[Git][ghc/ghc][wip/layouter] Implemented a layouter that does not work
Sebastian Graf (@sgraf812)
gitlab at gitlab.haskell.org
Tue Oct 15 10:03:15 UTC 2024
Sebastian Graf pushed to branch wip/layouter at Glasgow Haskell Compiler / GHC
Commits:
133923a6 by Sebastian Graf at 2024-10-15T12:03:04+02:00
Implemented a layouter that does not work
Counter example:
```hs
baz :: Bool -> Bool -> [Int]
baz p q = [case () of _ | p, q -> 0, 42]
```
- - - - -
6 changed files:
- compiler/GHC/Parser.y
- compiler/GHC/Parser/Header.hs
- + compiler/GHC/Parser/Layouter.hs
- + compiler/GHC/Parser/Layouter.hs-boot
- compiler/GHC/Parser/Lexer.x
- compiler/ghc.cabal.in
Changes:
=====================================
compiler/GHC/Parser.y
=====================================
@@ -83,6 +83,7 @@ import GHC.Core.DataCon ( DataCon, dataConName )
import GHC.Parser.PostProcess
import GHC.Parser.PostProcess.Haddock
+import GHC.Parser.Layouter
import GHC.Parser.Lexer
import GHC.Parser.HaddockLex
import GHC.Parser.Annotation
@@ -762,7 +763,7 @@ TH_QUASIQUOTE { L _ (ITquasiQuote _) }
TH_QQUASIQUOTE { L _ (ITqQuasiQuote _) }
%monad { P } { >>= } { return }
-%lexer { (lexer True) } { L _ ITeof }
+%lexer { layouter (lexer True) } { L _ ITeof }
-- Replace 'lexer' above with 'lexerDbg'
-- to dump the tokens fed to the parser.
%tokentype { (Located Token) }
@@ -797,7 +798,7 @@ identifier :: { LocatedN RdrName }
-- Backpack stuff
backpack :: { [LHsUnit PackageName] }
- : implicit_top units close { fromOL $2 }
+ : implicit_top units vccurly { fromOL $2 }
| '{' units '}' { fromOL $2 }
units :: { OrdList (LHsUnit PackageName) }
@@ -867,7 +868,7 @@ rn :: { LRenaming }
unitbody :: { OrdList (LHsUnitDecl PackageName) }
: '{' unitdecls '}' { $2 }
- | vocurly unitdecls close { $2 }
+ | vocurly unitdecls vccurly { $2 }
unitdecls :: { OrdList (LHsUnitDecl PackageName) }
: unitdecls ';' unitdecl { $1 `appOL` unitOL $3 }
@@ -944,13 +945,13 @@ body :: { ([TrailingAnn]
,([LImportDecl GhcPs], [LHsDecl GhcPs])
,EpLayout) }
: '{' top '}' { (fst $2, snd $2, epExplicitBraces $1 $3) }
- | vocurly top close { (fst $2, snd $2, EpVirtualBraces (getVOCURLY $1)) }
+ | vocurly top vccurly { (fst $2, snd $2, EpVirtualBraces (getVOCURLY $1)) }
body2 :: { ([TrailingAnn]
,([LImportDecl GhcPs], [LHsDecl GhcPs])
,EpLayout) }
: '{' top '}' { (fst $2, snd $2, epExplicitBraces $1 $3) }
- | missing_module_keyword top close { ([], snd $2, EpVirtualBraces leftmostColumn) }
+ | missing_module_keyword top vccurly { ([], snd $2, EpVirtualBraces leftmostColumn) }
top :: { ([TrailingAnn]
@@ -1467,11 +1468,11 @@ where_type_family :: { Located ([AddEpAnn],FamilyInfo GhcPs) }
ty_fam_inst_eqn_list :: { Located ([AddEpAnn],Maybe [LTyFamInstEqn GhcPs]) }
: '{' ty_fam_inst_eqns '}' { sLL $1 $> ([moc $1,mcc $3]
,Just (unLoc $2)) }
- | vocurly ty_fam_inst_eqns close { let (L loc _) = $2 in
+ | vocurly ty_fam_inst_eqns vccurly { let (L loc _) = $2 in
L loc ([],Just (unLoc $2)) }
| '{' '..' '}' { sLL $1 $> ([moc $1,mj AnnDotdot $2
,mcc $3],Nothing) }
- | vocurly '..' close { let (L loc _) = $2 in
+ | vocurly '..' vccurly { let (L loc _) = $2 in
L loc ([mj AnnDotdot $2],Nothing) }
ty_fam_inst_eqns :: { Located [LTyFamInstEqn GhcPs] }
@@ -1724,7 +1725,7 @@ cvars1 :: { [RecordPatSynField GhcPs] }
where_decls :: { LocatedL (OrdList (LHsDecl GhcPs)) }
: 'where' '{' decls '}' {% amsr (sLL $1 $> (snd $ unLoc $3))
(AnnList (Just $ glR $3) (Just $ moc $2) (Just $ mcc $4) (mj AnnWhere $1: (fst $ unLoc $3)) []) }
- | 'where' vocurly decls close {% amsr (sLL $1 $3 (snd $ unLoc $3))
+ | 'where' vocurly decls vccurly {% amsr (sLL $1 $3 (snd $ unLoc $3))
(AnnList (Just $ glR $3) Nothing Nothing (mj AnnWhere $1: (fst $ unLoc $3)) []) }
pattern_synonym_sig :: { LSig GhcPs }
@@ -1780,7 +1781,7 @@ decllist_cls
, EpLayout) } -- Reversed
: '{' decls_cls '}' { sLL $1 $> (moc $1:mcc $3:(fst $ unLoc $2)
,snd $ unLoc $2, epExplicitBraces $1 $3) }
- | vocurly decls_cls close { let { L l (anns, decls) = $2 }
+ | vocurly decls_cls vccurly { let { L l (anns, decls) = $2 }
in L l (anns, decls, EpVirtualBraces (getVOCURLY $1)) }
-- Class body
@@ -1824,7 +1825,7 @@ decllist_inst
:: { Located ([AddEpAnn]
, OrdList (LHsDecl GhcPs)) } -- Reversed
: '{' decls_inst '}' { sLL $1 $> (moc $1:mcc $3:(fst $ unLoc $2),snd $ unLoc $2) }
- | vocurly decls_inst close { L (gl $2) (unLoc $2) }
+ | vocurly decls_inst vccurly { L (gl $2) (unLoc $2) }
-- Instance body
--
@@ -1864,7 +1865,7 @@ decls :: { Located ([AddEpAnn], OrdList (LHsDecl GhcPs)) }
decllist :: { Located (AnnList,Located (OrdList (LHsDecl GhcPs))) }
: '{' decls '}' { sLL $1 $> (AnnList (Just $ glR $2) (Just $ moc $1) (Just $ mcc $3) (fst $ unLoc $2) []
,sL1 $2 $ snd $ unLoc $2) }
- | vocurly decls close { L (gl $2) (AnnList (Just $ glR $2) Nothing Nothing (fst $ unLoc $2) []
+ | vocurly decls vccurly { L (gl $2) (AnnList (Just $ glR $2) Nothing Nothing (fst $ unLoc $2) []
,sL1 $2 $ snd $ unLoc $2) }
-- Binding groups other than those of class and instance declarations
@@ -1879,7 +1880,7 @@ binds :: { Located (HsLocalBinds GhcPs) }
| '{' dbinds '}' {% acs (comb3 $1 $2 $3) (\loc cs -> (L loc
$ HsIPBinds (EpAnn (spanAsAnchor (comb3 $1 $2 $3)) (AnnList (Just$ glR $2) (Just $ moc $1) (Just $ mcc $3) [] []) cs) (IPBinds noExtField (reverse $ unLoc $2)))) }
- | vocurly dbinds close {% acs (gl $2) (\loc cs -> (L loc
+ | vocurly dbinds vccurly {% acs (gl $2) (\loc cs -> (L loc
$ HsIPBinds (EpAnn (glR $1) (AnnList (Just $ glR $2) Nothing Nothing [] []) cs) (IPBinds noExtField (reverse $ unLoc $2)))) }
@@ -2492,7 +2493,7 @@ gadt_constrlist :: { Located ([AddEpAnn]
,moc $2
,mcc $4]
, unLoc $3) }
- | 'where' vocurly gadt_constrs close {% checkEmptyGADTs $
+ | 'where' vocurly gadt_constrs vccurly {% checkEmptyGADTs $
L (comb2 $1 $3)
([mj AnnWhere $1]
, unLoc $3) }
@@ -3205,7 +3206,7 @@ acmd :: { LHsCmdTop GhcPs }
cvtopbody :: { ([AddEpAnn],[LHsDecl GhcPs]) }
: '{' cvtopdecls0 '}' { ([mj AnnOpenC $1
,mj AnnCloseC $3],$2) }
- | vocurly cvtopdecls0 close { ([],$2) }
+ | vocurly cvtopdecls0 vccurly { ([],$2) }
cvtopdecls0 :: { [LHsDecl GhcPs] }
: topdecls_semi { cvTopDecls $1 }
@@ -3436,11 +3437,11 @@ altslist(PATS) :: { forall b. DisambECP b => PV (LocatedL [LMatch GhcPs (Located
: '{' alts(PATS) '}' { $2 >>= \ $2 -> amsr
(sLL $1 $> (reverse (snd $ unLoc $2)))
(AnnList (Just $ glR $2) (Just $ moc $1) (Just $ mcc $3) (fst $ unLoc $2) []) }
- | vocurly alts(PATS) close { $2 >>= \ $2 -> amsr
+ | vocurly alts(PATS) vccurly { $2 >>= \ $2 -> amsr
(L (getLoc $2) (reverse (snd $ unLoc $2)))
(AnnList (Just $ glR $2) Nothing Nothing (fst $ unLoc $2) []) }
| '{' '}' { amsr (sLL $1 $> []) (AnnList Nothing (Just $ moc $1) (Just $ mcc $2) [] []) }
- | vocurly close { return $ noLocA [] }
+ | vocurly vccurly { return $ noLocA [] }
alts(PATS) :: { forall b. DisambECP b => PV (Located ([AddEpAnn],[LMatch GhcPs (LocatedA b)])) }
: alts1(PATS) { $1 >>= \ $1 -> return $
@@ -3492,14 +3493,11 @@ gdpats :: { forall b. DisambECP b => PV (Located [LGRHS GhcPs (LocatedA b)]) }
return $ sLL gdpats gdpat (gdpat : unLoc gdpats) }
| gdpat { $1 >>= \gdpat -> return $ sL1 gdpat [gdpat] }
--- layout for MultiWayIf doesn't begin with an open brace, because it's hard to
--- generate the open brace in addition to the vertical bar in the lexer, and
--- we don't need it.
ifgdpats :: { Located ((EpToken "{", EpToken "}"), [LGRHS GhcPs (LHsExpr GhcPs)]) }
- : '{' gdpats '}' {% runPV $2 >>= \ $2 ->
+ : '{' gdpats '}' {% runPV $2 >>= \ $2 ->
return $ sLL $1 $> ((epTok $1,epTok $3),unLoc $2) }
- | gdpats close {% runPV $1 >>= \ $1 ->
- return $ sL1 $1 ((NoEpTok, NoEpTok),unLoc $1) }
+ | vocurly gdpats vccurly {% runPV $2 >>= \ $2 ->
+ return $ sL1 $1 ((NoEpTok, NoEpTok),unLoc $2) }
gdpat :: { forall b. DisambECP b => PV (LGRHS GhcPs (LocatedA b)) }
: '|' guardquals '->' exp
@@ -3550,7 +3548,7 @@ apat : aexp {% (checkPattern <=< runPV) (unECP $1) }
stmtlist :: { forall b. DisambECP b => PV (LocatedL [LocatedA (Stmt GhcPs (LocatedA b))]) }
: '{' stmts '}' { $2 >>= \ $2 ->
amsr (sLL $1 $> (reverse $ snd $ unLoc $2)) (AnnList (stmtsAnchor $2) (Just $ moc $1) (Just $ mcc $3) (fromOL $ fst $ unLoc $2) []) }
- | vocurly stmts close { $2 >>= \ $2 -> amsr
+ | vocurly stmts vccurly { $2 >>= \ $2 -> amsr
(L (stmtsLoc $2) (reverse $ snd $ unLoc $2)) (AnnList (stmtsAnchor $2) Nothing Nothing (fromOL $ fst $ unLoc $2) []) }
-- do { ;; s ; s ; ; s ;; }
@@ -4133,7 +4131,7 @@ unrelated tokens.
-}
close :: { () }
: vccurly { () } -- context popped in lexer.
- | error {% popContext } -- See Note [Layout and error]
+-- | error {% popContext } -- See Note [Layout and error]
-----------------------------------------------------------------------------
-- Miscellaneous (mostly renamings)
=====================================
compiler/GHC/Parser/Header.hs
=====================================
@@ -28,6 +28,7 @@ import GHC.Driver.Errors.Types -- Unfortunate, needed due to the fact we throw e
import GHC.Parser.Errors.Types
import GHC.Parser ( parseHeader )
+import GHC.Parser.Layouter
import GHC.Parser.Lexer
import GHC.Hs
@@ -203,7 +204,7 @@ lazyGetToks popts filename handle = do
lazyLexBuf :: Handle -> PState -> Bool -> Int -> IO [Located Token]
lazyLexBuf handle state eof size =
- case unP (lexer False return) state of
+ case unP (layouter (lexer False) return) state of
POk state' t -> do
-- pprTrace "lazyLexBuf" (text (show (buffer state'))) (return ())
if atEnd (buffer state') && not eof
@@ -238,7 +239,7 @@ getToks popts filename buf = lexAll pstate
pstate = initPragState popts buf loc
loc = mkRealSrcLoc (mkFastString filename) 1 1
- lexAll state = case unP (lexer False return) state of
+ lexAll state = case unP (layouter (lexer False) return) state of
POk _ t@(L _ ITeof) -> [t]
POk state' t -> t : lexAll state'
_ -> [L (mkSrcSpanPs (last_loc state)) ITeof]
=====================================
compiler/GHC/Parser/Layouter.hs
=====================================
@@ -0,0 +1,275 @@
+{-# LANGUAGE MultiWayIf #-}
+
+module GHC.Parser.Layouter where
+
+import GHC.Prelude
+import GHC.Hs
+import GHC.Parser.Lexer
+import GHC.Types.SrcLoc
+import GHC.Utils.Panic
+import Data.Maybe
+import Control.Monad.Trans.Class
+import Control.Monad.Trans.Cont
+import GHC.Utils.Error
+import GHC.Parser.Errors.Types
+import Data.Sequence
+import Debug.Trace
+
+data LayItem
+ = LayFlexi !PsSpan !LayHerald
+ | LayImplicit !LayHerald !Int
+ -- ^ We are inside an implicit layout block.
+ -- We know the layout herald (e.g., `do`), the indentation level and have a
+ -- list of pending closing delimiters (such as `)`, `]`, `||]`) that must
+ -- be closed before closing the implicit layout context.
+ | LayExplicit
+ -- ^ We are inside an explicit layout block.
+ -- We know which delimiters must be closed before closing the layout block.
+
+data LayHerald
+ = LetHerald
+ | DoHerald
+ | IfHerald -- ^ For -XMultiWayIf
+ | RecHerald
+ | WhereHerald
+ | OfHerald
+ | LCaseHerald
+ | LCasesHerald
+ deriving (Eq, Ord, Show)
+
+type LayContext = (LayItem, [Token])
+
+data LayState = LS
+ { lay_stack :: ![LayContext]
+ , lay_output :: !(Seq (PsLocated Token))
+ }
+
+initLayState :: LayState
+initLayState = LS { lay_stack = [], lay_output = Empty }
+
+overLayState :: (LayState -> (a, LayState)) -> P a
+overLayState f = P $ \s -> case f (lay_state s) of (a, ls) -> POk s{lay_state=ls} a
+{-# INLINE overLayState #-}
+layouter, layouterDbg :: ((PsLocated Token -> P a) -> P a)
+ -> ((Located Token -> P a) -> P a)
+
+getLayStack :: P [LayContext]
+getLayStack = P $ \s -> POk s (lay_stack (lay_state s))
+
+-- Use this instead of 'lexer' in GHC.Parser to dump the tokens for debugging.
+layouterDbg lexer cont = layouter lexer contDbg
+ where
+ contDbg tok = trace ("token: " ++ show (unLoc tok)) (cont tok)
+
+layouter lexer = runContT $ yieldOutput $ ContT lexer >>= lift . interp lay
+
+data LayLang = PsLocated Token ::: LayLang | Done [LayContext]
+infixr :::
+
+interp :: ((ExtBits -> Bool) -> PsLocated Token -> [LayContext] -> LayLang) -> PsLocated Token -> P ()
+interp lay tok = do
+ stk <- getLayStack
+ bits <- pExtsBitmap <$> getParserOpts
+ go (lay (`xtest` bits) tok stk)
+ where
+ go (Done stk) = overLayState $ \s -> ((), s{lay_stack = stk})
+ go (tok ::: l) = enqueueOutput tok >> go l
+
+lay :: (ExtBits -> Bool) -> PsLocated Token -> [LayContext] -> LayLang
+lay ext ltok@(L span tok) = lay_module
+ where
+ offset | ITeof <- tok = 0
+ | otherwise = srcSpanStartCol (psRealSpan span)
+ indent_decreasing h old new
+ | isLayHeraldNonDecreasing h = old > new
+ | ext NondecreasingIndentationBit = old > new
+ | otherwise = old >= new
+
+ lay_module []
+ | ITocurly <- tok = ltok ::: Done [(LayExplicit,[])]
+ | ITwhere <- tok = ltok ::: Done [(LayFlexi span WhereHerald,[])]
+ | otherwise = ltok ::: Done []
+ lay_module stk = lay_bol stk
+
+ lay_bol [] | ITeof <- tok = ltok ::: Done []
+ | otherwise = panic (show span ++ " " ++ show tok)
+ lay_bol stk@((item,clos):stk') = case item of
+ LayImplicit herald offs -> case compare offset offs of
+ LT | LetHerald <- herald, ITin <- tok
+ -> L span ITvccurly ::: ltok ::: Done stk' -- So that `in` does not close multiple blocks
+ | otherwise
+ -> L span ITvccurly ::: lay_bol stk' -- NB: pop item
+ EQ | isInfixForm tok -- an (e.g.) `where` on the same indent would require something to the left of where; leave the current block
+ -> L span ITvccurly ::: lay_bol stk'
+ | generateSemis herald
+ -> L span ITsemi ::: lay_rest ((item,clos):stk')
+ _ -> lay_rest ((item,clos):stk')
+ LayFlexi span herald
+ | ITocurly <- tok
+ -> ltok ::: Done ((LayExplicit,[]):stk')
+ | IfHerald <- herald, not (isVBar tok)
+ -> lay_rest stk' -- Vanilla If -> no layout
+ | (LayImplicit _ prev_off, _) : _ <- stk'
+ , indent_decreasing herald prev_off offset
+ -> L span ITvocurly ::: L span ITvccurly ::: lay_bol stk'
+ | [] <- stk'
+ , ITeof <- tok -- Directory.Internal.Windows: `module M where\n <eof>`
+ -> L span ITvocurly ::: L span ITvccurly ::: lay_bol stk'
+ | otherwise
+ -> L span ITvocurly ::: lay_rest ((LayImplicit herald offset,[]):stk')
+ LayExplicit{} -> lay_rest stk
+ lay_rest stk = case tok of
+ ITccurly | (LayExplicit,_):stk' <- stk -> ltok ::: Done stk'
+ | (LayImplicit{},_):stk' <- stk -> L span ITvccurly ::: lay_rest stk'
+ ITocurly -> ltok ::: Done ((LayExplicit,[]):stk)
+ _ | (item at LayImplicit{},clos):stk' <- stk, isClosingDelim tok
+ -> case clos of
+ clo:clos | clo `eqClosingDelim` tok
+ -> ltok ::: Done ((item,clos):stk')
+ _ -> L span ITvccurly ::: lay_rest stk'
+ | (LayImplicit LetHerald _,_):stk' <- stk, ITin <- tok
+ -> L span ITvccurly ::: ltok ::: Done stk' -- for let .. in
+ | (LayImplicit herald _,_):stk' <- stk, tok `killsLayoutOf` herald
+ -> L span ITvccurly ::: lay_rest stk'
+ | Just clo <- isOpeningDelim_maybe tok
+ , (item,clos):stk' <- stk
+ -> ltok ::: Done ((item,clo:clos):stk')
+ | Just herald <- isLayHerald_maybe tok
+ -> ltok ::: Done ((LayFlexi span herald,[]):stk)
+ | otherwise
+ -> ltok ::: Done stk
+
+yieldOutput :: ContT r P () -> ContT r P (Located Token)
+yieldOutput next = lift dequeueOutput >>= \mb_ltok -> case mb_ltok of
+ Nothing -> next >> yieldOutput (panic "should not need to do next twice")
+ Just (L span tok) -> return (L (mkSrcSpanPs span) tok)
+
+enqueueOutput :: PsLocated Token -> P ()
+enqueueOutput tk = overLayState $ \s -> trace ("token: " ++ show (unLoc tk)) ((), s{lay_output = lay_output s :|> tk})
+
+dequeueOutput :: P (Maybe (PsLocated Token))
+dequeueOutput = overLayState $ \s -> case lay_output s of
+ Empty -> (Nothing, s)
+ tk :<| tks -> (Just tk, s {lay_output = tks})
+
+pushLayStack :: LayItem -> P ()
+pushLayStack l = overLayState $ \s -> ((), s{lay_stack = (l,[]):lay_stack s})
+
+popLayStack :: P (Maybe LayContext)
+popLayStack = overLayState $ \s -> case lay_stack s of
+ [] -> (Nothing, s)
+ l:stk -> (Just l, s{lay_stack = stk})
+
+pushClosingTok :: Token -> P ()
+pushClosingTok tok = overLayState $ \s -> case lay_stack s of
+ [] -> panic "impossible"
+ (l,toks):stk -> ((), s{lay_stack = (l,tok:toks):stk})
+
+popClosingTok :: P ()
+popClosingTok = overLayState $ \s -> case lay_stack s of
+ (l,_:toks):stk -> ((), s{lay_stack = (l,toks):stk})
+ (l,[]):stk -> ((), s{lay_stack = (l,[]):stk}) -- genuinely can happen on error, I think. ex: `do foo)`
+ [] -> panic "impossible"
+
+isInfixForm :: Token -> Bool
+isInfixForm ITwhere = True
+isInfixForm ITvarsym{} = True
+isInfixForm _ = False
+
+isOpeningDelim_maybe :: Token -> Maybe Token
+isOpeningDelim_maybe IToparen = Just ITcparen
+isOpeningDelim_maybe ITobrack = Just ITcbrack
+-- isOpeningDelim_maybe ITocurly = Just ITccurly
+isOpeningDelim_maybe IToubxparen = Just ITcubxparen
+isOpeningDelim_maybe (IToparenbar uni) = Just (ITcparenbar uni)
+isOpeningDelim_maybe (ITopenExpQuote _ uni) = Just (ITcloseQuote uni)
+isOpeningDelim_maybe ITopenTypQuote = Just (ITcloseQuote NormalSyntax)
+isOpeningDelim_maybe ITopenPatQuote = Just (ITcloseQuote NormalSyntax)
+isOpeningDelim_maybe ITopenDecQuote = Just (ITcloseQuote NormalSyntax)
+isOpeningDelim_maybe ITopenTExpQuote{} = Just ITcloseTExpQuote
+isOpeningDelim_maybe _ = Nothing
+
+isClosingDelim :: Token -> Bool
+isClosingDelim ITcparen = True
+isClosingDelim ITcbrack = True
+-- isClosingDelim ITccurly = True
+isClosingDelim ITcubxparen = True
+isClosingDelim ITcparenbar{} = True
+isClosingDelim ITcloseQuote{} = True
+isClosingDelim ITcloseTExpQuote = True
+isClosingDelim _ = False
+
+eqClosingDelim :: Token -> Token -> Bool
+eqClosingDelim ITcparen ITcparen = True
+eqClosingDelim ITcbrack ITcbrack = True
+-- eqClosingDelim ITccurly ITccurly = True
+eqClosingDelim ITcubxparen ITcubxparen = True
+eqClosingDelim (ITcparenbar uni1) (ITcparenbar uni2) = uni1 == uni2
+eqClosingDelim (ITcloseQuote uni1) (ITcloseQuote uni2) = uni1 == uni2
+eqClosingDelim ITcloseTExpQuote ITcloseTExpQuote = True
+eqClosingDelim _ _ = False
+
+separatesDelim :: Token -> Token -> Bool
+separatesDelim ITcomma ITcparen = True
+separatesDelim ITcomma ITcbrack = True
+separatesDelim ITcomma ITcubxparen = True
+separatesDelim _ _ = False
+
+generateSemis :: LayHerald -> Bool
+generateSemis IfHerald = False
+generateSemis _ = True
+
+isVBar :: Token -> Bool
+isVBar ITvbar = True
+isVBar _ = False
+
+isPragma :: Token -> Bool
+isPragma ITinline_prag{} = True
+isPragma ITopaque_prag{} = True
+isPragma ITspec_prag{} = True
+isPragma ITspec_inline_prag{} = True
+isPragma ITsource_prag{} = True
+isPragma ITrules_prag{} = True
+isPragma ITwarning_prag{} = True
+isPragma ITdeprecated_prag{} = True
+isPragma ITline_prag{} = True
+isPragma ITcolumn_prag{} = True
+isPragma ITscc_prag{} = True
+isPragma ITunpack_prag{} = True
+isPragma ITnounpack_prag{} = True
+isPragma ITann_prag{} = True
+isPragma ITcomplete_prag{} = True
+isPragma IToptions_prag{} = True
+isPragma ITinclude_prag{} = True
+isPragma ITlanguage_prag = True
+isPragma ITminimal_prag{} = True
+isPragma IToverlappable_prag{} = True
+isPragma IToverlapping_prag{} = True
+isPragma IToverlaps_prag{} = True
+isPragma ITincoherent_prag{} = True
+isPragma ITctype{} = True
+isPragma ITcomment_line_prag = True
+isPragma _ = False
+
+isLayHerald_maybe :: Token -> Maybe LayHerald
+isLayHerald_maybe (ITdo _) = Just DoHerald
+isLayHerald_maybe (ITmdo _) = Just DoHerald
+isLayHerald_maybe ITof = Just OfHerald
+isLayHerald_maybe ITlcase = Just LCaseHerald
+isLayHerald_maybe ITlcases = Just LCasesHerald
+isLayHerald_maybe ITlet = Just LetHerald
+isLayHerald_maybe ITwhere = Just WhereHerald
+isLayHerald_maybe ITrec = Just RecHerald
+isLayHerald_maybe ITif = Just IfHerald
+isLayHerald_maybe _ = Nothing
+
+isLayHeraldNonDecreasing :: LayHerald -> Bool
+isLayHeraldNonDecreasing DoHerald = True
+isLayHeraldNonDecreasing _ = False
+
+killsLayoutOf :: Token -> LayHerald -> Bool
+killsLayoutOf ITin LetHerald = True
+killsLayoutOf ITwhere DoHerald = True
+killsLayoutOf ITin OfHerald = True
+-- killsLayoutOf ITwhere OfHerald = True -- not true! `case x of True -> bar where ...; False -> foo where ...` is OK
+killsLayoutOf _ _ = False
=====================================
compiler/GHC/Parser/Layouter.hs-boot
=====================================
@@ -0,0 +1,6 @@
+module GHC.Parser.Layouter where
+
+import GHC.Prelude
+
+data LayState
+initLayState :: LayState
=====================================
compiler/GHC/Parser/Lexer.x
=====================================
@@ -60,7 +60,7 @@ module GHC.Parser.Lexer (
P(..), ParseResult(POk, PFailed),
allocateComments, allocatePriorComments, allocateFinalComments,
MonadP(..), getBit,
- getRealSrcLoc, getPState,
+ getRealSrcLoc, getPState, getLastLoc,
failMsgP, failLocMsgP, srcParseFail,
getPsErrorMessages, getPsMessages,
popContext, pushModuleContext, setLastToken, setSrcLoc,
@@ -93,6 +93,7 @@ import qualified Data.List.NonEmpty as NE
import Data.Maybe
import Data.Word
import Debug.Trace (trace)
+import {-# SOURCE #-} GHC.Parser.Layouter
import GHC.Data.EnumSet as EnumSet
@@ -1999,15 +2000,15 @@ do_bol span _str _len _buf2 = do
if b then return (L span ITcomment_line_prag) else do
(pos, gen_semic) <- getOffside
case pos of
- LT -> do
- --trace "layout: inserting '}'" $ do
- popContext
- -- do NOT pop the lex state, we might have a ';' to insert
- return (L span ITvccurly)
- EQ | gen_semic -> do
- --trace "layout: inserting ';'" $ do
- _ <- popLexState
- return (L span ITsemi)
+-- LT -> do
+-- --trace "layout: inserting '}'" $ do
+-- popContext
+-- -- do NOT pop the lex state, we might have a ';' to insert
+-- return (L span ITvccurly)
+-- EQ | gen_semic -> do
+-- --trace "layout: inserting ';'" $ do
+-- _ <- popLexState
+-- return (L span ITsemi)
_ -> do
_ <- popLexState
lexToken
@@ -2024,15 +2025,15 @@ maybe_layout t = do -- If the alternative layout rule is enabled then
-- context.
alr <- getBit AlternativeLayoutRuleBit
unless alr $ f t
- where f (ITdo _) = pushLexState layout_do
- f (ITmdo _) = pushLexState layout_do
- f ITof = pushLexState layout
- f ITlcase = pushLexState layout
- f ITlcases = pushLexState layout
- f ITlet = pushLexState layout
- f ITwhere = pushLexState layout
- f ITrec = pushLexState layout
- f ITif = pushLexState layout_if
+ where f (ITdo _) = return () -- pushLexState layout_do
+ f (ITmdo _) = return () -- pushLexState layout_do
+ f ITof = return () -- pushLexState layout
+ f ITlcase = return () -- pushLexState layout
+ f ITlcases = return () -- pushLexState layout
+ f ITlet = return () -- pushLexState layout
+ f ITwhere = return () -- pushLexState layout
+ f ITrec = return () -- pushLexState layout
+ f ITif = return () -- pushLexState layout_if
f _ = return ()
-- Pushing a new implicit layout context. If the indentation of the
@@ -2469,6 +2470,8 @@ data PState = PState {
-- token doesn't need to close anything:
alr_justClosedExplicitLetBlock :: Bool,
+ lay_state :: LayState,
+
-- The next three are used to implement Annotations giving the
-- locations of 'noise' tokens in the source, so that users of
-- the GHC API can do source to source conversions.
@@ -3009,6 +3012,7 @@ initParserState options buf loc =
alr_context = [],
alr_expecting_ocurly = Nothing,
alr_justClosedExplicitLetBlock = False,
+ lay_state = initLayState,
eof_pos = Strict.Nothing,
header_comments = Strict.Nothing,
comment_q = [],
@@ -3236,7 +3240,7 @@ lexError e = do
-- This is the top-level function: called from the parser each time a
-- new token is to be read from the input.
-lexer, lexerDbg :: Bool -> (Located Token -> P a) -> P a
+lexer, lexerDbg :: Bool -> (PsLocated Token -> P a) -> P a
lexer queueComments cont = do
alr <- getBit AlternativeLayoutRuleBit
@@ -3246,7 +3250,7 @@ lexer queueComments cont = do
if (queueComments && isComment tok)
then queueComment (L (psRealSpan span) tok) >> lexer queueComments cont
- else cont (L (mkSrcSpanPs span) tok)
+ else cont (L span tok)
-- Use this instead of 'lexer' in GHC.Parser to dump the tokens for debugging.
lexerDbg queueComments cont = lexer queueComments contDbg
@@ -3526,7 +3530,7 @@ lexTokenStream opts buf loc = unP go initState{ options = opts' }
ltok <- lexer False return
case ltok of
L _ ITeof -> return []
- _ -> liftM (ltok:) go
+ L span tk -> liftM (L (mkSrcSpanPs span) tk:) go
linePrags = Map.singleton "line" linePrag
=====================================
compiler/ghc.cabal.in
=====================================
@@ -642,6 +642,7 @@ Library
GHC.Parser.Errors.Ppr
GHC.Parser.Errors.Types
GHC.Parser.Header
+ GHC.Parser.Layouter
GHC.Parser.Lexer
GHC.Parser.HaddockLex
GHC.Parser.PostProcess
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/133923a6c07fe8ce47716fa7ea7b5e934dd9e2ba
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/133923a6c07fe8ce47716fa7ea7b5e934dd9e2ba
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