%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[Desugar]{@deSugar@: the main function}
\begin{code}
-#include "HsVersions.h"
-
-module Desugar ( deSugar, DsMatchContext, pprDsWarnings,
- DsWarnFlavour -- removed when compiling with 1.4
- ) where
+module Desugar ( deSugar ) where
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
-import HsSyn ( HsBinds, HsExpr )
-import TcHsSyn ( SYN_IE(TypecheckedHsBinds), SYN_IE(TypecheckedHsExpr) )
+import CmdLineOpts ( opt_D_dump_ds )
+import HsSyn ( MonoBinds, RuleDecl(..), RuleBndr(..), HsExpr(..), HsBinds(..), MonoBinds(..) )
+import TcHsSyn ( TypecheckedMonoBinds, TypecheckedForeignDecl, TypecheckedRuleDecl )
+import TcModule ( TcResults(..) )
import CoreSyn
-import Name ( isExported )
+import Rules ( ProtoCoreRule(..), pprProtoCoreRule )
+import Subst ( substExpr, mkSubst )
import DsMonad
-import DsBinds ( dsBinds, dsInstBinds )
+import DsExpr ( dsExpr )
+import DsBinds ( dsMonoBinds, AutoScc(..) )
+import DsForeign ( dsForeigns )
import DsUtils
-
-import Bag ( unionBags )
-import CmdLineOpts ( opt_DoCoreLinting, opt_AutoSccsOnAllToplevs,
- opt_AutoSccsOnExportedToplevs, opt_SccGroup
- )
-import CostCentre ( IsCafCC(..), mkAutoCC )
-import CoreLift ( liftCoreBindings )
-import CoreLint ( lintCoreBindings )
-import Id ( nullIdEnv, mkIdEnv, idType, SYN_IE(DictVar), GenId )
-import PprStyle ( PprStyle(..) )
-import UniqSupply ( splitUniqSupply )
+import DsExpr () -- Forces DsExpr to be compiled; DsBinds only
+ -- depends on DsExpr.hi-boot.
+import Module ( Module, moduleString )
+import Id ( Id )
+import Name ( isLocallyDefined )
+import VarEnv
+import VarSet
+import Bag ( isEmptyBag, unionBags )
+import CmdLineOpts ( opt_SccProfilingOn )
+import CoreLint ( beginPass, endPass )
+import ErrUtils ( doIfSet, pprBagOfWarnings )
+import Outputable
+import UniqSupply ( splitUniqSupply, UniqSupply )
\end{code}
+%************************************************************************
+%* *
+%* The main function: deSugar
+%* *
+%************************************************************************
+
The only trick here is to get the @DsMonad@ stuff off to a good
start.
\begin{code}
-deSugar :: UniqSupply -- name supply
- -> FAST_STRING -- module name
-
- -> (TypecheckedHsBinds, -- input: recsel, class, instance, and value
- TypecheckedHsBinds, -- bindings; see "tcModule" (which produces
- TypecheckedHsBinds, -- them)
- TypecheckedHsBinds,
- [(Id, TypecheckedHsExpr)])
--- ToDo: handling of const_inst thingies is certainly WRONG ***************************
-
- -> ([CoreBinding], -- output
- DsWarnings) -- Shadowing complaints
-
-deSugar us mod_name (recsel_binds, clas_binds, inst_binds, val_binds, const_inst_pairs)
- = let
- (us0, us0a) = splitUniqSupply us
- (us1, us1a) = splitUniqSupply us0a
- (us2, us2a) = splitUniqSupply us1a
- (us3, us3a) = splitUniqSupply us2a
- (us4, us5) = splitUniqSupply us3a
-
-
- module_and_group = (mod_name, grp_name)
- grp_name = case opt_SccGroup of
- Just xx -> _PK_ xx
- Nothing -> mod_name -- default: module name
-
- ((core_const_prs, consts_pairs), shadows1)
- = initDs us0 nullIdEnv mod_name (dsInstBinds [] const_inst_pairs)
-
- consts_env = mkIdEnv consts_pairs
-
- (core_clas_binds, shadows2)
- = initDs us1 consts_env mod_name (dsBinds clas_binds)
- core_clas_prs = pairsFromCoreBinds core_clas_binds
-
- (core_inst_binds, shadows3)
- = initDs us2 consts_env mod_name (dsBinds inst_binds)
- core_inst_prs = pairsFromCoreBinds core_inst_binds
-
- (core_val_binds, shadows4)
- = initDs us3 consts_env mod_name (dsBinds val_binds)
- core_val_pairs = map (addAutoScc module_and_group) (pairsFromCoreBinds core_val_binds)
-
- (core_recsel_binds, shadows5)
- = initDs us4 consts_env mod_name (dsBinds recsel_binds)
- core_recsel_prs = pairsFromCoreBinds core_recsel_binds
-
- final_binds
- = if (null core_clas_prs && null core_inst_prs
- && null core_recsel_prs {-???dont know???-} && null core_const_prs) then
- -- we don't have to make the whole thing recursive
- core_clas_binds ++ core_val_binds
-
- else -- gotta make it recursive (sigh)
- [Rec (core_clas_prs ++ core_inst_prs
- ++ core_const_prs ++ core_val_pairs ++ core_recsel_prs)]
-
- lift_final_binds = liftCoreBindings us5 final_binds
-
- really_final_binds = if opt_DoCoreLinting
- then lintCoreBindings PprDebug "Desugarer" False lift_final_binds
- else lift_final_binds
-
- shadows = shadows1 `unionBags` shadows2 `unionBags`
- shadows3 `unionBags` shadows4 `unionBags` shadows5
+deSugar :: Module
+ -> UniqSupply
+ -> TcResults
+ -> IO ([CoreBind], [ProtoCoreRule], SDoc, SDoc, [CoreBndr])
+
+deSugar mod_name us (TcResults {tc_env = global_val_env,
+ tc_binds = all_binds,
+ tc_rules = rules,
+ tc_fords = fo_decls})
+ = do
+ beginPass "Desugar"
+ -- Do desugaring
+ let (result, ds_warns) =
+ initDs us global_val_env mod_name
+ (dsProgram mod_name all_binds rules fo_decls)
+ (ds_binds, ds_rules, _, _, _) = result
+
+ -- Display any warnings
+ doIfSet (not (isEmptyBag ds_warns))
+ (printErrs (pprBagOfWarnings ds_warns))
+
+ -- Lint result if necessary
+ endPass "Desugar" opt_D_dump_ds ds_binds
+
+ doIfSet opt_D_dump_ds (printDump (ppr_ds_rules ds_rules))
+
+ return result
+
+dsProgram mod_name all_binds rules fo_decls
+ = dsMonoBinds auto_scc all_binds [] `thenDs` \ core_prs ->
+ dsForeigns mod_name fo_decls `thenDs` \ (fi_binds, fe_binds, h_code, c_code) ->
+ let
+ ds_binds = fi_binds ++ [Rec core_prs] ++ fe_binds
+ fe_binders = bindersOfBinds fe_binds
+ local_binders = mkVarSet (bindersOfBinds ds_binds)
in
- (really_final_binds, shadows)
+ mapDs (dsRule local_binders) rules `thenDs` \ rules' ->
+ returnDs (ds_binds, rules', h_code, c_code, fe_binders)
+ where
+ auto_scc | opt_SccProfilingOn = TopLevel
+ | otherwise = NoSccs
+
+ppr_ds_rules [] = empty
+ppr_ds_rules rules
+ = text "" $$ text "-------------- DESUGARED RULES -----------------" $$
+ vcat (map pprProtoCoreRule rules)
\end{code}
%************************************************************************
%* *
-\subsection[addAutoScc]{Adding automatic sccs}
+%* Desugaring transformation rules
%* *
%************************************************************************
\begin{code}
-addAutoScc :: (FAST_STRING, FAST_STRING) -- Module and group
- -> (Id, CoreExpr)
- -> (Id,CoreExpr)
-
-addAutoScc (mod, grp) pair@(bndr, core_expr)
- | worthSCC core_expr &&
- (opt_AutoSccsOnAllToplevs ||
- (isExported bndr && opt_AutoSccsOnExportedToplevs))
- = (bndr, SCC (mkAutoCC bndr mod grp IsNotCafCC) core_expr)
-
- | otherwise
- = pair
-
-worthSCC (SCC _ _) = False
-worthSCC (Con _ _) = False
-worthSCC core_expr = True
+dsRule :: IdSet -> TypecheckedRuleDecl -> DsM ProtoCoreRule
+dsRule in_scope (IfaceRuleOut fn rule)
+ = returnDs (ProtoCoreRule False {- non-local -} fn rule)
+
+dsRule in_scope (HsRule name sig_tvs vars lhs rhs loc)
+ = putSrcLocDs loc $
+ ds_lhs all_vars lhs `thenDs` \ (fn, args) ->
+ dsExpr rhs `thenDs` \ core_rhs ->
+ returnDs (ProtoCoreRule True {- local -} fn
+ (Rule name tpl_vars args core_rhs))
+ where
+ tpl_vars = sig_tvs ++ [var | RuleBndr var <- vars]
+ all_vars = in_scope `unionVarSet` mkVarSet tpl_vars
+
+ds_lhs all_vars lhs
+ = let
+ (dict_binds, body) = case lhs of
+ (HsLet (MonoBind dict_binds _ _) body) -> (dict_binds, body)
+ other -> (EmptyMonoBinds, lhs)
+ in
+ ds_dict_binds dict_binds `thenDs` \ dict_binds' ->
+ dsExpr body `thenDs` \ body' ->
+
+ -- Substitute the dict bindings eagerly,
+ -- and take the body apart into a (f args) form
+ let
+ subst_env = mkSubstEnv [id | (id,rhs) <- dict_binds']
+ [ContEx subst_env rhs | (id,rhs) <- dict_binds']
+ -- Note recursion here... substitution won't terminate
+ -- if there is genuine recursion... which there isn't
+
+ subst = mkSubst all_vars subst_env
+ body'' = substExpr subst body'
+ in
+
+ -- Now unpack the resulting body
+ let
+ pair = case collectArgs body'' of
+ (Var fn, args) -> (fn, args)
+ other -> pprPanic "dsRule" (ppr lhs)
+ in
+ returnDs pair
+
+ds_dict_binds EmptyMonoBinds = returnDs []
+ds_dict_binds (AndMonoBinds b1 b2) = ds_dict_binds b1 `thenDs` \ env1 ->
+ ds_dict_binds b2 `thenDs` \ env2 ->
+ returnDs (env1 ++ env2)
+ds_dict_binds (VarMonoBind id rhs) = dsExpr rhs `thenDs` \ rhs' ->
+ returnDs [(id,rhs')]
\end{code}
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