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
50 cvt_top :: Meta.Dec -> Either (HsDecl RdrName) Message
51 cvt_top d@(Val _ _ _) = Left $ ValD (cvtd d)
52 cvt_top d@(Fun _ _) = Left $ ValD (cvtd d)
54 cvt_top (TySyn tc tvs rhs)
55 = Left $ TyClD (TySynonym (tconName tc) (cvt_tvs tvs) (cvtType rhs) loc0)
57 cvt_top (Data tc tvs constrs derivs)
58 = Left $ TyClD (mkTyData DataType
59 (noContext, tconName tc, cvt_tvs tvs)
60 (DataCons (map mk_con constrs))
61 (mk_derivs derivs) loc0)
63 mk_con (Constr c strtys)
64 = ConDecl (cName c) noExistentials noContext
65 (PrefixCon (map mk_arg strtys)) loc0
66 mk_con (RecConstr c varstrtys)
67 = ConDecl (cName c) noExistentials noContext
68 (RecCon (map mk_id_arg varstrtys)) loc0
69 mk_con (InfixConstr st1 c st2)
70 = ConDecl (cName c) noExistentials noContext
71 (InfixCon (mk_arg st1) (mk_arg st2)) loc0
73 mk_arg (Strict, ty) = BangType MarkedUserStrict (cvtType ty)
74 mk_arg (NonStrict, ty) = BangType NotMarkedStrict (cvtType ty)
76 mk_id_arg (i, Strict, ty)
77 = (vName i, BangType MarkedUserStrict (cvtType ty))
78 mk_id_arg (i, NonStrict, ty)
79 = (vName i, BangType NotMarkedStrict (cvtType ty))
81 mk_derivs [] = Nothing
82 mk_derivs cs = Just [HsClassP (tconName c) [] | c <- cs]
84 cvt_top (Class ctxt cl tvs decs)
85 = Left $ TyClD (mkClassDecl (cvt_context ctxt, tconName cl, cvt_tvs tvs)
87 sigs (Just binds) loc0)
89 (binds,sigs) = cvtBindsAndSigs decs
91 cvt_top (Instance tys ty decs)
92 = Left $ InstD (InstDecl inst_ty binds sigs Nothing loc0)
94 (binds, sigs) = cvtBindsAndSigs decs
95 inst_ty = HsForAllTy Nothing
97 (HsPredTy (cvt_pred ty))
99 cvt_top (Proto nm typ) = Left $ SigD (Sig (vName nm) (cvtType typ) loc0)
101 cvt_top (Foreign (Import callconv safety from nm typ))
103 Just (c_header, cis) ->
104 let i = CImport callconv' safety' c_header nilFS cis
105 in Left $ ForD (ForeignImport (vName nm) (cvtType typ) i False loc0)
106 Nothing -> Right $ text (show from)
107 <+> ptext SLIT("is not a valid ccall impent")
108 where callconv' = case callconv of
110 StdCall -> StdCallConv
111 safety' = case safety of
113 Safe -> PlaySafe False
114 Threadsafe -> PlaySafe True
115 parsed = parse_ccall_impent nm from
117 parse_ccall_impent :: String -> String -> Maybe (FastString, CImportSpec)
118 parse_ccall_impent nm s
119 = case lex_ccall_impent s of
120 Just ["dynamic"] -> Just (nilFS, CFunction DynamicTarget)
121 Just ["wrapper"] -> Just (nilFS, CWrapper)
122 Just ("static":ts) -> parse_ccall_impent_static nm ts
123 Just ts -> parse_ccall_impent_static nm ts
126 parse_ccall_impent_static :: String
128 -> Maybe (FastString, CImportSpec)
129 parse_ccall_impent_static nm ts
130 = let ts' = case ts of
131 [ "&", cid] -> [ cid]
132 [fname, "&" ] -> [fname ]
133 [fname, "&", cid] -> [fname, cid]
136 [ cid] | is_cid cid -> Just (nilFS, mk_cid cid)
137 [fname, cid] | is_cid cid -> Just (mkFastString fname, mk_cid cid)
138 [ ] -> Just (nilFS, mk_cid nm)
139 [fname ] -> Just (mkFastString fname, mk_cid nm)
141 where is_cid :: String -> Bool
142 is_cid x = all (/= '.') x && (isAlpha (head x) || head x == '_')
143 mk_cid :: String -> CImportSpec
144 mk_cid = CFunction . StaticTarget . mkFastString
146 lex_ccall_impent :: String -> Maybe [String]
147 lex_ccall_impent "" = Just []
148 lex_ccall_impent ('&':xs) = fmap ("&":) $ lex_ccall_impent xs
149 lex_ccall_impent (' ':xs) = lex_ccall_impent xs
150 lex_ccall_impent ('\t':xs) = lex_ccall_impent xs
151 lex_ccall_impent xs = case span is_valid xs of
153 (t, xs') -> fmap (t:) $ lex_ccall_impent xs'
154 where is_valid :: Char -> Bool
155 is_valid c = isAscii c && (isAlphaNum c || c `elem` "._")
161 -------------------------------------------------------------------
162 convertToHsExpr :: Meta.Exp -> HsExpr RdrName
163 convertToHsExpr = cvt
165 cvt (Var s) = HsVar (vName s)
166 cvt (Con s) = HsVar (cName s)
168 | overloadedLit l = HsOverLit (cvtOverLit l)
169 | otherwise = HsLit (cvtLit l)
171 cvt (App x y) = HsApp (cvt x) (cvt y)
172 cvt (Lam ps e) = HsLam (mkSimpleMatch (map cvtp ps) (cvt e) void loc0)
173 cvt (Tup [e]) = cvt e
174 cvt (Tup es) = ExplicitTuple(map cvt es) Boxed
175 cvt (Cond x y z) = HsIf (cvt x) (cvt y) (cvt z) loc0
176 cvt (Let ds e) = HsLet (cvtdecs ds) (cvt e)
177 cvt (Case e ms) = HsCase (cvt e) (map cvtm ms) loc0
178 cvt (Do ss) = HsDo DoExpr (cvtstmts ss) [] void loc0
179 cvt (Comp ss) = HsDo ListComp (cvtstmts ss) [] void loc0
180 cvt (ArithSeq dd) = ArithSeqIn (cvtdd dd)
181 cvt (ListExp xs) = ExplicitList void (map cvt xs)
182 cvt (Infix (Just x) s (Just y))
183 = HsPar (OpApp (cvt x) (cvt s) undefined (cvt y))
184 cvt (Infix Nothing s (Just y)) = SectionR (cvt s) (cvt y)
185 cvt (Infix (Just x) s Nothing ) = SectionL (cvt x) (cvt s)
186 cvt (Infix Nothing s Nothing ) = cvt s -- Can I indicate this is an infix thing?
187 cvt (SigExp e t) = ExprWithTySig (cvt e) (cvtType t)
189 cvtdecs :: [Meta.Dec] -> HsBinds RdrName
190 cvtdecs [] = EmptyBinds
191 cvtdecs ds = MonoBind binds sigs Recursive
193 (binds, sigs) = cvtBindsAndSigs ds
196 = (cvtds non_sigs, map cvtSig sigs)
198 (sigs, non_sigs) = partition sigP ds
200 cvtSig (Proto nm typ) = Sig (vName nm) (cvtType typ) loc0
202 cvtds :: [Meta.Dec] -> MonoBinds RdrName
203 cvtds [] = EmptyMonoBinds
204 cvtds (d:ds) = AndMonoBinds (cvtd d) (cvtds ds)
206 cvtd :: Meta.Dec -> MonoBinds RdrName
207 -- Used only for declarations in a 'let/where' clause,
208 -- not for top level decls
209 cvtd (Val (Pvar s) body ds) = FunMonoBind (vName s) False
210 [cvtclause (Clause [] body ds)] loc0
211 cvtd (Fun nm cls) = FunMonoBind (vName nm) False (map cvtclause cls) loc0
212 cvtd (Val p body ds) = PatMonoBind (cvtp p) (GRHSs (cvtguard body)
215 cvtd x = panic "Illegal kind of declaration in where clause"
218 cvtclause :: Meta.Clause (Meta.Pat) (Meta.Exp) (Meta.Dec) -> Hs.Match RdrName
219 cvtclause (Clause ps body wheres)
220 = Match (map cvtp ps) Nothing (GRHSs (cvtguard body) (cvtdecs wheres) void)
224 cvtdd :: Meta.DDt -> ArithSeqInfo RdrName
225 cvtdd (Meta.From x) = (Hs.From (cvt x))
226 cvtdd (Meta.FromThen x y) = (Hs.FromThen (cvt x) (cvt y))
227 cvtdd (Meta.FromTo x y) = (Hs.FromTo (cvt x) (cvt y))
228 cvtdd (Meta.FromThenTo x y z) = (Hs.FromThenTo (cvt x) (cvt y) (cvt z))
231 cvtstmts :: [Meta.Stm] -> [Hs.Stmt RdrName]
232 cvtstmts [] = [] -- this is probably an error as every [stmt] should end with ResultStmt
233 cvtstmts [NoBindSt e] = [ResultStmt (cvt e) loc0] -- when its the last element use ResultStmt
234 cvtstmts (NoBindSt e : ss) = ExprStmt (cvt e) void loc0 : cvtstmts ss
235 cvtstmts (BindSt p e : ss) = BindStmt (cvtp p) (cvt e) loc0 : cvtstmts ss
236 cvtstmts (LetSt ds : ss) = LetStmt (cvtdecs ds) : cvtstmts ss
237 cvtstmts (ParSt dss : ss) = ParStmt(map cvtstmts dss) : cvtstmts ss
240 cvtm :: Meta.Mat -> Hs.Match RdrName
241 cvtm (Mat p body wheres)
242 = Match [cvtp p] Nothing (GRHSs (cvtguard body) (cvtdecs wheres) void)
244 cvtguard :: Meta.Rhs -> [GRHS RdrName]
245 cvtguard (Guarded pairs) = map cvtpair pairs
246 cvtguard (Normal e) = [GRHS [ ResultStmt (cvt e) loc0 ] loc0]
248 cvtpair :: (Meta.Exp,Meta.Exp) -> GRHS RdrName
249 cvtpair (x,y) = GRHS [BindStmt truePat (cvt x) loc0,
250 ResultStmt (cvt y) loc0] loc0
252 cvtOverLit :: Lit -> HsOverLit
253 cvtOverLit (Integer i) = mkHsIntegral i
254 cvtOverLit (Rational r) = mkHsFractional r
255 -- An Integer is like an an (overloaded) '3' in a Haskell source program
256 -- Similarly 3.5 for fractionals
258 cvtLit :: Lit -> HsLit
259 cvtLit (Char c) = HsChar (ord c)
260 cvtLit (String s) = HsString (mkFastString s)
262 cvtp :: Meta.Pat -> Hs.Pat RdrName
264 | overloadedLit l = NPatIn (cvtOverLit l) Nothing -- Not right for negative
265 -- patterns; need to think
267 | otherwise = LitPat (cvtLit l)
268 cvtp (Pvar s) = VarPat(vName s)
269 cvtp (Ptup [p]) = cvtp p
270 cvtp (Ptup ps) = TuplePat (map cvtp ps) Boxed
271 cvtp (Pcon s ps) = ConPatIn (cName s) (PrefixCon (map cvtp ps))
272 cvtp (Ptilde p) = LazyPat (cvtp p)
273 cvtp (Paspat s p) = AsPat (vName s) (cvtp p)
274 cvtp Pwild = WildPat void
276 -----------------------------------------------------------
277 -- Types and type variables
279 cvt_tvs :: [String] -> [HsTyVarBndr RdrName]
280 cvt_tvs tvs = map (UserTyVar . tName) tvs
282 cvt_context :: Cxt -> HsContext RdrName
283 cvt_context tys = map cvt_pred tys
285 cvt_pred :: Typ -> HsPred RdrName
286 cvt_pred ty = case split_ty_app ty of
287 (Tcon (TconName tc), tys) -> HsClassP (tconName tc) (map cvtType tys)
288 other -> panic "Malformed predicate"
290 cvtType :: Meta.Typ -> HsType RdrName
291 cvtType ty = trans (root ty [])
292 where root (Tapp a b) zs = root a (cvtType b : zs)
295 trans (Tcon (Tuple n),args) | length args == n
296 = HsTupleTy (HsTupCon Boxed n) args
297 trans (Tcon Arrow, [x,y]) = HsFunTy x y
298 trans (Tcon List, [x]) = HsListTy x
300 trans (Tvar nm, args) = foldl HsAppTy (HsTyVar (tName nm)) args
301 trans (Tcon tc, args) = foldl HsAppTy (HsTyVar (tc_name tc)) args
303 trans (TForall tvs cxt ty, []) = mkHsForAllTy (Just (cvt_tvs tvs))
307 tc_name (TconName nm) = tconName nm
308 tc_name Arrow = tconName "->"
309 tc_name List = tconName "[]"
310 tc_name (Tuple 0) = tconName "()"
311 tc_name (Tuple n) = tconName ("(" ++ replicate (n-1) ',' ++ ")")
313 split_ty_app :: Typ -> (Typ, [Typ])
314 split_ty_app ty = go ty []
316 go (Tapp f a) as = go f (a:as)
319 -----------------------------------------------------------
321 sigP (Proto _ _) = True
325 -----------------------------------------------------------
326 -- some useful things
328 truePat = ConPatIn (cName "True") (PrefixCon [])
329 falsePat = ConPatIn (cName "False") (PrefixCon [])
331 overloadedLit :: Lit -> Bool
332 -- True for literals that Haskell treats as overloaded
333 overloadedLit (Integer l) = True
334 overloadedLit (Rational l) = True
335 overloadedLit l = False
338 void = placeHolderType
341 loc0 = generatedSrcLoc
344 vName :: String -> RdrName
345 vName = mkName varName
347 -- Constructor function names; this is Haskell source, hence srcDataName
348 cName :: String -> RdrName
349 cName = mkName srcDataName
351 -- Type variable names
352 tName :: String -> RdrName
353 tName = mkName tvName
355 -- Type Constructor names
356 tconName = mkName tcName
358 mkName :: NameSpace -> String -> RdrName
359 -- Parse the string to see if it has a "." or ":" in it
360 -- so we know whether to generate a qualified or original name
361 -- It's a bit tricky because we need to parse
362 -- Foo.Baz.x as Qual Foo.Baz x
363 -- So we parse it from back to front
366 = split [] (reverse str)
368 split occ [] = mkRdrUnqual (mk_occ occ)
369 split occ (c:d:rev) -- 'd' is the last char before the separator
370 | is_sep c -- E.g. Fo.x d='o'
371 && isAlphaNum d -- Fo.+: d='+' perhaps
372 = mk_qual (reverse (d:rev)) c occ
373 split occ (c:rev) = split (c:occ) rev
375 mk_qual mod '.' occ = mkRdrQual (mk_mod mod) (mk_occ occ)
376 mk_qual mod ':' occ = mkOrig (mk_mod mod) (mk_occ occ)
378 mk_occ occ = mkOccFS ns (mkFastString occ)
379 mk_mod mod = mkModuleName mod