-- for details
module Convert( convertToHsExpr, convertToPat, convertToHsDecls,
- convertToHsType, thRdrName ) where
+ convertToHsType, thRdrNameGuesses ) where
import HsSyn as Hs
import qualified Class
convertToHsExpr :: SrcSpan -> TH.Exp -> Either Message (LHsExpr RdrName)
convertToHsExpr loc e
= case initCvt loc (cvtl e) of
- Left msg -> Left (msg $$ (ptext (sLit "When converting TH expression")
+ Left msg -> Left (msg $$ (ptext (sLit "When splicing TH expression:")
<+> text (show e)))
Right res -> Right res
convertToPat :: SrcSpan -> TH.Pat -> Either Message (LPat RdrName)
convertToPat loc e
= case initCvt loc (cvtPat e) of
- Left msg -> Left (msg $$ (ptext (sLit "When converting TH pattern")
+ Left msg -> Left (msg $$ (ptext (sLit "When splicing TH pattern:")
<+> text (show e)))
Right res -> Right res
; L loc pred' <- cvtPred ty
; inst_ty' <- returnL $ mkImplicitHsForAllTy ctxt' (L loc (HsPredTy pred'))
; returnL $ InstD (InstDecl inst_ty' binds' sigs' [])
- -- ^^no ATs in TH
+ -- no ATs in TH ^^
}
cvtTop (ForeignD ford) = do { ford' <- cvtForD ford; returnL $ ForD ford' }
; returnL $ mkFunBind s' [cl'] }
cvtBind (TH.FunD nm cls)
+ | null cls
+ = failWith (ptext (sLit "Function binding for")
+ <+> quotes (text (TH.pprint nm))
+ <+> ptext (sLit "has no equations"))
+ | otherwise
= do { nm' <- vNameL nm
; cls' <- mapM cvtClause cls
; returnL $ mkFunBind nm' cls' }
cvt (AppE x y) = do { x' <- cvtl x; y' <- cvtl y; return $ HsApp x' y' }
cvt (LamE ps e) = do { ps' <- cvtPats ps; e' <- cvtl e
; return $ HsLam (mkMatchGroup [mkSimpleMatch ps' e']) }
- cvt (TupE [e]) = cvt e
+ cvt (TupE [e]) = cvt e -- Singleton tuples treated like nothing (just parens)
cvt (TupE es) = do { es' <- mapM cvtl es; return $ ExplicitTuple es' Boxed }
cvt (CondE x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z
; return $ HsIf x' y' z' }
cvt (LetE ds e) = do { ds' <- cvtDecs ds; e' <- cvtl e; return $ HsLet ds' e' }
- cvt (CaseE e ms) = do { e' <- cvtl e; ms' <- mapM cvtMatch ms
+ cvt (CaseE e ms)
+ | null ms = failWith (ptext (sLit "Case expression with no alternatives"))
+ | otherwise = do { e' <- cvtl e; ms' <- mapM cvtMatch ms
; return $ HsCase e' (mkMatchGroup ms') }
cvt (DoE ss) = cvtHsDo DoExpr ss
cvt (CompE ss) = cvtHsDo ListComp ss
cvtHsDo :: HsStmtContext Name.Name -> [TH.Stmt] -> CvtM (HsExpr RdrName)
cvtHsDo do_or_lc stmts
+ | null stmts = failWith (ptext (sLit "Empty stmt list in do-block"))
+ | otherwise
= do { stmts' <- cvtStmts stmts
; let body = case last stmts' of
L _ (ExprStmt body _ _) -> body
_ -> failWith (ptext (sLit "Malformed predicate") <+> text (TH.pprint ty)) }
cvtType :: TH.Type -> CvtM (LHsType RdrName)
-cvtType ty = do { (head, tys') <- split_ty_app ty
- ; case head of
- TupleT n | length tys' == n -> returnL (HsTupleTy Boxed tys')
- | n == 0 -> mk_apps (HsTyVar (getRdrName unitTyCon)) tys'
+cvtType ty = do { (head_ty, tys') <- split_ty_app ty
+ ; case head_ty of
+ TupleT n | length tys' == n -- Saturated
+ -> if n==1 then return (head tys') -- Singleton tuples treated
+ -- like nothing (ie just parens)
+ else returnL (HsTupleTy Boxed tys')
+ | n == 1 -> failWith (ptext (sLit "Illegal 1-tuple type constructor"))
| otherwise -> mk_apps (HsTyVar (getRdrName (tupleTyCon Boxed n))) tys'
ArrowT | [x',y'] <- tys' -> returnL (HsFunTy x' y')
ListT | [x'] <- tys' -> returnL (HsListTy x')
_ -> failWith (ptext (sLit "Malformed type") <+> text (show ty))
}
where
- mk_apps head [] = returnL head
- mk_apps head (ty:tys) = do { head' <- returnL head; mk_apps (HsAppTy head' ty) tys }
+ mk_apps head_ty [] = returnL head_ty
+ mk_apps head_ty (ty:tys) = do { head_ty' <- returnL head_ty
+ ; mk_apps (HsAppTy head_ty' ty) tys }
split_ty_app :: TH.Type -> CvtM (TH.Type, [LHsType RdrName])
split_ty_app ty = go ty []
okOcc :: OccName.NameSpace -> String -> Bool
okOcc _ [] = False
okOcc ns str@(c:_)
- | OccName.isVarName ns = startsVarId c || startsVarSym c
- | otherwise = startsConId c || startsConSym c || str == "[]"
+ | OccName.isVarNameSpace ns = startsVarId c || startsVarSym c
+ | otherwise = startsConId c || startsConSym c || str == "[]"
badOcc :: OccName.NameSpace -> String -> SDoc
badOcc ctxt_ns occ
-- which will give confusing error messages later
--
-- The strict applications ensure that any buried exceptions get forced
-thRdrName _ occ (TH.NameG th_ns pkg mod) = (mkOrig $! (mkModule (mk_pkg pkg) (mk_mod mod))) $! (mk_occ (mk_ghc_ns th_ns) occ)
+thRdrName _ occ (TH.NameG th_ns pkg mod) = thOrigRdrName occ th_ns pkg mod
thRdrName ctxt_ns occ (TH.NameL uniq) = nameRdrName $! (((Name.mkInternalName $! (mk_uniq uniq)) $! (mk_occ ctxt_ns occ)) noSrcSpan)
thRdrName ctxt_ns occ (TH.NameQ mod) = (mkRdrQual $! (mk_mod mod)) $! (mk_occ ctxt_ns occ)
thRdrName ctxt_ns occ (TH.NameU uniq) = mkRdrUnqual $! (mk_uniq_occ ctxt_ns occ uniq)
| Just name <- isBuiltInOcc ctxt_ns occ = nameRdrName $! name
| otherwise = mkRdrUnqual $! (mk_occ ctxt_ns occ)
+thOrigRdrName :: String -> TH.NameSpace -> PkgName -> ModName -> RdrName
+thOrigRdrName occ th_ns pkg mod = (mkOrig $! (mkModule (mk_pkg pkg) (mk_mod mod))) $! (mk_occ (mk_ghc_ns th_ns) occ)
+
+thRdrNameGuesses :: TH.Name -> [RdrName]
+thRdrNameGuesses (TH.Name occ flavour)
+ -- This special case for NameG ensures that we don't generate duplicates in the output list
+ | TH.NameG th_ns pkg mod <- flavour = [thOrigRdrName occ_str th_ns pkg mod]
+ | otherwise = [ thRdrName gns occ_str flavour
+ | gns <- guessed_nss]
+ where
+ -- guessed_ns are the name spaces guessed from looking at the TH name
+ guessed_nss | isLexCon (mkFastString occ_str) = [OccName.tcName, OccName.dataName]
+ | otherwise = [OccName.varName, OccName.tvName]
+ occ_str = TH.occString occ
+
isBuiltInOcc :: OccName.NameSpace -> String -> Maybe Name.Name
-- Built in syntax isn't "in scope" so an Unqual RdrName won't do
-- We must generate an Exact name, just as the parser does
go_tuple _ _ = Nothing
tup_name n
- | OccName.isTcClsName ctxt_ns = Name.getName (tupleTyCon Boxed n)
- | otherwise = Name.getName (tupleCon Boxed n)
+ | OccName.isTcClsNameSpace ctxt_ns = Name.getName (tupleTyCon Boxed n)
+ | otherwise = Name.getName (tupleCon Boxed n)
mk_uniq_occ :: OccName.NameSpace -> String -> Int# -> OccName.OccName
mk_uniq_occ ns occ uniq
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