2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[DsExpr]{Matching expressions (Exprs)}
7 module DsExpr ( dsExpr, dsLet ) where
9 #include "HsVersions.h"
12 import HsSyn ( failureFreePat,
13 HsExpr(..), OutPat(..), HsLit(..), ArithSeqInfo(..),
14 Stmt(..), HsMatchContext(..), HsDoContext(..),
15 Match(..), HsBinds(..), MonoBinds(..),
18 import TcHsSyn ( TypecheckedHsExpr, TypecheckedHsBinds, TypecheckedStmt, outPatType )
20 -- NB: The desugarer, which straddles the source and Core worlds, sometimes
21 -- needs to see source types (newtypes etc), and sometimes not
22 -- So WATCH OUT; check each use of split*Ty functions.
23 -- Sigh. This is a pain.
25 import TcType ( tcSplitAppTy, tcSplitFunTys, tcTyConAppArgs,
26 isIntegerTy, tcSplitTyConApp, isUnLiftedType, Type )
27 import Type ( splitFunTys )
29 import CoreUtils ( exprType, mkIfThenElse, bindNonRec )
32 import DsBinds ( dsMonoBinds, AutoScc(..) )
33 import DsGRHSs ( dsGuarded )
34 import DsCCall ( dsCCall, resultWrapper )
35 import DsListComp ( dsListComp, dsPArrComp )
36 import DsUtils ( mkErrorAppDs, mkStringLit, mkStringLitFS,
37 mkConsExpr, mkNilExpr, mkIntegerLit
39 import Match ( matchWrapper, matchSimply )
41 import FieldLabel ( FieldLabel, fieldLabelTyCon )
42 import CostCentre ( mkUserCC )
43 import Id ( Id, idType, recordSelectorFieldLabel )
44 import PrelInfo ( rEC_CON_ERROR_ID, iRREFUT_PAT_ERROR_ID )
45 import DataCon ( DataCon, dataConWrapId, dataConFieldLabels, dataConInstOrigArgTys )
46 import DataCon ( isExistentialDataCon )
47 import Literal ( Literal(..) )
48 import TyCon ( tyConDataCons )
49 import TysWiredIn ( tupleCon, charDataCon, intDataCon )
50 import BasicTypes ( RecFlag(..), Boxity(..), ipNameName )
51 import Maybes ( maybeToBool )
52 import PrelNames ( hasKey, ratioTyConKey, toPName )
53 import Util ( zipEqual, zipWithEqual )
57 import Ratio ( numerator, denominator )
61 %************************************************************************
65 %************************************************************************
67 @dsLet@ is a match-result transformer, taking the @MatchResult@ for the body
68 and transforming it into one for the let-bindings enclosing the body.
70 This may seem a bit odd, but (source) let bindings can contain unboxed
75 This must be transformed to a case expression and, if the type has
76 more than one constructor, may fail.
79 dsLet :: TypecheckedHsBinds -> CoreExpr -> DsM CoreExpr
84 dsLet (ThenBinds b1 b2) body
85 = dsLet b2 body `thenDs` \ body' ->
88 -- Special case for bindings which bind unlifted variables
89 -- We need to do a case right away, rather than building
90 -- a tuple and doing selections.
91 -- Silently ignore INLINE pragmas...
92 dsLet bind@(MonoBind (AbsBinds [] [] exports inlines binds) sigs is_rec) body
93 | or [isUnLiftedType (idType g) | (_, g, l) <- exports]
94 = ASSERT (case is_rec of {NonRecursive -> True; other -> False})
95 -- Unlifted bindings are always non-recursive
96 -- and are always a Fun or Pat monobind
98 -- ToDo: in some bizarre case it's conceivable that there
99 -- could be dict binds in the 'binds'. (See the notes
100 -- below. Then pattern-match would fail. Urk.)
102 FunMonoBind fun _ matches loc
104 matchWrapper (FunRhs fun) matches `thenDs` \ (args, rhs) ->
105 ASSERT( null args ) -- Functions aren't lifted
106 returnDs (bindNonRec fun rhs body_w_exports)
108 PatMonoBind pat grhss loc
110 dsGuarded grhss `thenDs` \ rhs ->
111 mk_error_app pat `thenDs` \ error_expr ->
112 matchSimply rhs PatBindRhs pat body_w_exports error_expr
114 other -> pprPanic "dsLet: unlifted" (ppr bind $$ ppr body)
116 body_w_exports = foldr bind_export body exports
117 bind_export (tvs, g, l) body = ASSERT( null tvs )
118 bindNonRec g (Var l) body
120 mk_error_app pat = mkErrorAppDs iRREFUT_PAT_ERROR_ID
124 -- Ordinary case for bindings
125 dsLet (MonoBind binds sigs is_rec) body
126 = dsMonoBinds NoSccs binds [] `thenDs` \ prs ->
127 returnDs (Let (Rec prs) body)
128 -- Use a Rec regardless of is_rec.
129 -- Why? Because it allows the MonoBinds to be all
130 -- mixed up, which is what happens in one rare case
131 -- Namely, for an AbsBind with no tyvars and no dicts,
132 -- but which does have dictionary bindings.
133 -- See notes with TcSimplify.inferLoop [NO TYVARS]
134 -- It turned out that wrapping a Rec here was the easiest solution
136 -- NB The previous case dealt with unlifted bindings, so we
137 -- only have to deal with lifted ones now; so Rec is ok
140 %************************************************************************
142 \subsection[DsExpr-vars-and-cons]{Variables, constructors, literals}
144 %************************************************************************
147 dsExpr :: TypecheckedHsExpr -> DsM CoreExpr
149 dsExpr (HsVar var) = returnDs (Var var)
150 dsExpr (HsIPVar ip) = returnDs (Var (ipNameName ip))
151 dsExpr (HsLit lit) = dsLit lit
152 -- HsOverLit has been gotten rid of by the type checker
154 dsExpr expr@(HsLam a_Match)
155 = matchWrapper LambdaExpr [a_Match] `thenDs` \ (binders, matching_code) ->
156 returnDs (mkLams binders matching_code)
158 dsExpr expr@(HsApp fun arg)
159 = dsExpr fun `thenDs` \ core_fun ->
160 dsExpr arg `thenDs` \ core_arg ->
161 returnDs (core_fun `App` core_arg)
164 Operator sections. At first it looks as if we can convert
173 But no! expr might be a redex, and we can lose laziness badly this
178 for example. So we convert instead to
180 let y = expr in \x -> op y x
182 If \tr{expr} is actually just a variable, say, then the simplifier
186 dsExpr (OpApp e1 op _ e2)
187 = dsExpr op `thenDs` \ core_op ->
188 -- for the type of y, we need the type of op's 2nd argument
189 dsExpr e1 `thenDs` \ x_core ->
190 dsExpr e2 `thenDs` \ y_core ->
191 returnDs (mkApps core_op [x_core, y_core])
193 dsExpr (SectionL expr op)
194 = dsExpr op `thenDs` \ core_op ->
195 -- for the type of y, we need the type of op's 2nd argument
197 (x_ty:y_ty:_, _) = splitFunTys (exprType core_op)
198 -- Must look through an implicit-parameter type;
199 -- newtype impossible; hence Type.splitFunTys
201 dsExpr expr `thenDs` \ x_core ->
202 newSysLocalDs x_ty `thenDs` \ x_id ->
203 newSysLocalDs y_ty `thenDs` \ y_id ->
205 returnDs (bindNonRec x_id x_core $
206 Lam y_id (mkApps core_op [Var x_id, Var y_id]))
208 -- dsExpr (SectionR op expr) -- \ x -> op x expr
209 dsExpr (SectionR op expr)
210 = dsExpr op `thenDs` \ core_op ->
211 -- for the type of x, we need the type of op's 2nd argument
213 (x_ty:y_ty:_, _) = splitFunTys (exprType core_op)
214 -- See comment with SectionL
216 dsExpr expr `thenDs` \ y_core ->
217 newSysLocalDs x_ty `thenDs` \ x_id ->
218 newSysLocalDs y_ty `thenDs` \ y_id ->
220 returnDs (bindNonRec y_id y_core $
221 Lam x_id (mkApps core_op [Var x_id, Var y_id]))
223 dsExpr (HsCCall lbl args may_gc is_asm result_ty)
224 = mapDs dsExpr args `thenDs` \ core_args ->
225 dsCCall lbl core_args may_gc is_asm result_ty
226 -- dsCCall does all the unboxification, etc.
228 dsExpr (HsSCC cc expr)
229 = dsExpr expr `thenDs` \ core_expr ->
230 getModuleDs `thenDs` \ mod_name ->
231 returnDs (Note (SCC (mkUserCC cc mod_name)) core_expr)
233 -- special case to handle unboxed tuple patterns.
235 dsExpr (HsCase discrim matches src_loc)
236 | all ubx_tuple_match matches
237 = putSrcLocDs src_loc $
238 dsExpr discrim `thenDs` \ core_discrim ->
239 matchWrapper CaseAlt matches `thenDs` \ ([discrim_var], matching_code) ->
240 case matching_code of
241 Case (Var x) bndr alts | x == discrim_var ->
242 returnDs (Case core_discrim bndr alts)
243 _ -> panic ("dsExpr: tuple pattern:\n" ++ showSDoc (ppr matching_code))
245 ubx_tuple_match (Match [TuplePat ps Unboxed] _ _) = True
246 ubx_tuple_match _ = False
248 dsExpr (HsCase discrim matches src_loc)
249 = putSrcLocDs src_loc $
250 dsExpr discrim `thenDs` \ core_discrim ->
251 matchWrapper CaseAlt matches `thenDs` \ ([discrim_var], matching_code) ->
252 returnDs (bindNonRec discrim_var core_discrim matching_code)
254 dsExpr (HsLet binds body)
255 = dsExpr body `thenDs` \ body' ->
258 dsExpr (HsWith expr binds is_with)
259 = dsExpr expr `thenDs` \ expr' ->
260 foldlDs dsIPBind expr' binds
263 = dsExpr e `thenDs` \ e' ->
264 returnDs (Let (NonRec (ipNameName n) e') body)
266 -- We need the `ListComp' form to use `deListComp' (rather than the "do" form)
267 -- because the interpretation of `stmts' depends on what sort of thing it is.
269 dsExpr (HsDo ListComp stmts _ result_ty src_loc)
270 = -- Special case for list comprehensions
271 putSrcLocDs src_loc $
272 dsListComp stmts elt_ty
274 (_, [elt_ty]) = tcSplitTyConApp result_ty
276 dsExpr (HsDo DoExpr stmts ids result_ty src_loc)
277 = putSrcLocDs src_loc $
278 dsDo DoExpr stmts ids result_ty
280 dsExpr (HsDo PArrComp stmts _ result_ty src_loc)
281 = -- Special case for array comprehensions
282 putSrcLocDs src_loc $
283 dsPArrComp stmts elt_ty
285 (_, [elt_ty]) = tcSplitTyConApp result_ty
287 dsExpr (HsIf guard_expr then_expr else_expr src_loc)
288 = putSrcLocDs src_loc $
289 dsExpr guard_expr `thenDs` \ core_guard ->
290 dsExpr then_expr `thenDs` \ core_then ->
291 dsExpr else_expr `thenDs` \ core_else ->
292 returnDs (mkIfThenElse core_guard core_then core_else)
297 \underline{\bf Type lambda and application}
298 % ~~~~~~~~~~~~~~~~~~~~~~~~~~~
300 dsExpr (TyLam tyvars expr)
301 = dsExpr expr `thenDs` \ core_expr ->
302 returnDs (mkLams tyvars core_expr)
304 dsExpr (TyApp expr tys)
305 = dsExpr expr `thenDs` \ core_expr ->
306 returnDs (mkTyApps core_expr tys)
311 \underline{\bf Various data construction things}
312 % ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
314 dsExpr (ExplicitList ty xs)
317 go [] = returnDs (mkNilExpr ty)
318 go (x:xs) = dsExpr x `thenDs` \ core_x ->
319 go xs `thenDs` \ core_xs ->
320 returnDs (mkConsExpr ty core_x core_xs)
322 -- we create a list from the array elements and convert them into a list using
325 -- * the main disadvantage to this scheme is that `toP' traverses the list
326 -- twice: once to determine the length and a second time to put to elements
327 -- into the array; this inefficiency could be avoided by exposing some of
328 -- the innards of `PrelPArr' to the compiler (ie, have a `PrelPArrBase') so
329 -- that we can exploit the fact that we already know the length of the array
330 -- here at compile time
332 dsExpr (ExplicitPArr ty xs)
333 = dsLookupGlobalValue toPName `thenDs` \toP ->
334 dsExpr (ExplicitList ty xs) `thenDs` \coreList ->
335 returnDs (mkApps (Var toP) [Type ty, coreList])
337 dsExpr (ExplicitTuple expr_list boxity)
338 = mapDs dsExpr expr_list `thenDs` \ core_exprs ->
339 returnDs (mkConApp (tupleCon boxity (length expr_list))
340 (map (Type . exprType) core_exprs ++ core_exprs))
342 dsExpr (ArithSeqOut expr (From from))
343 = dsExpr expr `thenDs` \ expr2 ->
344 dsExpr from `thenDs` \ from2 ->
345 returnDs (App expr2 from2)
347 dsExpr (ArithSeqOut expr (FromTo from two))
348 = dsExpr expr `thenDs` \ expr2 ->
349 dsExpr from `thenDs` \ from2 ->
350 dsExpr two `thenDs` \ two2 ->
351 returnDs (mkApps expr2 [from2, two2])
353 dsExpr (ArithSeqOut expr (FromThen from thn))
354 = dsExpr expr `thenDs` \ expr2 ->
355 dsExpr from `thenDs` \ from2 ->
356 dsExpr thn `thenDs` \ thn2 ->
357 returnDs (mkApps expr2 [from2, thn2])
359 dsExpr (ArithSeqOut expr (FromThenTo from thn two))
360 = dsExpr expr `thenDs` \ expr2 ->
361 dsExpr from `thenDs` \ from2 ->
362 dsExpr thn `thenDs` \ thn2 ->
363 dsExpr two `thenDs` \ two2 ->
364 returnDs (mkApps expr2 [from2, thn2, two2])
366 dsExpr (PArrSeqOut expr (FromTo from two))
367 = dsExpr expr `thenDs` \ expr2 ->
368 dsExpr from `thenDs` \ from2 ->
369 dsExpr two `thenDs` \ two2 ->
370 returnDs (mkApps expr2 [from2, two2])
372 dsExpr (PArrSeqOut expr (FromThenTo from thn two))
373 = dsExpr expr `thenDs` \ expr2 ->
374 dsExpr from `thenDs` \ from2 ->
375 dsExpr thn `thenDs` \ thn2 ->
376 dsExpr two `thenDs` \ two2 ->
377 returnDs (mkApps expr2 [from2, thn2, two2])
379 dsExpr (PArrSeqOut expr _)
380 = panic "DsExpr.dsExpr: Infinite parallel array!"
381 -- the parser shouldn't have generated it and the renamer and typechecker
382 -- shouldn't have let it through
386 \underline{\bf Record construction and update}
387 % ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
388 For record construction we do this (assuming T has three arguments)
392 let err = /\a -> recConErr a
393 T (recConErr t1 "M.lhs/230/op1")
395 (recConErr t1 "M.lhs/230/op3")
397 @recConErr@ then converts its arugment string into a proper message
398 before printing it as
400 M.lhs, line 230: missing field op1 was evaluated
403 We also handle @C{}@ as valid construction syntax for an unlabelled
404 constructor @C@, setting all of @C@'s fields to bottom.
407 dsExpr (RecordConOut data_con con_expr rbinds)
408 = dsExpr con_expr `thenDs` \ con_expr' ->
410 (arg_tys, _) = tcSplitFunTys (exprType con_expr')
411 -- A newtype in the corner should be opaque;
412 -- hence TcType.tcSplitFunTys
415 = case [rhs | (sel_id,rhs,_) <- rbinds,
416 lbl == recordSelectorFieldLabel sel_id] of
417 (rhs:rhss) -> ASSERT( null rhss )
419 [] -> mkErrorAppDs rEC_CON_ERROR_ID arg_ty (showSDoc (ppr lbl))
420 unlabelled_bottom arg_ty = mkErrorAppDs rEC_CON_ERROR_ID arg_ty ""
422 labels = dataConFieldLabels data_con
426 then mapDs unlabelled_bottom arg_tys
427 else mapDs mk_arg (zipEqual "dsExpr:RecordCon" arg_tys labels))
428 `thenDs` \ con_args ->
430 returnDs (mkApps con_expr' con_args)
433 Record update is a little harder. Suppose we have the decl:
435 data T = T1 {op1, op2, op3 :: Int}
436 | T2 {op4, op2 :: Int}
439 Then we translate as follows:
445 T1 op1 _ op3 -> T1 op1 op2 op3
446 T2 op4 _ -> T2 op4 op2
447 other -> recUpdError "M.lhs/230"
449 It's important that we use the constructor Ids for @T1@, @T2@ etc on the
450 RHSs, and do not generate a Core constructor application directly, because the constructor
451 might do some argument-evaluation first; and may have to throw away some
455 dsExpr (RecordUpdOut record_expr record_in_ty record_out_ty [])
458 dsExpr expr@(RecordUpdOut record_expr record_in_ty record_out_ty rbinds)
459 = getSrcLocDs `thenDs` \ src_loc ->
460 dsExpr record_expr `thenDs` \ record_expr' ->
462 -- Desugar the rbinds, and generate let-bindings if
463 -- necessary so that we don't lose sharing
466 in_inst_tys = tcTyConAppArgs record_in_ty -- Newtype opaque
467 out_inst_tys = tcTyConAppArgs record_out_ty -- Newtype opaque
469 mk_val_arg field old_arg_id
470 = case [rhs | (sel_id, rhs, _) <- rbinds,
471 field == recordSelectorFieldLabel sel_id] of
472 (rhs:rest) -> ASSERT(null rest) rhs
473 [] -> HsVar old_arg_id
476 = newSysLocalsDs (dataConInstOrigArgTys con in_inst_tys) `thenDs` \ arg_ids ->
477 -- This call to dataConArgTys won't work for existentials
479 val_args = zipWithEqual "dsExpr:RecordUpd" mk_val_arg
480 (dataConFieldLabels con) arg_ids
481 rhs = foldl HsApp (TyApp (HsVar (dataConWrapId con)) out_inst_tys)
484 returnDs (mkSimpleMatch [ConPat con record_in_ty [] [] (map VarPat arg_ids)]
489 -- Record stuff doesn't work for existentials
490 -- The type checker checks for this, but we need
491 -- worry only about the constructors that are to be updated
492 ASSERT2( all (not . isExistentialDataCon) cons_to_upd, ppr expr )
494 -- It's important to generate the match with matchWrapper,
495 -- and the right hand sides with applications of the wrapper Id
496 -- so that everything works when we are doing fancy unboxing on the
497 -- constructor aguments.
498 mapDs mk_alt cons_to_upd `thenDs` \ alts ->
499 matchWrapper RecUpd alts `thenDs` \ ([discrim_var], matching_code) ->
501 returnDs (bindNonRec discrim_var record_expr' matching_code)
504 updated_fields :: [FieldLabel]
505 updated_fields = [recordSelectorFieldLabel sel_id | (sel_id,_,_) <- rbinds]
507 -- Get the type constructor from the first field label,
508 -- so that we are sure it'll have all its DataCons
509 -- (In GHCI, it's possible that some TyCons may not have all
510 -- their constructors, in a module-loop situation.)
511 tycon = fieldLabelTyCon (head updated_fields)
512 data_cons = tyConDataCons tycon
513 cons_to_upd = filter has_all_fields data_cons
515 has_all_fields :: DataCon -> Bool
516 has_all_fields con_id
517 = all (`elem` con_fields) updated_fields
519 con_fields = dataConFieldLabels con_id
524 \underline{\bf Dictionary lambda and application}
525 % ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
526 @DictLam@ and @DictApp@ turn into the regular old things.
527 (OLD:) @DictFunApp@ also becomes a curried application, albeit slightly more
528 complicated; reminiscent of fully-applied constructors.
530 dsExpr (DictLam dictvars expr)
531 = dsExpr expr `thenDs` \ core_expr ->
532 returnDs (mkLams dictvars core_expr)
536 dsExpr (DictApp expr dicts) -- becomes a curried application
537 = dsExpr expr `thenDs` \ core_expr ->
538 returnDs (foldl (\f d -> f `App` (Var d)) core_expr dicts)
544 -- HsSyn constructs that just shouldn't be here:
545 dsExpr (ExprWithTySig _ _) = panic "dsExpr:ExprWithTySig"
546 dsExpr (ArithSeqIn _) = panic "dsExpr:ArithSeqIn"
547 dsExpr (PArrSeqIn _) = panic "dsExpr:PArrSeqIn"
552 %--------------------------------------------------------------------
554 Basically does the translation given in the Haskell~1.3 report:
559 -> [Id] -- id for: [return,fail,>>=,>>]
560 -> Type -- Element type; the whole expression has type (m t)
563 dsDo do_or_lc stmts ids@[return_id, fail_id, bind_id, then_id] result_ty
565 (_, b_ty) = tcSplitAppTy result_ty -- result_ty must be of the form (m b)
566 is_do = case do_or_lc of
570 -- For ExprStmt, see the comments near HsExpr.Stmt about
571 -- exactly what ExprStmts mean!
573 -- In dsDo we can only see DoStmt and ListComp (no guards)
575 go [ResultStmt expr locn]
576 | is_do = do_expr expr locn
577 | otherwise = do_expr expr locn `thenDs` \ expr2 ->
578 returnDs (mkApps (Var return_id) [Type b_ty, expr2])
580 go (ExprStmt expr a_ty locn : stmts)
581 | is_do -- Do expression
582 = do_expr expr locn `thenDs` \ expr2 ->
583 go stmts `thenDs` \ rest ->
584 returnDs (mkApps (Var then_id) [Type a_ty, Type b_ty, expr2, rest])
586 | otherwise -- List comprehension
587 = do_expr expr locn `thenDs` \ expr2 ->
588 go stmts `thenDs` \ rest ->
590 msg = "Pattern match failure in do expression, " ++ showSDoc (ppr locn)
592 mkStringLit msg `thenDs` \ core_msg ->
593 returnDs (mkIfThenElse expr2 rest
594 (App (App (Var fail_id) (Type b_ty)) core_msg))
596 go (LetStmt binds : stmts )
597 = go stmts `thenDs` \ rest ->
600 go (BindStmt pat expr locn : stmts)
602 dsExpr expr `thenDs` \ expr2 ->
604 a_ty = outPatType pat
605 fail_expr = HsApp (TyApp (HsVar fail_id) [b_ty])
606 (HsLit (HsString (mkFastString msg)))
607 msg = "Pattern match failure in do expression, " ++ showSDoc (ppr locn)
608 main_match = mkSimpleMatch [pat]
609 (HsDo do_or_lc stmts ids result_ty locn)
612 | failureFreePat pat = [main_match]
615 , mkSimpleMatch [WildPat a_ty] fail_expr result_ty locn
618 matchWrapper (DoCtxt do_or_lc) the_matches `thenDs` \ (binders, matching_code) ->
619 returnDs (mkApps (Var bind_id) [Type a_ty, Type b_ty, expr2,
620 mkLams binders matching_code])
625 do_expr expr locn = putSrcLocDs locn (dsExpr expr)
629 %************************************************************************
631 \subsection[DsExpr-literals]{Literals}
633 %************************************************************************
635 We give int/float literals type @Integer@ and @Rational@, respectively.
636 The typechecker will (presumably) have put \tr{from{Integer,Rational}s}
639 ToDo: put in range checks for when converting ``@i@''
640 (or should that be in the typechecker?)
642 For numeric literals, we try to detect there use at a standard type
643 (@Int@, @Float@, etc.) are directly put in the right constructor.
644 [NB: down with the @App@ conversion.]
646 See also below where we look for @DictApps@ for \tr{plusInt}, etc.
649 dsLit :: HsLit -> DsM CoreExpr
650 dsLit (HsChar c) = returnDs (mkConApp charDataCon [mkLit (MachChar c)])
651 dsLit (HsCharPrim c) = returnDs (mkLit (MachChar c))
652 dsLit (HsString str) = mkStringLitFS str
653 dsLit (HsStringPrim s) = returnDs (mkLit (MachStr s))
654 dsLit (HsInteger i) = mkIntegerLit i
655 dsLit (HsInt i) = returnDs (mkConApp intDataCon [mkIntLit i])
656 dsLit (HsIntPrim i) = returnDs (mkIntLit i)
657 dsLit (HsFloatPrim f) = returnDs (mkLit (MachFloat f))
658 dsLit (HsDoublePrim d) = returnDs (mkLit (MachDouble d))
659 dsLit (HsLitLit str ty)
660 = ASSERT( maybeToBool maybe_ty )
661 returnDs (wrap_fn (mkLit (MachLitLit str rep_ty)))
663 (maybe_ty, wrap_fn) = resultWrapper ty
664 Just rep_ty = maybe_ty
667 = mkIntegerLit (numerator r) `thenDs` \ num ->
668 mkIntegerLit (denominator r) `thenDs` \ denom ->
669 returnDs (mkConApp ratio_data_con [Type integer_ty, num, denom])
671 (ratio_data_con, integer_ty)
672 = case tcSplitTyConApp ty of
673 (tycon, [i_ty]) -> ASSERT(isIntegerTy i_ty && tycon `hasKey` ratioTyConKey)
674 (head (tyConDataCons tycon), i_ty)