X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcSplice.lhs;h=bafddf8e3582334039af4bbb7353f85176f17ce0;hp=b0896064d008993592770f6e249f747685b7b2bd;hb=215ce9f15215399ce30ae55c9521087847d78646;hpb=17b297d97d327620ed6bfab942f8992b2446f1bf diff --git a/compiler/typecheck/TcSplice.lhs b/compiler/typecheck/TcSplice.lhs index b089606..bafddf8 100644 --- a/compiler/typecheck/TcSplice.lhs +++ b/compiler/typecheck/TcSplice.lhs @@ -5,15 +5,20 @@ TcSplice: Template Haskell splices + \begin{code} -{-# OPTIONS_GHC -w #-} +{-# OPTIONS -fno-warn-unused-imports -fno-warn-unused-binds #-} -- The above warning supression flag is a temporary kludge. -- While working on this module you are encouraged to remove it and fix -- any warnings in the module. See --- http://hackage.haskell.org/trac/ghc/wiki/WorkingConventions#Warnings +-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings -- for details -module TcSplice( tcSpliceExpr, tcSpliceDecls, tcBracket ) where +module TcSplice( kcSpliceType, tcSpliceExpr, tcSpliceDecls, tcBracket, + lookupThName_maybe, + runQuasiQuoteExpr, runQuasiQuotePat, + runQuasiQuoteDecl, runQuasiQuoteType, + runAnnotation ) where #include "HsVersions.h" @@ -28,6 +33,7 @@ import RnExpr import RnEnv import RdrName import RnTypes +import TcPat import TcExpr import TcHsSyn import TcSimplify @@ -40,13 +46,16 @@ import TcIface import TypeRep import Name import NameEnv +import NameSet +import PrelNames import HscTypes import OccName import Var import Module +import Annotations import TcRnMonad -import IfaceEnv import Class +import Inst import TyCon import DataCon import Id @@ -55,24 +64,217 @@ import TysWiredIn import DsMeta import DsExpr import DsMonad hiding (Splice) +import Serialized import ErrUtils import SrcLoc import Outputable import Unique -import DynFlags -import PackageConfig +import Data.Maybe import BasicTypes import Panic import FastString +import Exception +import Control.Monad ( when ) import qualified Language.Haskell.TH as TH -- THSyntax gives access to internal functions and data types import qualified Language.Haskell.TH.Syntax as TH +#ifdef GHCI +-- Because GHC.Desugar might not be in the base library of the bootstrapping compiler +import GHC.Desugar ( AnnotationWrapper(..) ) +#endif + import GHC.Exts ( unsafeCoerce#, Int#, Int(..) ) -import Control.Monad ( liftM ) +import System.IO.Error \end{code} +Note [How top-level splices are handled] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Top-level splices (those not inside a [| .. |] quotation bracket) are handled +very straightforwardly: + + 1. tcTopSpliceExpr: typecheck the body e of the splice $(e) + + 2. runMetaT: desugar, compile, run it, and convert result back to + HsSyn RdrName (of the appropriate flavour, eg HsType RdrName, + HsExpr RdrName etc) + + 3. treat the result as if that's what you saw in the first place + e.g for HsType, rename and kind-check + for HsExpr, rename and type-check + + (The last step is different for decls, becuase they can *only* be + top-level: we return the result of step 2.) + +Note [How brackets and nested splices are handled] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Nested splices (those inside a [| .. |] quotation bracket), are treated +quite differently. + + * After typechecking, the bracket [| |] carries + + a) A mutable list of PendingSplice + type PendingSplice = (Name, LHsExpr Id) + + b) The quoted expression e, *renamed*: (HsExpr Name) + The expression e has been typechecked, but the result of + that typechecking is discarded. + + * The brakcet is desugared by DsMeta.dsBracket. It + + a) Extends the ds_meta environment with the PendingSplices + attached to the bracket + + b) Converts the quoted (HsExpr Name) to a CoreExpr that, when + run, will produce a suitable TH expression/type/decl. This + is why we leave the *renamed* expression attached to the bracket: + the quoted expression should not be decorated with all the goop + added by the type checker + + * Each splice carries a unique Name, called a "splice point", thus + ${n}(e). The name is initialised to an (Unqual "splice") when the + splice is created; the renamer gives it a unique. + + * When the type checker type-checks a nested splice ${n}(e), it + - typechecks e + - adds the typechecked expression (of type (HsExpr Id)) + as a pending splice to the enclosing bracket + - returns something non-committal + Eg for [| f ${n}(g x) |], the typechecker + - attaches the typechecked term (g x) to the pending splices for n + in the outer bracket + - returns a non-committal type \alpha. + Remember that the bracket discards the typechecked term altogether + + * When DsMeta (used to desugar the body of the bracket) comes across + a splice, it looks up the splice's Name, n, in the ds_meta envt, + to find an (HsExpr Id) that should be substituted for the splice; + it just desugars it to get a CoreExpr (DsMeta.repSplice). + +Example: + Source: f = [| Just $(g 3) |] + The [| |] part is a HsBracket + + Typechecked: f = [| Just ${s7}(g 3) |]{s7 = g Int 3} + The [| |] part is a HsBracketOut, containing *renamed* + (not typechecked) expression + The "s7" is the "splice point"; the (g Int 3) part + is a typechecked expression + + Desugared: f = do { s7 <- g Int 3 + ; return (ConE "Data.Maybe.Just" s7) } + + +Note [Template Haskell state diagram] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Here are the ThStages, s, their corresponding level numbers +(the result of (thLevel s)), and their state transitions. + + ----------- $ ------------ $ + | Comp | ---------> | Splice | -----| + | 1 | | 0 | <----| + ----------- ------------ + ^ | ^ | + $ | | [||] $ | | [||] + | v | v + -------------- ---------------- + | Brack Comp | | Brack Splice | + | 2 | | 1 | + -------------- ---------------- + +* Normal top-level declarations start in state Comp + (which has level 1). + Annotations start in state Splice, since they are + treated very like a splice (only without a '$') + +* Code compiled in state Splice (and only such code) + will be *run at compile time*, with the result replacing + the splice + +* The original paper used level -1 instead of 0, etc. + +* The original paper did not allow a splice within a + splice, but there is no reason not to. This is the + $ transition in the top right. + +Note [Template Haskell levels] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +* Imported things are impLevel (= 0) + +* In GHCi, variables bound by a previous command are treated + as impLevel, because we have bytecode for them. + +* Variables are bound at the "current level" + +* The current level starts off at outerLevel (= 1) + +* The level is decremented by splicing $(..) + incremented by brackets [| |] + incremented by name-quoting 'f + +When a variable is used, we compare + bind: binding level, and + use: current level at usage site + + Generally + bind > use Always error (bound later than used) + [| \x -> $(f x) |] + + bind = use Always OK (bound same stage as used) + [| \x -> $(f [| x |]) |] + + bind < use Inside brackets, it depends + Inside splice, OK + Inside neither, OK + + For (bind < use) inside brackets, there are three cases: + - Imported things OK f = [| map |] + - Top-level things OK g = [| f |] + - Non-top-level Only if there is a liftable instance + h = \(x:Int) -> [| x |] + +See Note [What is a top-level Id?] + +Note [Quoting names] +~~~~~~~~~~~~~~~~~~~~ +A quoted name 'n is a bit like a quoted expression [| n |], except that we +have no cross-stage lifting (c.f. TcExpr.thBrackId). So, after incrementing +the use-level to account for the brackets, the cases are: + + bind > use Error + bind = use OK + bind < use + Imported things OK + Top-level things OK + Non-top-level Error + +See Note [What is a top-level Id?] in TcEnv. Examples: + + f 'map -- OK; also for top-level defns of this module + + \x. f 'x -- Not ok (whereas \x. f [| x |] might have been ok, by + -- cross-stage lifting + + \y. [| \x. $(f 'y) |] -- Not ok (same reason) + + [| \x. $(f 'x) |] -- OK + + +Note [What is a top-level Id?] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +In the level-control criteria above, we need to know what a "top level Id" is. +There are three kinds: + * Imported from another module (GlobalId, ExternalName) + * Bound at the top level of this module (ExternalName) + * In GHCi, bound by a previous stmt (GlobalId) +It's strange that there is no one criterion tht picks out all three, but that's +how it is right now. (The obvious thing is to give an ExternalName to GHCi Ids +bound in an earlier Stmt, but what module would you choose? See +Note [Interactively-bound Ids in GHCi] in TcRnDriver.) + +The predicate we use is TcEnv.thTopLevelId. + %************************************************************************ %* * @@ -81,14 +283,34 @@ import Control.Monad ( liftM ) %************************************************************************ \begin{code} +tcBracket :: HsBracket Name -> BoxyRhoType -> TcM (LHsExpr TcId) tcSpliceDecls :: LHsExpr Name -> TcM [LHsDecl RdrName] tcSpliceExpr :: HsSplice Name -> BoxyRhoType -> TcM (HsExpr TcId) -kcSpliceType :: HsSplice Name -> TcM (HsType Name, TcKind) +kcSpliceType :: HsSplice Name -> FreeVars -> TcM (HsType Name, TcKind) -- None of these functions add constraints to the LIE +lookupThName_maybe :: TH.Name -> TcM (Maybe Name) + +runQuasiQuoteExpr :: HsQuasiQuote RdrName -> RnM (LHsExpr RdrName) +runQuasiQuotePat :: HsQuasiQuote RdrName -> RnM (LPat RdrName) +runQuasiQuoteType :: HsQuasiQuote RdrName -> RnM (LHsType RdrName) +runQuasiQuoteDecl :: HsQuasiQuote RdrName -> RnM [LHsDecl RdrName] + +runAnnotation :: CoreAnnTarget -> LHsExpr Name -> TcM Annotation + #ifndef GHCI -tcSpliceExpr n e ty = pprPanic "Cant do tcSpliceExpr without GHCi" (ppr e) -tcSpliceDecls e = pprPanic "Cant do tcSpliceDecls without GHCi" (ppr e) +tcBracket x _ = pprPanic "Cant do tcBracket without GHCi" (ppr x) +tcSpliceExpr e = pprPanic "Cant do tcSpliceExpr without GHCi" (ppr e) +tcSpliceDecls x = pprPanic "Cant do tcSpliceDecls without GHCi" (ppr x) +kcSpliceType x fvs = pprPanic "Cant do kcSpliceType without GHCi" (ppr x) + +lookupThName_maybe n = pprPanic "Cant do lookupThName_maybe without GHCi" (ppr n) + +runQuasiQuoteExpr q = pprPanic "Cant do runQuasiQuoteExpr without GHCi" (ppr q) +runQuasiQuotePat q = pprPanic "Cant do runQuasiQuotePat without GHCi" (ppr q) +runQuasiQuoteType q = pprPanic "Cant do runQuasiQuoteType without GHCi" (ppr q) +runQuasiQuoteDecl q = pprPanic "Cant do runQuasiQuoteDecl without GHCi" (ppr q) +runAnnotation _ q = pprPanic "Cant do runAnnotation without GHCi" (ppr q) #else \end{code} @@ -98,74 +320,83 @@ tcSpliceDecls e = pprPanic "Cant do tcSpliceDecls without GHCi" (ppr e) %* * %************************************************************************ -Note [Handling brackets] -~~~~~~~~~~~~~~~~~~~~~~~~ -Source: f = [| Just $(g 3) |] - The [| |] part is a HsBracket - -Typechecked: f = [| Just ${s7}(g 3) |]{s7 = g Int 3} - The [| |] part is a HsBracketOut, containing *renamed* (not typechecked) expression - The "s7" is the "splice point"; the (g Int 3) part is a typechecked expression - -Desugared: f = do { s7 <- g Int 3 - ; return (ConE "Data.Maybe.Just" s7) } \begin{code} -tcBracket :: HsBracket Name -> BoxyRhoType -> TcM (LHsExpr TcId) -tcBracket brack res_ty - = getStage `thenM` \ level -> - case bracketOK level of { - Nothing -> failWithTc (illegalBracket level) ; - Just next_level -> +-- See Note [How brackets and nested splices are handled] +tcBracket brack res_ty + = addErrCtxt (hang (ptext (sLit "In the Template Haskell quotation")) + 2 (ppr brack)) $ + do { -- Check for nested brackets + cur_stage <- getStage + ; checkTc (not (isBrackStage cur_stage)) illegalBracket + + -- Brackets are desugared to code that mentions the TH package + ; recordThUse -- Typecheck expr to make sure it is valid, -- but throw away the results. We'll type check -- it again when we actually use it. - recordThUse `thenM_` - newMutVar [] `thenM` \ pending_splices -> - getLIEVar `thenM` \ lie_var -> + ; pending_splices <- newMutVar [] + ; lie_var <- getLIEVar - setStage (Brack next_level pending_splices lie_var) ( - getLIE (tc_bracket brack) - ) `thenM` \ (meta_ty, lie) -> - tcSimplifyBracket lie `thenM_` + ; (meta_ty, lie) <- setStage (Brack cur_stage pending_splices lie_var) + (getLIE (tc_bracket cur_stage brack)) + ; tcSimplifyBracket lie -- Make the expected type have the right shape - boxyUnify meta_ty res_ty `thenM_` + ; _ <- boxyUnify meta_ty res_ty -- Return the original expression, not the type-decorated one - readMutVar pending_splices `thenM` \ pendings -> - returnM (noLoc (HsBracketOut brack pendings)) - } - -tc_bracket :: HsBracket Name -> TcM TcType -tc_bracket (VarBr v) - = tcMetaTy nameTyConName -- Result type is Var (not Q-monadic) + ; pendings <- readMutVar pending_splices + ; return (noLoc (HsBracketOut brack pendings)) } + +tc_bracket :: ThStage -> HsBracket Name -> TcM TcType +tc_bracket outer_stage (VarBr name) -- Note [Quoting names] + = do { thing <- tcLookup name + ; case thing of + AGlobal _ -> return () + ATcId { tct_level = bind_lvl, tct_id = id } + | thTopLevelId id -- C.f TcExpr.checkCrossStageLifting + -> keepAliveTc id + | otherwise + -> do { checkTc (thLevel outer_stage + 1 == bind_lvl) + (quotedNameStageErr name) } + _ -> pprPanic "th_bracket" (ppr name) + + ; tcMetaTy nameTyConName -- Result type is Var (not Q-monadic) + } -tc_bracket (ExpBr expr) - = newFlexiTyVarTy liftedTypeKind `thenM` \ any_ty -> - tcMonoExpr expr any_ty `thenM_` - tcMetaTy expQTyConName - -- Result type is Expr (= Q Exp) +tc_bracket _ (ExpBr expr) + = do { any_ty <- newFlexiTyVarTy liftedTypeKind + ; _ <- tcMonoExprNC expr any_ty -- NC for no context; tcBracket does that + ; tcMetaTy expQTyConName } + -- Result type is ExpQ (= Q Exp) -tc_bracket (TypBr typ) - = tcHsSigType ExprSigCtxt typ `thenM_` - tcMetaTy typeQTyConName +tc_bracket _ (TypBr typ) + = do { _ <- tcHsSigTypeNC ThBrackCtxt typ + ; tcMetaTy typeQTyConName } -- Result type is Type (= Q Typ) -tc_bracket (DecBr decls) - = do { tcTopSrcDecls emptyModDetails decls - -- Typecheck the declarations, dicarding the result - -- We'll get all that stuff later, when we splice it in - - ; decl_ty <- tcMetaTy decTyConName - ; q_ty <- tcMetaTy qTyConName - ; return (mkAppTy q_ty (mkListTy decl_ty)) - -- Result type is Q [Dec] - } - -tc_bracket (PatBr _) - = failWithTc (ptext SLIT("Tempate Haskell pattern brackets are not supported yet")) +tc_bracket _ (DecBrG decls) + = do { _ <- tcTopSrcDecls emptyModDetails decls + -- Typecheck the declarations, dicarding the result + -- We'll get all that stuff later, when we splice it in + ; tcMetaTy decsQTyConName } -- Result type is Q [Dec] + +tc_bracket _ (PatBr pat) + = do { any_ty <- newFlexiTyVarTy liftedTypeKind + ; _ <- tcPat ThPatQuote pat any_ty unitTy $ \_ -> + return () + ; tcMetaTy patQTyConName } + -- Result type is PatQ (= Q Pat) + +tc_bracket _ (DecBrL _) + = panic "tc_bracket: Unexpected DecBrL" + +quotedNameStageErr :: Name -> SDoc +quotedNameStageErr v + = sep [ ptext (sLit "Stage error: the non-top-level quoted name") <+> ppr (VarBr v) + , ptext (sLit "must be used at the same stage at which is is bound")] \end{code} @@ -177,87 +408,83 @@ tc_bracket (PatBr _) \begin{code} tcSpliceExpr (HsSplice name expr) res_ty - = setSrcSpan (getLoc expr) $ - getStage `thenM` \ level -> - case spliceOK level of { - Nothing -> failWithTc (illegalSplice level) ; - Just next_level -> + = setSrcSpan (getLoc expr) $ do + { stage <- getStage + ; case stage of { + Splice -> tcTopSplice expr res_ty ; + Comp -> tcTopSplice expr res_ty ; - case level of { - Comp -> do { e <- tcTopSplice expr res_ty - ; returnM (unLoc e) } ; - Brack _ ps_var lie_var -> + Brack pop_stage ps_var lie_var -> do + -- See Note [How brackets and nested splices are handled] -- A splice inside brackets -- NB: ignore res_ty, apart from zapping it to a mono-type -- e.g. [| reverse $(h 4) |] -- Here (h 4) :: Q Exp -- but $(h 4) :: forall a.a i.e. anything! - unBox res_ty `thenM_` - tcMetaTy expQTyConName `thenM` \ meta_exp_ty -> - setStage (Splice next_level) ( - setLIEVar lie_var $ - tcMonoExpr expr meta_exp_ty - ) `thenM` \ expr' -> + { _ <- unBox res_ty + ; meta_exp_ty <- tcMetaTy expQTyConName + ; expr' <- setStage pop_stage $ + setLIEVar lie_var $ + tcMonoExpr expr meta_exp_ty -- Write the pending splice into the bucket - readMutVar ps_var `thenM` \ ps -> - writeMutVar ps_var ((name,expr') : ps) `thenM_` + ; ps <- readMutVar ps_var + ; writeMutVar ps_var ((name,expr') : ps) - returnM (panic "tcSpliceExpr") -- The returned expression is ignored - }} + ; return (panic "tcSpliceExpr") -- The returned expression is ignored + }}} --- tcTopSplice used to have this: --- Note that we do not decrement the level (to -1) before --- typechecking the expression. For example: --- f x = $( ...$(g 3) ... ) --- The recursive call to tcMonoExpr will simply expand the --- inner escape before dealing with the outer one - -tcTopSplice :: LHsExpr Name -> BoxyRhoType -> TcM (LHsExpr Id) +tcTopSplice :: LHsExpr Name -> BoxyRhoType -> TcM (HsExpr Id) +-- Note [How top-level splices are handled] tcTopSplice expr res_ty - = tcMetaTy expQTyConName `thenM` \ meta_exp_ty -> - - -- Typecheck the expression - tcTopSpliceExpr expr meta_exp_ty `thenM` \ zonked_q_expr -> + = do { meta_exp_ty <- tcMetaTy expQTyConName - -- Run the expression - traceTc (text "About to run" <+> ppr zonked_q_expr) `thenM_` - runMetaE convertToHsExpr zonked_q_expr `thenM` \ expr2 -> - - traceTc (text "Got result" <+> ppr expr2) `thenM_` + -- Typecheck the expression + ; zonked_q_expr <- tcTopSpliceExpr (tcMonoExpr expr meta_exp_ty) - showSplice "expression" - zonked_q_expr (ppr expr2) `thenM_` + -- Run the expression + ; expr2 <- runMetaE zonked_q_expr + ; showSplice "expression" expr (ppr expr2) - -- Rename it, but bale out if there are errors - -- otherwise the type checker just gives more spurious errors - checkNoErrs (rnLExpr expr2) `thenM` \ (exp3, fvs) -> + -- Rename it, but bale out if there are errors + -- otherwise the type checker just gives more spurious errors + ; addErrCtxt (spliceResultDoc expr) $ do + { (exp3, _fvs) <- checkNoErrs (rnLExpr expr2) - tcMonoExpr exp3 res_ty + ; exp4 <- tcMonoExpr exp3 res_ty + ; return (unLoc exp4) } } +spliceResultDoc :: LHsExpr Name -> SDoc +spliceResultDoc expr + = sep [ ptext (sLit "In the result of the splice:") + , nest 2 (char '$' <> pprParendExpr expr) + , ptext (sLit "To see what the splice expanded to, use -ddump-splices")] -tcTopSpliceExpr :: LHsExpr Name -> TcType -> TcM (LHsExpr Id) +------------------- +tcTopSpliceExpr :: TcM (LHsExpr Id) -> TcM (LHsExpr Id) +-- Note [How top-level splices are handled] -- Type check an expression that is the body of a top-level splice -- (the caller will compile and run it) -tcTopSpliceExpr expr meta_ty - = checkNoErrs $ -- checkNoErrs: must not try to run the thing - -- if the type checker fails! - - setStage topSpliceStage $ do - - - do { recordThUse -- Record that TH is used (for pkg depdendency) +-- Note that set the level to Splice, regardless of the original level, +-- before typechecking the expression. For example: +-- f x = $( ...$(g 3) ... ) +-- The recursive call to tcMonoExpr will simply expand the +-- inner escape before dealing with the outer one - -- Typecheck the expression - ; (expr', lie) <- getLIE (tcMonoExpr expr meta_ty) - +tcTopSpliceExpr tc_action + = checkNoErrs $ -- checkNoErrs: must not try to run the thing + -- if the type checker fails! + setStage Splice $ + do { -- Typecheck the expression + (expr', lie) <- getLIE tc_action + -- Solve the constraints ; const_binds <- tcSimplifyTop lie - -- And zonk it - ; zonkTopLExpr (mkHsDictLet const_binds expr') } + -- Zonk it and tie the knot of dictionary bindings + ; zonkTopLExpr (mkHsDictLet const_binds expr') } \end{code} @@ -270,56 +497,52 @@ tcTopSpliceExpr expr meta_ty Very like splicing an expression, but we don't yet share code. \begin{code} -kcSpliceType (HsSplice name hs_expr) +kcSpliceType splice@(HsSplice name hs_expr) fvs = setSrcSpan (getLoc hs_expr) $ do - { level <- getStage - ; case spliceOK level of { - Nothing -> failWithTc (illegalSplice level) ; - Just next_level -> do - - { case level of { - Comp -> do { (t,k) <- kcTopSpliceType hs_expr - ; return (unLoc t, k) } ; - Brack _ ps_var lie_var -> do - - { -- A splice inside brackets - ; meta_ty <- tcMetaTy typeQTyConName - ; expr' <- setStage (Splice next_level) $ - setLIEVar lie_var $ - tcMonoExpr hs_expr meta_ty - - -- Write the pending splice into the bucket - ; ps <- readMutVar ps_var - ; writeMutVar ps_var ((name,expr') : ps) - - -- e.g. [| Int -> $(h 4) |] - -- Here (h 4) :: Q Type - -- but $(h 4) :: forall a.a i.e. any kind - ; kind <- newKindVar - ; returnM (panic "kcSpliceType", kind) -- The returned type is ignored - }}}}} - -kcTopSpliceType :: LHsExpr Name -> TcM (LHsType Name, TcKind) + { stage <- getStage + ; case stage of { + Splice -> kcTopSpliceType hs_expr ; + Comp -> kcTopSpliceType hs_expr ; + + Brack pop_level ps_var lie_var -> do + -- See Note [How brackets and nested splices are handled] + -- A splice inside brackets + { meta_ty <- tcMetaTy typeQTyConName + ; expr' <- setStage pop_level $ + setLIEVar lie_var $ + tcMonoExpr hs_expr meta_ty + + -- Write the pending splice into the bucket + ; ps <- readMutVar ps_var + ; writeMutVar ps_var ((name,expr') : ps) + + -- e.g. [| f (g :: Int -> $(h 4)) |] + -- Here (h 4) :: Q Type + -- but $(h 4) :: a i.e. any type, of any kind + + ; kind <- newKindVar + ; return (HsSpliceTy splice fvs kind, kind) + }}} + +kcTopSpliceType :: LHsExpr Name -> TcM (HsType Name, TcKind) +-- Note [How top-level splices are handled] kcTopSpliceType expr = do { meta_ty <- tcMetaTy typeQTyConName -- Typecheck the expression - ; zonked_q_expr <- tcTopSpliceExpr expr meta_ty + ; zonked_q_expr <- tcTopSpliceExpr (tcMonoExpr expr meta_ty) -- Run the expression - ; traceTc (text "About to run" <+> ppr zonked_q_expr) - ; hs_ty2 <- runMetaT convertToHsType zonked_q_expr + ; hs_ty2 <- runMetaT zonked_q_expr + ; showSplice "type" expr (ppr hs_ty2) - ; traceTc (text "Got result" <+> ppr hs_ty2) - - ; showSplice "type" zonked_q_expr (ppr hs_ty2) - -- Rename it, but bale out if there are errors -- otherwise the type checker just gives more spurious errors - ; let doc = ptext SLIT("In the spliced type") <+> ppr hs_ty2 + ; addErrCtxt (spliceResultDoc expr) $ do + { let doc = ptext (sLit "In the spliced type") <+> ppr hs_ty2 ; hs_ty3 <- checkNoErrs (rnLHsType doc hs_ty2) - - ; kcHsType hs_ty3 } + ; (ty4, kind) <- kcLHsType hs_ty3 + ; return (unLoc ty4, kind) }} \end{code} %************************************************************************ @@ -329,30 +552,154 @@ kcTopSpliceType expr %************************************************************************ \begin{code} +-- Note [How top-level splices are handled] -- Always at top level -- Type sig at top of file: -- tcSpliceDecls :: LHsExpr Name -> TcM [LHsDecl RdrName] tcSpliceDecls expr - = do { meta_dec_ty <- tcMetaTy decTyConName - ; meta_q_ty <- tcMetaTy qTyConName - ; let list_q = mkAppTy meta_q_ty (mkListTy meta_dec_ty) - ; zonked_q_expr <- tcTopSpliceExpr expr list_q + = do { list_q <- tcMetaTy decsQTyConName -- Q [Dec] + ; zonked_q_expr <- tcTopSpliceExpr (tcMonoExpr expr list_q) -- Run the expression - ; traceTc (text "About to run" <+> ppr zonked_q_expr) - ; decls <- runMetaD convertToHsDecls zonked_q_expr - - ; traceTc (text "Got result" <+> vcat (map ppr decls)) - ; showSplice "declarations" - zonked_q_expr + ; decls <- runMetaD zonked_q_expr + ; showSplice "declarations" expr (ppr (getLoc expr) $$ (vcat (map ppr decls))) - ; returnM decls } - where handleErrors :: [Either a Message] -> TcM [a] - handleErrors [] = return [] - handleErrors (Left x:xs) = liftM (x:) (handleErrors xs) - handleErrors (Right m:xs) = do addErrTc m - handleErrors xs + ; return decls } +\end{code} + + +%************************************************************************ +%* * + Annotations +%* * +%************************************************************************ + +\begin{code} +runAnnotation target expr = do + -- Find the classes we want instances for in order to call toAnnotationWrapper + loc <- getSrcSpanM + data_class <- tcLookupClass dataClassName + to_annotation_wrapper_id <- tcLookupId toAnnotationWrapperName + + -- Check the instances we require live in another module (we want to execute it..) + -- and check identifiers live in other modules using TH stage checks. tcSimplifyStagedExpr + -- also resolves the LIE constraints to detect e.g. instance ambiguity + zonked_wrapped_expr' <- tcTopSpliceExpr $ + do { (expr', expr_ty) <- tcInferRhoNC expr + -- We manually wrap the typechecked expression in a call to toAnnotationWrapper + -- By instantiating the call >here< it gets registered in the + -- LIE consulted by tcTopSpliceExpr + -- and hence ensures the appropriate dictionary is bound by const_binds + ; wrapper <- instCall AnnOrigin [expr_ty] [mkClassPred data_class [expr_ty]] + ; let specialised_to_annotation_wrapper_expr + = L loc (HsWrap wrapper (HsVar to_annotation_wrapper_id)) + ; return (L loc (HsApp specialised_to_annotation_wrapper_expr expr')) } + + -- Run the appropriately wrapped expression to get the value of + -- the annotation and its dictionaries. The return value is of + -- type AnnotationWrapper by construction, so this conversion is + -- safe + flip runMetaAW zonked_wrapped_expr' $ \annotation_wrapper -> + case annotation_wrapper of + AnnotationWrapper value | let serialized = toSerialized serializeWithData value -> + -- Got the value and dictionaries: build the serialized value and + -- call it a day. We ensure that we seq the entire serialized value + -- in order that any errors in the user-written code for the + -- annotation are exposed at this point. This is also why we are + -- doing all this stuff inside the context of runMeta: it has the + -- facilities to deal with user error in a meta-level expression + seqSerialized serialized `seq` Annotation { + ann_target = target, + ann_value = serialized + } +\end{code} + + +%************************************************************************ +%* * + Quasi-quoting +%* * +%************************************************************************ + +Note [Quasi-quote overview] +~~~~~~~~~~~~~~~~~~~~~~~~~~~ +The GHC "quasi-quote" extension is described by Geoff Mainland's paper +"Why it's nice to be quoted: quasiquoting for Haskell" (Haskell +Workshop 2007). + +Briefly, one writes + [p| stuff |] +and the arbitrary string "stuff" gets parsed by the parser 'p', whose +type should be Language.Haskell.TH.Quote.QuasiQuoter. 'p' must be +defined in another module, because we are going to run it here. It's +a bit like a TH splice: + $(p "stuff") + +However, you can do this in patterns as well as terms. Becuase of this, +the splice is run by the *renamer* rather than the type checker. + +%************************************************************************ +%* * +\subsubsection{Quasiquotation} +%* * +%************************************************************************ + +See Note [Quasi-quote overview] in TcSplice. + +\begin{code} +runQuasiQuote :: Outputable hs_syn + => HsQuasiQuote RdrName -- Contains term of type QuasiQuoter, and the String + -> Name -- Of type QuasiQuoter -> String -> Q th_syn + -> Name -- Name of th_syn type + -> MetaOps th_syn hs_syn + -> RnM hs_syn +runQuasiQuote (HsQuasiQuote quoter q_span quote) quote_selector meta_ty meta_ops + = do { quoter' <- lookupOccRn quoter + -- We use lookupOcc rather than lookupGlobalOcc because in the + -- erroneous case of \x -> [x| ...|] we get a better error message + -- (stage restriction rather than out of scope). + + ; when (isUnboundName quoter') failM + -- If 'quoter' is not in scope, proceed no further + -- The error message was generated by lookupOccRn, but it then + -- succeeds with an "unbound name", which makes the subsequent + -- attempt to run the quote fail in a confusing way + + -- Check that the quoter is not locally defined, otherwise the TH + -- machinery will not be able to run the quasiquote. + ; this_mod <- getModule + ; let is_local = nameIsLocalOrFrom this_mod quoter' + ; checkTc (not is_local) (quoteStageError quoter') + + ; traceTc (text "runQQ" <+> ppr quoter <+> ppr is_local) + + -- Build the expression + ; let quoterExpr = L q_span $! HsVar $! quoter' + ; let quoteExpr = L q_span $! HsLit $! HsString quote + ; let expr = L q_span $ + HsApp (L q_span $ + HsApp (L q_span (HsVar quote_selector)) quoterExpr) quoteExpr + ; meta_exp_ty <- tcMetaTy meta_ty + + -- Typecheck the expression + ; zonked_q_expr <- tcTopSpliceExpr (tcMonoExpr expr meta_exp_ty) + + -- Run the expression + ; result <- runMetaQ meta_ops zonked_q_expr + ; showSplice (mt_desc meta_ops) quoteExpr (ppr result) + + ; return result } + +runQuasiQuoteExpr qq = runQuasiQuote qq quoteExpName expQTyConName exprMetaOps +runQuasiQuotePat qq = runQuasiQuote qq quotePatName patQTyConName patMetaOps +runQuasiQuoteType qq = runQuasiQuote qq quoteTypeName typeQTyConName typeMetaOps +runQuasiQuoteDecl qq = runQuasiQuote qq quoteDecName decsQTyConName declMetaOps + +quoteStageError :: Name -> SDoc +quoteStageError quoter + = sep [ptext (sLit "GHC stage restriction:") <+> ppr quoter, + nest 2 (ptext (sLit "is used in a quasiquote, and must be imported, not defined locally"))] \end{code} @@ -363,37 +710,81 @@ tcSpliceDecls expr %************************************************************************ \begin{code} -runMetaE :: (SrcSpan -> TH.Exp -> Either Message (LHsExpr RdrName)) - -> LHsExpr Id -- Of type (Q Exp) +data MetaOps th_syn hs_syn + = MT { mt_desc :: String -- Type of beast (expression, type etc) + , mt_show :: th_syn -> String -- How to show the th_syn thing + , mt_cvt :: SrcSpan -> th_syn -> Either Message hs_syn + -- How to convert to hs_syn + } + +exprMetaOps :: MetaOps TH.Exp (LHsExpr RdrName) +exprMetaOps = MT { mt_desc = "expression", mt_show = TH.pprint, mt_cvt = convertToHsExpr } + +patMetaOps :: MetaOps TH.Pat (LPat RdrName) +patMetaOps = MT { mt_desc = "pattern", mt_show = TH.pprint, mt_cvt = convertToPat } + +typeMetaOps :: MetaOps TH.Type (LHsType RdrName) +typeMetaOps = MT { mt_desc = "type", mt_show = TH.pprint, mt_cvt = convertToHsType } + +declMetaOps :: MetaOps [TH.Dec] [LHsDecl RdrName] +declMetaOps = MT { mt_desc = "declarations", mt_show = TH.pprint, mt_cvt = convertToHsDecls } + +---------------- +runMetaAW :: Outputable output + => (AnnotationWrapper -> output) + -> LHsExpr Id -- Of type AnnotationWrapper + -> TcM output +runMetaAW k = runMeta False (\_ -> return . Right . k) + -- We turn off showing the code in meta-level exceptions because doing so exposes + -- the toAnnotationWrapper function that we slap around the users code + +----------------- +runMetaQ :: Outputable hs_syn + => MetaOps th_syn hs_syn + -> LHsExpr Id + -> TcM hs_syn +runMetaQ (MT { mt_show = show_th, mt_cvt = cvt }) expr + = runMeta True run_and_cvt expr + where + run_and_cvt expr_span hval + = do { th_result <- TH.runQ hval + ; traceTc (text "Got TH result:" <+> text (show_th th_result)) + ; return (cvt expr_span th_result) } + +runMetaE :: LHsExpr Id -- Of type (Q Exp) -> TcM (LHsExpr RdrName) -runMetaE = runMeta +runMetaE = runMetaQ exprMetaOps -runMetaT :: (SrcSpan -> TH.Type -> Either Message (LHsType RdrName)) - -> LHsExpr Id -- Of type (Q Type) +runMetaT :: LHsExpr Id -- Of type (Q Type) -> TcM (LHsType RdrName) -runMetaT = runMeta +runMetaT = runMetaQ typeMetaOps -runMetaD :: (SrcSpan -> [TH.Dec] -> Either Message [LHsDecl RdrName]) - -> LHsExpr Id -- Of type Q [Dec] +runMetaD :: LHsExpr Id -- Of type Q [Dec] -> TcM [LHsDecl RdrName] -runMetaD = runMeta +runMetaD = runMetaQ declMetaOps -runMeta :: (SrcSpan -> th_syn -> Either Message hs_syn) - -> LHsExpr Id -- Of type X +--------------- +runMeta :: (Outputable hs_syn) + => Bool -- Whether code should be printed in the exception message + -> (SrcSpan -> x -> TcM (Either Message hs_syn)) -- How to run x + -> LHsExpr Id -- Of type x; typically x = Q TH.Exp, or something like that -> TcM hs_syn -- Of type t -runMeta convert expr - = do { -- Desugar - ds_expr <- initDsTc (dsLExpr expr) +runMeta show_code run_and_convert expr + = do { traceTc (text "About to run" <+> ppr expr) + + -- Desugar + ; ds_expr <- initDsTc (dsLExpr expr) -- Compile and link it; might fail if linking fails ; hsc_env <- getTopEnv ; src_span <- getSrcSpanM - ; either_hval <- tryM $ ioToTcRn $ + ; either_hval <- tryM $ liftIO $ HscMain.compileExpr hsc_env src_span ds_expr ; case either_hval of { Left exn -> failWithTc (mk_msg "compile and link" exn) ; Right hval -> do { -- Coerce it to Q t, and run it + -- Running might fail if it throws an exception of any kind (hence tryAllM) -- including, say, a pattern-match exception in the code we are running -- @@ -401,23 +792,60 @@ runMeta convert expr -- exception-cacthing thing so that if there are any lurking -- exceptions in the data structure returned by hval, we'll -- encounter them inside the try - either_th_syn <- tryAllM $ tryM $ TH.runQ $ unsafeCoerce# hval - ; case either_th_syn of - Left exn -> failWithTc (mk_msg "run" exn) - Right (Left exn) -> failM -- Error already in Tc monad - Right (Right th_syn) -> do - { either_hs_syn <- tryAllM $ return $! convert (getLoc expr) th_syn - ; case either_hs_syn of - Left exn -> failWithTc (mk_msg "interpret result of" exn) - Right (Left err) -> do { addErrTc err; failM } - Right (Right hs_syn) -> return hs_syn - }}}} + -- + -- See Note [Exceptions in TH] + let expr_span = getLoc expr + ; either_tval <- tryAllM $ + setSrcSpan expr_span $ -- Set the span so that qLocation can + -- see where this splice is + do { mb_result <- run_and_convert expr_span (unsafeCoerce# hval) + ; case mb_result of + Left err -> failWithTc err + Right result -> do { traceTc (ptext (sLit "Got HsSyn result:") <+> ppr result) + ; return $! result } } + + ; case either_tval of + Right v -> return v + Left se -> case fromException se of + Just IOEnvFailure -> failM -- Error already in Tc monad + _ -> failWithTc (mk_msg "run" se) -- Exception + }}} where mk_msg s exn = vcat [text "Exception when trying to" <+> text s <+> text "compile-time code:", nest 2 (text (Panic.showException exn)), - nest 2 (text "Code:" <+> ppr expr)] + if show_code then nest 2 (text "Code:" <+> ppr expr) else empty] \end{code} +Note [Exceptions in TH] +~~~~~~~~~~~~~~~~~~~~~~~ +Supppose we have something like this + $( f 4 ) +where + f :: Int -> Q [Dec] + f n | n>3 = fail "Too many declarations" + | otherwise = ... + +The 'fail' is a user-generated failure, and should be displayed as a +perfectly ordinary compiler error message, not a panic or anything +like that. Here's how it's processed: + + * 'fail' is the monad fail. The monad instance for Q in TH.Syntax + effectively transforms (fail s) to + qReport True s >> fail + where 'qReport' comes from the Quasi class and fail from its monad + superclass. + + * The TcM monad is an instance of Quasi (see TcSplice), and it implements + (qReport True s) by using addErr to add an error message to the bag of errors. + The 'fail' in TcM raises an IOEnvFailure exception + + * So, when running a splice, we catch all exceptions; then for + - an IOEnvFailure exception, we assume the error is already + in the error-bag (above) + - other errors, we add an error to the bag + and then fail + + To call runQ in the Tc monad, we need to make TcM an instance of Quasi: \begin{code} @@ -427,12 +855,16 @@ instance TH.Quasi (IOEnv (Env TcGblEnv TcLclEnv)) where ; return (TH.mkNameU s i) } qReport True msg = addErr (text msg) - qReport False msg = addReport (text msg) - - qCurrentModule = do { m <- getModule; - return (moduleNameString (moduleName m)) } - -- ToDo: is throwing away the package name ok here? - + qReport False msg = addReport (text msg) empty + + qLocation = do { m <- getModule + ; l <- getSrcSpanM + ; return (TH.Loc { TH.loc_filename = unpackFS (srcSpanFile l) + , TH.loc_module = moduleNameString (moduleName m) + , TH.loc_package = packageIdString (modulePackageId m) + , TH.loc_start = (srcSpanStartLine l, srcSpanStartCol l) + , TH.loc_end = (srcSpanEndLine l, srcSpanEndCol l) }) } + qReify v = reify v -- For qRecover, discard error messages if @@ -445,7 +877,7 @@ instance TH.Quasi (IOEnv (Env TcGblEnv TcLclEnv)) where Nothing -> recover -- Discard all msgs } - qRunIO io = ioToTcRn io + qRunIO io = liftIO io \end{code} @@ -456,20 +888,21 @@ instance TH.Quasi (IOEnv (Env TcGblEnv TcLclEnv)) where %************************************************************************ \begin{code} -showSplice :: String -> LHsExpr Id -> SDoc -> TcM () +showSplice :: String -> LHsExpr Name -> SDoc -> TcM () +-- Note that 'before' is *renamed* but not *typechecked* +-- Reason (a) less typechecking crap +-- (b) data constructors after type checking have been +-- changed to their *wrappers*, and that makes them +-- print always fully qualified showSplice what before after - = getSrcSpanM `thenM` \ loc -> - traceSplice (vcat [ppr loc <> colon <+> text "Splicing" <+> text what, - nest 2 (sep [nest 2 (ppr before), - text "======>", - nest 2 after])]) - -illegalBracket level - = ptext SLIT("Illegal bracket at level") <+> ppr level - -illegalSplice level - = ptext SLIT("Illegal splice at level") <+> ppr level - + = do { loc <- getSrcSpanM + ; traceSplice (vcat [ppr loc <> colon <+> text "Splicing" <+> text what, + nest 2 (sep [nest 2 (ppr before), + text "======>", + nest 2 after])]) } + +illegalBracket :: SDoc +illegalBracket = ptext (sLit "Template Haskell brackets cannot be nested (without intervening splices)") #endif /* GHCI */ \end{code} @@ -495,29 +928,28 @@ reify th_name ppr_ns (TH.Name _ (TH.NameG TH.DataName _pkg _mod)) = text "data" ppr_ns (TH.Name _ (TH.NameG TH.TcClsName _pkg _mod)) = text "tc" ppr_ns (TH.Name _ (TH.NameG TH.VarName _pkg _mod)) = text "var" + ppr_ns _ = panic "reify/ppr_ns" lookupThName :: TH.Name -> TcM Name -lookupThName th_name@(TH.Name occ flavour) - = do { let rdr_name = thRdrName guessed_ns occ_str flavour - - -- Repeat much of lookupOccRn, becase we want - -- to report errors in a TH-relevant way - ; rdr_env <- getLocalRdrEnv - ; case lookupLocalRdrEnv rdr_env rdr_name of - Just name -> return name - Nothing | not (isSrcRdrName rdr_name) -- Exact, Orig - -> lookupImportedName rdr_name - | otherwise -- Unqual, Qual - -> do { mb_name <- lookupSrcOcc_maybe rdr_name - ; case mb_name of - Just name -> return name - Nothing -> failWithTc (notInScope th_name) } - } +lookupThName th_name = do + mb_name <- lookupThName_maybe th_name + case mb_name of + Nothing -> failWithTc (notInScope th_name) + Just name -> return name + +lookupThName_maybe th_name + = do { names <- mapMaybeM lookup (thRdrNameGuesses th_name) + -- Pick the first that works + -- E.g. reify (mkName "A") will pick the class A in preference to the data constructor A + ; return (listToMaybe names) } where - -- guessed_ns is the name space guessed from looking at the TH name - guessed_ns | isLexCon (mkFastString occ_str) = OccName.dataName - | otherwise = OccName.varName - occ_str = TH.occString occ + lookup rdr_name + = do { -- Repeat much of lookupOccRn, becase we want + -- to report errors in a TH-relevant way + ; rdr_env <- getLocalRdrEnv + ; case lookupLocalRdrEnv rdr_env rdr_name of + Just name -> return (Just name) + Nothing -> lookupGlobalOccRn_maybe rdr_name } tcLookupTh :: Name -> TcM TcTyThing -- This is a specialised version of TcEnv.tcLookup; specialised mainly in that @@ -526,7 +958,7 @@ tcLookupTh :: Name -> TcM TcTyThing tcLookupTh name = do { (gbl_env, lcl_env) <- getEnvs ; case lookupNameEnv (tcl_env lcl_env) name of { - Just thing -> returnM thing; + Just thing -> return thing; Nothing -> do { if nameIsLocalOrFrom (tcg_mod gbl_env) name then -- It's defined in this module @@ -547,12 +979,12 @@ tcLookupTh name notInScope :: TH.Name -> SDoc notInScope th_name = quotes (text (TH.pprint th_name)) <+> - ptext SLIT("is not in scope at a reify") + ptext (sLit "is not in scope at a reify") -- Ugh! Rather an indirect way to display the name notInEnv :: Name -> SDoc notInEnv name = quotes (ppr name) <+> - ptext SLIT("is not in the type environment at a reify") + ptext (sLit "is not in the type environment at a reify") ------------------------------ reifyThing :: TcTyThing -> TcM TH.Info @@ -564,9 +996,9 @@ 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) + ; case idDetails id of + ClassOpId cls -> return (TH.ClassOpI v ty (reifyName cls) fix) + _ -> return (TH.VarI v ty Nothing fix) } reifyThing (AGlobal (ATyCon tc)) = reifyTyCon tc @@ -575,7 +1007,9 @@ 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) } + ; return (TH.DataConI (reifyName name) ty + (reifyName (dataConOrigTyCon dc)) fix) + } reifyThing (ATcId {tct_id = id, tct_type = ty}) = do { ty1 <- zonkTcType ty -- Make use of all the info we have, even @@ -589,16 +1023,31 @@ reifyThing (ATyVar tv ty) ; ty2 <- reifyType ty1 ; return (TH.TyVarI (reifyName tv) ty2) } +reifyThing (AThing {}) = panic "reifyThing AThing" + ------------------------------ reifyTyCon :: TyCon -> TcM TH.Info reifyTyCon tc - | isFunTyCon tc = return (TH.PrimTyConI (reifyName tc) 2 False) - | isPrimTyCon tc = return (TH.PrimTyConI (reifyName tc) (tyConArity tc) (isUnLiftedTyCon tc)) + | isFunTyCon tc + = return (TH.PrimTyConI (reifyName tc) 2 False) + | isPrimTyCon tc + = return (TH.PrimTyConI (reifyName tc) (tyConArity tc) (isUnLiftedTyCon tc)) + | isOpenTyCon tc + = let flavour = reifyFamFlavour tc + tvs = tyConTyVars tc + kind = tyConKind tc + kind' + | isLiftedTypeKind kind = Nothing + | otherwise = Just $ reifyKind kind + in + return (TH.TyConI $ + TH.FamilyD flavour (reifyName tc) (reifyTyVars tvs) kind') | isSynTyCon tc = do { let (tvs, rhs) = synTyConDefn tc ; rhs' <- reifyType rhs ; return (TH.TyConI $ - TH.TySynD (reifyName tc) (reifyTyVars tvs) rhs') } + TH.TySynD (reifyName tc) (reifyTyVars tvs) rhs') + } reifyTyCon tc = do { cxt <- reifyCxt (tyConStupidTheta tc) @@ -608,7 +1057,7 @@ reifyTyCon tc r_tvs = reifyTyVars tvs deriv = [] -- Don't know about deriving decl | isNewTyCon tc = TH.NewtypeD cxt name r_tvs (head cons) deriv - | otherwise = TH.DataD cxt name r_tvs cons deriv + | otherwise = TH.DataD cxt name r_tvs cons deriv ; return (TH.TyConI decl) } reifyDataCon :: [Type] -> DataCon -> TcM TH.Con @@ -630,7 +1079,7 @@ reifyDataCon tys dc else return (TH.NormalC name (stricts `zip` arg_tys)) } | otherwise - = failWithTc (ptext SLIT("Can't reify a non-Haskell-98 data constructor:") + = failWithTc (ptext (sLit "Can't reify a GADT data constructor:") <+> quotes (ppr dc)) ------------------------------ @@ -647,32 +1096,73 @@ reifyClass cls ------------------------------ reifyType :: TypeRep.Type -> TcM TH.Type +reifyType ty@(ForAllTy _ _) = reify_for_all ty +reifyType ty@(PredTy {} `FunTy` _) = reify_for_all ty -- Types like ((?x::Int) => Char -> Char) reifyType (TyVarTy tv) = return (TH.VarT (reifyName tv)) -reifyType (TyConApp tc tys) = reify_tc_app (reifyName tc) tys -reifyType (NoteTy _ ty) = reifyType ty +reifyType (TyConApp tc tys) = reify_tc_app (reifyName tc) tys -- Do not expand type synonyms here 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 +reifyType ty@(PredTy {}) = pprPanic "reifyType PredTy" (ppr ty) + +reify_for_all :: TypeRep.Type -> TcM TH.Type +reify_for_all ty + = do { cxt' <- reifyCxt cxt; + ; tau' <- reifyType tau + ; return (TH.ForallT (reifyTyVars tvs) cxt' tau') } + where + (tvs, cxt, tau) = tcSplitSigmaTy ty + +reifyTypes :: [Type] -> TcM [TH.Type] reifyTypes = mapM reifyType + +reifyKind :: Kind -> TH.Kind +reifyKind ki + = let (kis, ki') = splitKindFunTys ki + kis_rep = map reifyKind kis + ki'_rep = reifyNonArrowKind ki' + in + foldr TH.ArrowK ki'_rep kis_rep + where + reifyNonArrowKind k | isLiftedTypeKind k = TH.StarK + | otherwise = pprPanic "Exotic form of kind" + (ppr k) + +reifyCxt :: [PredType] -> TcM [TH.Pred] reifyCxt = mapM reifyPred reifyFunDep :: ([TyVar], [TyVar]) -> TH.FunDep reifyFunDep (xs, ys) = TH.FunDep (map reifyName xs) (map reifyName ys) -reifyTyVars :: [TyVar] -> [TH.Name] -reifyTyVars = map reifyName +reifyFamFlavour :: TyCon -> TH.FamFlavour +reifyFamFlavour tc | isOpenSynTyCon tc = TH.TypeFam + | isOpenTyCon tc = TH.DataFam + | otherwise + = panic "TcSplice.reifyFamFlavour: not a type family" + +reifyTyVars :: [TyVar] -> [TH.TyVarBndr] +reifyTyVars = map reifyTyVar + where + reifyTyVar tv | isLiftedTypeKind kind = TH.PlainTV name + | otherwise = TH.KindedTV name (reifyKind kind) + where + kind = tyVarKind tv + name = reifyName tv 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) +reifyPred :: TypeRep.PredType -> TcM TH.Pred +reifyPred (ClassP cls tys) + = do { tys' <- reifyTypes tys + ; return $ TH.ClassP (reifyName cls) tys' + } +reifyPred p@(IParam _ _) = noTH (sLit "implicit parameters") (ppr p) +reifyPred (EqPred ty1 ty2) + = do { ty1' <- reifyType ty1 + ; ty2' <- reifyType ty2 + ; return $ TH.EqualP ty1' ty2' + } ------------------------------ @@ -686,7 +1176,7 @@ reifyName thing -- have free variables, we may need to generate NameL's for them. where name = getName thing - mod = nameModule name + mod = ASSERT( isExternalName name ) nameModule name pkg_str = packageIdString (modulePackageId mod) mod_str = moduleNameString (moduleName mod) occ_str = occNameString occ @@ -707,14 +1197,13 @@ reifyFixity name 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 +reifyStrict :: BasicTypes.HsBang -> TH.Strict +reifyStrict bang | isBanged bang = TH.IsStrict + | otherwise = TH.NotStrict ------------------------------ noTH :: LitString -> SDoc -> TcM a -noTH s d = failWithTc (hsep [ptext SLIT("Can't represent") <+> ptext s <+> - ptext SLIT("in Template Haskell:"), +noTH s d = failWithTc (hsep [ptext (sLit "Can't represent") <+> ptext s <+> + ptext (sLit "in Template Haskell:"), nest 2 d]) \end{code}