-2%
+%
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[TcSplice]{Template Haskell splices}
#include "HsVersions.h"
import HscMain ( compileExpr )
-import TcRnDriver ( importSupportingDecls, tcTopSrcDecls )
+import TcRnDriver ( tcTopSrcDecls )
-- These imports are the reason that TcSplice
-- is very high up the module hierarchy
-import qualified Language.Haskell.THSyntax as Meta
-
-import HscTypes ( HscEnv(..), GhciMode(..), PersistentCompilerState(..), unQualInScope )
-import HsSyn ( HsBracket(..) )
-import Convert ( convertToHsExpr, convertToHsDecls )
-import RnExpr ( rnExpr )
-import RdrHsSyn ( RdrNameHsExpr, RdrNameHsDecl )
-import RnHsSyn ( RenamedHsExpr )
-import TcExpr ( tcMonoExpr )
-import TcHsSyn ( TcExpr, TypecheckedHsExpr, mkHsLet, zonkTopExpr )
-import TcSimplify ( tcSimplifyTop )
-import TcType ( TcType, openTypeKind, mkAppTy )
-import TcEnv ( spliceOK, tcMetaTy )
-import TcRnTypes ( TopEnv(..) )
-import TcMType ( newTyVarTy )
-import Name ( Name )
+import qualified Language.Haskell.TH as TH
+-- THSyntax gives access to internal functions and data types
+import qualified Language.Haskell.TH.Syntax as TH
+
+import HsSyn ( HsBracket(..), HsExpr(..), HsSplice(..), LHsExpr, LHsDecl,
+ HsType, LHsType )
+import Convert ( convertToHsExpr, convertToHsDecls, convertToHsType )
+import RnExpr ( rnLExpr )
+import RnEnv ( lookupFixityRn, lookupSrcOcc_maybe )
+import RdrName ( RdrName, mkRdrUnqual, lookupLocalRdrEnv )
+import RnTypes ( rnLHsType )
+import TcExpr ( tcCheckRho, tcMonoExpr )
+import TcHsSyn ( mkHsLet, zonkTopLExpr )
+import TcSimplify ( tcSimplifyTop, tcSimplifyBracket )
+import TcUnify ( Expected, zapExpectedTo, zapExpectedType )
+import TcType ( TcType, TcKind, liftedTypeKind, mkAppTy, tcSplitSigmaTy )
+import TcEnv ( spliceOK, tcMetaTy, bracketOK )
+import TcMType ( newTyFlexiVarTy, newKindVar, UserTypeCtxt(ExprSigCtxt), zonkTcType, zonkTcTyVar )
+import TcHsType ( tcHsSigType, kcHsType )
+import TcIface ( tcImportDecl )
+import TypeRep ( Type(..), PredType(..), TyThing(..) ) -- For reification
+import Name ( Name, NamedThing(..), nameOccName, nameModule, isExternalName,
+ mkInternalName, nameIsLocalOrFrom )
+import NameEnv ( lookupNameEnv )
+import HscTypes ( lookupType, ExternalPackageState(..) )
+import OccName
+import Var ( Id, TyVar, idType )
+import Module ( moduleUserString, mkModuleName )
import TcRnMonad
-
+import IfaceEnv ( lookupOrig )
+import Class ( Class, classExtraBigSig )
+import TyCon ( TyCon, AlgTyConRhs(..), tyConTyVars, getSynTyConDefn,
+ isSynTyCon, isNewTyCon, tyConDataCons, algTyConRhs )
+import DataCon ( DataCon, dataConTyCon, dataConOrigArgTys, dataConStrictMarks,
+ dataConName, dataConFieldLabels, dataConWrapId, dataConIsInfix,
+ isVanillaDataCon )
+import Id ( idName, globalIdDetails )
+import IdInfo ( GlobalIdDetails(..) )
import TysWiredIn ( mkListTy )
-import DsMeta ( exprTyConName, declTyConName, decTyConName, qTyConName )
+import DsMeta ( expQTyConName, typeQTyConName, decTyConName, qTyConName, nameTyConName )
+import ErrUtils ( Message )
+import SrcLoc ( noLoc, unLoc, getLoc, noSrcLoc )
import Outputable
-import GHC.Base ( unsafeCoerce# ) -- Should have a better home in the module hierarchy
+import Unique ( Unique, Uniquable(..), getKey, mkUniqueGrimily )
+
+import BasicTypes ( StrictnessMark(..), Fixity(..), FixityDirection(..) )
+import Panic ( showException )
+import FastString ( LitString )
+
+import GHC.Base ( unsafeCoerce#, Int#, Int(..) ) -- Should have a better home in the module hierarchy
+import Monad ( liftM )
+import Maybes ( orElse )
+
+#ifdef GHCI
+import FastString ( mkFastString )
+#endif
\end{code}
%************************************************************************
\begin{code}
-tcSpliceDecls :: RenamedHsExpr -> TcM [RdrNameHsDecl]
-
-tcSpliceExpr :: Name
- -> RenamedHsExpr
- -> TcType
- -> TcM TcExpr
+tcSpliceDecls :: LHsExpr Name -> TcM [LHsDecl RdrName]
+tcSpliceExpr :: HsSplice Name -> Expected TcType -> TcM (HsExpr TcId)
+kcSpliceType :: HsSplice Name -> TcM (HsType Name, TcKind)
#ifndef GHCI
tcSpliceExpr n e ty = pprPanic "Cant do tcSpliceExpr without GHCi" (ppr e)
%************************************************************************
%* *
-\subsection{Splicing an expression}
+\subsection{Quoting an expression}
%* *
%************************************************************************
\begin{code}
-tcBracket :: HsBracket Name -> TcM TcType
-tcBracket (ExpBr expr)
- = newTyVarTy openTypeKind `thenM` \ any_ty ->
- tcMonoExpr expr any_ty `thenM_`
- tcMetaTy exprTyConName
+tcBracket :: HsBracket Name -> Expected TcType -> TcM (LHsExpr Id)
+tcBracket brack res_ty
+ = getStage `thenM` \ level ->
+ case bracketOK level of {
+ Nothing -> failWithTc (illegalBracket level) ;
+ Just next_level ->
+
+ -- 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 ->
+
+ setStage (Brack next_level pending_splices lie_var) (
+ getLIE (tc_bracket brack)
+ ) `thenM` \ (meta_ty, lie) ->
+ tcSimplifyBracket lie `thenM_`
+
+ -- Make the expected type have the right shape
+ zapExpectedTo res_ty meta_ty `thenM_`
+
+ -- 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)
+
+tc_bracket (ExpBr expr)
+ = newTyFlexiVarTy liftedTypeKind `thenM` \ any_ty ->
+ tcCheckRho expr any_ty `thenM_`
+ tcMetaTy expQTyConName
-- Result type is Expr (= Q Exp)
-tcBracket (DecBr decls)
- = tcTopSrcDecls decls `thenM_`
- tcMetaTy decTyConName `thenM` \ decl_ty ->
- tcMetaTy qTyConName `thenM` \ q_ty ->
+tc_bracket (TypBr typ)
+ = tcHsSigType ExprSigCtxt typ `thenM_`
+ tcMetaTy typeQTyConName
+ -- Result type is Type (= Q Typ)
+
+tc_bracket (DecBr decls)
+ = tcTopSrcDecls [{- no boot-names -}] decls `thenM_`
+ -- Typecheck the declarations, dicarding the result
+ -- We'll get all that stuff later, when we splice it in
+
+ tcMetaTy decTyConName `thenM` \ decl_ty ->
+ tcMetaTy qTyConName `thenM` \ q_ty ->
returnM (mkAppTy q_ty (mkListTy decl_ty))
-- Result type is Q [Dec]
\end{code}
%************************************************************************
\begin{code}
-tcSpliceExpr name expr res_ty
- = getStage `thenM` \ level ->
+tcSpliceExpr (HsSplice name expr) res_ty
+ = setSrcSpan (getLoc expr) $
+ getStage `thenM` \ level ->
case spliceOK level of {
Nothing -> failWithTc (illegalSplice level) ;
Just next_level ->
case level of {
- Comp -> tcTopSplice expr res_ty ;
+ Comp -> do { e <- tcTopSplice expr res_ty
+ ; returnM (unLoc e) } ;
Brack _ ps_var lie_var ->
-- A splice inside brackets
- -- NB: ignore res_ty
+ -- 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!
- tcMetaTy exprTyConName `thenM` \ meta_exp_ty ->
+ zapExpectedType res_ty liftedTypeKind `thenM_`
+ tcMetaTy expQTyConName `thenM` \ meta_exp_ty ->
setStage (Splice next_level) (
setLIEVar lie_var $
- tcMonoExpr expr meta_exp_ty
+ tcCheckRho expr meta_exp_ty
) `thenM` \ expr' ->
-- Write the pending splice into the bucket
-- The recursive call to tcMonoExpr will simply expand the
-- inner escape before dealing with the outer one
+tcTopSplice :: LHsExpr Name -> Expected TcType -> TcM (LHsExpr Id)
tcTopSplice expr res_ty
- = tcMetaTy exprTyConName `thenM` \ meta_exp_ty ->
- setStage topSpliceStage (
- getLIE (tcMonoExpr expr meta_exp_ty)
- ) `thenM` \ (expr', lie) ->
+ = tcMetaTy expQTyConName `thenM` \ meta_exp_ty ->
- -- Solve the constraints
- tcSimplifyTop lie `thenM` \ const_binds ->
- let
- q_expr = mkHsLet const_binds expr'
- in
- zonkTopExpr q_expr `thenM` \ zonked_q_expr ->
+ -- Typecheck the expression
+ tcTopSpliceExpr expr meta_exp_ty `thenM` \ zonked_q_expr ->
-- Run the expression
traceTc (text "About to run" <+> ppr zonked_q_expr) `thenM_`
runMetaE zonked_q_expr `thenM` \ simple_expr ->
let
- -- simple_expr :: Meta.Exp
+ -- simple_expr :: TH.Exp
- expr2 :: RdrNameHsExpr
+ expr2 :: LHsExpr RdrName
expr2 = convertToHsExpr simple_expr
in
traceTc (text "Got result" <+> ppr expr2) `thenM_`
showSplice "expression"
zonked_q_expr (ppr expr2) `thenM_`
- initRn SourceMode (rnExpr expr2) `thenM` \ (exp3, fvs) ->
- importSupportingDecls fvs `thenM` \ env ->
- setGblEnv env (tcMonoExpr exp3 res_ty)
+ -- Rename it, but bale out if there are errors
+ -- otherwise the type checker just gives more spurious errors
+ checkNoErrs (rnLExpr expr2) `thenM` \ (exp3, fvs) ->
+
+ 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!
+
+ setStage topSpliceStage $ do
+
+
+ do { recordThUse -- Record that TH is used (for pkg depdendency)
+
+ -- Typecheck the expression
+ ; (expr', lie) <- getLIE (tcCheckRho expr meta_ty)
+
+ -- Solve the constraints
+ ; const_binds <- tcSimplifyTop lie
+
+ -- And zonk it
+ ; zonkTopLExpr (mkHsLet const_binds expr') }
\end{code}
%************************************************************************
%* *
+ Splicing a type
+%* *
+%************************************************************************
+
+Very like splicing an expression, but we don't yet share code.
+
+\begin{code}
+kcSpliceType (HsSplice name hs_expr)
+ = 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 $
+ tcCheckRho 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)
+kcTopSpliceType expr
+ = do { meta_ty <- tcMetaTy typeQTyConName
+
+ -- Typecheck the expression
+ ; zonked_q_expr <- tcTopSpliceExpr expr meta_ty
+
+ -- Run the expression
+ ; traceTc (text "About to run" <+> ppr zonked_q_expr)
+ ; simple_ty <- runMetaT zonked_q_expr
+
+ ; let -- simple_ty :: TH.Type
+ hs_ty2 :: LHsType RdrName
+ hs_ty2 = convertToHsType simple_ty
+
+ ; 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
+ ; hs_ty3 <- checkNoErrs (rnLHsType doc hs_ty2)
+
+ ; kcHsType hs_ty3 }
+\end{code}
+
+%************************************************************************
+%* *
\subsection{Splicing an expression}
%* *
%************************************************************************
\begin{code}
-- Always at top level
tcSpliceDecls expr
- = tcMetaTy decTyConName `thenM` \ meta_dec_ty ->
- tcMetaTy qTyConName `thenM` \ meta_q_ty ->
- setStage topSpliceStage (
- getLIE (tcMonoExpr expr (mkAppTy meta_q_ty (mkListTy meta_dec_ty)))
- ) `thenM` \ (expr', lie) ->
- -- Solve the constraints
- tcSimplifyTop lie `thenM` \ const_binds ->
- let
- q_expr = mkHsLet const_binds expr'
- in
- zonkTopExpr q_expr `thenM` \ zonked_q_expr ->
-
- -- Run the expression
- traceTc (text "About to run" <+> ppr zonked_q_expr) `thenM_`
- runMetaD zonked_q_expr `thenM` \ simple_expr ->
- let
- -- simple_expr :: [Meta.Dec]
- decls :: [RdrNameHsDecl]
- decls = convertToHsDecls simple_expr
- in
- traceTc (text "Got result" <+> vcat (map ppr decls)) `thenM_`
- showSplice "declarations"
- zonked_q_expr (vcat (map ppr decls)) `thenM_`
- returnM decls
+ = 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
+
+ -- Run the expression
+ ; traceTc (text "About to run" <+> ppr zonked_q_expr)
+ ; simple_expr <- runMetaD zonked_q_expr
+
+ -- simple_expr :: [TH.Dec]
+ -- decls :: [RdrNameHsDecl]
+ ; decls <- handleErrors (convertToHsDecls simple_expr)
+ ; traceTc (text "Got result" <+> vcat (map ppr decls))
+ ; showSplice "declarations"
+ zonked_q_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
\end{code}
%************************************************************************
\begin{code}
-runMetaE :: TypecheckedHsExpr -- Of type (Q Exp)
- -> TcM Meta.Exp -- Of type Exp
+runMetaE :: LHsExpr Id -- Of type (Q Exp)
+ -> TcM TH.Exp -- Of type Exp
runMetaE e = runMeta e
-runMetaD :: TypecheckedHsExpr -- Of type Q [Dec]
- -> TcM [Meta.Dec] -- Of type [Dec]
-runMetaD e = runMeta e
-
--- Warning: if Q is anything other than IO, we need to change this
-tcRunQ :: Meta.Q a -> TcM a
-tcRunQ thing = ioToTcRn thing
+runMetaT :: LHsExpr Id -- Of type (Q Type)
+ -> TcM TH.Type -- Of type Type
+runMetaT e = runMeta e
+runMetaD :: LHsExpr Id -- Of type Q [Dec]
+ -> TcM [TH.Dec] -- Of type [Dec]
+runMetaD e = runMeta e
-runMeta :: TypecheckedHsExpr -- Of type X
+runMeta :: LHsExpr Id -- Of type X
-> TcM t -- Of type t
runMeta expr
- = getTopEnv `thenM` \ top_env ->
- getEps `thenM` \ eps ->
- getNameCache `thenM` \ name_cache ->
- getModule `thenM` \ this_mod ->
- getGlobalRdrEnv `thenM` \ rdr_env ->
- let
- ghci_mode = top_mode top_env
-
- hsc_env = HscEnv { hsc_mode = ghci_mode, hsc_HPT = top_hpt top_env,
- hsc_dflags = top_dflags top_env }
-
- pcs = PCS { pcs_nc = name_cache, pcs_EPS = eps }
-
- print_unqual = unQualInScope rdr_env
- in
- if (ghci_mode == OneShot) then
- failWithTc (ptext SLIT("You must use --make or --interactive to run splice expressions"))
- -- The reason for this is that the demand-linker doesn't have
- -- enough information available to link all the things that
- -- are needed when you try to run a splice
- else
-
- ioToTcRn (HscMain.compileExpr hsc_env pcs this_mod
- print_unqual expr) `thenM` \ hval ->
-
- tryM (tcRunQ (unsafeCoerce# hval)) `thenM` \ either_tval ->
-
- case either_tval of
- Left exn -> failWithTc (vcat [text "Exception when running compile-time code:",
- nest 4 (vcat [text "Code:" <+> ppr expr,
- text ("Exn: " ++ show exn)])])
- Right v -> returnM v
+ = do { hsc_env <- getTopEnv
+ ; tcg_env <- getGblEnv
+ ; this_mod <- getModule
+ ; let type_env = tcg_type_env tcg_env
+ rdr_env = tcg_rdr_env tcg_env
+ -- Wrap the compile-and-run in an exception-catcher
+ -- Compiling might fail if linking fails
+ -- Running might fail if it throws an exception
+ ; either_tval <- tryM $ do
+ { -- Compile it
+ hval <- ioToTcRn (HscMain.compileExpr
+ hsc_env this_mod
+ rdr_env type_env expr)
+ -- Coerce it to Q t, and run it
+ ; TH.runQ (unsafeCoerce# hval) }
+
+ ; case either_tval of
+ Left exn -> failWithTc (vcat [text "Exception when trying to run compile-time code:",
+ nest 4 (vcat [text "Code:" <+> ppr expr,
+ text ("Exn: " ++ Panic.showException exn)])])
+ Right v -> returnM v }
\end{code}
+To call runQ in the Tc monad, we need to make TcM an instance of Quasi:
+\begin{code}
+instance TH.Quasi (IOEnv (Env TcGblEnv TcLclEnv)) where
+ qNewName s = do { u <- newUnique
+ ; let i = getKey u
+ ; return (TH.mkNameU s i) }
------------------------------------
- Random comments
-
-
- module Foo where
- import Lib( g :: Int -> M Exp )
- h x = not x
- f x y = [| \z -> (x, $(g y), z, map, h) |]
-
- h p = $( (\q r -> if q then [| \s -> (p,r,s) |]
- else ... ) True 3) )
-
-==> core
-
- f :: Liftable a => a -> Int -> M Exp
- f = /\a -> \d::Liftable a ->
- \ x y -> genSym "z" `bindM` \ z::String ->
- g y `bindM` \ vv::Exp ->
- Lam z (Tup [lift d x, v, Var z,
- Glob "Prelude" "map",
- Glob "Foo" "h"])
-
-
- h :: Tree Int -> M Exp
- h = \p -> \s' -> (p,3,s')
-
-
- Bound Used
-
- map: C0 C1 (top-level/imp)
- x: C0 C1 (lam/case)
- y: C0 C0
- z: C1 C1
-
- p: C0 S1
- r: S0 S1
- q: S0 S0
- s: S1 S1
-
--------
-
- f x y = lam "z" (tup [lift x, g y, var "z",
- [| map |], [| h |] ])
-==> core
-
- f = \x y -> lam "z" (tup [lift d x, g y, var "z",
- return (Glob "Prelude" "map"),
- return (Glob "Foo" "h")])
-
-
-
-
-
-
-
- h :: M Exp -> M Exp
- h v = [| \x -> map $v x |]
-
- g :: Tree Int -> M Exp
- g x = $(h [| x |])
-==>
- g x = \x' -> map x x'
-
-*** Simon claims x does not have to be liftable! **
-
-Level 0 compile time
-Level 1 run time
-Level 2 code returned by run time (generation time)
-
-Non-top-level variables
- x occurs at level 1
- inside brackets
- bound at level 0 --> x
- bound at level 1 --> var "x"
-
- not inside brackets --> x
-
- x at level 2
- inside brackets
- bound at level 0 --> x
- bound at level 1 --> var "x"
+ qReport True msg = addErr (text msg)
+ qReport False msg = addReport (text msg)
- f x = x
+ qCurrentModule = do { m <- getModule; return (moduleUserString m) }
+ qReify v = reify v
+ qRecover = recoverM
-Two successive brackets aren't allowed
+ qRunIO io = ioToTcRn io
+\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-showSplice :: String -> TypecheckedHsExpr -> SDoc -> TcM ()
+showSplice :: String -> LHsExpr Id -> SDoc -> TcM ()
showSplice what before after
- = getSrcLocM `thenM` \ loc ->
+ = 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
#endif /* GHCI */
\end{code}
+
+
+%************************************************************************
+%* *
+ Reification
+%* *
+%************************************************************************
+
+
+\begin{code}
+reify :: TH.Name -> TcM TH.Info
+reify th_name
+ = do { name <- lookupThName th_name
+ ; thing <- tcLookupTh name
+ -- ToDo: this tcLookup could fail, which would give a
+ -- rather unhelpful error message
+ ; reifyThing thing
+ }
+
+lookupThName :: TH.Name -> TcM Name
+lookupThName (TH.Name occ (TH.NameG th_ns mod))
+ = lookupOrig (mkModuleName (TH.modString mod))
+ (OccName.mkOccName ghc_ns (TH.occString occ))
+ where
+ ghc_ns = case th_ns of
+ TH.DataName -> dataName
+ TH.TcClsName -> tcClsName
+ TH.VarName -> varName
+
+lookupThName th_name@(TH.Name occ TH.NameS)
+ = do { let rdr_name = mkRdrUnqual (OccName.mkOccFS ns occ_fs)
+ ; rdr_env <- getLocalRdrEnv
+ ; case lookupLocalRdrEnv rdr_env rdr_name of
+ Just name -> return name
+ Nothing -> do
+ { mb_name <- lookupSrcOcc_maybe rdr_name
+ ; case mb_name of
+ Just name -> return name ;
+ Nothing -> failWithTc (notInScope th_name)
+ }}
+ where
+ ns | isLexCon occ_fs = OccName.dataName
+ | otherwise = OccName.varName
+ occ_fs = mkFastString (TH.occString occ)
+
+lookupThName (TH.Name occ (TH.NameU uniq))
+ = return (mkInternalName (mk_uniq uniq) (OccName.mkOccFS bogus_ns occ_fs) noSrcLoc)
+ where
+ occ_fs = mkFastString (TH.occString occ)
+ bogus_ns = OccName.varName -- Not yet recorded in the TH name
+ -- but only the unique matters
+
+tcLookupTh :: Name -> TcM TcTyThing
+-- This is a specialised version of TcEnv.tcLookup; specialised mainly in that
+-- it gives a reify-related error message on failure, whereas in the normal
+-- tcLookup, failure is a bug.
+tcLookupTh name
+ = do { (gbl_env, lcl_env) <- getEnvs
+ ; case lookupNameEnv (tcl_env lcl_env) name of
+ Just thing -> returnM thing
+ Nothing -> do
+ { if nameIsLocalOrFrom (tcg_mod gbl_env) name
+ then -- It's defined in this module
+ case lookupNameEnv (tcg_type_env gbl_env) name of
+ Just thing -> return (AGlobal thing)
+ Nothing -> failWithTc (notInEnv name)
+
+ else do -- It's imported
+ { (eps,hpt) <- getEpsAndHpt
+ ; case lookupType hpt (eps_PTE eps) name of
+ Just thing -> return (AGlobal thing)
+ Nothing -> do { traceIf (text "tcLookupGlobal" <+> ppr name)
+ ; thing <- initIfaceTcRn (tcImportDecl name)
+ ; return (AGlobal thing) }
+ -- Imported names should always be findable;
+ -- if not, we fail hard in tcImportDecl
+ }}}
+
+mk_uniq :: Int# -> Unique
+mk_uniq u = mkUniqueGrimily (I# u)
+
+notInScope :: TH.Name -> SDoc
+notInScope th_name = quotes (text (TH.pprint th_name)) <+>
+ 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")
+
+------------------------------
+reifyThing :: TcTyThing -> TcM TH.Info
+-- The only reason this is monadic is for error reporting,
+-- which in turn is mainly for the case when TH can't express
+-- some random GHC extension
+
+reifyThing (AGlobal (AnId id))
+ = do { ty <- reifyType (idType id)
+ ; fix <- reifyFixity (idName id)
+ ; let v = reifyName id
+ ; case globalIdDetails id of
+ ClassOpId cls -> return (TH.ClassOpI v ty (reifyName cls) fix)
+ other -> return (TH.VarI v ty Nothing fix)
+ }
+
+reifyThing (AGlobal (ATyCon tc)) = do { dec <- reifyTyCon tc; return (TH.TyConI dec) }
+reifyThing (AGlobal (AClass cls)) = do { dec <- reifyClass cls; return (TH.ClassI dec) }
+reifyThing (AGlobal (ADataCon dc))
+ = do { let name = dataConName dc
+ ; ty <- reifyType (idType (dataConWrapId dc))
+ ; fix <- reifyFixity name
+ ; return (TH.DataConI (reifyName name) ty (reifyName (dataConTyCon dc)) fix) }
+
+reifyThing (ATcId id _ _)
+ = do { ty1 <- zonkTcType (idType id) -- Make use of all the info we have, even
+ -- though it may be incomplete
+ ; ty2 <- reifyType ty1
+ ; fix <- reifyFixity (idName id)
+ ; return (TH.VarI (reifyName id) ty2 Nothing fix) }
+
+reifyThing (ATyVar tv)
+ = do { ty1 <- zonkTcTyVar tv
+ ; ty2 <- reifyType ty1
+ ; return (TH.TyVarI (reifyName tv) ty2) }
+
+------------------------------
+reifyTyCon :: TyCon -> TcM TH.Dec
+reifyTyCon tc
+ | isSynTyCon tc
+ = do { let (tvs, rhs) = getSynTyConDefn tc
+ ; rhs' <- reifyType rhs
+ ; return (TH.TySynD (reifyName tc) (reifyTyVars tvs) rhs') }
+
+reifyTyCon tc
+ = case algTyConRhs tc of
+ NewTyCon data_con _ _
+ -> do { con <- reifyDataCon data_con
+ ; return (TH.NewtypeD [] (reifyName tc) (reifyTyVars (tyConTyVars tc))
+ con [{- Don't know about deriving -}]) }
+
+ DataTyCon mb_cxt cons _
+ -> do { cxt <- reifyCxt (mb_cxt `orElse` [])
+ ; cons <- mapM reifyDataCon (tyConDataCons tc)
+ ; return (TH.DataD cxt (reifyName tc) (reifyTyVars (tyConTyVars tc))
+ cons [{- Don't know about deriving -}]) }
+
+reifyDataCon :: DataCon -> TcM TH.Con
+reifyDataCon dc
+ | isVanillaDataCon dc
+ = do { arg_tys <- reifyTypes (dataConOrigArgTys dc)
+ ; let stricts = map reifyStrict (dataConStrictMarks dc)
+ fields = dataConFieldLabels dc
+ name = reifyName dc
+ [a1,a2] = arg_tys
+ [s1,s2] = stricts
+ ; ASSERT( length arg_tys == length stricts )
+ if not (null fields) then
+ return (TH.RecC name (zip3 (map reifyName fields) stricts arg_tys))
+ else
+ if dataConIsInfix dc then
+ ASSERT( length arg_tys == 2 )
+ return (TH.InfixC (s1,a1) name (s1,a2))
+ else
+ return (TH.NormalC name (stricts `zip` arg_tys)) }
+ | otherwise
+ = failWithTc (ptext SLIT("Can't reify a non-Haskell-98 data constructor:")
+ <+> quotes (ppr dc))
+
+------------------------------
+reifyClass :: Class -> TcM TH.Dec
+reifyClass cls
+ = do { cxt <- reifyCxt theta
+ ; ops <- mapM reify_op op_stuff
+ ; return (TH.ClassD cxt (reifyName cls) (reifyTyVars tvs) fds' ops) }
+ where
+ (tvs, fds, theta, _, op_stuff) = classExtraBigSig cls
+ fds' = map reifyFunDep fds
+ reify_op (op, _) = do { ty <- reifyType (idType op)
+ ; return (TH.SigD (reifyName op) ty) }
+
+------------------------------
+reifyType :: TypeRep.Type -> TcM TH.Type
+reifyType (TyVarTy tv) = return (TH.VarT (reifyName tv))
+reifyType (TyConApp tc tys) = reify_tc_app (reifyName tc) tys
+reifyType (NoteTy _ ty) = reifyType ty
+reifyType (AppTy t1 t2) = do { [r1,r2] <- reifyTypes [t1,t2] ; return (r1 `TH.AppT` r2) }
+reifyType (FunTy t1 t2) = do { [r1,r2] <- reifyTypes [t1,t2] ; return (TH.ArrowT `TH.AppT` r1 `TH.AppT` r2) }
+reifyType ty@(ForAllTy _ _) = do { cxt' <- reifyCxt cxt;
+ ; tau' <- reifyType tau
+ ; return (TH.ForallT (reifyTyVars tvs) cxt' tau') }
+ where
+ (tvs, cxt, tau) = tcSplitSigmaTy ty
+reifyTypes = mapM reifyType
+reifyCxt = mapM reifyPred
+
+reifyFunDep :: ([TyVar], [TyVar]) -> TH.FunDep
+reifyFunDep (xs, ys) = TH.FunDep (map reifyName xs) (map reifyName ys)
+
+reifyTyVars :: [TyVar] -> [TH.Name]
+reifyTyVars = map reifyName
+
+reify_tc_app :: TH.Name -> [TypeRep.Type] -> TcM TH.Type
+reify_tc_app tc tys = do { tys' <- reifyTypes tys
+ ; return (foldl TH.AppT (TH.ConT tc) tys') }
+
+reifyPred :: TypeRep.PredType -> TcM TH.Type
+reifyPred (ClassP cls tys) = reify_tc_app (reifyName cls) tys
+reifyPred p@(IParam _ _) = noTH SLIT("implicit parameters") (ppr p)
+
+
+------------------------------
+reifyName :: NamedThing n => n -> TH.Name
+reifyName thing
+ | isExternalName name = mk_varg mod occ_str
+ | otherwise = TH.mkNameU occ_str (getKey (getUnique name))
+ where
+ name = getName thing
+ mod = moduleUserString (nameModule name)
+ occ_str = occNameUserString occ
+ occ = nameOccName name
+ mk_varg | OccName.isDataOcc occ = TH.mkNameG_d
+ | OccName.isVarOcc occ = TH.mkNameG_v
+ | OccName.isTcOcc occ = TH.mkNameG_tc
+ | otherwise = pprPanic "reifyName" (ppr name)
+
+------------------------------
+reifyFixity :: Name -> TcM TH.Fixity
+reifyFixity name
+ = do { fix <- lookupFixityRn name
+ ; return (conv_fix fix) }
+ where
+ conv_fix (BasicTypes.Fixity i d) = TH.Fixity i (conv_dir d)
+ conv_dir BasicTypes.InfixR = TH.InfixR
+ conv_dir BasicTypes.InfixL = TH.InfixL
+ conv_dir BasicTypes.InfixN = TH.InfixN
+
+reifyStrict :: BasicTypes.StrictnessMark -> TH.Strict
+reifyStrict MarkedStrict = TH.IsStrict
+reifyStrict MarkedUnboxed = TH.IsStrict
+reifyStrict NotMarkedStrict = TH.NotStrict
+
+------------------------------
+noTH :: LitString -> SDoc -> TcM a
+noTH s d = failWithTc (hsep [ptext SLIT("Can't represent") <+> ptext s <+>
+ ptext SLIT("in Template Haskell:"),
+ nest 2 d])
+\end{code}
projects / ghc-hetmet.git / blobdiff