
- = lookupEnvDs v `thenDs` \ maybe_expr ->
- mkAppDs (case maybe_expr of { Nothing -> Var v; Just expr -> expr }) args
-
dsApp anything_else args
= dsExpr anything_else `thenDs` \ core_expr ->
mkAppDs core_expr args
+
+dsId v
+ = lookupEnvDs v `thenDs` \ maybe_expr ->
+ returnDs (case maybe_expr of { Nothing -> Var v; Just expr -> expr })
\end{code}
\begin{code}
Basically does the translation given in the Haskell~1.3 report:
\begin{code}
-dsDo :: Id -- id for: (>>=) m
- -> Id -- id for: zero m
+dsDo :: DoOrListComp
-> [TypecheckedStmt]
+ -> Id -- id for: return m
+ -> Id -- id for: (>>=) m
+ -> Id -- id for: zero m
+ -> Type -- Element type; the whole expression has type (m t)
-> DsM CoreExpr
-dsDo then_id zero_id (stmt:stmts)
- = case stmt of
- ExprStmt expr locn -> ASSERT( null stmts ) do_expr expr locn
-
- ExprStmtOut expr locn a b ->
- do_expr expr locn `thenDs` \ expr2 ->
- ds_rest `thenDs` \ rest ->
- newSysLocalDs a `thenDs` \ ignored_result_id ->
- dsApp (HsVar then_id) [TyArg a, TyArg b, VarArg expr2,
- VarArg (mkValLam [ignored_result_id] rest)]
-
- LetStmt binds ->
- dsBinds False binds `thenDs` \ binds2 ->
- ds_rest `thenDs` \ rest ->
- returnDs (mkCoLetsAny binds2 rest)
-
- BindStmtOut pat expr locn a b ->
- do_expr expr locn `thenDs` \ expr2 ->
- let
- zero_expr = TyApp (HsVar zero_id) [b]
- main_match
- = PatMatch pat (SimpleMatch (HsDoOut stmts then_id zero_id locn))
- the_matches
- = if failureFreePat pat
- then [main_match]
- else [main_match, PatMatch (WildPat a) (SimpleMatch zero_expr)]
- in
- matchWrapper DoBindMatch the_matches "`do' statement"
- `thenDs` \ (binders, matching_code) ->
- dsApp (HsVar then_id) [TyArg a, TyArg b,
- VarArg expr2, VarArg (mkValLam binders matching_code)]
+dsDo do_or_lc stmts return_id then_id zero_id result_ty
+ = dsId return_id `thenDs` \ return_ds ->
+ dsId then_id `thenDs` \ then_ds ->
+ dsId zero_id `thenDs` \ zero_ds ->
+ let
+ (_, b_ty) = splitAppTy result_ty -- result_ty must be of the form (m b)
+
+ go [ReturnStmt expr]
+ = dsExpr expr `thenDs` \ expr2 ->
+ mkAppDs return_ds [TyArg b_ty, VarArg expr2]
+
+ go (GuardStmt expr locn : stmts)
+ = do_expr expr locn `thenDs` \ expr2 ->
+ go stmts `thenDs` \ rest ->
+ mkAppDs zero_ds [TyArg b_ty] `thenDs` \ zero_expr ->
+ returnDs (mkCoreIfThenElse expr2 rest zero_expr)
+
+ go (ExprStmt expr locn : stmts)
+ = do_expr expr locn `thenDs` \ expr2 ->
+ let
+ (_, a_ty) = splitAppTy (coreExprType expr2) -- Must be of form (m a)
+ in
+ if null stmts then
+ returnDs expr2
+ else
+ go stmts `thenDs` \ rest ->
+ newSysLocalDs a_ty `thenDs` \ ignored_result_id ->
+ mkAppDs then_ds [TyArg a_ty, TyArg b_ty, VarArg expr2,
+ VarArg (mkValLam [ignored_result_id] rest)]
+
+ go (LetStmt binds : stmts )
+ = dsBinds binds `thenDs` \ binds2 ->
+ go stmts `thenDs` \ rest ->
+ returnDs (mkCoLetsAny binds2 rest)
+
+ go (BindStmt pat expr locn : stmts)
+ = putSrcLocDs locn $
+ dsExpr expr `thenDs` \ expr2 ->
+ let
+ (_, a_ty) = splitAppTy (coreExprType expr2) -- Must be of form (m a)
+ zero_expr = TyApp (HsVar zero_id) [b_ty]
+ main_match = PatMatch pat (SimpleMatch (
+ HsDoOut do_or_lc stmts return_id then_id zero_id result_ty locn))
+ the_matches
+ = if failureFreePat pat
+ then [main_match]
+ else [main_match, PatMatch (WildPat a_ty) (SimpleMatch zero_expr)]
+ in
+ matchWrapper DoBindMatch the_matches match_msg
+ `thenDs` \ (binders, matching_code) ->
+ mkAppDs then_ds [TyArg a_ty, TyArg b_ty,
+ VarArg expr2, VarArg (mkValLam binders matching_code)]
+ in
+ go stmts
+
where
- ds_rest = dsDo then_id zero_id stmts
do_expr expr locn = putSrcLocDs locn (dsExpr expr)
-#ifdef DEBUG
-dsDo then_expr zero_expr [] = panic "dsDo:[]"
-#endif
+ match_msg = case do_or_lc of
+ DoStmt -> "`do' statement"
+ ListComp -> "comprehension"
\end{code}
projects / ghc-hetmet.git / blobdiff