-2%
+%
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[TcSplice]{Template Haskell splices}
#include "HsVersions.h"
import HscMain ( compileExpr )
-import TcRnDriver ( importSupportingDecls, tcTopSrcDecls )
+import TcRnDriver ( tcTopSrcDecls )
-- These imports are the reason that TcSplice
-- is very high up the module hierarchy
-import qualified Language.Haskell.THSyntax as Meta
+import qualified Language.Haskell.TH.THSyntax as TH
+-- THSyntax gives access to internal functions and data types
-import HscTypes ( HscEnv(..), GhciMode(..), PersistentCompilerState(..), unQualInScope )
+import HscTypes ( HscEnv(..) )
import HsSyn ( HsBracket(..), HsExpr(..) )
import Convert ( convertToHsExpr, convertToHsDecls )
import RnExpr ( rnExpr )
+import RnEnv ( lookupFixityRn )
import RdrHsSyn ( RdrNameHsExpr, RdrNameHsDecl )
import RnHsSyn ( RenamedHsExpr )
import TcExpr ( tcCheckRho, tcMonoExpr )
import TcHsSyn ( TcExpr, TypecheckedHsExpr, mkHsLet, zonkTopExpr )
import TcSimplify ( tcSimplifyTop, tcSimplifyBracket )
-import TcUnify ( Expected, unifyTauTy, zapExpectedTo, zapExpectedType )
-import TcType ( TcType, openTypeKind, mkAppTy )
-import TcEnv ( spliceOK, tcMetaTy, tcWithTempInstEnv, bracketOK )
-import TcRnTypes ( TopEnv(..) )
-import TcMType ( newTyVarTy, UserTypeCtxt(ExprSigCtxt) )
-import TcMonoType ( tcHsSigType )
-import Name ( Name )
+import TcUnify ( Expected, zapExpectedTo, zapExpectedType )
+import TcType ( TcType, openTypeKind, mkAppTy, tcSplitSigmaTy )
+import TcEnv ( spliceOK, tcMetaTy, bracketOK, tcLookup )
+import TcMType ( newTyVarTy, UserTypeCtxt(ExprSigCtxt), zonkTcType, zonkTcTyVar )
+import TcHsType ( tcHsSigType )
+import TypeRep ( Type(..), PredType(..), TyThing(..) ) -- For reification
+import Name ( Name, NamedThing(..), nameOccName, nameModule, isExternalName )
+import OccName
+import Var ( TyVar, idType )
+import Module ( moduleUserString, mkModuleName )
import TcRnMonad
-
+import IfaceEnv ( lookupOrig )
+
+import Class ( Class, classBigSig )
+import TyCon ( TyCon, tyConTheta, tyConTyVars, getSynTyConDefn, isSynTyCon, isNewTyCon, tyConDataCons )
+import DataCon ( DataCon, dataConTyCon, dataConOrigArgTys, dataConStrictMarks,
+ dataConName, dataConFieldLabels, dataConWrapId )
+import Id ( idName, globalIdDetails )
+import IdInfo ( GlobalIdDetails(..) )
import TysWiredIn ( mkListTy )
-import DsMeta ( expQTyConName, decQTyConName, typQTyConName, decTyConName, qTyConName )
-import ErrUtils (Message)
+import DsMeta ( expQTyConName, typeQTyConName, decTyConName, qTyConName, nameTyConName )
+import ErrUtils ( Message )
import Outputable
+import Unique ( Unique, Uniquable(..), getKey )
+import IOEnv ( IOEnv )
+import BasicTypes ( StrictnessMark(..), Fixity(..), FixityDirection(..) )
+import Module ( moduleUserString )
import Panic ( showException )
-import GHC.Base ( unsafeCoerce# ) -- Should have a better home in the module hierarchy
-import Monad (liftM)
+import GHC.Base ( unsafeCoerce#, Int(..) ) -- Should have a better home in the module hierarchy
+import Monad ( liftM )
+import FastString ( LitString )
+import FastTypes ( iBox )
\end{code}
}
tc_bracket :: HsBracket Name -> TcM TcType
+tc_bracket (VarBr v)
+ = tcMetaTy nameTyConName
+ -- Result type is Var (not Q-monadic)
+
tc_bracket (ExpBr expr)
= newTyVarTy openTypeKind `thenM` \ any_ty ->
tcCheckRho expr any_ty `thenM_`
tc_bracket (TypBr typ)
= tcHsSigType ExprSigCtxt typ `thenM_`
- tcMetaTy typQTyConName
+ tcMetaTy typeQTyConName
-- Result type is Type (= Q Typ)
tc_bracket (DecBr decls)
- = tcWithTempInstEnv (tcTopSrcDecls decls) `thenM_`
- -- Typecheck the declarations, dicarding any side effects
- -- on the instance environment (which is in a mutable variable)
- -- and the extended environment. We'll get all that stuff
- -- later, when we splice it in
-
- tcMetaTy decTyConName `thenM` \ decl_ty ->
- tcMetaTy qTyConName `thenM` \ q_ty ->
+ = tcTopSrcDecls decls `thenM_`
+ -- Typecheck the declarations, dicarding the result
+ -- We'll get all that stuff later, when we splice it in
+
+ tcMetaTy decTyConName `thenM` \ decl_ty ->
+ tcMetaTy qTyConName `thenM` \ q_ty ->
returnM (mkAppTy q_ty (mkListTy decl_ty))
-- Result type is Q [Dec]
\end{code}
runMetaE zonked_q_expr `thenM` \ simple_expr ->
let
- -- simple_expr :: Meta.Exp
+ -- simple_expr :: TH.Exp
expr2 :: RdrNameHsExpr
expr2 = convertToHsExpr simple_expr
showSplice "expression"
zonked_q_expr (ppr expr2) `thenM_`
- initRn SourceMode (rnExpr expr2) `thenM` \ (exp3, fvs) ->
- importSupportingDecls fvs `thenM` \ env ->
+ rnExpr expr2 `thenM` \ (exp3, fvs) ->
- setGblEnv env (tcMonoExpr exp3 res_ty)
+ tcMonoExpr exp3 res_ty
tcTopSpliceExpr :: RenamedHsExpr -> TcType -> TcM TypecheckedHsExpr
-- Run the expression
traceTc (text "About to run" <+> ppr zonked_q_expr) `thenM_`
runMetaD zonked_q_expr `thenM` \ simple_expr ->
- -- simple_expr :: [Meta.Dec]
+ -- simple_expr :: [TH.Dec]
-- decls :: [RdrNameHsDecl]
handleErrors (convertToHsDecls simple_expr) `thenM` \ decls ->
traceTc (text "Got result" <+> vcat (map ppr decls)) `thenM_`
\begin{code}
runMetaE :: TypecheckedHsExpr -- Of type (Q Exp)
- -> TcM Meta.Exp -- Of type Exp
+ -> TcM TH.Exp -- Of type Exp
runMetaE e = runMeta e
runMetaD :: TypecheckedHsExpr -- Of type Q [Dec]
- -> TcM [Meta.Dec] -- Of type [Dec]
+ -> TcM [TH.Dec] -- Of type [Dec]
runMetaD e = runMeta e
runMeta :: TypecheckedHsExpr -- Of type X
-> TcM t -- Of type t
runMeta expr
- = getTopEnv `thenM` \ top_env ->
- getGblEnv `thenM` \ tcg_env ->
- getEps `thenM` \ eps ->
- getNameCache `thenM` \ name_cache ->
- getModule `thenM` \ this_mod ->
- let
- ghci_mode = top_mode top_env
-
- hsc_env = HscEnv { hsc_mode = ghci_mode, hsc_HPT = top_hpt top_env,
- hsc_dflags = top_dflags top_env }
-
- pcs = PCS { pcs_nc = name_cache, pcs_EPS = eps }
-
- type_env = tcg_type_env tcg_env
- rdr_env = tcg_rdr_env tcg_env
- in
+ = do { hsc_env <- getTopEnv
+ ; tcg_env <- getGblEnv
+ ; this_mod <- getModule
+ ; let type_env = tcg_type_env tcg_env
+ rdr_env = tcg_rdr_env tcg_env
-- Wrap the compile-and-run in an exception-catcher
-- Compiling might fail if linking fails
-- Running might fail if it throws an exception
- tryM (ioToTcRn (do
- hval <- HscMain.compileExpr
- hsc_env pcs this_mod
- rdr_env type_env expr
- Meta.runQ (unsafeCoerce# hval) -- Coerce it to Q t, and run it
- )) `thenM` \ either_tval ->
-
- case either_tval of
- Left exn -> failWithTc (vcat [text "Exception when trying to run compile-time code:",
- nest 4 (vcat [text "Code:" <+> ppr expr,
+ ; either_tval <- tryM $ do
+ { -- Compile it
+ hval <- ioToTcRn (HscMain.compileExpr
+ hsc_env this_mod
+ rdr_env type_env expr)
+ -- Coerce it to Q t, and run it
+ ; TH.runQ (unsafeCoerce# hval) }
+
+ ; case either_tval of
+ Left exn -> failWithTc (vcat [text "Exception when trying to run compile-time code:",
+ nest 4 (vcat [text "Code:" <+> ppr expr,
text ("Exn: " ++ Panic.showException exn)])])
- Right v -> returnM v
+ Right v -> returnM v }
\end{code}
+To call runQ in the Tc monad, we need to make TcM an instance of Quasi:
+\begin{code}
+instance TH.Quasi (IOEnv (Env TcGblEnv TcLclEnv)) where
+ qNewName s = do { u <- newUnique
+ ; let i = getKey u
+ ; return (TH.mkNameU s i) }
------------------------------------
- Random comments
-
-
- module Foo where
- import Lib( g :: Int -> M Exp )
- h x = not x
- f x y = [| \z -> (x, $(g y), z, map, h) |]
-
- h p = $( (\q r -> if q then [| \s -> (p,r,s) |]
- else ... ) True 3) )
-
-==> core
-
- f :: Liftable a => a -> Int -> M Exp
- f = /\a -> \d::Liftable a ->
- \ x y -> genSym "z" `bindM` \ z::String ->
- g y `bindM` \ vv::Exp ->
- Lam z (Tup [lift d x, v, Var z,
- Glob "Prelude" "map",
- Glob "Foo" "h"])
-
-
- h :: Tree Int -> M Exp
- h = \p -> \s' -> (p,3,s')
-
-
- Bound Used
-
- map: C0 C1 (top-level/imp)
- x: C0 C1 (lam/case)
- y: C0 C0
- z: C1 C1
-
- p: C0 S1
- r: S0 S1
- q: S0 S0
- s: S1 S1
-
--------
-
- f x y = lam "z" (tup [lift x, g y, var "z",
- [| map |], [| h |] ])
-==> core
-
- f = \x y -> lam "z" (tup [lift d x, g y, var "z",
- return (Glob "Prelude" "map"),
- return (Glob "Foo" "h")])
-
-
-
-
-
-
-
- h :: M Exp -> M Exp
- h v = [| \x -> map $v x |]
-
- g :: Tree Int -> M Exp
- g x = $(h [| x |])
-==>
- g x = \x' -> map x x'
-
-*** Simon claims x does not have to be liftable! **
-
-Level 0 compile time
-Level 1 run time
-Level 2 code returned by run time (generation time)
-
-Non-top-level variables
- x occurs at level 1
- inside brackets
- bound at level 0 --> x
- bound at level 1 --> var "x"
-
- not inside brackets --> x
-
- x at level 2
- inside brackets
- bound at level 0 --> x
- bound at level 1 --> var "x"
+ qReport True msg = addErr (text msg)
+ qReport False msg = addReport (text msg)
- f x = x
+ qCurrentModule = do { m <- getModule; return (moduleUserString m) }
+ qReify v = reify v
+ qRecover = recoverM
-Two successive brackets aren't allowed
+ qRunIO io = ioToTcRn io
+\end{code}
%************************************************************************
#endif /* GHCI */
\end{code}
+
+
+%************************************************************************
+%* *
+ Reification
+%* *
+%************************************************************************
+
+
+\begin{code}
+reify :: TH.Name -> TcM TH.Info
+reify (TH.Name occ (TH.NameG th_ns mod))
+ = do { name <- lookupOrig (mkModuleName (TH.modString mod))
+ (OccName.mkOccName ghc_ns (TH.occString occ))
+ ; thing <- tcLookup name
+ ; reifyThing thing
+ }
+ where
+ ghc_ns = case th_ns of
+ TH.DataName -> dataName
+ TH.TcClsName -> tcClsName
+ TH.VarName -> varName
+
+------------------------------
+reifyThing :: TcTyThing -> TcM TH.Info
+-- The only reason this is monadic is for error reporting,
+-- which in turn is mainly for the case when TH can't express
+-- some random GHC extension
+
+reifyThing (AGlobal (AnId id))
+ = do { ty <- reifyType (idType id)
+ ; fix <- reifyFixity (idName id)
+ ; let v = reifyName id
+ ; case globalIdDetails id of
+ ClassOpId cls -> return (TH.ClassOpI v ty (reifyName cls) fix)
+ other -> return (TH.VarI v ty Nothing fix)
+ }
+
+reifyThing (AGlobal (ATyCon tc)) = do { dec <- reifyTyCon tc; return (TH.TyConI dec) }
+reifyThing (AGlobal (AClass cls)) = do { dec <- reifyClass cls; return (TH.ClassI dec) }
+reifyThing (AGlobal (ADataCon dc))
+ = do { let name = dataConName dc
+ ; ty <- reifyType (idType (dataConWrapId dc))
+ ; fix <- reifyFixity name
+ ; return (TH.DataConI (reifyName name) ty (reifyName (dataConTyCon dc)) fix) }
+
+reifyThing (ATcId id _ _)
+ = do { ty1 <- zonkTcType (idType id) -- Make use of all the info we have, even
+ -- though it may be incomplete
+ ; ty2 <- reifyType ty1
+ ; fix <- reifyFixity (idName id)
+ ; return (TH.VarI (reifyName id) ty2 Nothing fix) }
+
+reifyThing (ATyVar tv)
+ = do { ty1 <- zonkTcTyVar tv
+ ; ty2 <- reifyType ty1
+ ; return (TH.TyVarI (reifyName tv) ty2) }
+
+------------------------------
+reifyTyCon :: TyCon -> TcM TH.Dec
+reifyTyCon tc
+ | isSynTyCon tc
+ = do { let (tvs, rhs) = getSynTyConDefn tc
+ ; rhs' <- reifyType rhs
+ ; return (TH.TySynD (reifyName tc) (reifyTyVars tvs) rhs') }
+
+ | isNewTyCon tc
+ = do { cxt <- reifyCxt (tyConTheta tc)
+ ; con <- reifyDataCon (head (tyConDataCons tc))
+ ; return (TH.NewtypeD cxt (reifyName tc) (reifyTyVars (tyConTyVars tc))
+ con [{- Don't know about deriving -}]) }
+
+ | otherwise -- Algebraic
+ = do { cxt <- reifyCxt (tyConTheta tc)
+ ; cons <- mapM reifyDataCon (tyConDataCons tc)
+ ; return (TH.DataD cxt (reifyName tc) (reifyTyVars (tyConTyVars tc))
+ cons [{- Don't know about deriving -}]) }
+
+reifyDataCon :: DataCon -> TcM TH.Con
+reifyDataCon dc
+ = do { arg_tys <- reifyTypes (dataConOrigArgTys dc)
+ ; let stricts = map reifyStrict (dataConStrictMarks dc)
+ fields = dataConFieldLabels dc
+ ; if null fields then
+ return (TH.NormalC (reifyName dc) (stricts `zip` arg_tys))
+ else
+ return (TH.RecC (reifyName dc) (zip3 (map reifyName fields) stricts arg_tys)) }
+ -- NB: we don't remember whether the constructor was declared in an infix way
+
+------------------------------
+reifyClass :: Class -> TcM TH.Dec
+reifyClass cls
+ = do { cxt <- reifyCxt theta
+ ; ops <- mapM reify_op op_stuff
+ ; return (TH.ClassD cxt (reifyName cls) (reifyTyVars tvs) ops) }
+ where
+ (tvs, theta, _, op_stuff) = classBigSig cls
+ reify_op (op, _) = do { ty <- reifyType (idType op)
+ ; return (TH.SigD (reifyName op) ty) }
+
+------------------------------
+reifyType :: TypeRep.Type -> TcM TH.Type
+reifyType (TyVarTy tv) = return (TH.VarT (reifyName tv))
+reifyType (TyConApp tc tys) = reify_tc_app (reifyName tc) tys
+reifyType (NewTcApp tc tys) = reify_tc_app (reifyName tc) tys
+reifyType (NoteTy _ ty) = reifyType ty
+reifyType (AppTy t1 t2) = do { [r1,r2] <- reifyTypes [t1,t2] ; return (r1 `TH.AppT` r2) }
+reifyType (FunTy t1 t2) = do { [r1,r2] <- reifyTypes [t1,t2] ; return (TH.ArrowT `TH.AppT` r1 `TH.AppT` r2) }
+reifyType ty@(ForAllTy _ _) = do { cxt' <- reifyCxt cxt;
+ ; tau' <- reifyType tau
+ ; return (TH.ForallT (reifyTyVars tvs) cxt' tau') }
+ where
+ (tvs, cxt, tau) = tcSplitSigmaTy ty
+reifyTypes = mapM reifyType
+reifyCxt = mapM reifyPred
+
+reifyTyVars :: [TyVar] -> [TH.Name]
+reifyTyVars = map reifyName
+
+reify_tc_app :: TH.Name -> [TypeRep.Type] -> TcM TH.Type
+reify_tc_app tc tys = do { tys' <- reifyTypes tys
+ ; return (foldl TH.AppT (TH.ConT tc) tys') }
+
+reifyPred :: TypeRep.PredType -> TcM TH.Type
+reifyPred (ClassP cls tys) = reify_tc_app (reifyName cls) tys
+reifyPred p@(IParam _ _) = noTH SLIT("implicit parameters") (ppr p)
+
+
+------------------------------
+reifyName :: NamedThing n => n -> TH.Name
+reifyName thing
+ | isExternalName name = mk_varg mod occ_str
+ | otherwise = TH.mkNameU occ_str (getKey (getUnique name))
+ where
+ name = getName thing
+ mod = moduleUserString (nameModule name)
+ occ_str = occNameUserString occ
+ occ = nameOccName name
+ mk_varg | OccName.isDataOcc occ = TH.mkNameG_d
+ | OccName.isVarOcc occ = TH.mkNameG_v
+ | OccName.isTcOcc occ = TH.mkNameG_tc
+ | otherwise = pprPanic "reifyName" (ppr name)
+
+------------------------------
+reifyFixity :: Name -> TcM TH.Fixity
+reifyFixity name
+ = do { fix <- lookupFixityRn name
+ ; return (conv_fix fix) }
+ where
+ conv_fix (BasicTypes.Fixity i d) = TH.Fixity i (conv_dir d)
+ conv_dir BasicTypes.InfixR = TH.InfixR
+ conv_dir BasicTypes.InfixL = TH.InfixL
+ conv_dir BasicTypes.InfixN = TH.InfixN
+
+reifyStrict :: BasicTypes.StrictnessMark -> TH.Strict
+reifyStrict MarkedStrict = TH.IsStrict
+reifyStrict MarkedUnboxed = TH.IsStrict
+reifyStrict NotMarkedStrict = TH.NotStrict
+
+------------------------------
+noTH :: LitString -> SDoc -> TcM a
+noTH s d = failWithTc (hsep [ptext SLIT("Can't represent") <+> ptext s <+>
+ ptext SLIT("in Template Haskell:"),
+ nest 2 d])
+\end{code}
\ No newline at end of file