TcSplice: Template Haskell splices
\begin{code}
-{-# OPTIONS -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/Commentary/CodingStyle#Warnings
-- for details
-module TcSplice( tcSpliceExpr, tcSpliceDecls, tcBracket ) where
+module TcSplice( kcSpliceType, tcSpliceExpr, tcSpliceDecls, tcBracket,
+ lookupThName_maybe,
+ runQuasiQuoteExpr, runQuasiQuotePat, runAnnotation ) where
#include "HsVersions.h"
import TypeRep
import Name
import NameEnv
+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
import DsMeta
import DsExpr
import DsMonad hiding (Splice)
+import Serialized
import ErrUtils
import SrcLoc
import Outputable
import Unique
-import DynFlags
-import PackageConfig
import Maybe
import BasicTypes
import Panic
import FastString
+import Exception
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 qualified Control.Exception as Exception( userErrors )
+import System.IO.Error
\end{code}
Note [Template Haskell levels]
%************************************************************************
\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)
-- None of these functions add constraints to the LIE
+lookupThName_maybe :: TH.Name -> TcM (Maybe Name)
+
+runQuasiQuoteExpr :: HsQuasiQuote Name -> TcM (LHsExpr RdrName)
+runQuasiQuotePat :: HsQuasiQuote Name -> TcM (LPat 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 = 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)
+runAnnotation _ q = pprPanic "Cant do runAnnotation without GHCi" (ppr q)
#else
\end{code}
; 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 ->
+tcBracket brack res_ty
+ = addErrCtxt (hang (ptext (sLit "In the Template Haskell quotation"))
+ 2 (ppr brack)) $
+ do { level <- getStage
+ ; case bracketOK level of {
+ Nothing -> failWithTc (illegalBracket level) ;
+ Just next_level -> do {
-- 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 ->
+ recordThUse
+ ; pending_splices <- newMutVar []
+ ; lie_var <- getLIEVar
- setStage (Brack next_level pending_splices lie_var) (
- getLIE (tc_bracket next_level brack)
- ) `thenM` \ (meta_ty, lie) ->
- tcSimplifyBracket lie `thenM_`
+ ; (meta_ty, lie) <- setStage (Brack next_level pending_splices lie_var)
+ (getLIE (tc_bracket next_level 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))
- }
+ ; pendings <- readMutVar pending_splices
+ ; return (noLoc (HsBracketOut brack pendings)) }}}
tc_bracket :: ThLevel -> HsBracket Name -> TcM TcType
tc_bracket use_lvl (VarBr name) -- Note [Quoting names]
| otherwise
-> do { checkTc (use_lvl == bind_lvl)
(quotedNameStageErr name) }
- other -> pprPanic "th_bracket" (ppr name)
+ _ -> pprPanic "th_bracket" (ppr name)
; tcMetaTy nameTyConName -- Result type is Var (not Q-monadic)
}
-tc_bracket use_lvl (ExpBr expr)
+tc_bracket _ (ExpBr expr)
= do { any_ty <- newFlexiTyVarTy liftedTypeKind
- ; tcMonoExpr expr any_ty
+ ; tcMonoExprNC expr any_ty -- NC for no context; tcBracket does that
; tcMetaTy expQTyConName }
-- Result type is Expr (= Q Exp)
-tc_bracket use_lvl (TypBr typ)
- = do { tcHsSigType ExprSigCtxt typ
+tc_bracket _ (TypBr typ)
+ = do { tcHsSigTypeNC ThBrackCtxt typ
; tcMetaTy typeQTyConName }
-- Result type is Type (= Q Typ)
-tc_bracket use_lvl (DecBr decls)
+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
-- Result type is Q [Dec]
}
-tc_bracket use_lvl (PatBr _)
- = failWithTc (ptext SLIT("Tempate Haskell pattern brackets are not supported yet"))
+tc_bracket _ (PatBr _)
+ = failWithTc (ptext (sLit "Tempate Haskell pattern brackets are not supported yet"))
+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")]
+ = 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}
\begin{code}
tcSpliceExpr (HsSplice name expr) res_ty
- = setSrcSpan (getLoc expr) $
- getStage `thenM` \ level ->
+ = setSrcSpan (getLoc expr) $ do
+ level <- getStage
case spliceOK level of {
Nothing -> failWithTc (illegalSplice level) ;
Just next_level ->
- case level of {
- Comp -> do { e <- tcTopSplice expr res_ty
- ; returnM (unLoc e) } ;
- Brack _ ps_var lie_var ->
+ case level of {
+ Comp _ -> do { e <- tcTopSplice expr res_ty
+ ; return (unLoc e) } ;
+ Brack _ ps_var lie_var -> do
-- A splice inside brackets
-- NB: ignore res_ty, apart from zapping it to a mono-type
-- 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 (Splice next_level) (
+ 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
+
+ ; Splice {} -> panic "tcSpliceExpr Splice"
+ }}
-- tcTopSplice used to have this:
-- Note that we do not decrement the level (to -1) before
-- inner escape before dealing with the outer one
tcTopSplice :: LHsExpr Name -> BoxyRhoType -> TcM (LHsExpr Id)
-tcTopSplice expr res_ty
- = tcMetaTy expQTyConName `thenM` \ meta_exp_ty ->
+tcTopSplice expr res_ty = do
+ meta_exp_ty <- tcMetaTy expQTyConName
- -- Typecheck the expression
- tcTopSpliceExpr expr meta_exp_ty `thenM` \ zonked_q_expr ->
+ -- Typecheck the expression
+ zonked_q_expr <- tcTopSpliceExpr expr meta_exp_ty
- -- 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_`
+ -- Run the expression
+ traceTc (text "About to run" <+> ppr zonked_q_expr)
+ expr2 <- runMetaE convertToHsExpr zonked_q_expr
+
+ traceTc (text "Got result" <+> ppr expr2)
showSplice "expression"
- zonked_q_expr (ppr expr2) `thenM_`
+ zonked_q_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
+ (exp3, _fvs) <- checkNoErrs (rnLExpr expr2)
tcMonoExpr exp3 res_ty
tcTopSpliceExpr :: LHsExpr Name -> TcType -> TcM (LHsExpr Id)
-- 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!
+tcTopSpliceExpr expr meta_ty
+ = checkNoErrs $ -- checkNoErrs: must not try to run the thing
+ -- if the type checker fails!
+ do { (expr', const_binds) <- tcSimplifyStagedExpr topSpliceStage $
+ (recordThUse >> tcMonoExpr expr meta_ty)
+ -- Zonk it and tie the knot of dictionary bindings
+ ; zonkTopLExpr (mkHsDictLet const_binds expr') }
+\end{code}
- setStage topSpliceStage $ do
-
- do { recordThUse -- Record that TH is used (for pkg depdendency)
+%************************************************************************
+%* *
+ Annotations
+%* *
+%************************************************************************
- -- Typecheck the expression
- ; (expr', lie) <- getLIE (tcMonoExpr expr meta_ty)
-
- -- Solve the constraints
- ; const_binds <- tcSimplifyTop lie
-
- -- And zonk it
- ; zonkTopLExpr (mkHsDictLet const_binds expr') }
+\begin{code}
+runAnnotation target expr = do
+ expr_ty <- newFlexiTyVarTy liftedTypeKind
+
+ -- Find the classes we want instances for in order to call toAnnotationWrapper
+ data_class <- tcLookupClass dataClassName
+
+ -- 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
+ ((wrapper, expr'), const_binds) <- tcSimplifyStagedExpr topAnnStage $ do
+ expr' <- tcPolyExprNC expr expr_ty
+ -- By instantiating the call >here< it gets registered in the
+ -- LIE consulted by tcSimplifyStagedExpr
+ -- and hence ensures the appropriate dictionary is bound by const_binds
+ wrapper <- instCall AnnOrigin [expr_ty] [mkClassPred data_class [expr_ty]]
+ return (wrapper, expr')
+
+ -- We manually wrap the typechecked expression in a call to toAnnotationWrapper
+ loc <- getSrcSpanM
+ to_annotation_wrapper_id <- tcLookupId toAnnotationWrapperName
+ let specialised_to_annotation_wrapper_expr = L loc (HsWrap wrapper (HsVar to_annotation_wrapper_id))
+ wrapped_expr' = mkHsDictLet const_binds $
+ L loc (HsApp specialised_to_annotation_wrapper_expr expr')
+
+ -- If we have type checking problems then potentially zonking
+ -- (and certainly compilation) may fail. Give up NOW!
+ failIfErrsM
+
+ -- Zonk the type variables out of that raw expression. Note that
+ -- in particular we don't call recordThUse, since we don't
+ -- necessarily use any code or definitions from that package.
+ zonked_wrapped_expr' <- zonkTopLExpr wrapped_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.
+
+\begin{code}
+runQuasiQuote :: Outputable hs_syn
+ => HsQuasiQuote Name -- Contains term of type QuasiQuoter, and the String
+ -> Name -- Of type QuasiQuoter -> String -> Q th_syn
+ -> String -- Documentation string only
+ -> Name -- Name of th_syn type
+ -> (SrcSpan -> th_syn -> Either Message hs_syn)
+ -> TcM hs_syn
+runQuasiQuote (HsQuasiQuote _name quoter q_span quote) quote_selector desc meta_ty convert
+ = do { -- 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 = case nameModule_maybe quoter of
+ Just mod | mod == this_mod -> True
+ | otherwise -> False
+ Nothing -> True
+ ; traceTc (text "runQQ" <+> ppr quoter <+> ppr is_local)
+ ; checkTc (not is_local) (quoteStageError quoter)
+
+ -- 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
+ ; recordThUse
+ ; meta_exp_ty <- tcMetaTy meta_ty
+
+ -- Typecheck the expression
+ ; zonked_q_expr <- tcTopSpliceExpr expr meta_exp_ty
+
+ -- Run the expression
+ ; traceTc (text "About to run" <+> ppr zonked_q_expr)
+ ; result <- runMetaQ convert zonked_q_expr
+ ; traceTc (text "Got result" <+> ppr result)
+ ; showSplice desc zonked_q_expr (ppr result)
+ ; return result
+ }
+
+runQuasiQuoteExpr quasiquote
+ = runQuasiQuote quasiquote quoteExpName "expression" expQTyConName convertToHsExpr
+
+runQuasiQuotePat quasiquote
+ = runQuasiQuote quasiquote quotePatName "pattern" patQTyConName convertToPat
+
+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}
Just next_level -> do
{ case level of {
- Comp -> do { (t,k) <- kcTopSpliceType hs_expr
+ Comp _ -> do { (t,k) <- kcTopSpliceType hs_expr
; return (unLoc t, k) } ;
Brack _ ps_var lie_var -> do
-- 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
- }}}}}
+ ; return (panic "kcSpliceType", kind) -- The returned type is ignored
+ }
+ ; Splice {} -> panic "kcSpliceType Splice"
+ }}}}
kcTopSpliceType :: LHsExpr Name -> TcM (LHsType Name, TcKind)
kcTopSpliceType expr
-- 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
+ ; let doc = ptext (sLit "In the spliced type") <+> ppr hs_ty2
; hs_ty3 <- checkNoErrs (rnLHsType doc hs_ty2)
- ; kcHsType hs_ty3 }
+ ; kcLHsType hs_ty3 }
\end{code}
%************************************************************************
; showSplice "declarations"
zonked_q_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}
%************************************************************************
\begin{code}
+runMetaAW :: (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
+
+runQThen :: (SrcSpan -> input -> Either Message output)
+ -> SrcSpan
+ -> TH.Q input
+ -> TcM (Either Message output)
+runQThen f expr_span what = TH.runQ what >>= (return . f expr_span)
+
+runMetaQ :: (SrcSpan -> input -> Either Message output)
+ -> LHsExpr Id
+ -> TcM output
+runMetaQ = runMeta True . runQThen
+
runMetaE :: (SrcSpan -> TH.Exp -> Either Message (LHsExpr RdrName))
-> LHsExpr Id -- Of type (Q Exp)
-> TcM (LHsExpr RdrName)
-runMetaE = runMeta
+runMetaE = runMetaQ
+
+runMetaP :: (SrcSpan -> TH.Pat -> Either Message (Pat RdrName))
+ -> LHsExpr Id -- Of type (Q Pat)
+ -> TcM (Pat RdrName)
+runMetaP = runMetaQ
runMetaT :: (SrcSpan -> TH.Type -> Either Message (LHsType RdrName))
-> LHsExpr Id -- Of type (Q Type)
-> TcM (LHsType RdrName)
-runMetaT = runMeta
+runMetaT = runMetaQ
runMetaD :: (SrcSpan -> [TH.Dec] -> Either Message [LHsDecl RdrName])
-> LHsExpr Id -- Of type Q [Dec]
-> TcM [LHsDecl RdrName]
-runMetaD = runMeta
+runMetaD = runMetaQ
-runMeta :: (SrcSpan -> th_syn -> Either Message hs_syn)
+runMeta :: Bool -- Whether code should be printed in the exception message
+ -> (SrcSpan -> input -> TcM (Either Message output))
-> LHsExpr Id -- Of type X
- -> TcM hs_syn -- Of type t
-runMeta convert expr
+ -> TcM output -- Of type t
+runMeta show_code run_and_convert expr
= do { -- 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) ;
-- encounter them inside the try
--
-- See Note [Exceptions in TH]
- either_tval <- tryAllM $ do
- { th_syn <- TH.runQ (unsafeCoerce# hval)
- ; case convert (getLoc expr) th_syn of
+ 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 hs_syn -> return hs_syn }
+ Right result -> return $! result }
; case either_tval of
Right v -> return v
- Left exn | Just s <- Exception.userErrors exn
- , s == "IOEnv failure"
- -> failM -- Error already in Tc monad
- | otherwise -> failWithTc (mk_msg "run" exn) -- Exception
+ 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]
* 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 a UserError, with the uninteresting string
- "IOEnv failure"
+ The 'fail' in TcM raises an IOEnvFailure exception
* So, when running a splice, we catch all exceptions; then for
- - a UserError "IOEnv failure", we assume the error is already
+ - 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
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?
-
+ 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
Nothing -> recover -- Discard all msgs
}
- qRunIO io = ioToTcRn io
+ qRunIO io = liftIO io
\end{code}
\begin{code}
showSplice :: String -> LHsExpr Id -> SDoc -> TcM ()
-showSplice what before after
- = getSrcSpanM `thenM` \ loc ->
+showSplice what before after = do
+ loc <- getSrcSpanM
traceSplice (vcat [ppr loc <> colon <+> text "Splicing" <+> text what,
nest 2 (sep [nest 2 (ppr before),
text "======>",
nest 2 after])])
+illegalBracket :: ThStage -> SDoc
illegalBracket level
- = ptext SLIT("Illegal bracket at level") <+> ppr level
+ = ptext (sLit "Illegal bracket at level") <+> ppr level
+illegalSplice :: ThStage -> SDoc
illegalSplice level
- = ptext SLIT("Illegal splice at level") <+> ppr level
+ = ptext (sLit "Illegal splice at level") <+> ppr level
#endif /* GHCI */
\end{code}
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
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
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
= do { ty <- reifyType (idType id)
; fix <- reifyFixity (idName id)
; let v = reifyName id
- ; case globalIdDetails id of
+ ; case idDetails id of
ClassOpId cls -> return (TH.ClassOpI v ty (reifyName cls) fix)
- other -> return (TH.VarI v ty Nothing fix)
+ _ -> return (TH.VarI v ty Nothing fix)
}
reifyThing (AGlobal (ATyCon tc)) = reifyTyCon tc
= 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
; 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)
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
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))
------------------------------
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 (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;
; return (TH.ForallT (reifyTyVars tvs) cxt' tau') }
where
(tvs, cxt, tau) = tcSplitSigmaTy ty
+reifyType (PredTy {}) = panic "reifyType PredTy"
+
+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
+ foldl 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'
+ }
------------------------------
-- 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
------------------------------
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}
projects / ghc-hetmet.git / blobdiff