%
-% (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, pprDsWarnings
-#if __GLASGOW_HASKELL__ < 200
- , DsMatchContext
- , DsWarnFlavour -- fluff needed for closure,
- -- removed when compiling with 1.4
-#endif
- ) where
+module Desugar ( deSugar ) where
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
import CmdLineOpts ( opt_D_dump_ds )
-import HsSyn ( HsBinds, HsExpr, MonoBinds,
- SYN_IE(RecFlag), nonRecursive, recursive
- )
-import TcHsSyn ( SYN_IE(TypecheckedMonoBinds), SYN_IE(TypecheckedHsExpr)
- )
+import HsSyn ( MonoBinds, RuleDecl(..), RuleBndr(..), HsExpr(..), HsBinds(..), MonoBinds(..) )
+import HsCore ( UfRuleBody(..) )
+import TcHsSyn ( TypecheckedMonoBinds, TypecheckedForeignDecl, TypecheckedRuleDecl )
+import TcModule ( TcResults(..) )
import CoreSyn
-import PprCore ( pprCoreBindings )
-import Name ( isExported )
+import Rules ( ProtoCoreRule(..), pprProtoCoreRule )
+import Subst ( substExpr, mkSubst )
import DsMonad
-import DsBinds ( dsMonoBinds )
+import DsExpr ( dsExpr )
+import DsBinds ( dsMonoBinds, AutoScc(..) )
+import DsForeign ( dsForeigns )
import DsUtils
-
-import Bag ( unionBags, isEmptyBag )
-import BasicTypes ( SYN_IE(Module) )
-import CmdLineOpts ( opt_DoCoreLinting, opt_SccGroup, opt_SccProfilingOn )
-import CostCentre ( IsCafCC(..), mkAutoCC )
-import CoreLift ( liftCoreBindings )
-import CoreLint ( lintCoreBindings )
-import Id ( nullIdEnv, mkIdEnv, idType,
- SYN_IE(DictVar), GenId, SYN_IE(Id) )
-import ErrUtils ( dumpIfSet, doIfSet )
-import Outputable ( PprStyle(..), pprDumpStyle, pprErrorsStyle, printErrs )
-import Pretty ( Doc )
+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
- -> Module -- module name
- -> TypecheckedMonoBinds
- -> IO [CoreBinding] -- output
+deSugar :: Module
+ -> UniqSupply
+ -> TcResults
+ -> IO ([CoreBind], [ProtoCoreRule], SDoc, SDoc, [CoreBndr])
-deSugar us mod_name all_binds
- = let
- (us1, us2) = splitUniqSupply us
+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))
- module_and_group = (mod_name, grp_name)
- grp_name = case opt_SccGroup of
- Just xx -> _PK_ xx
- Nothing -> mod_name -- default: module name
+ -- Lint result if necessary
+ endPass "Desugar" opt_D_dump_ds ds_binds
- (core_prs, ds_warns) = initDs us1 nullIdEnv module_and_group
- (dsMonoBinds opt_SccProfilingOn recursive all_binds [])
+ doIfSet opt_D_dump_ds (printDump (ppr_ds_rules ds_rules))
- ds_binds = liftCoreBindings us2 [Rec core_prs]
+ 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) ->
+ mapDs dsRule rules `thenDs` \ rules' ->
+ let
+ ds_binds = fi_binds ++ [Rec core_prs] ++ fe_binds
+ fe_binders = bindersOfBinds fe_binds
in
+ 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}
+
- -- Display any warnings
- doIfSet (not (isEmptyBag ds_warns))
- (printErrs (pprDsWarnings pprErrorsStyle ds_warns)) >>
+%************************************************************************
+%* *
+%* Desugaring transformation rules
+%* *
+%************************************************************************
- -- Lint result if necessary
- lintCoreBindings "Desugarer" False ds_binds >>
+\begin{code}
+dsRule :: TypecheckedRuleDecl -> DsM ProtoCoreRule
+dsRule (IfaceRuleDecl fn (CoreRuleBody name all_vars args rhs) loc)
+ = returnDs (ProtoCoreRule False {- non-local -} fn
+ (Rule name all_vars args rhs))
+
+dsRule (RuleDecl 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 all_vars args core_rhs))
+ where
+ all_vars = sig_tvs ++ [var | RuleBndr var <- vars]
- -- Dump output
- dumpIfSet opt_D_dump_ds "Desugared:"
- (pprCoreBindings pprDumpStyle ds_binds) >>
+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 (mkVarSet 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
- return ds_binds
+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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