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 LoadIface ( loadHomeInterface )
23 import Convert ( convertToHsExpr, convertToHsDecls, convertToHsType, thRdrName )
24 import RnExpr ( rnLExpr )
25 import RnEnv ( lookupFixityRn, lookupSrcOcc_maybe, lookupImportedName )
26 import RdrName ( RdrName, lookupLocalRdrEnv, isSrcRdrName )
27 import RnTypes ( rnLHsType )
28 import TcExpr ( tcCheckRho, tcMonoExpr )
29 import TcHsSyn ( mkHsDictLet, zonkTopLExpr )
30 import TcSimplify ( tcSimplifyTop, tcSimplifyBracket )
31 import TcUnify ( Expected, zapExpectedTo, zapExpectedType )
32 import TcType ( TcType, TcKind, liftedTypeKind, mkAppTy, tcSplitSigmaTy )
33 import TcEnv ( spliceOK, tcMetaTy, bracketOK )
34 import TcMType ( newTyFlexiVarTy, newKindVar, UserTypeCtxt(ExprSigCtxt), zonkTcType )
35 import TcHsType ( tcHsSigType, kcHsType )
36 import TcIface ( tcImportDecl )
37 import TypeRep ( Type(..), PredType(..), TyThing(..) ) -- For reification
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 = do { loadHomeInterface msg v -- Reason: deprecation checking asumes the
130 -- home interface is loaded, and this is the
131 -- only way that is going to happen
132 ; tcMetaTy nameTyConName -- Result type is Var (not Q-monadic)
135 msg = ptext SLIT("Need interface for Template Haskell quoted Name")
137 tc_bracket (ExpBr expr)
138 = newTyFlexiVarTy liftedTypeKind `thenM` \ any_ty ->
139 tcCheckRho expr any_ty `thenM_`
140 tcMetaTy expQTyConName
141 -- Result type is Expr (= Q Exp)
143 tc_bracket (TypBr typ)
144 = tcHsSigType ExprSigCtxt typ `thenM_`
145 tcMetaTy typeQTyConName
146 -- Result type is Type (= Q Typ)
148 tc_bracket (DecBr decls)
149 = tcTopSrcDecls emptyModDetails decls `thenM_`
150 -- Typecheck the declarations, dicarding the result
151 -- We'll get all that stuff later, when we splice it in
153 tcMetaTy decTyConName `thenM` \ decl_ty ->
154 tcMetaTy qTyConName `thenM` \ q_ty ->
155 returnM (mkAppTy q_ty (mkListTy decl_ty))
156 -- Result type is Q [Dec]
160 %************************************************************************
162 \subsection{Splicing an expression}
164 %************************************************************************
167 tcSpliceExpr (HsSplice name expr) res_ty
168 = setSrcSpan (getLoc expr) $
169 getStage `thenM` \ level ->
170 case spliceOK level of {
171 Nothing -> failWithTc (illegalSplice level) ;
175 Comp -> do { e <- tcTopSplice expr res_ty
176 ; returnM (unLoc e) } ;
177 Brack _ ps_var lie_var ->
179 -- A splice inside brackets
180 -- NB: ignore res_ty, apart from zapping it to a mono-type
181 -- e.g. [| reverse $(h 4) |]
182 -- Here (h 4) :: Q Exp
183 -- but $(h 4) :: forall a.a i.e. anything!
185 zapExpectedType res_ty liftedTypeKind `thenM_`
186 tcMetaTy expQTyConName `thenM` \ meta_exp_ty ->
187 setStage (Splice next_level) (
189 tcCheckRho expr meta_exp_ty
192 -- Write the pending splice into the bucket
193 readMutVar ps_var `thenM` \ ps ->
194 writeMutVar ps_var ((name,expr') : ps) `thenM_`
196 returnM (panic "tcSpliceExpr") -- The returned expression is ignored
199 -- tcTopSplice used to have this:
200 -- Note that we do not decrement the level (to -1) before
201 -- typechecking the expression. For example:
202 -- f x = $( ...$(g 3) ... )
203 -- The recursive call to tcMonoExpr will simply expand the
204 -- inner escape before dealing with the outer one
206 tcTopSplice :: LHsExpr Name -> Expected TcType -> TcM (LHsExpr Id)
207 tcTopSplice expr res_ty
208 = tcMetaTy expQTyConName `thenM` \ meta_exp_ty ->
210 -- Typecheck the expression
211 tcTopSpliceExpr expr meta_exp_ty `thenM` \ zonked_q_expr ->
213 -- Run the expression
214 traceTc (text "About to run" <+> ppr zonked_q_expr) `thenM_`
215 runMetaE zonked_q_expr `thenM` \ simple_expr ->
218 -- simple_expr :: TH.Exp
220 expr2 :: LHsExpr RdrName
221 expr2 = convertToHsExpr (getLoc expr) simple_expr
223 traceTc (text "Got result" <+> ppr expr2) `thenM_`
225 showSplice "expression"
226 zonked_q_expr (ppr expr2) `thenM_`
228 -- Rename it, but bale out if there are errors
229 -- otherwise the type checker just gives more spurious errors
230 checkNoErrs (rnLExpr expr2) `thenM` \ (exp3, fvs) ->
232 tcMonoExpr exp3 res_ty
235 tcTopSpliceExpr :: LHsExpr Name -> TcType -> TcM (LHsExpr Id)
236 -- Type check an expression that is the body of a top-level splice
237 -- (the caller will compile and run it)
238 tcTopSpliceExpr expr meta_ty
239 = checkNoErrs $ -- checkNoErrs: must not try to run the thing
240 -- if the type checker fails!
242 setStage topSpliceStage $ do
245 do { recordThUse -- Record that TH is used (for pkg depdendency)
247 -- Typecheck the expression
248 ; (expr', lie) <- getLIE (tcCheckRho expr meta_ty)
250 -- Solve the constraints
251 ; const_binds <- tcSimplifyTop lie
254 ; zonkTopLExpr (mkHsDictLet const_binds expr') }
258 %************************************************************************
262 %************************************************************************
264 Very like splicing an expression, but we don't yet share code.
267 kcSpliceType (HsSplice name hs_expr)
268 = setSrcSpan (getLoc hs_expr) $ do
270 ; case spliceOK level of {
271 Nothing -> failWithTc (illegalSplice level) ;
272 Just next_level -> do
275 Comp -> do { (t,k) <- kcTopSpliceType hs_expr
276 ; return (unLoc t, k) } ;
277 Brack _ ps_var lie_var -> do
279 { -- A splice inside brackets
280 ; meta_ty <- tcMetaTy typeQTyConName
281 ; expr' <- setStage (Splice next_level) $
283 tcCheckRho hs_expr meta_ty
285 -- Write the pending splice into the bucket
286 ; ps <- readMutVar ps_var
287 ; writeMutVar ps_var ((name,expr') : ps)
289 -- e.g. [| Int -> $(h 4) |]
290 -- Here (h 4) :: Q Type
291 -- but $(h 4) :: forall a.a i.e. any kind
293 ; returnM (panic "kcSpliceType", kind) -- The returned type is ignored
296 kcTopSpliceType :: LHsExpr Name -> TcM (LHsType Name, TcKind)
298 = do { meta_ty <- tcMetaTy typeQTyConName
300 -- Typecheck the expression
301 ; zonked_q_expr <- tcTopSpliceExpr expr meta_ty
303 -- Run the expression
304 ; traceTc (text "About to run" <+> ppr zonked_q_expr)
305 ; simple_ty <- runMetaT zonked_q_expr
307 ; let -- simple_ty :: TH.Type
308 hs_ty2 :: LHsType RdrName
309 hs_ty2 = convertToHsType (getLoc expr) simple_ty
311 ; traceTc (text "Got result" <+> ppr hs_ty2)
313 ; showSplice "type" zonked_q_expr (ppr hs_ty2)
315 -- Rename it, but bale out if there are errors
316 -- otherwise the type checker just gives more spurious errors
317 ; let doc = ptext SLIT("In the spliced type") <+> ppr hs_ty2
318 ; hs_ty3 <- checkNoErrs (rnLHsType doc hs_ty2)
323 %************************************************************************
325 \subsection{Splicing an expression}
327 %************************************************************************
330 -- Always at top level
331 -- Type sig at top of file:
332 -- tcSpliceDecls :: LHsExpr Name -> TcM [LHsDecl RdrName]
334 = do { meta_dec_ty <- tcMetaTy decTyConName
335 ; meta_q_ty <- tcMetaTy qTyConName
336 ; let list_q = mkAppTy meta_q_ty (mkListTy meta_dec_ty)
337 ; zonked_q_expr <- tcTopSpliceExpr expr list_q
339 -- Run the expression
340 ; traceTc (text "About to run" <+> ppr zonked_q_expr)
341 ; simple_expr <- runMetaD zonked_q_expr
343 -- simple_expr :: [TH.Dec]
344 -- decls :: [RdrNameHsDecl]
345 ; decls <- handleErrors (convertToHsDecls (getLoc expr) simple_expr)
346 ; traceTc (text "Got result" <+> vcat (map ppr decls))
347 ; showSplice "declarations"
349 (ppr (getLoc expr) $$ (vcat (map ppr decls)))
352 where handleErrors :: [Either a Message] -> TcM [a]
353 handleErrors [] = return []
354 handleErrors (Left x:xs) = liftM (x:) (handleErrors xs)
355 handleErrors (Right m:xs) = do addErrTc m
360 %************************************************************************
362 \subsection{Running an expression}
364 %************************************************************************
367 runMetaE :: LHsExpr Id -- Of type (Q Exp)
368 -> TcM TH.Exp -- Of type Exp
369 runMetaE e = runMeta e
371 runMetaT :: LHsExpr Id -- Of type (Q Type)
372 -> TcM TH.Type -- Of type Type
373 runMetaT e = runMeta e
375 runMetaD :: LHsExpr Id -- Of type Q [Dec]
376 -> TcM [TH.Dec] -- Of type [Dec]
377 runMetaD e = runMeta e
379 runMeta :: LHsExpr Id -- Of type X
380 -> TcM t -- Of type t
382 = do { hsc_env <- getTopEnv
383 ; tcg_env <- getGblEnv
384 ; this_mod <- getModule
385 ; let type_env = tcg_type_env tcg_env
386 rdr_env = tcg_rdr_env tcg_env
388 -- Compile and link it; might fail if linking fails
389 ; either_hval <- tryM $ ioToTcRn $
392 rdr_env type_env expr
393 ; case either_hval of {
394 Left exn -> failWithTc (mk_msg "compile and link" exn) ;
397 { -- Coerce it to Q t, and run it
398 -- Running might fail if it throws an exception of any kind (hence tryAllM)
399 -- including, say, a pattern-match exception in the code we are running
400 either_tval <- tryAllM (TH.runQ (unsafeCoerce# hval))
402 ; case either_tval of
403 Left exn -> failWithTc (mk_msg "run" exn)
407 mk_msg s exn = vcat [text "Exception when trying to" <+> text s <+> text "compile-time code:",
408 nest 2 (text (Panic.showException exn)),
409 nest 2 (text "Code:" <+> ppr expr)]
412 To call runQ in the Tc monad, we need to make TcM an instance of Quasi:
415 instance TH.Quasi (IOEnv (Env TcGblEnv TcLclEnv)) where
416 qNewName s = do { u <- newUnique
418 ; return (TH.mkNameU s i) }
420 qReport True msg = addErr (text msg)
421 qReport False msg = addReport (text msg)
423 qCurrentModule = do { m <- getModule; return (moduleUserString m) }
427 qRunIO io = ioToTcRn io
431 %************************************************************************
433 \subsection{Errors and contexts}
435 %************************************************************************
438 showSplice :: String -> LHsExpr Id -> SDoc -> TcM ()
439 showSplice what before after
440 = getSrcSpanM `thenM` \ loc ->
441 traceSplice (vcat [ppr loc <> colon <+> text "Splicing" <+> text what,
442 nest 2 (sep [nest 2 (ppr before),
447 = ptext SLIT("Illegal bracket at level") <+> ppr level
450 = ptext SLIT("Illegal splice at level") <+> ppr level
456 %************************************************************************
460 %************************************************************************
464 reify :: TH.Name -> TcM TH.Info
466 = do { name <- lookupThName th_name
467 ; thing <- tcLookupTh name
468 -- ToDo: this tcLookup could fail, which would give a
469 -- rather unhelpful error message
470 ; traceIf (text "reify" <+> text (show th_name) <+> brackets (ppr_ns th_name) <+> ppr name)
474 ppr_ns (TH.Name _ (TH.NameG TH.DataName mod)) = text "data"
475 ppr_ns (TH.Name _ (TH.NameG TH.TcClsName mod)) = text "tc"
476 ppr_ns (TH.Name _ (TH.NameG TH.VarName mod)) = text "var"
478 lookupThName :: TH.Name -> TcM Name
480 = do { let rdr_name = thRdrName guessed_ns th_name
482 -- Repeat much of lookupOccRn, becase we want
483 -- to report errors in a TH-relevant way
484 ; rdr_env <- getLocalRdrEnv
485 ; case lookupLocalRdrEnv rdr_env rdr_name of
486 Just name -> return name
487 Nothing | not (isSrcRdrName rdr_name) -- Exact, Orig
488 -> lookupImportedName rdr_name
489 | otherwise -- Unqual, Qual
491 mb_name <- lookupSrcOcc_maybe rdr_name
493 Just name -> return name
494 Nothing -> failWithTc (notInScope th_name) }
497 -- guessed_ns is the name space guessed from looking at the TH name
498 guessed_ns | isLexCon occ_fs = OccName.dataName
499 | otherwise = OccName.varName
500 occ_fs = mkFastString (TH.nameBase th_name)
502 tcLookupTh :: Name -> TcM TcTyThing
503 -- This is a specialised version of TcEnv.tcLookup; specialised mainly in that
504 -- it gives a reify-related error message on failure, whereas in the normal
505 -- tcLookup, failure is a bug.
507 = do { (gbl_env, lcl_env) <- getEnvs
508 ; case lookupNameEnv (tcl_env lcl_env) name of {
509 Just thing -> returnM thing;
511 { if nameIsLocalOrFrom (tcg_mod gbl_env) name
512 then -- It's defined in this module
513 case lookupNameEnv (tcg_type_env gbl_env) name of
514 Just thing -> return (AGlobal thing)
515 Nothing -> failWithTc (notInEnv name)
517 else do -- It's imported
518 { (eps,hpt) <- getEpsAndHpt
519 ; case lookupType hpt (eps_PTE eps) name of
520 Just thing -> return (AGlobal thing)
521 Nothing -> do { thing <- tcImportDecl name
522 ; return (AGlobal thing) }
523 -- Imported names should always be findable;
524 -- if not, we fail hard in tcImportDecl
527 notInScope :: TH.Name -> SDoc
528 notInScope th_name = quotes (text (TH.pprint th_name)) <+>
529 ptext SLIT("is not in scope at a reify")
530 -- Ugh! Rather an indirect way to display the name
532 notInEnv :: Name -> SDoc
533 notInEnv name = quotes (ppr name) <+>
534 ptext SLIT("is not in the type environment at a reify")
536 ------------------------------
537 reifyThing :: TcTyThing -> TcM TH.Info
538 -- The only reason this is monadic is for error reporting,
539 -- which in turn is mainly for the case when TH can't express
540 -- some random GHC extension
542 reifyThing (AGlobal (AnId id))
543 = do { ty <- reifyType (idType id)
544 ; fix <- reifyFixity (idName id)
545 ; let v = reifyName id
546 ; case globalIdDetails id of
547 ClassOpId cls -> return (TH.ClassOpI v ty (reifyName cls) fix)
548 other -> return (TH.VarI v ty Nothing fix)
551 reifyThing (AGlobal (ATyCon tc)) = reifyTyCon tc
552 reifyThing (AGlobal (AClass cls)) = reifyClass cls
553 reifyThing (AGlobal (ADataCon dc))
554 = do { let name = dataConName dc
555 ; ty <- reifyType (idType (dataConWrapId dc))
556 ; fix <- reifyFixity name
557 ; return (TH.DataConI (reifyName name) ty (reifyName (dataConTyCon dc)) fix) }
559 reifyThing (ATcId id _)
560 = do { ty1 <- zonkTcType (idType id) -- Make use of all the info we have, even
561 -- though it may be incomplete
562 ; ty2 <- reifyType ty1
563 ; fix <- reifyFixity (idName id)
564 ; return (TH.VarI (reifyName id) ty2 Nothing fix) }
566 reifyThing (ATyVar tv ty)
567 = do { ty1 <- zonkTcType ty
568 ; ty2 <- reifyType ty1
569 ; return (TH.TyVarI (reifyName tv) ty2) }
571 ------------------------------
572 reifyTyCon :: TyCon -> TcM TH.Info
574 | isFunTyCon tc = return (TH.PrimTyConI (reifyName tc) 2 False)
575 | isPrimTyCon tc = return (TH.PrimTyConI (reifyName tc) (tyConArity tc) (isUnLiftedTyCon tc))
577 = do { let (tvs, rhs) = getSynTyConDefn tc
578 ; rhs' <- reifyType rhs
579 ; return (TH.TyConI $ TH.TySynD (reifyName tc) (reifyTyVars tvs) rhs') }
582 = do { cxt <- reifyCxt (tyConStupidTheta tc)
583 ; cons <- mapM reifyDataCon (tyConDataCons tc)
584 ; let name = reifyName tc
585 tvs = reifyTyVars (tyConTyVars tc)
586 deriv = [] -- Don't know about deriving
587 decl | isNewTyCon tc = TH.NewtypeD cxt name tvs (head cons) deriv
588 | otherwise = TH.DataD cxt name tvs cons deriv
589 ; return (TH.TyConI decl) }
591 reifyDataCon :: DataCon -> TcM TH.Con
593 | isVanillaDataCon dc
594 = do { arg_tys <- reifyTypes (dataConOrigArgTys dc)
595 ; let stricts = map reifyStrict (dataConStrictMarks dc)
596 fields = dataConFieldLabels dc
600 ; ASSERT( length arg_tys == length stricts )
601 if not (null fields) then
602 return (TH.RecC name (zip3 (map reifyName fields) stricts arg_tys))
604 if dataConIsInfix dc then
605 ASSERT( length arg_tys == 2 )
606 return (TH.InfixC (s1,a1) name (s2,a2))
608 return (TH.NormalC name (stricts `zip` arg_tys)) }
610 = failWithTc (ptext SLIT("Can't reify a non-Haskell-98 data constructor:")
613 ------------------------------
614 reifyClass :: Class -> TcM TH.Info
616 = do { cxt <- reifyCxt theta
617 ; ops <- mapM reify_op op_stuff
618 ; return (TH.ClassI $ TH.ClassD cxt (reifyName cls) (reifyTyVars tvs) fds' ops) }
620 (tvs, fds, theta, _, op_stuff) = classExtraBigSig cls
621 fds' = map reifyFunDep fds
622 reify_op (op, _) = do { ty <- reifyType (idType op)
623 ; return (TH.SigD (reifyName op) ty) }
625 ------------------------------
626 reifyType :: TypeRep.Type -> TcM TH.Type
627 reifyType (TyVarTy tv) = return (TH.VarT (reifyName tv))
628 reifyType (TyConApp tc tys) = reify_tc_app (reifyName tc) tys
629 reifyType (NoteTy _ ty) = reifyType ty
630 reifyType (AppTy t1 t2) = do { [r1,r2] <- reifyTypes [t1,t2] ; return (r1 `TH.AppT` r2) }
631 reifyType (FunTy t1 t2) = do { [r1,r2] <- reifyTypes [t1,t2] ; return (TH.ArrowT `TH.AppT` r1 `TH.AppT` r2) }
632 reifyType ty@(ForAllTy _ _) = do { cxt' <- reifyCxt cxt;
633 ; tau' <- reifyType tau
634 ; return (TH.ForallT (reifyTyVars tvs) cxt' tau') }
636 (tvs, cxt, tau) = tcSplitSigmaTy ty
637 reifyTypes = mapM reifyType
638 reifyCxt = mapM reifyPred
640 reifyFunDep :: ([TyVar], [TyVar]) -> TH.FunDep
641 reifyFunDep (xs, ys) = TH.FunDep (map reifyName xs) (map reifyName ys)
643 reifyTyVars :: [TyVar] -> [TH.Name]
644 reifyTyVars = map reifyName
646 reify_tc_app :: TH.Name -> [TypeRep.Type] -> TcM TH.Type
647 reify_tc_app tc tys = do { tys' <- reifyTypes tys
648 ; return (foldl TH.AppT (TH.ConT tc) tys') }
650 reifyPred :: TypeRep.PredType -> TcM TH.Type
651 reifyPred (ClassP cls tys) = reify_tc_app (reifyName cls) tys
652 reifyPred p@(IParam _ _) = noTH SLIT("implicit parameters") (ppr p)
655 ------------------------------
656 reifyName :: NamedThing n => n -> TH.Name
658 | isExternalName name = mk_varg mod occ_str
659 | otherwise = TH.mkNameU occ_str (getKey (getUnique name))
660 -- Many of the things we reify have local bindings, and
661 -- NameL's aren't supposed to appear in binding positions, so
662 -- we use NameU. When/if we start to reify nested things, that
663 -- have free variables, we may need to generate NameL's for them.
666 mod = moduleUserString (nameModule name)
667 occ_str = occNameUserString occ
668 occ = nameOccName name
669 mk_varg | OccName.isDataOcc occ = TH.mkNameG_d
670 | OccName.isVarOcc occ = TH.mkNameG_v
671 | OccName.isTcOcc occ = TH.mkNameG_tc
672 | otherwise = pprPanic "reifyName" (ppr name)
674 ------------------------------
675 reifyFixity :: Name -> TcM TH.Fixity
677 = do { fix <- lookupFixityRn name
678 ; return (conv_fix fix) }
680 conv_fix (BasicTypes.Fixity i d) = TH.Fixity i (conv_dir d)
681 conv_dir BasicTypes.InfixR = TH.InfixR
682 conv_dir BasicTypes.InfixL = TH.InfixL
683 conv_dir BasicTypes.InfixN = TH.InfixN
685 reifyStrict :: BasicTypes.StrictnessMark -> TH.Strict
686 reifyStrict MarkedStrict = TH.IsStrict
687 reifyStrict MarkedUnboxed = TH.IsStrict
688 reifyStrict NotMarkedStrict = TH.NotStrict
690 ------------------------------
691 noTH :: LitString -> SDoc -> TcM a
692 noTH s d = failWithTc (hsep [ptext SLIT("Can't represent") <+> ptext s <+>
693 ptext SLIT("in Template Haskell:"),