2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcSplice]{Template Haskell splices}
7 module TcSplice( tcSpliceExpr, tcSpliceDecls, tcBracket ) where
9 #include "HsVersions.h"
11 import HscMain ( compileExpr )
12 import TcRnDriver ( tcTopSrcDecls )
13 -- These imports are the reason that TcSplice
14 -- is very high up the module hierarchy
16 import qualified Language.Haskell.TH as TH
17 -- THSyntax gives access to internal functions and data types
18 import qualified Language.Haskell.TH.Syntax as TH
20 import HsSyn ( HsBracket(..), HsExpr(..), HsSplice(..), LHsExpr, LHsDecl,
22 import Convert ( convertToHsExpr, convertToHsDecls, convertToHsType, thRdrName )
23 import RnExpr ( rnLExpr )
24 import RnEnv ( lookupFixityRn, lookupSrcOcc_maybe, lookupImportedName )
25 import RdrName ( RdrName, lookupLocalRdrEnv, isSrcRdrName )
26 import RnTypes ( rnLHsType )
27 import TcExpr ( tcCheckRho, tcMonoExpr )
28 import TcHsSyn ( mkHsDictLet, zonkTopLExpr )
29 import TcSimplify ( tcSimplifyTop, tcSimplifyBracket )
30 import TcUnify ( Expected, zapExpectedTo, zapExpectedType )
31 import TcType ( TcType, TcKind, liftedTypeKind, mkAppTy, tcSplitSigmaTy )
32 import TcEnv ( spliceOK, tcMetaTy, bracketOK )
33 import TcMType ( newTyFlexiVarTy, newKindVar, UserTypeCtxt(ExprSigCtxt), zonkTcType )
34 import TcHsType ( tcHsSigType, kcHsType )
35 import TcIface ( tcImportDecl )
36 import TypeRep ( Type(..), PredType(..), TyThing(..) ) -- For reification
37 import PrelNames ( thFAKE )
38 import Name ( Name, NamedThing(..), nameOccName, nameModule, isExternalName,
40 import NameEnv ( lookupNameEnv )
41 import HscTypes ( lookupType, ExternalPackageState(..), emptyModDetails )
43 import Var ( Id, TyVar, idType )
44 import Module ( moduleUserString )
46 import IfaceEnv ( lookupOrig )
47 import Class ( Class, classExtraBigSig )
48 import TyCon ( TyCon, tyConTyVars, getSynTyConDefn,
49 isSynTyCon, isNewTyCon, tyConDataCons, isPrimTyCon, isFunTyCon,
50 tyConArity, tyConStupidTheta, isUnLiftedTyCon )
51 import DataCon ( DataCon, dataConTyCon, dataConOrigArgTys, dataConStrictMarks,
52 dataConName, dataConFieldLabels, dataConWrapId, dataConIsInfix,
54 import Id ( idName, globalIdDetails )
55 import IdInfo ( GlobalIdDetails(..) )
56 import TysWiredIn ( mkListTy )
57 import DsMeta ( expQTyConName, typeQTyConName, decTyConName, qTyConName, nameTyConName )
58 import ErrUtils ( Message )
59 import SrcLoc ( noLoc, unLoc, getLoc )
61 import Unique ( Unique, Uniquable(..), getKey, mkUniqueGrimily )
63 import BasicTypes ( StrictnessMark(..), Fixity(..), FixityDirection(..) )
64 import Panic ( showException )
65 import FastString ( LitString )
67 import GHC.Base ( unsafeCoerce#, Int#, Int(..) ) -- Should have a better home in the module hierarchy
68 import Monad ( liftM )
71 import FastString ( mkFastString )
76 %************************************************************************
78 \subsection{Main interface + stubs for the non-GHCI case
80 %************************************************************************
83 tcSpliceDecls :: LHsExpr Name -> TcM [LHsDecl RdrName]
84 tcSpliceExpr :: HsSplice Name -> Expected TcType -> TcM (HsExpr TcId)
85 kcSpliceType :: HsSplice Name -> TcM (HsType Name, TcKind)
88 tcSpliceExpr n e ty = pprPanic "Cant do tcSpliceExpr without GHCi" (ppr e)
89 tcSpliceDecls e = pprPanic "Cant do tcSpliceDecls without GHCi" (ppr e)
93 %************************************************************************
95 \subsection{Quoting an expression}
97 %************************************************************************
100 tcBracket :: HsBracket Name -> Expected TcType -> TcM (LHsExpr Id)
101 tcBracket brack res_ty
102 = getStage `thenM` \ level ->
103 case bracketOK level of {
104 Nothing -> failWithTc (illegalBracket level) ;
107 -- Typecheck expr to make sure it is valid,
108 -- but throw away the results. We'll type check
109 -- it again when we actually use it.
111 newMutVar [] `thenM` \ pending_splices ->
112 getLIEVar `thenM` \ lie_var ->
114 setStage (Brack next_level pending_splices lie_var) (
115 getLIE (tc_bracket brack)
116 ) `thenM` \ (meta_ty, lie) ->
117 tcSimplifyBracket lie `thenM_`
119 -- Make the expected type have the right shape
120 zapExpectedTo res_ty meta_ty `thenM_`
122 -- Return the original expression, not the type-decorated one
123 readMutVar pending_splices `thenM` \ pendings ->
124 returnM (noLoc (HsBracketOut brack pendings))
127 tc_bracket :: HsBracket Name -> TcM TcType
129 = tcMetaTy nameTyConName -- Result type is Var (not Q-monadic)
131 tc_bracket (ExpBr expr)
132 = newTyFlexiVarTy liftedTypeKind `thenM` \ any_ty ->
133 tcCheckRho expr any_ty `thenM_`
134 tcMetaTy expQTyConName
135 -- Result type is Expr (= Q Exp)
137 tc_bracket (TypBr typ)
138 = tcHsSigType ExprSigCtxt typ `thenM_`
139 tcMetaTy typeQTyConName
140 -- Result type is Type (= Q Typ)
142 tc_bracket (DecBr decls)
143 = do { setModule thFAKE $ tcTopSrcDecls emptyModDetails decls
144 -- Typecheck the declarations, dicarding the result
145 -- We'll get all that stuff later, when we splice it in
146 -- See comments with RnExpr.rnBracket for the thFAKE stuff;
147 -- the type checker uses the module name to decide which
148 -- names are local (and hence can be found in the local
149 -- type envt), so we do need to set the module here too.
151 ; decl_ty <- tcMetaTy decTyConName
152 ; q_ty <- tcMetaTy qTyConName
153 ; return (mkAppTy q_ty (mkListTy decl_ty))
154 -- Result type is Q [Dec]
159 %************************************************************************
161 \subsection{Splicing an expression}
163 %************************************************************************
166 tcSpliceExpr (HsSplice name expr) res_ty
167 = setSrcSpan (getLoc expr) $
168 getStage `thenM` \ level ->
169 case spliceOK level of {
170 Nothing -> failWithTc (illegalSplice level) ;
174 Comp -> do { e <- tcTopSplice expr res_ty
175 ; returnM (unLoc e) } ;
176 Brack _ ps_var lie_var ->
178 -- A splice inside brackets
179 -- NB: ignore res_ty, apart from zapping it to a mono-type
180 -- e.g. [| reverse $(h 4) |]
181 -- Here (h 4) :: Q Exp
182 -- but $(h 4) :: forall a.a i.e. anything!
184 zapExpectedType res_ty liftedTypeKind `thenM_`
185 tcMetaTy expQTyConName `thenM` \ meta_exp_ty ->
186 setStage (Splice next_level) (
188 tcCheckRho expr meta_exp_ty
191 -- Write the pending splice into the bucket
192 readMutVar ps_var `thenM` \ ps ->
193 writeMutVar ps_var ((name,expr') : ps) `thenM_`
195 returnM (panic "tcSpliceExpr") -- The returned expression is ignored
198 -- tcTopSplice used to have this:
199 -- Note that we do not decrement the level (to -1) before
200 -- typechecking the expression. For example:
201 -- f x = $( ...$(g 3) ... )
202 -- The recursive call to tcMonoExpr will simply expand the
203 -- inner escape before dealing with the outer one
205 tcTopSplice :: LHsExpr Name -> Expected TcType -> TcM (LHsExpr Id)
206 tcTopSplice expr res_ty
207 = tcMetaTy expQTyConName `thenM` \ meta_exp_ty ->
209 -- Typecheck the expression
210 tcTopSpliceExpr expr meta_exp_ty `thenM` \ zonked_q_expr ->
212 -- Run the expression
213 traceTc (text "About to run" <+> ppr zonked_q_expr) `thenM_`
214 runMetaE zonked_q_expr `thenM` \ simple_expr ->
217 -- simple_expr :: TH.Exp
219 expr2 :: LHsExpr RdrName
220 expr2 = convertToHsExpr (getLoc expr) simple_expr
222 traceTc (text "Got result" <+> ppr expr2) `thenM_`
224 showSplice "expression"
225 zonked_q_expr (ppr expr2) `thenM_`
227 -- Rename it, but bale out if there are errors
228 -- otherwise the type checker just gives more spurious errors
229 checkNoErrs (rnLExpr expr2) `thenM` \ (exp3, fvs) ->
231 tcMonoExpr exp3 res_ty
234 tcTopSpliceExpr :: LHsExpr Name -> TcType -> TcM (LHsExpr Id)
235 -- Type check an expression that is the body of a top-level splice
236 -- (the caller will compile and run it)
237 tcTopSpliceExpr expr meta_ty
238 = checkNoErrs $ -- checkNoErrs: must not try to run the thing
239 -- if the type checker fails!
241 setStage topSpliceStage $ do
244 do { recordThUse -- Record that TH is used (for pkg depdendency)
246 -- Typecheck the expression
247 ; (expr', lie) <- getLIE (tcCheckRho expr meta_ty)
249 -- Solve the constraints
250 ; const_binds <- tcSimplifyTop lie
253 ; zonkTopLExpr (mkHsDictLet const_binds expr') }
257 %************************************************************************
261 %************************************************************************
263 Very like splicing an expression, but we don't yet share code.
266 kcSpliceType (HsSplice name hs_expr)
267 = setSrcSpan (getLoc hs_expr) $ do
269 ; case spliceOK level of {
270 Nothing -> failWithTc (illegalSplice level) ;
271 Just next_level -> do
274 Comp -> do { (t,k) <- kcTopSpliceType hs_expr
275 ; return (unLoc t, k) } ;
276 Brack _ ps_var lie_var -> do
278 { -- A splice inside brackets
279 ; meta_ty <- tcMetaTy typeQTyConName
280 ; expr' <- setStage (Splice next_level) $
282 tcCheckRho hs_expr meta_ty
284 -- Write the pending splice into the bucket
285 ; ps <- readMutVar ps_var
286 ; writeMutVar ps_var ((name,expr') : ps)
288 -- e.g. [| Int -> $(h 4) |]
289 -- Here (h 4) :: Q Type
290 -- but $(h 4) :: forall a.a i.e. any kind
292 ; returnM (panic "kcSpliceType", kind) -- The returned type is ignored
295 kcTopSpliceType :: LHsExpr Name -> TcM (LHsType Name, TcKind)
297 = do { meta_ty <- tcMetaTy typeQTyConName
299 -- Typecheck the expression
300 ; zonked_q_expr <- tcTopSpliceExpr expr meta_ty
302 -- Run the expression
303 ; traceTc (text "About to run" <+> ppr zonked_q_expr)
304 ; simple_ty <- runMetaT zonked_q_expr
306 ; let -- simple_ty :: TH.Type
307 hs_ty2 :: LHsType RdrName
308 hs_ty2 = convertToHsType (getLoc expr) simple_ty
310 ; traceTc (text "Got result" <+> ppr hs_ty2)
312 ; showSplice "type" zonked_q_expr (ppr hs_ty2)
314 -- Rename it, but bale out if there are errors
315 -- otherwise the type checker just gives more spurious errors
316 ; let doc = ptext SLIT("In the spliced type") <+> ppr hs_ty2
317 ; hs_ty3 <- checkNoErrs (rnLHsType doc hs_ty2)
322 %************************************************************************
324 \subsection{Splicing an expression}
326 %************************************************************************
329 -- Always at top level
330 -- Type sig at top of file:
331 -- tcSpliceDecls :: LHsExpr Name -> TcM [LHsDecl RdrName]
333 = do { meta_dec_ty <- tcMetaTy decTyConName
334 ; meta_q_ty <- tcMetaTy qTyConName
335 ; let list_q = mkAppTy meta_q_ty (mkListTy meta_dec_ty)
336 ; zonked_q_expr <- tcTopSpliceExpr expr list_q
338 -- Run the expression
339 ; traceTc (text "About to run" <+> ppr zonked_q_expr)
340 ; simple_expr <- runMetaD zonked_q_expr
342 -- simple_expr :: [TH.Dec]
343 -- decls :: [RdrNameHsDecl]
344 ; decls <- handleErrors (convertToHsDecls (getLoc expr) simple_expr)
345 ; traceTc (text "Got result" <+> vcat (map ppr decls))
346 ; showSplice "declarations"
348 (ppr (getLoc expr) $$ (vcat (map ppr decls)))
351 where handleErrors :: [Either a Message] -> TcM [a]
352 handleErrors [] = return []
353 handleErrors (Left x:xs) = liftM (x:) (handleErrors xs)
354 handleErrors (Right m:xs) = do addErrTc m
359 %************************************************************************
361 \subsection{Running an expression}
363 %************************************************************************
366 runMetaE :: LHsExpr Id -- Of type (Q Exp)
367 -> TcM TH.Exp -- Of type Exp
368 runMetaE e = runMeta e
370 runMetaT :: LHsExpr Id -- Of type (Q Type)
371 -> TcM TH.Type -- Of type Type
372 runMetaT e = runMeta e
374 runMetaD :: LHsExpr Id -- Of type Q [Dec]
375 -> TcM [TH.Dec] -- Of type [Dec]
376 runMetaD e = runMeta e
378 runMeta :: LHsExpr Id -- Of type X
379 -> TcM t -- Of type t
381 = do { hsc_env <- getTopEnv
382 ; tcg_env <- getGblEnv
383 ; this_mod <- getModule
384 ; let type_env = tcg_type_env tcg_env
385 rdr_env = tcg_rdr_env tcg_env
387 -- Compile and link it; might fail if linking fails
388 ; either_hval <- tryM $ ioToTcRn $
391 rdr_env type_env expr
392 ; case either_hval of {
393 Left exn -> failWithTc (mk_msg "compile and link" exn) ;
396 { -- Coerce it to Q t, and run it
397 -- Running might fail if it throws an exception of any kind (hence tryAllM)
398 -- including, say, a pattern-match exception in the code we are running
399 either_tval <- tryAllM (TH.runQ (unsafeCoerce# hval))
401 ; case either_tval of
402 Left exn -> failWithTc (mk_msg "run" exn)
406 mk_msg s exn = vcat [text "Exception when trying to" <+> text s <+> text "compile-time code:",
407 nest 2 (text (Panic.showException exn)),
408 nest 2 (text "Code:" <+> ppr expr)]
411 To call runQ in the Tc monad, we need to make TcM an instance of Quasi:
414 instance TH.Quasi (IOEnv (Env TcGblEnv TcLclEnv)) where
415 qNewName s = do { u <- newUnique
417 ; return (TH.mkNameU s i) }
419 qReport True msg = addErr (text msg)
420 qReport False msg = addReport (text msg)
422 qCurrentModule = do { m <- getModule; return (moduleUserString m) }
426 qRunIO io = ioToTcRn io
430 %************************************************************************
432 \subsection{Errors and contexts}
434 %************************************************************************
437 showSplice :: String -> LHsExpr Id -> SDoc -> TcM ()
438 showSplice what before after
439 = getSrcSpanM `thenM` \ loc ->
440 traceSplice (vcat [ppr loc <> colon <+> text "Splicing" <+> text what,
441 nest 2 (sep [nest 2 (ppr before),
446 = ptext SLIT("Illegal bracket at level") <+> ppr level
449 = ptext SLIT("Illegal splice at level") <+> ppr level
455 %************************************************************************
459 %************************************************************************
463 reify :: TH.Name -> TcM TH.Info
465 = do { name <- lookupThName th_name
466 ; thing <- tcLookupTh name
467 -- ToDo: this tcLookup could fail, which would give a
468 -- rather unhelpful error message
469 ; traceIf (text "reify" <+> text (show th_name) <+> brackets (ppr_ns th_name) <+> ppr name)
473 ppr_ns (TH.Name _ (TH.NameG TH.DataName mod)) = text "data"
474 ppr_ns (TH.Name _ (TH.NameG TH.TcClsName mod)) = text "tc"
475 ppr_ns (TH.Name _ (TH.NameG TH.VarName mod)) = text "var"
477 lookupThName :: TH.Name -> TcM Name
479 = do { let rdr_name = thRdrName guessed_ns th_name
481 -- Repeat much of lookupOccRn, becase we want
482 -- to report errors in a TH-relevant way
483 ; rdr_env <- getLocalRdrEnv
484 ; case lookupLocalRdrEnv rdr_env rdr_name of
485 Just name -> return name
486 Nothing | not (isSrcRdrName rdr_name) -- Exact, Orig
487 -> lookupImportedName rdr_name
488 | otherwise -- Unqual, Qual
490 mb_name <- lookupSrcOcc_maybe rdr_name
492 Just name -> return name
493 Nothing -> failWithTc (notInScope th_name) }
496 -- guessed_ns is the name space guessed from looking at the TH name
497 guessed_ns | isLexCon occ_fs = OccName.dataName
498 | otherwise = OccName.varName
499 occ_fs = mkFastString (TH.nameBase th_name)
501 tcLookupTh :: Name -> TcM TcTyThing
502 -- This is a specialised version of TcEnv.tcLookup; specialised mainly in that
503 -- it gives a reify-related error message on failure, whereas in the normal
504 -- tcLookup, failure is a bug.
506 = do { (gbl_env, lcl_env) <- getEnvs
507 ; case lookupNameEnv (tcl_env lcl_env) name of {
508 Just thing -> returnM thing;
510 { if nameIsLocalOrFrom (tcg_mod gbl_env) name
511 then -- It's defined in this module
512 case lookupNameEnv (tcg_type_env gbl_env) name of
513 Just thing -> return (AGlobal thing)
514 Nothing -> failWithTc (notInEnv name)
516 else do -- It's imported
517 { (eps,hpt) <- getEpsAndHpt
518 ; case lookupType hpt (eps_PTE eps) name of
519 Just thing -> return (AGlobal thing)
520 Nothing -> do { thing <- tcImportDecl name
521 ; return (AGlobal thing) }
522 -- Imported names should always be findable;
523 -- if not, we fail hard in tcImportDecl
526 notInScope :: TH.Name -> SDoc
527 notInScope th_name = quotes (text (TH.pprint th_name)) <+>
528 ptext SLIT("is not in scope at a reify")
529 -- Ugh! Rather an indirect way to display the name
531 notInEnv :: Name -> SDoc
532 notInEnv name = quotes (ppr name) <+>
533 ptext SLIT("is not in the type environment at a reify")
535 ------------------------------
536 reifyThing :: TcTyThing -> TcM TH.Info
537 -- The only reason this is monadic is for error reporting,
538 -- which in turn is mainly for the case when TH can't express
539 -- some random GHC extension
541 reifyThing (AGlobal (AnId id))
542 = do { ty <- reifyType (idType id)
543 ; fix <- reifyFixity (idName id)
544 ; let v = reifyName id
545 ; case globalIdDetails id of
546 ClassOpId cls -> return (TH.ClassOpI v ty (reifyName cls) fix)
547 other -> return (TH.VarI v ty Nothing fix)
550 reifyThing (AGlobal (ATyCon tc)) = reifyTyCon tc
551 reifyThing (AGlobal (AClass cls)) = reifyClass cls
552 reifyThing (AGlobal (ADataCon dc))
553 = do { let name = dataConName dc
554 ; ty <- reifyType (idType (dataConWrapId dc))
555 ; fix <- reifyFixity name
556 ; return (TH.DataConI (reifyName name) ty (reifyName (dataConTyCon dc)) fix) }
558 reifyThing (ATcId id _)
559 = do { ty1 <- zonkTcType (idType id) -- Make use of all the info we have, even
560 -- though it may be incomplete
561 ; ty2 <- reifyType ty1
562 ; fix <- reifyFixity (idName id)
563 ; return (TH.VarI (reifyName id) ty2 Nothing fix) }
565 reifyThing (ATyVar tv ty)
566 = do { ty1 <- zonkTcType ty
567 ; ty2 <- reifyType ty1
568 ; return (TH.TyVarI (reifyName tv) ty2) }
570 ------------------------------
571 reifyTyCon :: TyCon -> TcM TH.Info
573 | isFunTyCon tc = return (TH.PrimTyConI (reifyName tc) 2 False)
574 | isPrimTyCon tc = return (TH.PrimTyConI (reifyName tc) (tyConArity tc) (isUnLiftedTyCon tc))
576 = do { let (tvs, rhs) = getSynTyConDefn tc
577 ; rhs' <- reifyType rhs
578 ; return (TH.TyConI $ TH.TySynD (reifyName tc) (reifyTyVars tvs) rhs') }
581 = do { cxt <- reifyCxt (tyConStupidTheta tc)
582 ; cons <- mapM reifyDataCon (tyConDataCons tc)
583 ; let name = reifyName tc
584 tvs = reifyTyVars (tyConTyVars tc)
585 deriv = [] -- Don't know about deriving
586 decl | isNewTyCon tc = TH.NewtypeD cxt name tvs (head cons) deriv
587 | otherwise = TH.DataD cxt name tvs cons deriv
588 ; return (TH.TyConI decl) }
590 reifyDataCon :: DataCon -> TcM TH.Con
592 | isVanillaDataCon dc
593 = do { arg_tys <- reifyTypes (dataConOrigArgTys dc)
594 ; let stricts = map reifyStrict (dataConStrictMarks dc)
595 fields = dataConFieldLabels dc
599 ; ASSERT( length arg_tys == length stricts )
600 if not (null fields) then
601 return (TH.RecC name (zip3 (map reifyName fields) stricts arg_tys))
603 if dataConIsInfix dc then
604 ASSERT( length arg_tys == 2 )
605 return (TH.InfixC (s1,a1) name (s2,a2))
607 return (TH.NormalC name (stricts `zip` arg_tys)) }
609 = failWithTc (ptext SLIT("Can't reify a non-Haskell-98 data constructor:")
612 ------------------------------
613 reifyClass :: Class -> TcM TH.Info
615 = do { cxt <- reifyCxt theta
616 ; ops <- mapM reify_op op_stuff
617 ; return (TH.ClassI $ TH.ClassD cxt (reifyName cls) (reifyTyVars tvs) fds' ops) }
619 (tvs, fds, theta, _, op_stuff) = classExtraBigSig cls
620 fds' = map reifyFunDep fds
621 reify_op (op, _) = do { ty <- reifyType (idType op)
622 ; return (TH.SigD (reifyName op) ty) }
624 ------------------------------
625 reifyType :: TypeRep.Type -> TcM TH.Type
626 reifyType (TyVarTy tv) = return (TH.VarT (reifyName tv))
627 reifyType (TyConApp tc tys) = reify_tc_app (reifyName tc) tys
628 reifyType (NoteTy _ ty) = reifyType ty
629 reifyType (AppTy t1 t2) = do { [r1,r2] <- reifyTypes [t1,t2] ; return (r1 `TH.AppT` r2) }
630 reifyType (FunTy t1 t2) = do { [r1,r2] <- reifyTypes [t1,t2] ; return (TH.ArrowT `TH.AppT` r1 `TH.AppT` r2) }
631 reifyType ty@(ForAllTy _ _) = do { cxt' <- reifyCxt cxt;
632 ; tau' <- reifyType tau
633 ; return (TH.ForallT (reifyTyVars tvs) cxt' tau') }
635 (tvs, cxt, tau) = tcSplitSigmaTy ty
636 reifyTypes = mapM reifyType
637 reifyCxt = mapM reifyPred
639 reifyFunDep :: ([TyVar], [TyVar]) -> TH.FunDep
640 reifyFunDep (xs, ys) = TH.FunDep (map reifyName xs) (map reifyName ys)
642 reifyTyVars :: [TyVar] -> [TH.Name]
643 reifyTyVars = map reifyName
645 reify_tc_app :: TH.Name -> [TypeRep.Type] -> TcM TH.Type
646 reify_tc_app tc tys = do { tys' <- reifyTypes tys
647 ; return (foldl TH.AppT (TH.ConT tc) tys') }
649 reifyPred :: TypeRep.PredType -> TcM TH.Type
650 reifyPred (ClassP cls tys) = reify_tc_app (reifyName cls) tys
651 reifyPred p@(IParam _ _) = noTH SLIT("implicit parameters") (ppr p)
654 ------------------------------
655 reifyName :: NamedThing n => n -> TH.Name
657 | isExternalName name = mk_varg mod occ_str
658 | otherwise = TH.mkNameU occ_str (getKey (getUnique name))
659 -- Many of the things we reify have local bindings, and
660 -- NameL's aren't supposed to appear in binding positions, so
661 -- we use NameU. When/if we start to reify nested things, that
662 -- have free variables, we may need to generate NameL's for them.
665 mod = moduleUserString (nameModule name)
666 occ_str = occNameUserString occ
667 occ = nameOccName name
668 mk_varg | OccName.isDataOcc occ = TH.mkNameG_d
669 | OccName.isVarOcc occ = TH.mkNameG_v
670 | OccName.isTcOcc occ = TH.mkNameG_tc
671 | otherwise = pprPanic "reifyName" (ppr name)
673 ------------------------------
674 reifyFixity :: Name -> TcM TH.Fixity
676 = do { fix <- lookupFixityRn name
677 ; return (conv_fix fix) }
679 conv_fix (BasicTypes.Fixity i d) = TH.Fixity i (conv_dir d)
680 conv_dir BasicTypes.InfixR = TH.InfixR
681 conv_dir BasicTypes.InfixL = TH.InfixL
682 conv_dir BasicTypes.InfixN = TH.InfixN
684 reifyStrict :: BasicTypes.StrictnessMark -> TH.Strict
685 reifyStrict MarkedStrict = TH.IsStrict
686 reifyStrict MarkedUnboxed = TH.IsStrict
687 reifyStrict NotMarkedStrict = TH.NotStrict
689 ------------------------------
690 noTH :: LitString -> SDoc -> TcM a
691 noTH s d = failWithTc (hsep [ptext SLIT("Can't represent") <+> ptext s <+>
692 ptext SLIT("in Template Haskell:"),