2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
5 This module converts Template Haskell syntax into HsSyn
9 module Convert( convertToHsExpr, convertToHsDecls ) where
11 #include "HsVersions.h"
13 import Language.Haskell.THSyntax as Meta
16 ( HsExpr(..), HsLit(..), ArithSeqInfo(..),
17 HsStmtContext(..), TyClDecl(..),
18 Match(..), GRHSs(..), GRHS(..), HsPred(..),
19 HsDecl(..), TyClDecl(..), InstDecl(..), ConDecl(..),
20 Stmt(..), HsBinds(..), MonoBinds(..), Sig(..),
21 Pat(..), HsConDetails(..), HsOverLit, BangType(..),
22 placeHolderType, HsType(..), HsTupCon(..),
23 HsTyVarBndr(..), HsContext,
24 mkSimpleMatch, mkHsForAllTy
27 import RdrName ( RdrName, mkRdrUnqual, mkRdrQual, mkOrig )
28 import Module ( mkModuleName )
29 import RdrHsSyn ( mkHsIntegral, mkHsFractional, mkClassDecl, mkTyData )
31 import SrcLoc ( SrcLoc, generatedSrcLoc )
32 import TyCon ( DataConDetails(..) )
34 import BasicTypes( Boxity(..), RecFlag(Recursive),
35 NewOrData(..), StrictnessMark(..) )
36 import ForeignCall ( Safety(..), CCallConv(..), CCallTarget(..) )
37 import HsDecls ( CImportSpec(..), ForeignImport(..), ForeignDecl(..) )
38 import FastString( FastString, mkFastString, nilFS )
39 import Char ( ord, isAscii, isAlphaNum, isAlpha )
40 import List ( partition )
41 import ErrUtils (Message)
45 -------------------------------------------------------------------
46 convertToHsDecls :: [Meta.Dec] -> [Either (HsDecl RdrName) Message]
47 convertToHsDecls ds = map cvt_top ds
49 mk_con con = case con of
51 -> ConDecl (cName c) noExistentials noContext
52 (PrefixCon (map mk_arg strtys)) loc0
54 -> ConDecl (cName c) noExistentials noContext
55 (Hs.RecCon (map mk_id_arg varstrtys)) loc0
57 -> ConDecl (cName c) noExistentials noContext
58 (InfixCon (mk_arg st1) (mk_arg st2)) loc0
60 mk_arg (Strict, ty) = BangType MarkedUserStrict (cvtType ty)
61 mk_arg (NonStrict, ty) = BangType NotMarkedStrict (cvtType ty)
63 mk_id_arg (i, Strict, ty)
64 = (vName i, BangType MarkedUserStrict (cvtType ty))
65 mk_id_arg (i, NonStrict, ty)
66 = (vName i, BangType NotMarkedStrict (cvtType ty))
68 mk_derivs [] = Nothing
69 mk_derivs cs = Just [HsClassP (tconName c) [] | c <- cs]
71 cvt_top :: Meta.Dec -> Either (HsDecl RdrName) Message
72 cvt_top d@(Val _ _ _) = Left $ ValD (cvtd d)
73 cvt_top d@(Fun _ _) = Left $ ValD (cvtd d)
75 cvt_top (TySyn tc tvs rhs)
76 = Left $ TyClD (TySynonym (tconName tc) (cvt_tvs tvs) (cvtType rhs) loc0)
78 cvt_top (Data ctxt tc tvs constrs derivs)
79 = Left $ TyClD (mkTyData DataType
80 (cvt_context ctxt, tconName tc, cvt_tvs tvs)
81 (DataCons (map mk_con constrs))
82 (mk_derivs derivs) loc0)
84 cvt_top (Newtype ctxt tc tvs constr derivs)
85 = Left $ TyClD (mkTyData NewType
86 (cvt_context ctxt, tconName tc, cvt_tvs tvs)
87 (DataCons [mk_con constr])
88 (mk_derivs derivs) loc0)
90 cvt_top (Class ctxt cl tvs decs)
91 = Left $ TyClD (mkClassDecl (cvt_context ctxt, tconName cl, cvt_tvs tvs)
95 (binds,sigs) = cvtBindsAndSigs decs
97 cvt_top (Instance tys ty decs)
98 = Left $ InstD (InstDecl inst_ty binds sigs Nothing loc0)
100 (binds, sigs) = cvtBindsAndSigs decs
101 inst_ty = HsForAllTy Nothing
103 (HsPredTy (cvt_pred ty))
105 cvt_top (Proto nm typ) = Left $ SigD (Sig (vName nm) (cvtType typ) loc0)
107 cvt_top (Foreign (Import callconv safety from nm typ))
109 Just (c_header, cis) ->
110 let i = CImport callconv' safety' c_header nilFS cis
111 in Left $ ForD (ForeignImport (vName nm) (cvtType typ) i False loc0)
112 Nothing -> Right $ text (show from)
113 <+> ptext SLIT("is not a valid ccall impent")
114 where callconv' = case callconv of
116 StdCall -> StdCallConv
117 safety' = case safety of
119 Safe -> PlaySafe False
120 Threadsafe -> PlaySafe True
121 parsed = parse_ccall_impent nm from
123 parse_ccall_impent :: String -> String -> Maybe (FastString, CImportSpec)
124 parse_ccall_impent nm s
125 = case lex_ccall_impent s of
126 Just ["dynamic"] -> Just (nilFS, CFunction DynamicTarget)
127 Just ["wrapper"] -> Just (nilFS, CWrapper)
128 Just ("static":ts) -> parse_ccall_impent_static nm ts
129 Just ts -> parse_ccall_impent_static nm ts
132 parse_ccall_impent_static :: String
134 -> Maybe (FastString, CImportSpec)
135 parse_ccall_impent_static nm ts
136 = let ts' = case ts of
137 [ "&", cid] -> [ cid]
138 [fname, "&" ] -> [fname ]
139 [fname, "&", cid] -> [fname, cid]
142 [ cid] | is_cid cid -> Just (nilFS, mk_cid cid)
143 [fname, cid] | is_cid cid -> Just (mkFastString fname, mk_cid cid)
144 [ ] -> Just (nilFS, mk_cid nm)
145 [fname ] -> Just (mkFastString fname, mk_cid nm)
147 where is_cid :: String -> Bool
148 is_cid x = all (/= '.') x && (isAlpha (head x) || head x == '_')
149 mk_cid :: String -> CImportSpec
150 mk_cid = CFunction . StaticTarget . mkFastString
152 lex_ccall_impent :: String -> Maybe [String]
153 lex_ccall_impent "" = Just []
154 lex_ccall_impent ('&':xs) = fmap ("&":) $ lex_ccall_impent xs
155 lex_ccall_impent (' ':xs) = lex_ccall_impent xs
156 lex_ccall_impent ('\t':xs) = lex_ccall_impent xs
157 lex_ccall_impent xs = case span is_valid xs of
159 (t, xs') -> fmap (t:) $ lex_ccall_impent xs'
160 where is_valid :: Char -> Bool
161 is_valid c = isAscii c && (isAlphaNum c || c `elem` "._")
167 -------------------------------------------------------------------
168 convertToHsExpr :: Meta.Exp -> HsExpr RdrName
169 convertToHsExpr = cvt
171 cvt (Var s) = HsVar (vName s)
172 cvt (Con s) = HsVar (cName s)
174 | overloadedLit l = HsOverLit (cvtOverLit l)
175 | otherwise = HsLit (cvtLit l)
177 cvt (App x y) = HsApp (cvt x) (cvt y)
178 cvt (Lam ps e) = HsLam (mkSimpleMatch (map cvtp ps) (cvt e) void loc0)
179 cvt (Tup [e]) = cvt e
180 cvt (Tup es) = ExplicitTuple(map cvt es) Boxed
181 cvt (Cond x y z) = HsIf (cvt x) (cvt y) (cvt z) loc0
182 cvt (Let ds e) = HsLet (cvtdecs ds) (cvt e)
183 cvt (Case e ms) = HsCase (cvt e) (map cvtm ms) loc0
184 cvt (Do ss) = HsDo DoExpr (cvtstmts ss) [] void loc0
185 cvt (Comp ss) = HsDo ListComp (cvtstmts ss) [] void loc0
186 cvt (ArithSeq dd) = ArithSeqIn (cvtdd dd)
187 cvt (ListExp xs) = ExplicitList void (map cvt xs)
188 cvt (Infix (Just x) s (Just y))
189 = HsPar (OpApp (cvt x) (cvt s) undefined (cvt y))
190 cvt (Infix Nothing s (Just y)) = SectionR (cvt s) (cvt y)
191 cvt (Infix (Just x) s Nothing ) = SectionL (cvt x) (cvt s)
192 cvt (Infix Nothing s Nothing ) = cvt s -- Can I indicate this is an infix thing?
193 cvt (SigExp e t) = ExprWithTySig (cvt e) (cvtType t)
194 cvt (Meta.RecCon c flds) = RecordCon (cName c) (map (\(x,y) -> (vName x, cvt y)) flds)
195 cvt (RecUpd e flds) = RecordUpd (cvt e) (map (\(x,y) -> (vName x, cvt y)) flds)
197 cvtdecs :: [Meta.Dec] -> HsBinds RdrName
198 cvtdecs [] = EmptyBinds
199 cvtdecs ds = MonoBind binds sigs Recursive
201 (binds, sigs) = cvtBindsAndSigs ds
204 = (cvtds non_sigs, map cvtSig sigs)
206 (sigs, non_sigs) = partition sigP ds
208 cvtSig (Proto nm typ) = Sig (vName nm) (cvtType typ) loc0
210 cvtds :: [Meta.Dec] -> MonoBinds RdrName
211 cvtds [] = EmptyMonoBinds
212 cvtds (d:ds) = AndMonoBinds (cvtd d) (cvtds ds)
214 cvtd :: Meta.Dec -> MonoBinds RdrName
215 -- Used only for declarations in a 'let/where' clause,
216 -- not for top level decls
217 cvtd (Val (Pvar s) body ds) = FunMonoBind (vName s) False
218 [cvtclause (Clause [] body ds)] loc0
219 cvtd (Fun nm cls) = FunMonoBind (vName nm) False (map cvtclause cls) loc0
220 cvtd (Val p body ds) = PatMonoBind (cvtp p) (GRHSs (cvtguard body)
223 cvtd x = panic "Illegal kind of declaration in where clause"
226 cvtclause :: Meta.Clause -> Hs.Match RdrName
227 cvtclause (Clause ps body wheres)
228 = Hs.Match (map cvtp ps) Nothing (GRHSs (cvtguard body) (cvtdecs wheres) void)
232 cvtdd :: Meta.DotDot -> ArithSeqInfo RdrName
233 cvtdd (Meta.From x) = (Hs.From (cvt x))
234 cvtdd (Meta.FromThen x y) = (Hs.FromThen (cvt x) (cvt y))
235 cvtdd (Meta.FromTo x y) = (Hs.FromTo (cvt x) (cvt y))
236 cvtdd (Meta.FromThenTo x y z) = (Hs.FromThenTo (cvt x) (cvt y) (cvt z))
239 cvtstmts :: [Meta.Statement] -> [Hs.Stmt RdrName]
240 cvtstmts [] = [] -- this is probably an error as every [stmt] should end with ResultStmt
241 cvtstmts [NoBindSt e] = [ResultStmt (cvt e) loc0] -- when its the last element use ResultStmt
242 cvtstmts (NoBindSt e : ss) = ExprStmt (cvt e) void loc0 : cvtstmts ss
243 cvtstmts (BindSt p e : ss) = BindStmt (cvtp p) (cvt e) loc0 : cvtstmts ss
244 cvtstmts (LetSt ds : ss) = LetStmt (cvtdecs ds) : cvtstmts ss
245 cvtstmts (ParSt dss : ss) = ParStmt(map cvtstmts dss) : cvtstmts ss
248 cvtm :: Meta.Match -> Hs.Match RdrName
249 cvtm (Meta.Match p body wheres)
250 = Hs.Match [cvtp p] Nothing (GRHSs (cvtguard body) (cvtdecs wheres) void)
252 cvtguard :: Meta.RightHandSide -> [GRHS RdrName]
253 cvtguard (Guarded pairs) = map cvtpair pairs
254 cvtguard (Normal e) = [GRHS [ ResultStmt (cvt e) loc0 ] loc0]
256 cvtpair :: (Meta.Exp,Meta.Exp) -> GRHS RdrName
257 cvtpair (x,y) = GRHS [BindStmt truePat (cvt x) loc0,
258 ResultStmt (cvt y) loc0] loc0
260 cvtOverLit :: Lit -> HsOverLit
261 cvtOverLit (Integer i) = mkHsIntegral i
262 cvtOverLit (Rational r) = mkHsFractional r
263 -- An Integer is like an an (overloaded) '3' in a Haskell source program
264 -- Similarly 3.5 for fractionals
266 cvtLit :: Lit -> HsLit
267 cvtLit (IntPrim i) = HsIntPrim i
268 cvtLit (FloatPrim f) = HsFloatPrim f
269 cvtLit (DoublePrim f) = HsDoublePrim f
270 cvtLit (Char c) = HsChar (ord c)
271 cvtLit (String s) = HsString (mkFastString s)
273 cvtp :: Meta.Pat -> Hs.Pat RdrName
275 | overloadedLit l = NPatIn (cvtOverLit l) Nothing -- Not right for negative
276 -- patterns; need to think
278 | otherwise = LitPat (cvtLit l)
279 cvtp (Pvar s) = VarPat(vName s)
280 cvtp (Ptup [p]) = cvtp p
281 cvtp (Ptup ps) = TuplePat (map cvtp ps) Boxed
282 cvtp (Pcon s ps) = ConPatIn (cName s) (PrefixCon (map cvtp ps))
283 cvtp (Ptilde p) = LazyPat (cvtp p)
284 cvtp (Paspat s p) = AsPat (vName s) (cvtp p)
285 cvtp Pwild = WildPat void
286 cvtp (Prec c fs) = ConPatIn (cName c) $ Hs.RecCon (map (\(s,p) -> (vName s,cvtp p)) fs)
288 -----------------------------------------------------------
289 -- Types and type variables
291 cvt_tvs :: [String] -> [HsTyVarBndr RdrName]
292 cvt_tvs tvs = map (UserTyVar . tName) tvs
294 cvt_context :: Cxt -> HsContext RdrName
295 cvt_context tys = map cvt_pred tys
297 cvt_pred :: Typ -> HsPred RdrName
298 cvt_pred ty = case split_ty_app ty of
299 (Tcon (TconName tc), tys) -> HsClassP (tconName tc) (map cvtType tys)
300 other -> panic "Malformed predicate"
302 cvtType :: Meta.Typ -> HsType RdrName
303 cvtType ty = trans (root ty [])
304 where root (Tapp a b) zs = root a (cvtType b : zs)
307 trans (Tcon (Tuple n),args) | length args == n
308 = HsTupleTy (HsTupCon Boxed n) args
309 trans (Tcon Arrow, [x,y]) = HsFunTy x y
310 trans (Tcon List, [x]) = HsListTy x
312 trans (Tvar nm, args) = foldl HsAppTy (HsTyVar (tName nm)) args
313 trans (Tcon tc, args) = foldl HsAppTy (HsTyVar (tc_name tc)) args
315 trans (TForall tvs cxt ty, []) = mkHsForAllTy (Just (cvt_tvs tvs))
319 tc_name (TconName nm) = tconName nm
320 tc_name Arrow = tconName "->"
321 tc_name List = tconName "[]"
322 tc_name (Tuple 0) = tconName "()"
323 tc_name (Tuple n) = tconName ("(" ++ replicate (n-1) ',' ++ ")")
325 split_ty_app :: Typ -> (Typ, [Typ])
326 split_ty_app ty = go ty []
328 go (Tapp f a) as = go f (a:as)
331 -----------------------------------------------------------
333 sigP (Proto _ _) = True
337 -----------------------------------------------------------
338 -- some useful things
340 truePat = ConPatIn (cName "True") (PrefixCon [])
341 falsePat = ConPatIn (cName "False") (PrefixCon [])
343 overloadedLit :: Lit -> Bool
344 -- True for literals that Haskell treats as overloaded
345 overloadedLit (Integer l) = True
346 overloadedLit (Rational l) = True
347 overloadedLit l = False
350 void = placeHolderType
353 loc0 = generatedSrcLoc
356 vName :: String -> RdrName
357 vName = mkName varName
359 -- Constructor function names; this is Haskell source, hence srcDataName
360 cName :: String -> RdrName
361 cName = mkName srcDataName
363 -- Type variable names
364 tName :: String -> RdrName
365 tName = mkName tvName
367 -- Type Constructor names
368 tconName = mkName tcName
370 mkName :: NameSpace -> String -> RdrName
371 -- Parse the string to see if it has a "." or ":" in it
372 -- so we know whether to generate a qualified or original name
373 -- It's a bit tricky because we need to parse
374 -- Foo.Baz.x as Qual Foo.Baz x
375 -- So we parse it from back to front
378 = split [] (reverse str)
380 split occ [] = mkRdrUnqual (mk_occ occ)
381 split occ (c:d:rev) -- 'd' is the last char before the separator
382 | is_sep c -- E.g. Fo.x d='o'
383 && isAlphaNum d -- Fo.+: d='+' perhaps
384 = mk_qual (reverse (d:rev)) c occ
385 split occ (c:rev) = split (c:occ) rev
387 mk_qual mod '.' occ = mkRdrQual (mk_mod mod) (mk_occ occ)
388 mk_qual mod ':' occ = mkOrig (mk_mod mod) (mk_occ occ)
390 mk_occ occ = mkOccFS ns (mkFastString occ)
391 mk_mod mod = mkModuleName mod