X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FhsSyn%2FHsExpr.lhs;h=bde737a25387a3deef726f30de0025a1a0f88918;hp=a28b26a787e33f1bcae4578006e2117b5361b1cb;hb=b4556cace1b420341c3e3bc6c1d7a7f693c655e4;hpb=92eeda1e1d846a082a60caab1b75593d7cc668ed diff --git a/compiler/hsSyn/HsExpr.lhs b/compiler/hsSyn/HsExpr.lhs index a28b26a..bde737a 100644 --- a/compiler/hsSyn/HsExpr.lhs +++ b/compiler/hsSyn/HsExpr.lhs @@ -2,10 +2,9 @@ % (c) The University of Glasgow 2006 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % - -HsExpr: Abstract Haskell syntax: expressions - \begin{code} + +-- | Abstract Haskell syntax for expressions. module HsExpr where #include "HsVersions.h" @@ -15,7 +14,6 @@ import HsDecls import HsPat import HsLit import HsTypes -import HsImpExp import HsBinds -- others: @@ -36,14 +34,16 @@ import FastString %************************************************************************ \begin{code} +-- * Expressions proper + type LHsExpr id = Located (HsExpr id) ------------------------- --- PostTcExpr is an evidence expression attached to the --- syntax tree by the type checker (c.f. postTcType) --- We use a PostTcTable where there are a bunch of pieces of --- evidence, more than is convenient to keep individually +-- | PostTcExpr is an evidence expression attached to the syntax tree by the +-- type checker (c.f. postTcType). type PostTcExpr = HsExpr Id +-- | We use a PostTcTable where there are a bunch of pieces of evidence, more +-- than is convenient to keep individually. type PostTcTable = [(Name, Id)] noPostTcExpr :: PostTcExpr @@ -53,11 +53,12 @@ noPostTcTable :: PostTcTable noPostTcTable = [] ------------------------- --- SyntaxExpr is like PostTcExpr, but it's filled in a little earlier, +-- | SyntaxExpr is like 'PostTcExpr', but it's filled in a little earlier, -- by the renamer. It's used for rebindable syntax. --- E.g. (>>=) is filled in before the renamer by the appropriate Name --- for (>>=), and then instantiated by the type checker with its --- type args tec +-- +-- E.g. @(>>=)@ is filled in before the renamer by the appropriate 'Name' for +-- @(>>=)@, and then instantiated by the type checker with its type args +-- tec type SyntaxExpr id = HsExpr id @@ -67,29 +68,33 @@ noSyntaxExpr = HsLit (HsString (fsLit "noSyntaxExpr")) type SyntaxTable id = [(Name, SyntaxExpr id)] --- *** Currently used only for CmdTop (sigh) *** --- * Before the renamer, this list is noSyntaxTable +-- ^ Currently used only for 'CmdTop' (sigh) +-- +-- * Before the renamer, this list is 'noSyntaxTable' -- --- * After the renamer, it takes the form [(std_name, HsVar actual_name)] +-- * After the renamer, it takes the form @[(std_name, HsVar actual_name)]@ -- For example, for the 'return' op of a monad --- normal case: (GHC.Base.return, HsVar GHC.Base.return) --- with rebindable syntax: (GHC.Base.return, return_22) --- where return_22 is whatever "return" is in scope -- --- * After the type checker, it takes the form [(std_name, )] --- where is the evidence for the method +-- * normal case: @(GHC.Base.return, HsVar GHC.Base.return)@ +-- +-- * with rebindable syntax: @(GHC.Base.return, return_22)@ +-- where @return_22@ is whatever @return@ is in scope +-- +-- * After the type checker, it takes the form @[(std_name, )]@ +-- where @@ is the evidence for the method noSyntaxTable :: SyntaxTable id noSyntaxTable = [] ------------------------- +-- | A Haskell expression. data HsExpr id - = HsVar id -- variable - | HsIPVar (IPName id) -- implicit parameter - | HsOverLit (HsOverLit id) -- Overloaded literals + = HsVar id -- ^ variable + | HsIPVar (IPName id) -- ^ implicit parameter + | HsOverLit (HsOverLit id) -- ^ Overloaded literals - | HsLit HsLit -- Simple (non-overloaded) literals + | HsLit HsLit -- ^ Simple (non-overloaded) literals | HsLam (MatchGroup id) -- Currently always a single match @@ -116,6 +121,10 @@ data HsExpr id | SectionR (LHsExpr id) -- operator (LHsExpr id) -- operand + | ExplicitTuple -- Used for explicit tuples and sections thereof + [HsTupArg id] + Boxity + | HsCase (LHsExpr id) (MatchGroup id) @@ -142,14 +151,6 @@ data HsExpr id PostTcType -- type of elements of the parallel array [LHsExpr id] - | ExplicitTuple -- tuple - [LHsExpr id] - -- NB: Unit is ExplicitTuple [] - -- for tuples, we can get the types - -- direct from the components - Boxity - - -- Record construction | RecordCon (Located id) -- The constructor. After type checking -- it's the dataConWrapId of the constructor @@ -159,6 +160,8 @@ data HsExpr id -- Record update | RecordUpd (LHsExpr id) (HsRecordBinds id) +-- (HsMatchGroup Id) -- Filled in by the type checker to be +-- -- a match that does the job [DataCon] -- Filled in by the type checker to the -- _non-empty_ list of DataCons that have -- all the upd'd fields @@ -273,6 +276,17 @@ data HsExpr id | HsWrap HsWrapper -- TRANSLATION (HsExpr id) +-- HsTupArg is used for tuple sections +-- (,a,) is represented by ExplicitTuple [Mising ty1, Present a, Missing ty3] +-- Which in turn stands for (\x:ty1 \y:ty2. (x,a,y)) +data HsTupArg id + = Present (LHsExpr id) -- The argument + | Missing PostTcType -- The argument is missing, but this is its type + +tupArgPresent :: HsTupArg id -> Bool +tupArgPresent (Present {}) = True +tupArgPresent (Missing {}) = False + type PendingSplice = (Name, LHsExpr Id) -- Typechecked splices, waiting to be -- pasted back in by the desugarer \end{code} @@ -346,7 +360,7 @@ ppr_expr (OpApp e1 op _ e2) = hang (ppr op) 2 (sep [pp_e1, pp_e2]) pp_infixly v - = sep [nest 2 pp_e1, pprInfix v, nest 2 pp_e2] + = sep [nest 2 pp_e1, pprHsInfix v, nest 2 pp_e2] ppr_expr (NegApp e _) = char '-' <+> pprDebugParendExpr e @@ -359,7 +373,7 @@ ppr_expr (SectionL expr op) pp_prefixly = hang (hsep [text " \\ x_ ->", ppr op]) 4 (hsep [pp_expr, ptext (sLit "x_ )")]) - pp_infixly v = (sep [pp_expr, pprInfix v]) + pp_infixly v = (sep [pp_expr, pprHsInfix v]) ppr_expr (SectionR op expr) = case unLoc op of @@ -371,7 +385,18 @@ ppr_expr (SectionR op expr) pp_prefixly = hang (hsep [text "( \\ x_ ->", ppr op, ptext (sLit "x_")]) 4 ((<>) pp_expr rparen) pp_infixly v - = (sep [pprInfix v, pp_expr]) + = (sep [pprHsInfix v, pp_expr]) + +ppr_expr (ExplicitTuple exprs boxity) + = tupleParens boxity (fcat (ppr_tup_args exprs)) + where + ppr_tup_args [] = [] + ppr_tup_args (Present e : es) = (ppr_lexpr e <> punc es) : ppr_tup_args es + ppr_tup_args (Missing _ : es) = punc es : ppr_tup_args es + + punc (Present {} : _) = comma <> space + punc (Missing {} : _) = comma + punc [] = empty --avoid using PatternSignatures for stage1 code portability ppr_expr exprType@(HsLam matches) @@ -379,8 +404,8 @@ ppr_expr exprType@(HsLam matches) where idType :: HsExpr id -> HsMatchContext id; idType = undefined ppr_expr exprType@(HsCase expr matches) - = sep [ sep [ptext (sLit "case"), nest 4 (ppr expr), ptext (sLit "of")], - nest 2 (pprMatches (CaseAlt `asTypeOf` idType exprType) matches) ] + = sep [ sep [ptext (sLit "case"), nest 4 (ppr expr), ptext (sLit "of {")], + nest 2 (pprMatches (CaseAlt `asTypeOf` idType exprType) matches <+> char '}') ] where idType :: HsExpr id -> HsMatchContext id; idType = undefined ppr_expr (HsIf e1 e2 e3) @@ -406,9 +431,6 @@ ppr_expr (ExplicitList _ exprs) ppr_expr (ExplicitPArr _ exprs) = pa_brackets (pprDeeperList fsep (punctuate comma (map ppr_lexpr exprs))) -ppr_expr (ExplicitTuple exprs boxity) - = tupleParens boxity (sep (punctuate comma (map ppr_lexpr exprs))) - ppr_expr (RecordCon con_id _ rbinds) = hang (ppr con_id) 2 (ppr rbinds) @@ -447,21 +469,24 @@ ppr_expr (HsProc pat (L _ (HsCmdTop cmd _ _ _))) = hsep [ptext (sLit "proc"), ppr pat, ptext (sLit "->"), ppr cmd] ppr_expr (HsTick tickId vars exp) - = hcat [ptext (sLit "tick<"), - ppr tickId, - ptext (sLit ">("), - hsep (map pprHsVar vars), - ppr exp, - ptext (sLit ")")] + = pprTicks (ppr exp) $ + hcat [ptext (sLit "tick<"), + ppr tickId, + ptext (sLit ">("), + hsep (map pprHsVar vars), + ppr exp, + ptext (sLit ")")] ppr_expr (HsBinTick tickIdTrue tickIdFalse exp) - = hcat [ptext (sLit "bintick<"), + = pprTicks (ppr exp) $ + hcat [ptext (sLit "bintick<"), ppr tickIdTrue, ptext (sLit ","), ppr tickIdFalse, ptext (sLit ">("), ppr exp,ptext (sLit ")")] ppr_expr (HsTickPragma externalSrcLoc exp) - = hcat [ptext (sLit "tickpragma<"), + = pprTicks (ppr exp) $ + hcat [ptext (sLit "tickpragma<"), ppr externalSrcLoc, ptext (sLit ">("), ppr exp, @@ -477,7 +502,7 @@ ppr_expr (HsArrApp arrow arg _ HsHigherOrderApp False) = hsep [ppr_lexpr arg, ptext (sLit ">>-"), ppr_lexpr arrow] ppr_expr (HsArrForm (L _ (HsVar v)) (Just _) [arg1, arg2]) - = sep [pprCmdArg (unLoc arg1), hsep [pprInfix v, pprCmdArg (unLoc arg2)]] + = sep [pprCmdArg (unLoc arg1), hsep [pprHsInfix v, pprCmdArg (unLoc arg2)]] ppr_expr (HsArrForm op _ args) = hang (ptext (sLit "(|") <> ppr_lexpr op) 4 (sep (map (pprCmdArg.unLoc) args) <> ptext (sLit "|)")) @@ -491,12 +516,6 @@ pprCmdArg (HsCmdTop cmd _ _ _) instance OutputableBndr id => Outputable (HsCmdTop id) where ppr = pprCmdArg --- Put a var in backquotes if it's not an operator already -pprInfix :: Outputable name => name -> SDoc -pprInfix v | isOperator ppr_v = ppr_v - | otherwise = char '`' <> ppr_v <> char '`' - where ppr_v = ppr v - -- add parallel array brackets around a document -- pa_brackets :: SDoc -> SDoc @@ -528,16 +547,18 @@ pprParendExpr expr -- I think that is usually (always?) right in case unLoc expr of - HsLit _ -> pp_as_was - HsOverLit _ -> pp_as_was - HsVar _ -> pp_as_was - HsIPVar _ -> pp_as_was - ExplicitList _ _ -> pp_as_was - ExplicitPArr _ _ -> pp_as_was - ExplicitTuple _ _ -> pp_as_was - HsPar _ -> pp_as_was - HsBracket _ -> pp_as_was - HsBracketOut _ [] -> pp_as_was + ArithSeq {} -> pp_as_was + PArrSeq {} -> pp_as_was + HsLit {} -> pp_as_was + HsOverLit {} -> pp_as_was + HsVar {} -> pp_as_was + HsIPVar {} -> pp_as_was + ExplicitTuple {} -> pp_as_was + ExplicitList {} -> pp_as_was + ExplicitPArr {} -> pp_as_was + HsPar {} -> pp_as_was + HsBracket {} -> pp_as_was + HsBracketOut _ [] -> pp_as_was HsDo sc _ _ _ | isListCompExpr sc -> pp_as_was _ -> parens pp_as_was @@ -670,9 +691,12 @@ data Match id -- Nothing after typechecking (GRHSs id) +isEmptyMatchGroup :: MatchGroup id -> Bool +isEmptyMatchGroup (MatchGroup ms _) = null ms + matchGroupArity :: MatchGroup id -> Arity matchGroupArity (MatchGroup [] _) - = panic "matchGroupArity" -- MatchGroup is never empty + = panic "matchGroupArity" -- Precondition: MatchGroup is non-empty matchGroupArity (MatchGroup (match:matches) _) = ASSERT( all ((== n_pats) . length . hsLMatchPats) matches ) -- Assertion just checks that all the matches have the same number of pats @@ -683,13 +707,16 @@ matchGroupArity (MatchGroup (match:matches) _) hsLMatchPats :: LMatch id -> [LPat id] hsLMatchPats (L _ (Match pats _ _)) = pats --- GRHSs are used both for pattern bindings and for Matches +-- | GRHSs are used both for pattern bindings and for Matches data GRHSs id - = GRHSs [LGRHS id] -- Guarded RHSs - (HsLocalBinds id) -- The where clause + = GRHSs { + grhssGRHSs :: [LGRHS id], -- ^ Guarded RHSs + grhssLocalBinds :: (HsLocalBinds id) -- ^ The where clause + } type LGRHS id = Located (GRHS id) +-- | Guarded Right Hand Side. data GRHS id = GRHS [LStmt id] -- Guards (LHsExpr id) -- Right hand side \end{code} @@ -717,7 +744,7 @@ pprPatBind pat ty@(grhss) pprMatch :: (OutputableBndr idL, OutputableBndr idR) => HsMatchContext idL -> Match idR -> SDoc pprMatch ctxt (Match pats maybe_ty grhss) - = herald <+> sep [sep (map ppr other_pats), + = herald <+> sep [sep (map pprParendLPat other_pats), ppr_maybe_ty, nest 2 (pprGRHSs ctxt grhss)] where @@ -729,18 +756,21 @@ pprMatch ctxt (Match pats maybe_ty grhss) -- Not pprBndr; the AbsBinds will -- have printed the signature - | null pats3 -> (pp_infix, []) + | null pats2 -> (pp_infix, []) -- x &&& y = e - | otherwise -> (parens pp_infix, pats3) + | otherwise -> (parens pp_infix, pats2) -- (x &&& y) z = e where - (pat1:pat2:pats3) = pats - pp_infix = ppr pat1 <+> ppr fun <+> ppr pat2 + pp_infix = pprParendLPat pat1 <+> ppr fun <+> pprParendLPat pat2 LambdaExpr -> (char '\\', pats) - _ -> (empty, pats) + + _ -> ASSERT( null pats1 ) + (ppr pat1, []) -- No parens around the single pat + (pat1:pats1) = pats + (pat2:pats2) = pats1 ppr_maybe_ty = case maybe_ty of Just ty -> dcolon <+> ppr ty Nothing -> empty @@ -750,8 +780,8 @@ pprGRHSs :: (OutputableBndr idL, OutputableBndr idR) => HsMatchContext idL -> GRHSs idR -> SDoc pprGRHSs ctxt (GRHSs grhss binds) = vcat (map (pprGRHS ctxt . unLoc) grhss) - $$ if isEmptyLocalBinds binds then empty - else text "where" $$ nest 4 (pprBinds binds) + $$ ppUnless (isEmptyLocalBinds binds) + (text "where" $$ nest 4 (pprBinds binds)) pprGRHS :: (OutputableBndr idL, OutputableBndr idR) => HsMatchContext idL -> GRHS idR -> SDoc @@ -778,15 +808,6 @@ type LStmtLR idL idR = Located (StmtLR idL idR) type Stmt id = StmtLR id id -data GroupByClause id - = GroupByNothing (LHsExpr id) -- Using expression, i.e. - -- "then group using f" ==> GroupByNothing f - | GroupBySomething (Either (LHsExpr id) (SyntaxExpr id)) (LHsExpr id) - -- "then group using f by e" ==> GroupBySomething (Left f) e - -- "then group by e" ==> GroupBySomething (Right _) e: in - -- this case the expression is filled - -- in by the renamer - -- The SyntaxExprs in here are used *only* for do-notation, which -- has rebindable syntax. Otherwise they are unused. data StmtLR idL idR @@ -797,7 +818,7 @@ data StmtLR idL idR -- The fail operator is noSyntaxExpr -- if the pattern match can't fail - | ExprStmt (LHsExpr idR) + | ExprStmt (LHsExpr idR) -- See Note [ExprStmt] (SyntaxExpr idR) -- The (>>) operator PostTcType -- Element type of the RHS (used for arrows) @@ -808,40 +829,86 @@ data StmtLR idL idR -- After renaming, the ids are the binders bound by the stmts and used -- after them - | TransformStmt ([LStmt idL], [idR]) (LHsExpr idR) (Maybe (LHsExpr idR)) - -- After renaming, the IDs are the binders occurring within this - -- transform statement that are used after it - -- "qs, then f by e" ==> TransformStmt (qs, binders) f (Just e) - -- "qs, then f" ==> TransformStmt (qs, binders) f Nothing - - | GroupStmt ([LStmt idL], [(idR, idR)]) (GroupByClause idR) - -- After renaming, the IDs are the binders occurring within this - -- transform statement that are used after it which are paired with - -- the names which they group over in statements - - -- Recursive statement (see Note [RecStmt] below) - | RecStmt [LStmtLR idL idR] - --- The next two fields are only valid after renaming - [idR] -- The ids are a subset of the variables bound by the - -- stmts that are used in stmts that follow the RecStmt - - [idR] -- Ditto, but these variables are the "recursive" ones, - -- that are used before they are bound in the stmts of - -- the RecStmt. From a type-checking point of view, - -- these ones have to be monomorphic - - --- These fields are only valid after typechecking - [PostTcExpr] -- These expressions correspond 1-to-1 with - -- the "recursive" [id], and are the - -- expressions that should be returned by - -- the recursion. - -- They may not quite be the Ids themselves, - -- because the Id may be *polymorphic*, but - -- the returned thing has to be *monomorphic*. - (DictBinds idR) -- Method bindings of Ids bound by the - -- RecStmt, and used afterwards + -- "qs, then f by e" ==> TransformStmt qs binders f (Just e) + -- "qs, then f" ==> TransformStmt qs binders f Nothing + | TransformStmt + [LStmt idL] -- Stmts are the ones to the left of the 'then' + + [idR] -- After renaming, the IDs are the binders occurring + -- within this transform statement that are used after it + + (LHsExpr idR) -- "then f" + + (Maybe (LHsExpr idR)) -- "by e" (optional) + + | GroupStmt + [LStmt idL] -- Stmts to the *left* of the 'group' + -- which generates the tuples to be grouped + + [(idR, idR)] -- See Note [GroupStmt binder map] + + (Maybe (LHsExpr idR)) -- "by e" (optional) + + (Either -- "using f" + (LHsExpr idR) -- Left f => explicit "using f" + (SyntaxExpr idR)) -- Right f => implicit; filled in with 'groupWith' + + + -- Recursive statement (see Note [How RecStmt works] below) + | RecStmt + { recS_stmts :: [LStmtLR idL idR] + + -- The next two fields are only valid after renaming + , recS_later_ids :: [idR] -- The ids are a subset of the variables bound by the + -- stmts that are used in stmts that follow the RecStmt + + , recS_rec_ids :: [idR] -- Ditto, but these variables are the "recursive" ones, + -- that are used before they are bound in the stmts of + -- the RecStmt. + -- An Id can be in both groups + -- Both sets of Ids are (now) treated monomorphically + -- See Note [How RecStmt works] for why they are separate + + -- Rebindable syntax + , recS_bind_fn :: SyntaxExpr idR -- The bind function + , recS_ret_fn :: SyntaxExpr idR -- The return function + , recS_mfix_fn :: SyntaxExpr idR -- The mfix function + + -- These fields are only valid after typechecking + , recS_rec_rets :: [PostTcExpr] -- These expressions correspond 1-to-1 with + -- recS_rec_ids, and are the + -- expressions that should be returned by + -- the recursion. + -- They may not quite be the Ids themselves, + -- because the Id may be *polymorphic*, but + -- the returned thing has to be *monomorphic*, + -- so they may be type applications + + , recS_dicts :: DictBinds idR -- Method bindings of Ids bound by the + -- RecStmt, and used afterwards + } \end{code} +Note [GroupStmt binder map] +~~~~~~~~~~~~~~~~~~~~~~~~~~~ +The [(idR,idR)] in a GroupStmt behaves as follows: + + * Before renaming: [] + + * After renaming: + [ (x27,x27), ..., (z35,z35) ] + These are the variables + bound by the stmts to the left of the 'group' + and used either in the 'by' clause, + or in the stmts following the 'group' + Each item is a pair of identical variables. + + * After typechecking: + [ (x27:Int, x27:[Int]), ..., (z35:Bool, z35:[Bool]) ] + Each pair has the same unique, but different *types*. + +Note [ExprStmt] +~~~~~~~~~~~~~~~ ExprStmts are a bit tricky, because what they mean depends on the context. Consider the following contexts: @@ -867,28 +934,44 @@ depends on the context. Consider the following contexts: Array comprehensions are handled like list comprehensions -=chak -Note [RecStmt] -~~~~~~~~~~~~~~ +Note [How RecStmt works] +~~~~~~~~~~~~~~~~~~~~~~~~ Example: - HsDo [ BindStmt x ex + HsDo [ BindStmt x ex - , RecStmt [a::forall a. a -> a, b] - [a::Int -> Int, c] - [ BindStmt b (return x) - , LetStmt a = ea - , BindStmt c ec ] + , RecStmt { recS_rec_ids = [a, c] + , recS_stmts = [ BindStmt b (return (a,c)) + , LetStmt a = ...b... + , BindStmt c ec ] + , recS_later_ids = [a, b] - , return (a b) ] + , return (a b) ] Here, the RecStmt binds a,b,c; but - Only a,b are used in the stmts *following* the RecStmt, - This 'a' is *polymorphic' - Only a,c are used in the stmts *inside* the RecStmt *before* their bindings - This 'a' is monomorphic -Nota Bene: the two a's have different types, even though they -have the same Name. +Why do we need *both* rec_ids and later_ids? For monads they could be +combined into a single set of variables, but not for arrows. That +follows from the types of the respective feedback operators: + + mfix :: MonadFix m => (a -> m a) -> m a + loop :: ArrowLoop a => a (b,d) (c,d) -> a b c + +* For mfix, the 'a' covers the union of the later_ids and the rec_ids +* For 'loop', 'c' is the later_ids and 'd' is the rec_ids + +Note [Typing a RecStmt] +~~~~~~~~~~~~~~~~~~~~~~~ +A (RecStmt stmts) types as if you had written + + (v1,..,vn, _, ..., _) <- mfix (\~(_, ..., _, r1, ..., rm) -> + do { stmts + ; return (v1,..vn, r1, ..., rm) }) + +where v1..vn are the later_ids + r1..rm are the rec_ids \begin{code} @@ -901,31 +984,57 @@ pprStmt (LetStmt binds) = hsep [ptext (sLit "let"), pprBinds binds] pprStmt (ExprStmt expr _ _) = ppr expr pprStmt (ParStmt stmtss) = hsep (map doStmts stmtss) where doStmts stmts = ptext (sLit "| ") <> ppr stmts -pprStmt (TransformStmt (stmts, _) usingExpr maybeByExpr) - = (hsep [stmtsDoc, ptext (sLit "then"), ppr usingExpr, byExprDoc]) - where stmtsDoc = interpp'SP stmts - byExprDoc = maybe empty (\byExpr -> hsep [ptext (sLit "by"), ppr byExpr]) maybeByExpr -pprStmt (GroupStmt (stmts, _) groupByClause) = (hsep [stmtsDoc, ptext (sLit "then group"), pprGroupByClause groupByClause]) - where stmtsDoc = interpp'SP stmts -pprStmt (RecStmt segment _ _ _ _) = ptext (sLit "rec") <+> braces (vcat (map ppr segment)) - -pprGroupByClause :: (OutputableBndr id) => GroupByClause id -> SDoc -pprGroupByClause (GroupByNothing usingExpr) = hsep [ptext (sLit "using"), ppr usingExpr] -pprGroupByClause (GroupBySomething eitherUsingExpr byExpr) = hsep [ptext (sLit "by"), ppr byExpr, usingExprDoc] - where usingExprDoc = either (\usingExpr -> hsep [ptext (sLit "using"), ppr usingExpr]) (const empty) eitherUsingExpr + +pprStmt (TransformStmt stmts _ using by) + = sep (ppr_lc_stmts stmts ++ [pprTransformStmt using by]) + +pprStmt (GroupStmt stmts _ by using) + = sep (ppr_lc_stmts stmts ++ [pprGroupStmt by using]) + +pprStmt (RecStmt { recS_stmts = segment, recS_rec_ids = rec_ids + , recS_later_ids = later_ids }) + = ptext (sLit "rec") <+> + vcat [ braces (vcat (map ppr segment)) + , ifPprDebug (vcat [ ptext (sLit "rec_ids=") <> ppr rec_ids + , ptext (sLit "later_ids=") <> ppr later_ids])] + +pprTransformStmt :: OutputableBndr id => LHsExpr id -> Maybe (LHsExpr id) -> SDoc +pprTransformStmt using by = sep [ ptext (sLit "then"), nest 2 (ppr using), nest 2 (pprBy by)] + +pprGroupStmt :: OutputableBndr id => Maybe (LHsExpr id) + -> Either (LHsExpr id) (SyntaxExpr is) + -> SDoc +pprGroupStmt by using + = sep [ ptext (sLit "then group"), nest 2 (pprBy by), nest 2 (ppr_using using)] + where + ppr_using (Right _) = empty + ppr_using (Left e) = ptext (sLit "using") <+> ppr e + +pprBy :: OutputableBndr id => Maybe (LHsExpr id) -> SDoc +pprBy Nothing = empty +pprBy (Just e) = ptext (sLit "by") <+> ppr e pprDo :: OutputableBndr id => HsStmtContext any -> [LStmt id] -> LHsExpr id -> SDoc -pprDo DoExpr stmts body = ptext (sLit "do") <+> pprDeeperList vcat (map ppr stmts ++ [ppr body]) -pprDo (MDoExpr _) stmts body = ptext (sLit "mdo") <+> pprDeeperList vcat (map ppr stmts ++ [ppr body]) -pprDo ListComp stmts body = pprComp brackets stmts body -pprDo PArrComp stmts body = pprComp pa_brackets stmts body +pprDo DoExpr stmts body = ptext (sLit "do") <+> ppr_do_stmts stmts body +pprDo GhciStmt stmts body = ptext (sLit "do") <+> ppr_do_stmts stmts body +pprDo (MDoExpr _) stmts body = ptext (sLit "mdo") <+> ppr_do_stmts stmts body +pprDo ListComp stmts body = brackets $ pprComp stmts body +pprDo PArrComp stmts body = pa_brackets $ pprComp stmts body pprDo _ _ _ = panic "pprDo" -- PatGuard, ParStmtCxt -pprComp :: OutputableBndr id => (SDoc -> SDoc) -> [LStmt id] -> LHsExpr id -> SDoc -pprComp brack quals body - = brack $ - hang (ppr body <+> char '|') - 4 (interpp'SP quals) +ppr_do_stmts :: OutputableBndr id => [LStmt id] -> LHsExpr id -> SDoc +-- Print a bunch of do stmts, with explicit braces and semicolons, +-- so that we are not vulnerable to layout bugs +ppr_do_stmts stmts body + = lbrace <+> pprDeeperList vcat ([ppr s <> semi | s <- stmts] ++ [ppr body]) + <+> rbrace + +ppr_lc_stmts :: OutputableBndr id => [LStmt id] -> [SDoc] +ppr_lc_stmts stmts = [ppr s <> comma | s <- stmts] + +pprComp :: OutputableBndr id => [LStmt id] -> LHsExpr id -> SDoc +pprComp quals body -- Prints: body | qual1, ..., qualn + = hang (ppr body <+> char '|') 2 (interpp'SP quals) \end{code} %************************************************************************ @@ -947,22 +1056,24 @@ pprSplice (HsSplice n e) = char '$' <> ifPprDebug (brackets (ppr n)) <> pprParendExpr e -data HsBracket id = ExpBr (LHsExpr id) -- [| expr |] - | PatBr (LPat id) -- [p| pat |] - | DecBr (HsGroup id) -- [d| decls |] - | TypBr (LHsType id) -- [t| type |] - | VarBr id -- 'x, ''T +data HsBracket id = ExpBr (LHsExpr id) -- [| expr |] + | PatBr (LPat id) -- [p| pat |] + | DecBrL [LHsDecl id] -- [d| decls |]; result of parser + | DecBrG (HsGroup id) -- [d| decls |]; result of renamer + | TypBr (LHsType id) -- [t| type |] + | VarBr id -- 'x, ''T instance OutputableBndr id => Outputable (HsBracket id) where ppr = pprHsBracket pprHsBracket :: OutputableBndr id => HsBracket id -> SDoc -pprHsBracket (ExpBr e) = thBrackets empty (ppr e) -pprHsBracket (PatBr p) = thBrackets (char 'p') (ppr p) -pprHsBracket (DecBr d) = thBrackets (char 'd') (ppr d) -pprHsBracket (TypBr t) = thBrackets (char 't') (ppr t) -pprHsBracket (VarBr n) = char '\'' <> ppr n +pprHsBracket (ExpBr e) = thBrackets empty (ppr e) +pprHsBracket (PatBr p) = thBrackets (char 'p') (ppr p) +pprHsBracket (DecBrG gp) = thBrackets (char 'd') (ppr gp) +pprHsBracket (DecBrL ds) = thBrackets (char 'd') (vcat (map ppr ds)) +pprHsBracket (TypBr t) = thBrackets (char 't') (ppr t) +pprHsBracket (VarBr n) = char '\'' <> ppr n -- Infelicity: can't show ' vs '', because -- we can't ask n what its OccName is, because the -- pretty-printer for HsExpr doesn't ask for NamedThings @@ -1013,19 +1124,21 @@ pp_dotdot = ptext (sLit " .. ") \begin{code} data HsMatchContext id -- Context of a Match = FunRhs id Bool -- Function binding for f; True <=> written infix - | CaseAlt -- Guard on a case alternative - | LambdaExpr -- Pattern of a lambda - | ProcExpr -- Pattern of a proc - | PatBindRhs -- Pattern binding + | CaseAlt -- Patterns and guards on a case alternative + | LambdaExpr -- Patterns of a lambda + | ProcExpr -- Patterns of a proc + | PatBindRhs -- Patterns in the *guards* of a pattern binding | RecUpd -- Record update [used only in DsExpr to -- tell matchWrapper what sort of -- runtime error message to generate] | StmtCtxt (HsStmtContext id) -- Pattern of a do-stmt or list comprehension + | ThPatQuote -- A Template Haskell pattern quotation [p| (a,b) |] deriving () data HsStmtContext id = ListComp | DoExpr + | GhciStmt -- A command-line Stmt in GHCi pat <- rhs | MDoExpr PostTcTable -- Recursive do-expression -- (tiresomely, it needs table -- of its return/bind ops) @@ -1056,6 +1169,7 @@ matchSeparator ProcExpr = ptext (sLit "->") matchSeparator PatBindRhs = ptext (sLit "=") matchSeparator (StmtCtxt _) = ptext (sLit "<-") matchSeparator RecUpd = panic "unused" +matchSeparator ThPatQuote = panic "unused" \end{code} \begin{code} @@ -1064,6 +1178,7 @@ pprMatchContext (FunRhs fun _) = ptext (sLit "the definition of") <+> quotes (ppr fun) pprMatchContext CaseAlt = ptext (sLit "a case alternative") pprMatchContext RecUpd = ptext (sLit "a record-update construct") +pprMatchContext ThPatQuote = ptext (sLit "a Template Haskell pattern quotation") pprMatchContext PatBindRhs = ptext (sLit "a pattern binding") pprMatchContext LambdaExpr = ptext (sLit "a lambda abstraction") pprMatchContext ProcExpr = ptext (sLit "an arrow abstraction") @@ -1077,6 +1192,7 @@ pprStmtContext (TransformStmtCtxt c) = sep [ptext (sLit "a transformed branch of"), pprStmtContext c] pprStmtContext (PatGuard ctxt) = ptext (sLit "a pattern guard for") $$ pprMatchContext ctxt +pprStmtContext GhciStmt = ptext (sLit "an interactive GHCi command") pprStmtContext DoExpr = ptext (sLit "a 'do' expression") pprStmtContext (MDoExpr _) = ptext (sLit "an 'mdo' expression") pprStmtContext ListComp = ptext (sLit "a list comprehension") @@ -1098,20 +1214,22 @@ pprStmtResultContext other = ptext (sLit "the result of") <+> pprStmtC -} -- Used to generate the string for a *runtime* error message -matchContextErrString :: Outputable id => HsMatchContext id -> String -matchContextErrString (FunRhs fun _) = "function " ++ showSDoc (ppr fun) -matchContextErrString CaseAlt = "case" -matchContextErrString PatBindRhs = "pattern binding" -matchContextErrString RecUpd = "record update" -matchContextErrString LambdaExpr = "lambda" -matchContextErrString ProcExpr = "proc" +matchContextErrString :: Outputable id => HsMatchContext id -> SDoc +matchContextErrString (FunRhs fun _) = ptext (sLit "function") <+> ppr fun +matchContextErrString CaseAlt = ptext (sLit "case") +matchContextErrString PatBindRhs = ptext (sLit "pattern binding") +matchContextErrString RecUpd = ptext (sLit "record update") +matchContextErrString LambdaExpr = ptext (sLit "lambda") +matchContextErrString ProcExpr = ptext (sLit "proc") +matchContextErrString ThPatQuote = panic "matchContextErrString" -- Not used at runtime matchContextErrString (StmtCtxt (ParStmtCtxt c)) = matchContextErrString (StmtCtxt c) matchContextErrString (StmtCtxt (TransformStmtCtxt c)) = matchContextErrString (StmtCtxt c) -matchContextErrString (StmtCtxt (PatGuard _)) = "pattern guard" -matchContextErrString (StmtCtxt DoExpr) = "'do' expression" -matchContextErrString (StmtCtxt (MDoExpr _)) = "'mdo' expression" -matchContextErrString (StmtCtxt ListComp) = "list comprehension" -matchContextErrString (StmtCtxt PArrComp) = "array comprehension" +matchContextErrString (StmtCtxt (PatGuard _)) = ptext (sLit "pattern guard") +matchContextErrString (StmtCtxt GhciStmt) = ptext (sLit "interactive GHCi command") +matchContextErrString (StmtCtxt DoExpr) = ptext (sLit "'do' expression") +matchContextErrString (StmtCtxt (MDoExpr _)) = ptext (sLit "'mdo' expression") +matchContextErrString (StmtCtxt ListComp) = ptext (sLit "list comprehension") +matchContextErrString (StmtCtxt PArrComp) = ptext (sLit "array comprehension") \end{code} \begin{code} @@ -1123,5 +1241,10 @@ pprMatchInCtxt ctxt match = hang (ptext (sLit "In") <+> pprMatchContext ctxt <> pprStmtInCtxt :: (OutputableBndr idL, OutputableBndr idR) => HsStmtContext idL -> StmtLR idL idR -> SDoc pprStmtInCtxt ctxt stmt = hang (ptext (sLit "In a stmt of") <+> pprStmtContext ctxt <> colon) - 4 (ppr stmt) + 4 (ppr_stmt stmt) + where + -- For Group and Transform Stmts, don't print the nested stmts! + ppr_stmt (GroupStmt _ _ by using) = pprGroupStmt by using + ppr_stmt (TransformStmt _ _ using by) = pprTransformStmt using by + ppr_stmt stmt = pprStmt stmt \end{code}