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,
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( mkFastString, nilFS )
39 import Char ( ord, isAlphaNum )
40 import List ( partition )
44 -------------------------------------------------------------------
45 convertToHsDecls :: [Meta.Dec] -> [HsDecl RdrName]
46 convertToHsDecls ds = map cvt_top ds
49 cvt_top d@(Val _ _ _) = ValD (cvtd d)
50 cvt_top d@(Fun _ _) = ValD (cvtd d)
52 cvt_top (TySyn tc tvs rhs)
53 = TyClD (TySynonym (tconName tc) (cvt_tvs tvs) (cvtType rhs) loc0)
55 cvt_top (Data tc tvs constrs derivs)
56 = TyClD (mkTyData DataType
57 (noContext, tconName tc, cvt_tvs tvs)
58 (DataCons (map mk_con constrs))
59 (mk_derivs derivs) loc0)
62 = ConDecl (cName c) noExistentials noContext
63 (PrefixCon (map mk_arg tys)) loc0
65 mk_arg ty = BangType NotMarkedStrict (cvtType ty)
67 mk_derivs [] = Nothing
68 mk_derivs cs = Just [HsClassP (tconName c) [] | c <- cs]
70 cvt_top (Class ctxt cl tvs decs)
71 = TyClD (mkClassDecl (cvt_context ctxt, tconName cl, cvt_tvs tvs)
73 sigs (Just binds) loc0)
75 (binds,sigs) = cvtBindsAndSigs decs
77 cvt_top (Instance tys ty decs)
78 = InstD (InstDecl inst_ty binds sigs Nothing loc0)
80 (binds, sigs) = cvtBindsAndSigs decs
81 inst_ty = HsForAllTy Nothing
83 (HsPredTy (cvt_pred ty))
85 cvt_top (Proto nm typ) = SigD (Sig (vName nm) (cvtType typ) loc0)
87 cvt_top (Foreign (Import callconv safety from nm typ))
88 = ForD (ForeignImport (vName nm) (cvtType typ) fi False loc0)
89 where fi = CImport callconv' safety' c_header nilFS cis
90 callconv' = case callconv of
92 StdCall -> StdCallConv
93 safety' = case safety of
95 Safe -> PlaySafe False
96 Threadsafe -> PlaySafe True
97 (c_header', c_func') = break (== ' ') from
98 c_header = mkFastString c_header'
100 cis = CFunction (StaticTarget (mkFastString c_func))
106 -------------------------------------------------------------------
107 convertToHsExpr :: Meta.Exp -> HsExpr RdrName
108 convertToHsExpr = cvt
110 cvt (Var s) = HsVar(vName s)
111 cvt (Con s) = HsVar(cName s)
113 | overloadedLit l = HsOverLit (cvtOverLit l)
114 | otherwise = HsLit (cvtLit l)
116 cvt (App x y) = HsApp (cvt x) (cvt y)
117 cvt (Lam ps e) = HsLam (mkSimpleMatch (map cvtp ps) (cvt e) void loc0)
118 cvt (Tup es) = ExplicitTuple(map cvt es) Boxed
119 cvt (Cond x y z) = HsIf (cvt x) (cvt y) (cvt z) loc0
120 cvt (Let ds e) = HsLet (cvtdecs ds) (cvt e)
121 cvt (Case e ms) = HsCase (cvt e) (map cvtm ms) loc0
122 cvt (Do ss) = HsDo DoExpr (cvtstmts ss) [] void loc0
123 cvt (Comp ss) = HsDo ListComp (cvtstmts ss) [] void loc0
124 cvt (ArithSeq dd) = ArithSeqIn (cvtdd dd)
125 cvt (ListExp xs) = ExplicitList void (map cvt xs)
126 cvt (Infix (Just x) s (Just y))
127 = HsPar (OpApp (cvt x) (HsVar(vName s)) undefined (cvt y))
128 cvt (Infix Nothing s (Just y)) = SectionR (HsVar(vName s)) (cvt y)
129 cvt (Infix (Just x) s Nothing ) = SectionL (cvt x) (HsVar(vName s))
130 cvt (Infix Nothing s Nothing ) = HsVar(vName s) -- Can I indicate this is an infix thing?
131 cvt (SigExp e t) = ExprWithTySig (cvt e) (cvtType t)
133 cvtdecs :: [Meta.Dec] -> HsBinds RdrName
134 cvtdecs [] = EmptyBinds
135 cvtdecs ds = MonoBind binds sigs Recursive
137 (binds, sigs) = cvtBindsAndSigs ds
140 = (cvtds non_sigs, map cvtSig sigs)
142 (sigs, non_sigs) = partition sigP ds
144 cvtSig (Proto nm typ) = Sig (vName nm) (cvtType typ) loc0
146 cvtds :: [Meta.Dec] -> MonoBinds RdrName
147 cvtds [] = EmptyMonoBinds
148 cvtds (d:ds) = AndMonoBinds (cvtd d) (cvtds ds)
150 cvtd :: Meta.Dec -> MonoBinds RdrName
151 -- Used only for declarations in a 'let/where' clause,
152 -- not for top level decls
153 cvtd (Val (Pvar s) body ds) = FunMonoBind (vName s) False
154 (panic "what now?") loc0
155 cvtd (Fun nm cls) = FunMonoBind (vName nm) False (map cvtclause cls) loc0
156 cvtd (Val p body ds) = PatMonoBind (cvtp p) (GRHSs (cvtguard body)
159 cvtd x = panic "Illegal kind of declaration in where clause"
162 cvtclause :: Meta.Clause (Meta.Pat) (Meta.Exp) (Meta.Dec) -> Hs.Match RdrName
163 cvtclause (ps,body,wheres) = Match (map cvtp ps) Nothing
164 (GRHSs (cvtguard body) (cvtdecs wheres) void)
168 cvtdd :: Meta.DDt -> ArithSeqInfo RdrName
169 cvtdd (Meta.From x) = (Hs.From (cvt x))
170 cvtdd (Meta.FromThen x y) = (Hs.FromThen (cvt x) (cvt y))
171 cvtdd (Meta.FromTo x y) = (Hs.FromTo (cvt x) (cvt y))
172 cvtdd (Meta.FromThenTo x y z) = (Hs.FromThenTo (cvt x) (cvt y) (cvt z))
175 cvtstmts :: [Meta.Stm] -> [Hs.Stmt RdrName]
176 cvtstmts [] = [] -- this is probably an error as every [stmt] should end with ResultStmt
177 cvtstmts [NoBindSt e] = [ResultStmt (cvt e) loc0] -- when its the last element use ResultStmt
178 cvtstmts (NoBindSt e : ss) = ExprStmt (cvt e) void loc0 : cvtstmts ss
179 cvtstmts (BindSt p e : ss) = BindStmt (cvtp p) (cvt e) loc0 : cvtstmts ss
180 cvtstmts (LetSt ds : ss) = LetStmt (cvtdecs ds) : cvtstmts ss
181 cvtstmts (ParSt dss : ss) = ParStmt(map cvtstmts dss) : cvtstmts ss
184 cvtm :: Meta.Mat -> Hs.Match RdrName
185 cvtm (p,body,wheres) = Match [cvtp p] Nothing
186 (GRHSs (cvtguard body) (cvtdecs wheres) void)
188 cvtguard :: Meta.Rhs -> [GRHS RdrName]
189 cvtguard (Guarded pairs) = map cvtpair pairs
190 cvtguard (Normal e) = [GRHS [ ResultStmt (cvt e) loc0 ] loc0]
192 cvtpair :: (Meta.Exp,Meta.Exp) -> GRHS RdrName
193 cvtpair (x,y) = GRHS [BindStmt truePat (cvt x) loc0,
194 ResultStmt (cvt y) loc0] loc0
196 cvtOverLit :: Lit -> HsOverLit
197 cvtOverLit (Integer i) = mkHsIntegral i
198 cvtOverLit (Rational r) = mkHsFractional r
199 -- An Integer is like an an (overloaded) '3' in a Haskell source program
200 -- Similarly 3.5 for fractionals
202 cvtLit :: Lit -> HsLit
203 cvtLit (Char c) = HsChar (ord c)
204 cvtLit (String s) = HsString (mkFastString s)
206 cvtp :: Meta.Pat -> Hs.Pat RdrName
208 | overloadedLit l = NPatIn (cvtOverLit l) Nothing -- Not right for negative
209 -- patterns; need to think
211 | otherwise = LitPat (cvtLit l)
212 cvtp (Pvar s) = VarPat(vName s)
213 cvtp (Ptup ps) = TuplePat (map cvtp ps) Boxed
214 cvtp (Pcon s ps) = ConPatIn (cName s) (PrefixCon (map cvtp ps))
215 cvtp (Ptilde p) = LazyPat (cvtp p)
216 cvtp (Paspat s p) = AsPat (vName s) (cvtp p)
217 cvtp Pwild = WildPat void
219 -----------------------------------------------------------
220 -- Types and type variables
222 cvt_tvs :: [String] -> [HsTyVarBndr RdrName]
223 cvt_tvs tvs = map (UserTyVar . tName) tvs
225 cvt_context :: Cxt -> HsContext RdrName
226 cvt_context tys = map cvt_pred tys
228 cvt_pred :: Typ -> HsPred RdrName
229 cvt_pred ty = case split_ty_app ty of
230 (Tvar tc, tys) -> HsClassP (tconName tc) (map cvtType tys)
231 other -> panic "Malformed predicate"
233 cvtType :: Meta.Typ -> HsType RdrName
234 cvtType ty = trans (root ty [])
235 where root (Tapp a b) zs = root a (cvtType b : zs)
238 trans (Tcon (Tuple n),args) | length args == n
239 = HsTupleTy (HsTupCon Boxed n) args
240 trans (Tcon Arrow, [x,y]) = HsFunTy x y
241 trans (Tcon List, [x]) = HsListTy x
243 trans (Tvar nm, args) = foldl HsAppTy (HsTyVar (tName nm)) args
244 trans (Tcon tc, args) = foldl HsAppTy (HsTyVar (tc_name tc)) args
246 tc_name (TconName nm) = tconName nm
247 tc_name Arrow = tconName "->"
248 tc_name List = tconName "[]"
249 tc_name (Tuple 0) = tconName "()"
250 tc_name (Tuple n) = tconName ("(" ++ replicate (n-1) ',' ++ ")")
252 split_ty_app :: Typ -> (Typ, [Typ])
253 split_ty_app ty = go ty []
255 go (Tapp f a) as = go f (a:as)
258 -----------------------------------------------------------
260 sigP (Proto _ _) = True
264 -----------------------------------------------------------
265 -- some useful things
267 truePat = ConPatIn (cName "True") (PrefixCon [])
268 falsePat = ConPatIn (cName "False") (PrefixCon [])
270 overloadedLit :: Lit -> Bool
271 -- True for literals that Haskell treats as overloaded
272 overloadedLit (Integer l) = True
273 overloadedLit (Rational l) = True
274 overloadedLit l = False
277 void = placeHolderType
280 loc0 = generatedSrcLoc
283 vName :: String -> RdrName
284 vName = mkName varName
286 -- Constructor function names
287 cName :: String -> RdrName
288 cName = mkName dataName
290 -- Type variable names
291 tName :: String -> RdrName
292 tName = mkName tvName
294 -- Type Constructor names
295 tconName = mkName tcName
297 mkName :: NameSpace -> String -> RdrName
298 -- Parse the string to see if it has a "." or ":" in it
299 -- so we know whether to generate a qualified or original name
300 -- It's a bit tricky because we need to parse
301 -- Foo.Baz.x as Qual Foo.Baz x
302 -- So we parse it from back to front
305 = split [] (reverse str)
307 split occ [] = mkRdrUnqual (mk_occ occ)
308 split occ (c:d:rev) -- 'd' is the last char before the separator
309 | is_sep c -- E.g. Fo.x d='o'
310 && isAlphaNum d -- Fo.+: d='+' perhaps
311 = mk_qual (reverse (d:rev)) c occ
312 split occ (c:rev) = split (c:occ) rev
314 mk_qual mod '.' occ = mkRdrQual (mk_mod mod) (mk_occ occ)
315 mk_qual mod ':' occ = mkOrig (mk_mod mod) (mk_occ occ)
317 mk_occ occ = mkOccFS ns (mkFastString occ)
318 mk_mod mod = mkModuleName mod