DsMeta.hs 90.9 KB
Newer Older
1
-----------------------------------------------------------------------------
Simon Marlow's avatar
Simon Marlow committed
2 3 4
--
-- (c) The University of Glasgow 2006
--
5 6 7 8
-- The purpose of this module is to transform an HsExpr into a CoreExpr which
-- when evaluated, returns a (Meta.Q Meta.Exp) computation analogous to the
-- input HsExpr. We do this in the DsM monad, which supplies access to
-- CoreExpr's of the "smart constructors" of the Meta.Exp datatype.
9 10 11 12 13
--
-- It also defines a bunch of knownKeyNames, in the same way as is done
-- in prelude/PrelNames.  It's much more convenient to do it here, becuase
-- otherwise we have to recompile PrelNames whenever we add a Name, which is
-- a Royal Pain (triggers other recompilation).
14 15
-----------------------------------------------------------------------------

Ian Lynagh's avatar
Ian Lynagh committed
16 17 18 19 20 21 22
{-# OPTIONS -fno-warn-tabs #-}
-- The above warning supression flag is a temporary kludge.
-- While working on this module you are encouraged to remove it and
-- detab the module (please do the detabbing in a separate patch). See
--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#TabsvsSpaces
-- for details

23 24
module DsMeta( dsBracket, 
	       templateHaskellNames, qTyConName, nameTyConName,
25 26
	       liftName, liftStringName, expQTyConName, patQTyConName, 
               decQTyConName, decsQTyConName, typeQTyConName,
27
	       decTyConName, typeTyConName, mkNameG_dName, mkNameG_vName, mkNameG_tcName,
28
	       quoteExpName, quotePatName, quoteDecName, quoteTypeName
29
	        ) where
30

31 32
#include "HsVersions.h"

33 34
import {-# SOURCE #-}	DsExpr ( dsExpr )

Simon Marlow's avatar
Simon Marlow committed
35
import MatchLit
36 37
import DsMonad

38
import qualified Language.Haskell.TH as TH
39

40
import HsSyn
Simon Marlow's avatar
Simon Marlow committed
41 42 43 44 45 46
import Class
import PrelNames
-- To avoid clashes with DsMeta.varName we must make a local alias for
-- OccName.varName we do this by removing varName from the import of
-- OccName above, making a qualified instance of OccName and using
-- OccNameAlias.varName where varName ws previously used in this file.
47
import qualified OccName( isDataOcc, isVarOcc, isTcOcc, varName, tcName ) 
48

Simon Marlow's avatar
Simon Marlow committed
49 50
import Module
import Id
51
import Name hiding( isVarOcc, isTcOcc, varName, tcName ) 
52
import NameEnv
Simon Marlow's avatar
Simon Marlow committed
53 54 55
import TcType
import TyCon
import TysWiredIn
dreixel's avatar
dreixel committed
56
import TysPrim ( liftedTypeKindTyConName )
57
import CoreSyn
58
import MkCore
Simon Marlow's avatar
Simon Marlow committed
59 60 61 62
import CoreUtils
import SrcLoc
import Unique
import BasicTypes
63
import Outputable
Simon Marlow's avatar
Simon Marlow committed
64 65 66
import Bag
import FastString
import ForeignCall
67
import MonadUtils
68
import Util( equalLength )
69

Simon Marlow's avatar
Simon Marlow committed
70 71 72
import Data.Maybe
import Control.Monad
import Data.List
Ian Lynagh's avatar
Ian Lynagh committed
73

74 75
-----------------------------------------------------------------------------
dsBracket :: HsBracket Name -> [PendingSplice] -> DsM CoreExpr
76
-- Returns a CoreExpr of type TH.ExpQ
77 78 79
-- The quoted thing is parameterised over Name, even though it has
-- been type checked.  We don't want all those type decorations!

80 81
dsBracket brack splices
  = dsExtendMetaEnv new_bit (do_brack brack)
82
  where
83
    new_bit = mkNameEnv [(n, Splice (unLoc e)) | (n,e) <- splices]
84

dreixel's avatar
dreixel committed
85
    do_brack (VarBr _ n) = do { MkC e1  <- lookupOcc n ; return e1 }
86 87 88 89 90
    do_brack (ExpBr e)   = do { MkC e1  <- repLE e     ; return e1 }
    do_brack (PatBr p)   = do { MkC p1  <- repTopP p   ; return p1 }
    do_brack (TypBr t)   = do { MkC t1  <- repLTy t    ; return t1 }
    do_brack (DecBrG gp) = do { MkC ds1 <- repTopDs gp ; return ds1 }
    do_brack (DecBrL _)  = panic "dsBracket: unexpected DecBrL"
91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106

{- -------------- Examples --------------------

  [| \x -> x |]
====>
  gensym (unpackString "x"#) `bindQ` \ x1::String ->
  lam (pvar x1) (var x1)


  [| \x -> $(f [| x |]) |]
====>
  gensym (unpackString "x"#) `bindQ` \ x1::String ->
  lam (pvar x1) (f (var x1))
-}


107 108 109 110
-------------------------------------------------------
-- 			Declarations
-------------------------------------------------------

111 112 113
repTopP :: LPat Name -> DsM (Core TH.PatQ)
repTopP pat = do { ss <- mkGenSyms (collectPatBinders pat) 
                 ; pat' <- addBinds ss (repLP pat)
114
                 ; wrapGenSyms ss pat' }
115

116
repTopDs :: HsGroup Name -> DsM (Core (TH.Q [TH.Dec]))
117
repTopDs group
118
 = do { let { bndrs = hsGroupBinders group } ;
119
	ss <- mkGenSyms bndrs ;
120

121 122 123 124 125
	-- Bind all the names mainly to avoid repeated use of explicit strings.
	-- Thus	we get
	--	do { t :: String <- genSym "T" ;
	--	     return (Data t [] ...more t's... }
	-- The other important reason is that the output must mention
126
	-- only "T", not "Foo:T" where Foo is the current module
127
	
128
	decls <- addBinds ss (do {
129
                        fix_ds  <- mapM repFixD (hs_fixds group) ;
130
			val_ds  <- rep_val_binds (hs_valds group) ;
131
			tycl_ds <- mapM repTyClD (concat (hs_tyclds group)) ;
132
			inst_ds <- mapM repInstD (hs_instds group) ;
133
			for_ds <- mapM repForD (hs_fords group) ;
134
			-- more needed
135
			return (de_loc $ sort_by_loc $ 
136
                                val_ds ++ catMaybes tycl_ds ++ fix_ds
137
                                       ++ catMaybes inst_ds ++ for_ds) }) ;
138

139
	decl_ty <- lookupType decQTyConName ;
140
	let { core_list = coreList' decl_ty decls } ;
141 142 143

	dec_ty <- lookupType decTyConName ;
	q_decs  <- repSequenceQ dec_ty core_list ;
144

145
	wrapGenSyms ss q_decs
146 147 148
      }


149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166
{- 	Note [Binders and occurrences]
	~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
When we desugar [d| data T = MkT |]
we want to get
	Data "T" [] [Con "MkT" []] []
and *not*
	Data "Foo:T" [] [Con "Foo:MkT" []] []
That is, the new data decl should fit into whatever new module it is
asked to fit in.   We do *not* clone, though; no need for this:
	Data "T79" ....

But if we see this:
	data T = MkT 
	foo = reifyDecl T

then we must desugar to
	foo = Data "Foo:T" [] [Con "Foo:MkT" []] []

167 168
So in repTopDs we bring the binders into scope with mkGenSyms and addBinds.
And we use lookupOcc, rather than lookupBinder
169 170 171 172
in repTyClD and repC.

-}

173
repTyClD :: LTyClDecl Name -> DsM (Maybe (SrcSpan, Core TH.DecQ))
174

175 176 177
repTyClD tydecl@(L _ (TyFamily {}))
  = repTyFamily tydecl addTyVarBinds

178
repTyClD (L loc (TyData { tcdND = DataType, tcdCtxt = cxt, tcdKindSig = mb_kind,
179 180 181
		          tcdLName = tc, tcdTyVars = tvs, tcdTyPats = opt_tys,
		          tcdCons = cons, tcdDerivs = mb_derivs }))
  = do { tc1 <- lookupLOcc tc 		-- See note [Binders and occurrences] 
182 183
       ; tc_tvs <- mk_extra_tvs tvs mb_kind
       ; dec <- addTyVarBinds tc_tvs $ \bndrs -> 
184 185 186
           do { cxt1     <- repLContext cxt
              ; opt_tys1 <- maybeMapM repLTys opt_tys   -- only for family insts
              ; opt_tys2 <- maybeMapM (coreList typeQTyConName) opt_tys1
187
              ; cons1    <- mapM (repC (hsLTyVarNames tc_tvs)) cons
188 189
      	      ; cons2    <- coreList conQTyConName cons1
      	      ; derivs1  <- repDerivs mb_derivs
190
	      ; bndrs1   <- coreList tyVarBndrTyConName bndrs
191 192 193 194
      	      ; repData cxt1 tc1 bndrs1 opt_tys2 cons2 derivs1 
              }
       ; return $ Just (loc, dec) 
       }
195

196
repTyClD (L loc (TyData { tcdND = NewType, tcdCtxt = cxt, tcdKindSig = mb_kind,
197 198 199
		          tcdLName = tc, tcdTyVars = tvs, tcdTyPats = opt_tys,
		          tcdCons = [con], tcdDerivs = mb_derivs }))
  = do { tc1 <- lookupLOcc tc 		-- See note [Binders and occurrences] 
200 201
       ; tc_tvs <- mk_extra_tvs tvs mb_kind
       ; dec <- addTyVarBinds tc_tvs $ \bndrs -> 
202 203 204
           do { cxt1     <- repLContext cxt
              ; opt_tys1 <- maybeMapM repLTys opt_tys   -- only for family insts
              ; opt_tys2 <- maybeMapM (coreList typeQTyConName) opt_tys1
205
              ; con1     <- repC (hsLTyVarNames tc_tvs) con
206
      	      ; derivs1  <- repDerivs mb_derivs
207
	      ; bndrs1   <- coreList tyVarBndrTyConName bndrs
208 209 210 211 212 213 214 215 216 217 218 219
      	      ; repNewtype cxt1 tc1 bndrs1 opt_tys2 con1 derivs1
              }
       ; return $ Just (loc, dec) 
       }

repTyClD (L loc (TySynonym { tcdLName = tc, tcdTyVars = tvs, tcdTyPats = opt_tys,
                             tcdSynRhs = ty }))
  = do { tc1 <- lookupLOcc tc 		-- See note [Binders and occurrences] 
       ; dec <- addTyVarBinds tvs $ \bndrs -> 
           do { opt_tys1 <- maybeMapM repLTys opt_tys   -- only for family insts
              ; opt_tys2 <- maybeMapM (coreList typeQTyConName) opt_tys1
	      ; ty1      <- repLTy ty
220
	      ; bndrs1   <- coreList tyVarBndrTyConName bndrs
221 222 223 224
	      ; repTySyn tc1 bndrs1 opt_tys2 ty1 
              }
       ; return (Just (loc, dec)) 
       }
225

226
repTyClD (L loc (ClassDecl { tcdCtxt = cxt, tcdLName = cls, 
227 228
		             tcdTyVars = tvs, tcdFDs = fds,
		             tcdSigs = sigs, tcdMeths = meth_binds, 
229
                             tcdATs = ats, tcdATDefs = [] }))
230 231 232 233 234 235 236 237
  = do { cls1 <- lookupLOcc cls 	-- See note [Binders and occurrences] 
       ; dec  <- addTyVarBinds tvs $ \bndrs -> 
           do { cxt1   <- repLContext cxt
 	      ; sigs1  <- rep_sigs sigs
 	      ; binds1 <- rep_binds meth_binds
	      ; fds1   <- repLFunDeps fds
              ; ats1   <- repLAssocFamilys ats
 	      ; decls1 <- coreList decQTyConName (ats1 ++ sigs1 ++ binds1)
238
	      ; bndrs1 <- coreList tyVarBndrTyConName bndrs
239 240 241 242
 	      ; repClass cxt1 cls1 bndrs1 fds1 decls1 
              }
       ; return $ Just (loc, dec) 
       }
243 244

-- Un-handled cases
245
repTyClD (L loc d) = putSrcSpanDs loc $
246
		     do { warnDs (hang ds_msg 4 (ppr d))
247
			; return Nothing }
248

249
-------------------------
250
mk_extra_tvs :: [LHsTyVarBndr Name] -> Maybe (HsBndrSig (LHsKind Name)) -> DsM [LHsTyVarBndr Name]
251 252 253
-- If there is a kind signature it must be of form
--    k1 -> .. -> kn -> *
-- Return type variables [tv1:k1, tv2:k2, .., tvn:kn]
254 255 256 257 258
mk_extra_tvs tvs Nothing 
  = return tvs
mk_extra_tvs tvs (Just (HsBSig hs_kind _))
  = do { extra_tvs <- go hs_kind
       ; return (tvs ++ extra_tvs) }
259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277
  where
    go :: LHsKind Name -> DsM [LHsTyVarBndr Name]
    go (L loc (HsFunTy kind rest))
      = do { uniq <- newUnique
           ; let { occ = mkTyVarOccFS (fsLit "t")
                 ; nm = mkInternalName uniq occ loc
                 ; hs_tv = L loc (KindedTyVar nm (HsBSig kind placeHolderBndrs)) }
           ; hs_tvs <- go rest
           ; return (hs_tv : hs_tvs) }

    go (L _ (HsTyVar n))
      | n == liftedTypeKindTyConName
      = return []
   
    go _ = failWithDs (hang (ptext (sLit "Malformed kind signature"))
                          2 (ppr hs_kind))


-------------------------
278 279 280 281 282 283 284 285
-- The type variables in the head of families are treated differently when the
-- family declaration is associated.  In that case, they are usage, not binding
-- occurences.
--
repTyFamily :: LTyClDecl Name 
            -> ProcessTyVarBinds TH.Dec
            -> DsM (Maybe (SrcSpan, Core TH.DecQ))
repTyFamily (L loc (TyFamily { tcdFlavour = flavour,
286 287
		               tcdLName   = tc, tcdTyVars = tvs, 
		               tcdKindSig = opt_kind }))
288 289 290 291
            tyVarBinds
  = do { tc1 <- lookupLOcc tc 		-- See note [Binders and occurrences] 
       ; dec <- tyVarBinds tvs $ \bndrs ->
           do { flav   <- repFamilyFlavour flavour
292 293 294
	      ; bndrs1 <- coreList tyVarBndrTyConName bndrs
              ; case opt_kind of 
                  Nothing -> repFamilyNoKind flav tc1 bndrs1
295 296 297
                  Just (HsBSig ki _) 
                    -> do { ki1 <- repKind ki 
                          ; repFamilyKind flav tc1 bndrs1 ki1 }
298 299 300 301 302
              }
       ; return $ Just (loc, dec)
       }
repTyFamily _ _ = panic "DsMeta.repTyFamily: internal error"

303 304 305 306 307 308 309 310 311 312 313 314 315
-- represent fundeps
--
repLFunDeps :: [Located (FunDep Name)] -> DsM (Core [TH.FunDep])
repLFunDeps fds = do fds' <- mapM repLFunDep fds
                     fdList <- coreList funDepTyConName fds'
                     return fdList

repLFunDep :: Located (FunDep Name) -> DsM (Core TH.FunDep)
repLFunDep (L _ (xs, ys)) = do xs' <- mapM lookupBinder xs
                               ys' <- mapM lookupBinder ys
                               xs_list <- coreList nameTyConName xs'
                               ys_list <- coreList nameTyConName ys'
                               repFunDep xs_list ys_list
316

317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342
-- represent family declaration flavours
--
repFamilyFlavour :: FamilyFlavour -> DsM (Core TH.FamFlavour)
repFamilyFlavour TypeFamily = rep2 typeFamName []
repFamilyFlavour DataFamily = rep2 dataFamName []

-- represent associated family declarations
--
repLAssocFamilys :: [LTyClDecl Name] -> DsM [Core TH.DecQ]
repLAssocFamilys = mapM repLAssocFamily
  where
    repLAssocFamily tydecl@(L _ (TyFamily {})) 
      = liftM (snd . fromJust) $ repTyFamily tydecl lookupTyVarBinds
    repLAssocFamily tydecl
      = failWithDs msg
      where
        msg = ptext (sLit "Illegal associated declaration in class:") <+> 
              ppr tydecl

-- represent associated family instances
--
repLAssocFamInst :: [LTyClDecl Name] -> DsM [Core TH.DecQ]
repLAssocFamInst = liftM de_loc . mapMaybeM repTyClD

-- represent instance declarations
--
343 344 345 346 347
repInstD :: LInstDecl Name -> DsM (Maybe (SrcSpan, Core TH.DecQ))
repInstD (L loc (FamInstDecl fi_decl))
  = repTyClD (L loc fi_decl)


348
repInstD (L loc (ClsInstDecl ty binds prags ats))
349 350 351 352 353 354 355 356 357 358 359
  = do { dec <- addTyVarBinds tvs $ \_ ->
	    -- We must bring the type variables into scope, so their
	    -- occurrences don't fail, even though the binders don't 
            -- appear in the resulting data structure
	    --
	    -- But we do NOT bring the binders of 'binds' into scope
	    -- becuase they are properly regarded as occurrences
	    -- For example, the method names should be bound to
	    -- the selector Ids, not to fresh names (Trac #5410)
	    --
            do { cxt1 <- repContext cxt
batterseapower's avatar
batterseapower committed
360 361 362
               ; cls_tcon <- repTy (HsTyVar cls)
               ; cls_tys <- repLTys tys
               ; inst_ty1 <- repTapps cls_tcon cls_tys
363
               ; binds1 <- rep_binds binds
364
               ; prags1 <- rep_sigs prags
365
               ; ats1 <- repLAssocFamInst ats
366
               ; decls <- coreList decQTyConName (ats1 ++ binds1 ++ prags1)
367
               ; repInst cxt1 inst_ty1 decls }
368
       ; return (Just (loc, dec)) }
369
 where
batterseapower's avatar
batterseapower committed
370
   Just (tvs, cxt, cls, tys) = splitHsInstDeclTy_maybe (unLoc ty)
371

372
repForD :: Located (ForeignDecl Name) -> DsM (SrcSpan, Core TH.DecQ)
373
repForD (L loc (ForeignImport name typ _ (CImport cc s mch cis)))
374 375 376 377
 = do MkC name' <- lookupLOcc name
      MkC typ' <- repLTy typ
      MkC cc' <- repCCallConv cc
      MkC s' <- repSafety s
378
      cis' <- conv_cimportspec cis
379
      MkC str <- coreStringLit (static ++ chStr ++ cis')
380 381 382
      dec <- rep2 forImpDName [cc', s', str, name', typ']
      return (loc, dec)
 where
383 384
    conv_cimportspec (CLabel cls) = notHandled "Foreign label" (doubleQuotes (ppr cls))
    conv_cimportspec (CFunction DynamicTarget) = return "dynamic"
385 386
    conv_cimportspec (CFunction (StaticTarget fs _ True)) = return (unpackFS fs)
    conv_cimportspec (CFunction (StaticTarget _  _ False)) = panic "conv_cimportspec: values not supported yet"
387
    conv_cimportspec CWrapper = return "wrapper"
388
    static = case cis of
389
                 CFunction (StaticTarget _ _ _) -> "static "
390
                 _ -> ""
391 392 393
    chStr = case mch of
            Nothing -> ""
            Just (Header h) -> unpackFS h ++ " "
394
repForD decl = notHandled "Foreign declaration" (ppr decl)
395 396 397 398

repCCallConv :: CCallConv -> DsM (Core TH.Callconv)
repCCallConv CCallConv = rep2 cCallName []
repCCallConv StdCallConv = rep2 stdCallName []
399
repCCallConv callConv    = notHandled "repCCallConv" (ppr callConv)
400 401 402

repSafety :: Safety -> DsM (Core TH.Safety)
repSafety PlayRisky = rep2 unsafeName []
403
repSafety PlayInterruptible = rep2 interruptibleName []
Ian Lynagh's avatar
Ian Lynagh committed
404
repSafety PlaySafe = rep2 safeName []
405

406 407 408 409 410 411 412 413 414 415 416
repFixD :: LFixitySig Name -> DsM (SrcSpan, Core TH.DecQ)
repFixD (L loc (FixitySig name (Fixity prec dir)))
  = do { MkC name' <- lookupLOcc name
       ; MkC prec' <- coreIntLit prec
       ; let rep_fn = case dir of 
                        InfixL -> infixLDName
                        InfixR -> infixRDName
                        InfixN -> infixNDName
       ; dec <- rep2 rep_fn [prec', name']
       ; return (loc, dec) }

Ian Lynagh's avatar
Ian Lynagh committed
417
ds_msg :: SDoc
Ian Lynagh's avatar
Ian Lynagh committed
418
ds_msg = ptext (sLit "Cannot desugar this Template Haskell declaration:")
419

420 421 422 423
-------------------------------------------------------
-- 			Constructors
-------------------------------------------------------

424 425 426
repC :: [Name] -> LConDecl Name -> DsM (Core TH.ConQ)
repC _ (L _ (ConDecl { con_name = con, con_qvars = [], con_cxt = L _ []
                       , con_details = details, con_res = ResTyH98 }))
427
  = do { con1 <- lookupLOcc con 	-- See note [Binders and occurrences] 
428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448
       ; repConstr con1 details  }
repC tvs (L _ (ConDecl { con_name = con
                       , con_qvars = con_tvs, con_cxt = L _ ctxt
                       , con_details = details
                       , con_res = res_ty }))
  = do { (eq_ctxt, con_tv_subst) <- mkGadtCtxt tvs res_ty
       ; let ex_tvs = [ tv | tv <- con_tvs, not (hsLTyVarName tv `in_subst` con_tv_subst)]
       ; binds <- mapM dupBinder con_tv_subst 
       ; dsExtendMetaEnv (mkNameEnv binds) $     -- Binds some of the con_tvs
         addTyVarBinds ex_tvs $ \ ex_bndrs ->   -- Binds the remaining con_tvs
    do { con1      <- lookupLOcc con 	-- See note [Binders and occurrences] 
       ; c'        <- repConstr con1 details
       ; ctxt'     <- repContext (eq_ctxt ++ ctxt)
       ; ex_bndrs' <- coreList tyVarBndrTyConName ex_bndrs
       ; rep2 forallCName [unC ex_bndrs', unC ctxt', unC c'] } }

in_subst :: Name -> [(Name,Name)] -> Bool
in_subst _ []          = False
in_subst n ((n',_):ns) = n==n' || in_subst n ns

mkGadtCtxt :: [Name]		-- Tyvars of the data type
449
           -> ResType (LHsType Name)
450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471
	   -> DsM (HsContext Name, [(Name,Name)])
-- Given a data type in GADT syntax, figure out the equality 
-- context, so that we can represent it with an explicit 
-- equality context, because that is the only way to express
-- the GADT in TH syntax
--
-- Example:   
-- data T a b c where { MkT :: forall d e. d -> e -> T d [e] e
--     mkGadtCtxt [a,b,c] [d,e] (T d [e] e)
--   returns 
--     (b~[e], c~e), [d->a] 
-- 
-- This function is fiddly, but not really hard
mkGadtCtxt _ ResTyH98
  = return ([], [])
mkGadtCtxt data_tvs (ResTyGADT res_ty)
  | let (head_ty, tys) = splitHsAppTys res_ty []
  , Just _ <- is_hs_tyvar head_ty
  , data_tvs `equalLength` tys
  = return (go [] [] (data_tvs `zip` tys))

  | otherwise 
472
  = failWithDs (ptext (sLit "Malformed constructor result type:") <+> ppr res_ty)
473 474 475 476 477 478 479 480 481 482 483
  where
    go cxt subst [] = (cxt, subst)
    go cxt subst ((data_tv, ty) : rest)
       | Just con_tv <- is_hs_tyvar ty
       , isTyVarName con_tv
       , not (in_subst con_tv subst)
       = go cxt ((con_tv, data_tv) : subst) rest
       | otherwise
       = go (eq_pred : cxt) subst rest
       where
         loc = getLoc ty
batterseapower's avatar
batterseapower committed
484
         eq_pred = L loc (HsEqTy (L loc (HsTyVar data_tv)) ty)
485 486 487 488 489 490

    is_hs_tyvar (L _ (HsTyVar n))  = Just n   -- Type variables *and* tycons
    is_hs_tyvar (L _ (HsParTy ty)) = is_hs_tyvar ty
    is_hs_tyvar _                  = Nothing

    
491
repBangTy :: LBangType Name -> DsM (Core (TH.StrictTypeQ))
492 493 494
repBangTy ty= do 
  MkC s <- rep2 str []
  MkC t <- repLTy ty'
495
  rep2 strictTypeName [s, t]
496 497
  where 
    (str, ty') = case ty of
498 499 500
		   L _ (HsBangTy HsUnpack ty) -> (unpackedName,  ty)
		   L _ (HsBangTy _ ty)        -> (isStrictName,  ty)
		   _                          -> (notStrictName, ty)
501 502 503 504 505

-------------------------------------------------------
-- 			Deriving clause
-------------------------------------------------------

506
repDerivs :: Maybe [LHsType Name] -> DsM (Core [TH.Name])
507
repDerivs Nothing = coreList nameTyConName []
508
repDerivs (Just ctxt)
509
  = do { strs <- mapM rep_deriv ctxt ; 
510
	 coreList nameTyConName strs }
511
  where
512
    rep_deriv :: LHsType Name -> DsM (Core TH.Name)
513
	-- Deriving clauses must have the simple H98 form
batterseapower's avatar
batterseapower committed
514 515 516 517 518
    rep_deriv ty
      | Just (cls, []) <- splitHsClassTy_maybe (unLoc ty)
      = lookupOcc cls
      | otherwise
      = notHandled "Non-H98 deriving clause" (ppr ty)
519 520 521 522 523 524


-------------------------------------------------------
--   Signatures in a class decl, or a group of bindings
-------------------------------------------------------

525
rep_sigs :: [LSig Name] -> DsM [Core TH.DecQ]
526 527 528
rep_sigs sigs = do locs_cores <- rep_sigs' sigs
                   return $ de_loc $ sort_by_loc locs_cores

529
rep_sigs' :: [LSig Name] -> DsM [(SrcSpan, Core TH.DecQ)]
530
	-- We silently ignore ones we don't recognise
531
rep_sigs' sigs = do { sigs1 <- mapM rep_sig sigs ;
532 533
		     return (concat sigs1) }

534
rep_sig :: LSig Name -> DsM [(SrcSpan, Core TH.DecQ)]
535 536
	-- Singleton => Ok
	-- Empty     => Too hard, signature ignored
537
rep_sig (L loc (TypeSig nms ty))      = rep_proto nms ty loc
dreixel's avatar
dreixel committed
538 539 540 541
rep_sig (L _   (GenericSig nm _))     = failWithDs msg
  where msg = vcat  [ ptext (sLit "Illegal default signature for") <+> quotes (ppr nm)
                    , ptext (sLit "Default signatures are not supported by Template Haskell") ]

542 543 544 545
rep_sig (L loc (InlineSig nm ispec))  = rep_inline nm ispec loc
rep_sig (L loc (SpecSig nm ty ispec)) = rep_specialise nm ty ispec loc
rep_sig _                             = return []

546
rep_proto :: [Located Name] -> LHsType Name -> SrcSpan
547
          -> DsM [(SrcSpan, Core TH.DecQ)]
548 549 550 551 552 553 554 555
rep_proto nms ty loc
  = mapM f nms
  where
    f nm = do { nm1 <- lookupLOcc nm
              ; ty1 <- repLTy ty
              ; sig <- repProto nm1 ty1
              ; return (loc, sig)
              }
556

557 558 559
rep_inline :: Located Name 
           -> InlinePragma	-- Never defaultInlinePragma
           -> SrcSpan 
560 561 562
           -> DsM [(SrcSpan, Core TH.DecQ)]
rep_inline nm ispec loc
  = do { nm1 <- lookupLOcc nm
563
       ; ispec1 <- rep_InlinePrag ispec
564 565 566 567
       ; pragma <- repPragInl nm1 ispec1
       ; return [(loc, pragma)]
       }

568
rep_specialise :: Located Name -> LHsType Name -> InlinePragma -> SrcSpan 
569 570 571 572
               -> DsM [(SrcSpan, Core TH.DecQ)]
rep_specialise nm ty ispec loc
  = do { nm1 <- lookupLOcc nm
       ; ty1 <- repLTy ty
573 574 575 576
       ; pragma <- if isDefaultInlinePragma ispec
                   then repPragSpec nm1 ty1                  -- SPECIALISE
                   else do { ispec1 <- rep_InlinePrag ispec  -- SPECIALISE INLINE
                           ; repPragSpecInl nm1 ty1 ispec1 } 
577 578
       ; return [(loc, pragma)]
       }
579

580
-- Extract all the information needed to build a TH.InlinePrag
581
--
582 583 584
rep_InlinePrag :: InlinePragma	-- Never defaultInlinePragma
               -> DsM (Core TH.InlineSpecQ)
rep_InlinePrag (InlinePragma { inl_act = activation, inl_rule = match, inl_inline = inline })
585
  | Just (flag, phase) <- activation1 
586 587 588 589
  = repInlineSpecPhase inline1 match1 flag phase
  | otherwise
  = repInlineSpecNoPhase inline1 match1
  where
590 591
      match1      = coreBool (rep_RuleMatchInfo match)
      activation1 = rep_Activation activation
592 593 594 595
      inline1     = case inline of 
                       Inline -> coreBool True
 		       _other -> coreBool False
		       -- We have no representation for Inlinable
596 597 598 599

      rep_RuleMatchInfo FunLike = False
      rep_RuleMatchInfo ConLike = True

600 601
      rep_Activation NeverActive          = Nothing	-- We never have NOINLINE/AlwaysActive
      rep_Activation AlwaysActive         = Nothing	-- or            INLINE/NeverActive
602 603 604 605
      rep_Activation (ActiveBefore phase) = Just (coreBool False, 
                                                  MkC $ mkIntExprInt phase)
      rep_Activation (ActiveAfter phase)  = Just (coreBool True, 
                                                  MkC $ mkIntExprInt phase)
606 607 608 609 610


-------------------------------------------------------
-- 			Types
-------------------------------------------------------
611

612 613 614 615 616
-- We process type variable bindings in two ways, either by generating fresh
-- names or looking up existing names.  The difference is crucial for type
-- families, depending on whether they are associated or not.
--
type ProcessTyVarBinds a = 
617 618
         [LHsTyVarBndr Name]	                       -- the binders to be added
      -> ([Core TH.TyVarBndr] -> DsM (Core (TH.Q a)))  -- action in the ext env
619 620
      -> DsM (Core (TH.Q a))

621 622
-- gensym a list of type variables and enter them into the meta environment;
-- the computations passed as the second argument is executed in that extended
623
-- meta environment and gets the *new* names on Core-level as an argument
624
--
625
addTyVarBinds :: ProcessTyVarBinds a
626 627 628 629 630 631 632 633
addTyVarBinds tvs m
  = do { freshNames <- mkGenSyms (hsLTyVarNames tvs)
       ; term <- addBinds freshNames $ 
	    	 do { kindedBndrs <- mapM mk_tv_bndr (tvs `zip` freshNames)
	    	    ; m kindedBndrs }
       ; wrapGenSyms freshNames term }
  where
    mk_tv_bndr (tv, (_,v)) = repTyVarBndrWithKind tv (coreVar v)
634

635 636 637 638 639 640
-- Look up a list of type variables; the computations passed as the second 
-- argument gets the *new* names on Core-level as an argument
--
lookupTyVarBinds :: ProcessTyVarBinds a
lookupTyVarBinds tvs m =
  do
641 642 643 644 645 646 647 648 649 650
    let names       = hsLTyVarNames tvs
        mkWithKinds = map repTyVarBndrWithKind tvs
    bndrs       <- mapM lookupBinder names 
    kindedBndrs <- zipWithM ($) mkWithKinds bndrs
    m kindedBndrs

-- Produce kinded binder constructors from the Haskell tyvar binders
--
repTyVarBndrWithKind :: LHsTyVarBndr Name 
                     -> Core TH.Name -> DsM (Core TH.TyVarBndr)
651 652
repTyVarBndrWithKind (L _ (UserTyVar {})) nm
  = repPlainTV nm
653
repTyVarBndrWithKind (L _ (KindedTyVar _ (HsBSig ki _))) nm
654
  = repKind ki >>= repKindedTV nm
655

656 657
-- represent a type context
--
658 659 660
repLContext :: LHsContext Name -> DsM (Core TH.CxtQ)
repLContext (L _ ctxt) = repContext ctxt

661
repContext :: HsContext Name -> DsM (Core TH.CxtQ)
662
repContext ctxt = do 
663
	            preds    <- mapM repLPred ctxt
664
		    predList <- coreList predQTyConName preds
665
		    repCtxt predList
666

667 668
-- represent a type predicate
--
batterseapower's avatar
batterseapower committed
669
repLPred :: LHsType Name -> DsM (Core TH.PredQ)
670 671
repLPred (L _ p) = repPred p

batterseapower's avatar
batterseapower committed
672 673 674
repPred :: HsType Name -> DsM (Core TH.PredQ)
repPred ty
  | Just (cls, tys) <- splitHsClassTy_maybe ty
675 676 677 678 679
  = do
      cls1 <- lookupOcc cls
      tys1 <- repLTys tys
      tys2 <- coreList typeQTyConName tys1
      repClassP cls1 tys2
batterseapower's avatar
batterseapower committed
680
repPred (HsEqTy tyleft tyright) 
681 682 683 684
  = do
      tyleft1  <- repLTy tyleft
      tyright1 <- repLTy tyright
      repEqualP tyleft1 tyright1
batterseapower's avatar
batterseapower committed
685 686
repPred ty
  = notHandled "Exotic predicate type" (ppr ty)
687

688 689
-- yield the representation of a list of types
--
690 691
repLTys :: [LHsType Name] -> DsM [Core TH.TypeQ]
repLTys tys = mapM repLTy tys
692

693 694
-- represent a type
--
695 696 697
repLTy :: LHsType Name -> DsM (Core TH.TypeQ)
repLTy (L _ ty) = repTy ty

698 699 700
repTy :: HsType Name -> DsM (Core TH.TypeQ)
repTy (HsForAllTy _ tvs ctxt ty)  = 
  addTyVarBinds tvs $ \bndrs -> do
701 702
    ctxt1  <- repLContext ctxt
    ty1    <- repLTy ty
703
    bndrs1 <- coreList tyVarBndrTyConName bndrs
704
    repTForall bndrs1 ctxt1 ty1
705

706
repTy (HsTyVar n)
707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729
  | isTvOcc (nameOccName n) = do 
			        tv1 <- lookupTvOcc n
			        repTvar tv1
  | otherwise		    = do 
			        tc1 <- lookupOcc n
			        repNamedTyCon tc1
repTy (HsAppTy f a)         = do 
			        f1 <- repLTy f
			        a1 <- repLTy a
			        repTapp f1 a1
repTy (HsFunTy f a)         = do 
			        f1   <- repLTy f
			        a1   <- repLTy a
			        tcon <- repArrowTyCon
			        repTapps tcon [f1, a1]
repTy (HsListTy t)	    = do
			        t1   <- repLTy t
			        tcon <- repListTyCon
			        repTapp tcon t1
repTy (HsPArrTy t)          = do
			        t1   <- repLTy t
			        tcon <- repTy (HsTyVar (tyConName parrTyCon))
			        repTapp tcon t1
batterseapower's avatar
batterseapower committed
730
repTy (HsTupleTy HsUnboxedTuple tys) = do
731 732 733
			        tys1 <- repLTys tys
			        tcon <- repUnboxedTupleTyCon (length tys)
			        repTapps tcon tys1
734 735 736
repTy (HsTupleTy _ tys)     = do tys1 <- repLTys tys 
                                 tcon <- repTupleTyCon (length tys)
                                 repTapps tcon tys1
dreixel's avatar
dreixel committed
737
repTy (HsOpTy ty1 (_, n) ty2) = repLTy ((nlHsTyVar (unLoc n) `nlHsAppTy` ty1)
738 739 740 741 742 743
			    	   `nlHsAppTy` ty2)
repTy (HsParTy t)  	    = repLTy t
repTy (HsKindSig t k)       = do
                                t1 <- repLTy t
                                k1 <- repKind k
                                repTSig t1 k1
744 745
repTy (HsSpliceTy splice _ _) = repSplice splice
repTy ty		      = notHandled "Exotic form of type" (ppr ty)
746

747 748
-- represent a kind
--
dreixel's avatar
dreixel committed
749
repKind :: LHsKind Name -> DsM (Core TH.Kind)
750
repKind ki
dreixel's avatar
dreixel committed
751
  = do { let (kis, ki') = splitHsFunType ki
752 753
       ; kis_rep <- mapM repKind kis
       ; ki'_rep <- repNonArrowKind ki'
754
       ; foldrM repArrowK ki'_rep kis_rep
755 756
       }
  where
dreixel's avatar
dreixel committed
757 758
    repNonArrowKind (L _ (HsTyVar name)) | name == liftedTypeKindTyConName = repStarK
    repNonArrowKind k = notHandled "Exotic form of kind" (ppr k)
759

760 761 762 763 764 765 766 767 768 769 770 771 772 773 774
-----------------------------------------------------------------------------
-- 		Splices
-----------------------------------------------------------------------------

repSplice :: HsSplice Name -> DsM (Core a)
-- See Note [How brackets and nested splices are handled] in TcSplice
-- We return a CoreExpr of any old type; the context should know
repSplice (HsSplice n _) 
 = do { mb_val <- dsLookupMetaEnv n
       ; case mb_val of
	   Just (Splice e) -> do { e' <- dsExpr e
				 ; return (MkC e') }
	   _ -> pprPanic "HsSplice" (ppr n) }
			-- Should not happen; statically checked

775
-----------------------------------------------------------------------------
776
-- 		Expressions
777
-----------------------------------------------------------------------------
778

779 780 781
repLEs :: [LHsExpr Name] -> DsM (Core [TH.ExpQ])
repLEs es = do { es'  <- mapM repLE es ;
		 coreList expQTyConName es' }
782

783 784 785
-- FIXME: some of these panics should be converted into proper error messages
--	  unless we can make sure that constructs, which are plainly not
--	  supported in TH already lead to error messages at an earlier stage
786
repLE :: LHsExpr Name -> DsM (Core TH.ExpQ)
787
repLE (L loc e) = putSrcSpanDs loc (repE e)
788

789
repE :: HsExpr Name -> DsM (Core TH.ExpQ)
790 791 792
repE (HsVar x)            =
  do { mb_val <- dsLookupMetaEnv x 
     ; case mb_val of
793
	Nothing	         -> do { str <- globalVar x
794 795 796 797
			       ; repVarOrCon x str }
	Just (Bound y)   -> repVarOrCon x (coreVar y)
	Just (Splice e)  -> do { e' <- dsExpr e
			       ; return (MkC e') } }
Ian Lynagh's avatar
Ian Lynagh committed
798
repE e@(HsIPVar _) = notHandled "Implicit parameters" (ppr e)
799 800 801 802 803

	-- Remember, we're desugaring renamer output here, so
	-- HsOverlit can definitely occur
repE (HsOverLit l) = do { a <- repOverloadedLiteral l; repLit a }
repE (HsLit l)     = do { a <- repLiteral l;           repLit a }
804
repE (HsLam (MatchGroup [m] _)) = repLambda m
805
repE (HsApp x y)   = do {a <- repLE x; b <- repLE y; repApp a b}
806

Ian Lynagh's avatar
Ian Lynagh committed
807
repE (OpApp e1 op _ e2) =
808 809 810
  do { arg1 <- repLE e1; 
       arg2 <- repLE e2; 
       the_op <- repLE op ;
811
       repInfixApp arg1 the_op arg2 } 
Ian Lynagh's avatar
Ian Lynagh committed
812
repE (NegApp x _)        = do
813
			      a         <- repLE x
814 815
			      negateVar <- lookupOcc negateName >>= repVar
			      negateVar `repApp` a
816 817 818
repE (HsPar x)            = repLE x
repE (SectionL x y)       = do { a <- repLE x; b <- repLE y; repSectionL a b } 
repE (SectionR x y)       = do { a <- repLE x; b <- repLE y; repSectionR a b } 
819 820 821
repE (HsCase e (MatchGroup ms _)) = do { arg <- repLE e
				       ; ms2 <- mapM repMatchTup ms
				       ; repCaseE arg (nonEmptyCoreList ms2) }
822
repE (HsIf _ x y z)         = do
823 824 825
			      a <- repLE x
			      b <- repLE y
			      c <- repLE z
826 827
			      repCond a b c
repE (HsLet bs e)         = do { (ss,ds) <- repBinds bs
828
			       ; e2 <- addBinds ss (repLE e)
829
			       ; z <- repLetE ds e2
830
			       ; wrapGenSyms ss z }
831

832
-- FIXME: I haven't got the types here right yet
833
repE e@(HsDo ctxt sts _) 
834
 | case ctxt of { DoExpr -> True; GhciStmt -> True; _ -> False }
835
 = do { (ss,zs) <- repLSts sts; 
836
        e'      <- repDoE (nonEmptyCoreList zs);
837
        wrapGenSyms ss e' }
838 839

 | ListComp <- ctxt
840
 = do { (ss,zs) <- repLSts sts; 
841
        e'      <- repComp (nonEmptyCoreList zs);
842
        wrapGenSyms ss e' }
843 844

  | otherwise
845
  = notHandled "mdo, monad comprehension and [: :]" (ppr e)
846

Ian Lynagh's avatar
Ian Lynagh committed
847 848
repE (ExplicitList _ es) = do { xs <- repLEs es; repListExp xs }
repE e@(ExplicitPArr _ _) = notHandled "Parallel arrays" (ppr e)
849
repE e@(ExplicitTuple es boxed) 
850
  | not (all tupArgPresent es) = notHandled "Tuple sections" (ppr e)
851 852
  | isBoxed boxed              = do { xs <- repLEs [e | Present e <- es]; repTup xs }
  | otherwise                  = do { xs <- repLEs [e | Present e <- es]; repUnboxedTup xs }
853

854
repE (RecordCon c _ flds)
855
 = do { x <- lookupLOcc c;
856 857
        fs <- repFields flds;
        repRecCon x fs }
858
repE (RecordUpd e flds _ _ _)
859
 = do { x <- repLE e;
860 861
        fs <- repFields flds;
        repRecUpd x fs }
862

863
repE (ExprWithTySig e ty) = do { e1 <- repLE e; t1 <- repLTy ty; repSigExp e1 t1 }
864
repE (ArithSeq _ aseq) =
865
  case aseq of
866
    From e              -> do { ds1 <- repLE e; repFrom ds1 }
867
    FromThen e1 e2      -> do 
868 869
		             ds1 <- repLE e1
			     ds2 <- repLE e2
870 871
			     repFromThen ds1 ds2
    FromTo   e1 e2      -> do 
872 873
			     ds1 <- repLE e1
			     ds2 <- repLE e2
874 875
			     repFromTo ds1 ds2
    FromThenTo e1 e2 e3 -> do 
876 877 878
			     ds1 <- repLE e1
			     ds2 <- repLE e2
			     ds3 <- repLE e3
879
			     repFromThenTo ds1 ds2 ds3
880

881
repE (HsSpliceE splice)  = repSplice splice
882 883 884
repE e@(PArrSeq {})      = notHandled "Parallel arrays" (ppr e)
repE e@(HsCoreAnn {})    = notHandled "Core annotations" (ppr e)
repE e@(HsSCC {})        = notHandled "Cost centres" (ppr e)
andy@galois.com's avatar
andy@galois.com committed
885
repE e@(HsTickPragma {}) = notHandled "Tick Pragma" (ppr e)
886 887
repE e@(HsBracketOut {}) = notHandled "TH brackets" (ppr e)
repE e 			 = notHandled "Expression form" (ppr e)
888 889 890 891

-----------------------------------------------------------------------------
-- Building representations of auxillary structures like Match, Clause, Stmt, 

892
repMatchTup ::  LMatch Name -> DsM (Core TH.MatchQ) 
Ian Lynagh's avatar
Ian Lynagh committed
893
repMatchTup (L _ (Match [p] _ (GRHSs guards wheres))) =
894
  do { ss1 <- mkGenSyms (collectPatBinders p) 
895
     ; addBinds ss1 $ do {
896
     ; p1 <- repLP p
897
     ; (ss2,ds) <- repBinds wheres
898 899 900
     ; addBinds ss2 $ do {
     ; gs    <- repGuards guards
     ; match <- repMatch p1 gs ds
901
     ; wrapGenSyms (ss1++ss2) match }}}
Ian Lynagh's avatar
Ian Lynagh committed
902
repMatchTup _ = panic "repMatchTup: case alt with more than one arg"
903

904
repClauseTup ::  LMatch Name -> DsM (Core TH.ClauseQ)
Ian Lynagh's avatar
Ian Lynagh committed
905
repClauseTup (L _ (Match ps _ (GRHSs guards wheres))) =
906
  do { ss1 <- mkGenSyms (collectPatsBinders ps) 
907
     ; addBinds ss1 $ do {
908
       ps1 <- repLPs ps
909
     ; (ss2,ds) <- repBinds wheres
910 911 912
     ; addBinds ss2 $ do {
       gs <- repGuards guards
     ; clause <- repClause ps1 gs ds
913
     ; wrapGenSyms (ss1++ss2) clause }}}
914

915
repGuards ::  [LGRHS Name] ->  DsM (Core TH.BodyQ)
916
repGuards [L _ (GRHS [] e)]
917
  = do {a <- repLE e; repNormal a }
918
repGuards other 
919 920 921
  = do { zs <- mapM process other;
     let {(xs, ys) = unzip zs};
	 gd <- repGuarded (nonEmptyCoreList ys);
922
     wrapGenSyms (concat xs) gd }
923
  where 
924
    process :: LGRHS Name -> DsM ([GenSymBind], (Core (TH.Q (TH.Guard, TH.Exp))))
925
    process (L _ (GRHS [L _ (ExprStmt e1 _ _ _)] e2))
926 927
           = do { x <- repLNormalGE e1 e2;
                  return ([], x) }
928
    process (L _ (GRHS ss rhs))
929
           = do (gs, ss') <- repLSts ss
930
		rhs' <- addBinds gs $ repLE rhs
931
                g <- repPatGE (nonEmptyCoreList ss') rhs'
932
                return (gs, g)
933

934 935
repFields :: HsRecordBinds Name -> DsM (Core [TH.Q TH.FieldExp])
repFields (HsRecFields { rec_flds = flds })
936 937 938 939
  = do	{ fnames <- mapM lookupLOcc (map hsRecFieldId flds)
	; es <- mapM repLE (map hsRecFieldArg flds)
	; fs <- zipWithM repFieldExp fnames es
	; coreList fieldExpQTyConName fs }
940

941 942 943

-----------------------------------------------------------------------------
-- Representing Stmt's is tricky, especially if bound variables
944
-- shadow each other. Consider:  [| do { x <- f 1; x <- f x; g x } |]
945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966
-- First gensym new names for every variable in any of the patterns.
-- both static (x'1 and x'2), and dynamic ((gensym "x") and (gensym "y"))
-- if variables didn't shaddow, the static gensym wouldn't be necessary
-- and we could reuse the original names (x and x).
--
-- do { x'1 <- gensym "x"
--    ; x'2 <- gensym "x"   
--    ; doE [ BindSt (pvar x'1) [| f 1 |]
--          , BindSt (pvar x'2) [| f x |] 
--          , NoBindSt [| g x |] 
--          ]
--    }

-- The strategy is to translate a whole list of do-bindings by building a
-- bigger environment, and a bigger set of meta bindings 
-- (like:  x'1 <- gensym "x" ) and then combining these with the translations
-- of the expressions within the Do
      
-----------------------------------------------------------------------------
-- The helper function repSts computes the translation of each sub expression
-- and a bunch of prefix bindings denoting the dynamic renaming.

967 968 969
repLSts :: [LStmt Name] -> DsM ([GenSymBind], [Core TH.StmtQ])
repLSts stmts = repSts (map unLoc stmts)

970
repSts :: [Stmt Name] -> DsM ([GenSymBind], [Core TH.StmtQ])
971
repSts (BindStmt p e _ _ : ss) =
972
   do { e2 <- repLE e 
973
      ; ss1 <- mkGenSyms (collectPatBinders p) 
974
      ; addBinds ss1 $ do {
975
      ; p1 <- repLP p; 
976 977 978 979
      ; (ss2,zs) <- repSts ss
      ; z <- repBindSt p1 e2
      ; return (ss1++ss2, z : zs) }}
repSts (LetStmt bs : ss) =
980
   do { (ss1,ds) <- repBinds bs
981 982 983
      ; z <- repLetSt ds
      ; (ss2,zs) <- addBinds ss1 (repSts ss)
      ; return (ss1++ss2, z : zs) } 
984
repSts (ExprStmt e _ _ _ : ss) =       
985
   do { e2 <- repLE e
986 987 988
      ; z <- repNoBindSt e2 
      ; (ss2,zs) <- repSts ss
      ; return (ss2, z : zs) }
989 990 991 992
repSts [LastStmt e _] 
  = do { e2 <- repLE e
       ; z <- repNoBindSt e2
       ; return ([], [z]) }
993 994
repSts []    = return ([],[])
repSts other = notHandled "Exotic statement" (ppr other)
995 996


997 998 999
-----------------------------------------------------------
--			Bindings
-----------------------------------------------------------
1000

1001 1002 1003 1004 1005
repBinds :: HsLocalBinds Name -> DsM ([GenSymBind], Core [TH.DecQ]) 
repBinds EmptyLocalBinds
  = do	{ core_list <- coreList decQTyConName []
	; return ([], core_list) }

1006
repBinds b@(HsIPBinds _) = notHandled "Implicit parameters" (ppr b)
1007 1008

repBinds (HsValBinds decs)
1009
 = do	{ let { bndrs = collectHsValBinders decs }
1010 1011 1012 1013
		-- No need to worrry about detailed scopes within
		-- the binding group, because we are talking Names
		-- here, so we can safely treat it as a mutually 
		-- recursive group
1014
	; ss        <- mkGenSyms bndrs
1015 1016 1017
	; prs       <- addBinds ss (rep_val_binds decs)
	; core_list <- coreList decQTyConName 
				(de_loc (sort_by_loc prs))
1018
	; return (ss, core_list) }
1019

1020
rep_val_binds :: HsValBinds Name -> DsM [(SrcSpan, Core TH.DecQ)]
1021
-- Assumes: all the binders of the binding are alrady in the meta-env
1022 1023
rep_val_binds (ValBindsOut binds sigs)
 = do { core1 <- rep_binds' (unionManyBags (map snd binds))
1024
      ;	core2 <- rep_sigs' sigs
1025
      ;	return (core1 ++ core2) }
Ian Lynagh's avatar
Ian Lynagh committed
1026
rep_val_binds (ValBindsIn _ _)
1027
 = panic "rep_val_binds: ValBindsIn"
1028

1029
rep_binds :: LHsBinds Name -> DsM [Core TH.DecQ]
1030 1031 1032 1033 1034
rep_binds binds = do { binds_w_locs <- rep_binds' binds
		     ; return (de_loc (sort_by_loc binds_w_locs)) }

rep_binds' :: LHsBinds Name -> DsM [(SrcSpan, Core TH.DecQ)]
rep_binds' binds = mapM rep_bind (bagToList binds)
1035

1036
rep_bind :: LHsBind Name -> DsM (SrcSpan, Core TH.DecQ)
1037
-- Assumes: all the binders of the binding are alrady in the meta-env
1038 1039 1040 1041

-- Note GHC treats declarations of a variable (not a pattern) 
-- e.g.  x = g 5 as a Fun MonoBinds. This is indicated by a single match 
-- with an empty list of patterns
1042
rep_bind (L loc (FunBind { fun_id = fn, 
Ian Lynagh's avatar
Ian Lynagh committed
1043
			   fun_matches = MatchGroup [L _ (Match [] _ (GRHSs