-- qualified varids.
{
-{-# OPTIONS -Wwarn -w #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
--- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
--- for details
---
--- Note that Alex itself generates code with with some unused bindings and
--- without type signatures, so removing the flag might not be possible.
+-- XXX The above flags turn off warnings in the generated code:
+{-# OPTIONS_GHC -fno-warn-unused-matches #-}
+{-# OPTIONS_GHC -fno-warn-unused-binds #-}
+{-# OPTIONS_GHC -fno-warn-unused-imports #-}
+{-# OPTIONS_GHC -fno-warn-missing-signatures #-}
+-- But alex still generates some code that causes the "lazy unlifted bindings"
+-- warning, and old compilers don't know about it so we can't easily turn
+-- it off, so for now we use the sledge hammer:
+{-# OPTIONS_GHC -w #-}
{-# OPTIONS_GHC -funbox-strict-fields #-}
module Lexer (
Token(..), lexer, pragState, mkPState, PState(..),
P(..), ParseResult(..), getSrcLoc,
- getPState,
+ getPState, getDynFlags, withThisPackage,
failLocMsgP, failSpanMsgP, srcParseFail,
- getMessages,
+ getMessages,
popContext, pushCurrentContext, setLastToken, setSrcLoc,
getLexState, popLexState, pushLexState,
extension, standaloneDerivingEnabled, bangPatEnabled,
import SrcLoc
import UniqFM
import DynFlags
+import Module
import Ctype
import Util ( readRational )
| ITstdcallconv
| ITccallconv
| ITprimcallconv
- | ITdotnet
| ITmdo
| ITfamily
| ITgroup
| ITdupipvarid FastString -- GHC extension: implicit param: ?x
- | ITpragma StringBuffer
-
| ITchar Char
| ITstring FastString
| ITinteger Integer
| ITprimfloat Rational
| ITprimdouble Rational
- -- MetaHaskell extension tokens
+ -- Template Haskell extension tokens
| ITopenExpQuote -- [| or [e|
| ITopenPatQuote -- [p|
| ITopenDecQuote -- [d|
( "stdcall", ITstdcallconv, bit ffiBit),
( "ccall", ITccallconv, bit ffiBit),
( "prim", ITprimcallconv, bit ffiBit),
- ( "dotnet", ITdotnet, bit ffiBit),
- ( "rec", ITrec, bit arrowsBit),
+ ( "rec", ITrec, bit recBit),
( "proc", ITproc, bit arrowsBit)
]
,("→", ITrarrow, unicodeSyntaxEnabled)
,("←", ITlarrow, unicodeSyntaxEnabled)
,("⋯", ITdotdot, unicodeSyntaxEnabled)
+
+ ,("⤙", ITlarrowtail, \i -> unicodeSyntaxEnabled i && arrowsEnabled i)
+ ,("⤚", ITrarrowtail, \i -> unicodeSyntaxEnabled i && arrowsEnabled i)
+ ,("⤛", ITLarrowtail, \i -> unicodeSyntaxEnabled i && arrowsEnabled i)
+ ,("⤜", ITRarrowtail, \i -> unicodeSyntaxEnabled i && arrowsEnabled i)
+
+ ,("★", ITstar, unicodeSyntaxEnabled)
+
-- ToDo: ideally, → and ∷ should be "specials", so that they cannot
-- form part of a large operator. This would let us have a better
-- syntax for kinds: ɑ∷*→* would be a legal kind signature. (maybe).
begin code _span _str _len = do pushLexState code; lexToken
pop :: Action
-pop _span _buf _len = do popLexState; lexToken
+pop _span _buf _len = do _ <- popLexState
+ lexToken
pop_and :: Action -> Action
-pop_and act span buf len = do popLexState; act span buf len
+pop_and act span buf len = do _ <- popLexState
+ act span buf len
{-# INLINE nextCharIs #-}
nextCharIs :: StringBuffer -> (Char -> Bool) -> Bool
-- RULES pragmas turn on the forall and '.' keywords, and we turn them
-- off again at the end of the pragma.
rulePrag :: Action
-rulePrag span _ _ = do
+rulePrag span _buf _len = do
setExts (.|. bit inRulePragBit)
return (L span ITrules_prag)
endPrag :: Action
-endPrag span _ _ = do
+endPrag span _buf _len = do
setExts (.&. complement (bit inRulePragBit))
return (L span ITclose_prag)
return (L span ITvccurly)
EQ -> do
--trace "layout: inserting ';'" $ do
- popLexState
+ _ <- popLexState
return (L span ITsemi)
GT -> do
- popLexState
+ _ <- popLexState
lexToken
-- certain keywords put us in the "layout" state, where we might
-- add an opening curly brace.
maybe_layout :: Token -> P ()
-maybe_layout ITdo = pushLexState layout_do
-maybe_layout ITmdo = pushLexState layout_do
-maybe_layout ITof = pushLexState layout
-maybe_layout ITlet = pushLexState layout
-maybe_layout ITwhere = pushLexState layout
-maybe_layout ITrec = pushLexState layout
-maybe_layout _ = return ()
+maybe_layout t = do -- If the alternative layout rule is enabled then
+ -- we never create an implicit layout context here.
+ -- Layout is handled XXX instead.
+ -- The code for closing implicit contexts, or
+ -- inserting implicit semi-colons, is therefore
+ -- irrelevant as it only applies in an implicit
+ -- context.
+ alr <- extension alternativeLayoutRule
+ unless alr $ f t
+ where f ITdo = pushLexState layout_do
+ f ITmdo = pushLexState layout_do
+ f ITof = pushLexState layout
+ f ITlet = pushLexState layout
+ f ITwhere = pushLexState layout
+ f ITrec = pushLexState layout
+ f _ = return ()
-- Pushing a new implicit layout context. If the indentation of the
-- next token is not greater than the previous layout context, then
--
new_layout_context :: Bool -> Action
new_layout_context strict span _buf _len = do
- popLexState
+ _ <- popLexState
(AI _ offset _) <- getInput
ctx <- getContext
case ctx of
do_layout_left :: Action
do_layout_left span _buf _len = do
- popLexState
+ _ <- popLexState
pushLexState bol -- we must be at the start of a line
return (L span ITvccurly)
setLine :: Int -> Action
setLine code span buf len = do
let line = parseUnsignedInteger buf len 10 octDecDigit
- setSrcLoc (mkSrcLoc (srcSpanFile span) (fromIntegral line - 1) 0)
+ setSrcLoc (mkSrcLoc (srcSpanFile span) (fromIntegral line - 1) 1)
-- subtract one: the line number refers to the *following* line
- popLexState
+ _ <- popLexState
pushLexState code
lexToken
setFile :: Int -> Action
setFile code span buf len = do
let file = lexemeToFastString (stepOn buf) (len-2)
+ setAlrLastLoc noSrcSpan
setSrcLoc (mkSrcLoc file (srcSpanEndLine span) (srcSpanEndCol span))
- popLexState
+ _ <- popLexState
pushLexState code
lexToken
loc :: SrcLoc, -- current loc (end of prev token + 1)
extsBitmap :: !Int, -- bitmap that determines permitted extensions
context :: [LayoutContext],
- lex_state :: [Int]
+ lex_state :: [Int],
+ -- Used in the alternative layout rule:
+ alr_pending_implicit_tokens :: [Located Token],
+ alr_next_token :: Maybe (Located Token),
+ alr_last_loc :: SrcSpan,
+ alr_context :: [ALRContext],
+ alr_expecting_ocurly :: Maybe ALRLayout
}
-- last_loc and last_len are used when generating error messages,
-- and in pushCurrentContext only. Sigh, if only Happy passed the
-- Getting rid of last_loc would require finding another way to
-- implement pushCurrentContext (which is only called from one place).
+data ALRContext = ALRNoLayout Bool{- does it contain commas? -}
+ | ALRLayout ALRLayout Int
+data ALRLayout = ALRLayoutLet
+ | ALRLayoutWhere
+ | ALRLayoutOf
+ | ALRLayoutDo
+
newtype P a = P { unP :: PState -> ParseResult a }
instance Monad P where
getPState :: P PState
getPState = P $ \s -> POk s s
+getDynFlags :: P DynFlags
+getDynFlags = P $ \s -> POk s (dflags s)
+
+withThisPackage :: (PackageId -> a) -> P a
+withThisPackage f
+ = do pkg <- liftM thisPackage getDynFlags
+ return $ f pkg
+
extension :: (Int -> Bool) -> P Bool
extension p = P $ \s -> POk s (p $! extsBitmap s)
getLexState :: P Int
getLexState = P $ \s@PState{ lex_state=ls:_ } -> POk s ls
+popNextToken :: P (Maybe (Located Token))
+popNextToken
+ = P $ \s@PState{ alr_next_token = m } ->
+ POk (s {alr_next_token = Nothing}) m
+
+setAlrLastLoc :: SrcSpan -> P ()
+setAlrLastLoc l = P $ \s -> POk (s {alr_last_loc = l}) ()
+
+getAlrLastLoc :: P SrcSpan
+getAlrLastLoc = P $ \s@(PState {alr_last_loc = l}) -> POk s l
+
+getALRContext :: P [ALRContext]
+getALRContext = P $ \s@(PState {alr_context = cs}) -> POk s cs
+
+setALRContext :: [ALRContext] -> P ()
+setALRContext cs = P $ \s -> POk (s {alr_context = cs}) ()
+
+setNextToken :: Located Token -> P ()
+setNextToken t = P $ \s -> POk (s {alr_next_token = Just t}) ()
+
+popPendingImplicitToken :: P (Maybe (Located Token))
+popPendingImplicitToken
+ = P $ \s@PState{ alr_pending_implicit_tokens = ts } ->
+ case ts of
+ [] -> POk s Nothing
+ (t : ts') -> POk (s {alr_pending_implicit_tokens = ts'}) (Just t)
+
+setPendingImplicitTokens :: [Located Token] -> P ()
+setPendingImplicitTokens ts = P $ \s -> POk (s {alr_pending_implicit_tokens = ts}) ()
+
+getAlrExpectingOCurly :: P (Maybe ALRLayout)
+getAlrExpectingOCurly = P $ \s@(PState {alr_expecting_ocurly = b}) -> POk s b
+
+setAlrExpectingOCurly :: Maybe ALRLayout -> P ()
+setAlrExpectingOCurly b = P $ \s -> POk (s {alr_expecting_ocurly = b}) ()
+
-- for reasons of efficiency, flags indicating language extensions (eg,
-- -fglasgow-exts or -XParr) are represented by a bitmap stored in an unboxed
-- integer
rawTokenStreamBit = 20 -- producing a token stream with all comments included
newQualOpsBit :: Int
newQualOpsBit = 21 -- Haskell' qualified operator syntax, e.g. Prelude.(+)
+recBit :: Int
+recBit = 22 -- rec
+alternativeLayoutRuleBit :: Int
+alternativeLayoutRuleBit = 23
always :: Int -> Bool
always _ = True
newQualOps flags = testBit flags newQualOpsBit
oldQualOps :: Int -> Bool
oldQualOps flags = not (newQualOps flags)
+alternativeLayoutRule :: Int -> Bool
+alternativeLayoutRule flags = testBit flags alternativeLayoutRuleBit
-- PState for parsing options pragmas
--
loc = loc,
extsBitmap = 0,
context = [],
- lex_state = [bol, option_prags, 0]
+ lex_state = [bol, option_prags, 0],
+ alr_pending_implicit_tokens = [],
+ alr_next_token = Nothing,
+ alr_last_loc = noSrcSpan,
+ alr_context = [],
+ alr_expecting_ocurly = Nothing
}
loc = loc,
extsBitmap = fromIntegral bitmap,
context = [],
- lex_state = [bol, 0]
+ lex_state = [bol, 0],
-- we begin in the layout state if toplev_layout is set
+ alr_pending_implicit_tokens = [],
+ alr_next_token = Nothing,
+ alr_last_loc = noSrcSpan,
+ alr_context = [],
+ alr_expecting_ocurly = Nothing
}
where
bitmap = genericsBit `setBitIf` dopt Opt_Generics flags
- .|. ffiBit `setBitIf` dopt Opt_ForeignFunctionInterface flags
- .|. parrBit `setBitIf` dopt Opt_PArr flags
- .|. arrowsBit `setBitIf` dopt Opt_Arrows flags
- .|. thBit `setBitIf` dopt Opt_TemplateHaskell flags
- .|. qqBit `setBitIf` dopt Opt_QuasiQuotes flags
- .|. ipBit `setBitIf` dopt Opt_ImplicitParams flags
- .|. explicitForallBit `setBitIf` dopt Opt_ScopedTypeVariables flags
- .|. explicitForallBit `setBitIf` dopt Opt_LiberalTypeSynonyms flags
- .|. explicitForallBit `setBitIf` dopt Opt_PolymorphicComponents flags
- .|. explicitForallBit `setBitIf` dopt Opt_ExistentialQuantification flags
- .|. explicitForallBit `setBitIf` dopt Opt_Rank2Types flags
- .|. explicitForallBit `setBitIf` dopt Opt_RankNTypes flags
- .|. bangPatBit `setBitIf` dopt Opt_BangPatterns flags
- .|. tyFamBit `setBitIf` dopt Opt_TypeFamilies flags
- .|. haddockBit `setBitIf` dopt Opt_Haddock flags
- .|. magicHashBit `setBitIf` dopt Opt_MagicHash flags
- .|. kindSigsBit `setBitIf` dopt Opt_KindSignatures flags
- .|. recursiveDoBit `setBitIf` dopt Opt_RecursiveDo flags
- .|. unicodeSyntaxBit `setBitIf` dopt Opt_UnicodeSyntax flags
- .|. unboxedTuplesBit `setBitIf` dopt Opt_UnboxedTuples flags
+ .|. ffiBit `setBitIf` dopt Opt_ForeignFunctionInterface flags
+ .|. parrBit `setBitIf` dopt Opt_PArr flags
+ .|. arrowsBit `setBitIf` dopt Opt_Arrows flags
+ .|. thBit `setBitIf` dopt Opt_TemplateHaskell flags
+ .|. qqBit `setBitIf` dopt Opt_QuasiQuotes flags
+ .|. ipBit `setBitIf` dopt Opt_ImplicitParams flags
+ .|. explicitForallBit `setBitIf` dopt Opt_ExplicitForAll flags
+ .|. bangPatBit `setBitIf` dopt Opt_BangPatterns flags
+ .|. tyFamBit `setBitIf` dopt Opt_TypeFamilies flags
+ .|. haddockBit `setBitIf` dopt Opt_Haddock flags
+ .|. magicHashBit `setBitIf` dopt Opt_MagicHash flags
+ .|. kindSigsBit `setBitIf` dopt Opt_KindSignatures flags
+ .|. recursiveDoBit `setBitIf` dopt Opt_RecursiveDo flags
+ .|. recBit `setBitIf` dopt Opt_DoRec flags
+ .|. recBit `setBitIf` dopt Opt_Arrows flags
+ .|. unicodeSyntaxBit `setBitIf` dopt Opt_UnicodeSyntax flags
+ .|. unboxedTuplesBit `setBitIf` dopt Opt_UnboxedTuples flags
.|. standaloneDerivingBit `setBitIf` dopt Opt_StandaloneDeriving flags
.|. transformComprehensionsBit `setBitIf` dopt Opt_TransformListComp flags
.|. rawTokenStreamBit `setBitIf` dopt Opt_KeepRawTokenStream flags
.|. newQualOpsBit `setBitIf` dopt Opt_NewQualifiedOperators flags
+ .|. alternativeLayoutRuleBit `setBitIf` dopt Opt_AlternativeLayoutRule flags
--
setBitIf :: Int -> Bool -> Int
b `setBitIf` cond | cond = bit b
lexer :: (Located Token -> P a) -> P a
lexer cont = do
- tok@(L _span _tok__) <- lexToken
+ alr <- extension alternativeLayoutRule
+ let lexTokenFun = if alr then lexTokenAlr else lexToken
+ tok@(L _span _tok__) <- lexTokenFun
-- trace ("token: " ++ show tok__) $ do
cont tok
+lexTokenAlr :: P (Located Token)
+lexTokenAlr = do mPending <- popPendingImplicitToken
+ t <- case mPending of
+ Nothing ->
+ do mNext <- popNextToken
+ t <- case mNext of
+ Nothing -> lexToken
+ Just next -> return next
+ alternativeLayoutRuleToken t
+ Just t ->
+ return t
+ setAlrLastLoc (getLoc t)
+ case unLoc t of
+ ITwhere -> setAlrExpectingOCurly (Just ALRLayoutWhere)
+ ITlet -> setAlrExpectingOCurly (Just ALRLayoutLet)
+ ITof -> setAlrExpectingOCurly (Just ALRLayoutOf)
+ ITdo -> setAlrExpectingOCurly (Just ALRLayoutDo)
+ _ -> return ()
+ return t
+
+alternativeLayoutRuleToken :: Located Token -> P (Located Token)
+alternativeLayoutRuleToken t
+ = do context <- getALRContext
+ lastLoc <- getAlrLastLoc
+ mExpectingOCurly <- getAlrExpectingOCurly
+ let thisLoc = getLoc t
+ thisCol = srcSpanStartCol thisLoc
+ newLine = (lastLoc == noSrcSpan)
+ || (srcSpanStartLine thisLoc > srcSpanEndLine lastLoc)
+ case (unLoc t, context, mExpectingOCurly) of
+ -- This case handles a GHC extension to the original H98
+ -- layout rule...
+ (ITocurly, _, Just _) ->
+ do setAlrExpectingOCurly Nothing
+ setALRContext (ALRNoLayout (containsCommas ITocurly) : context)
+ return t
+ -- ...and makes this case unnecessary
+ {-
+ -- I think our implicit open-curly handling is slightly
+ -- different to John's, in how it interacts with newlines
+ -- and "in"
+ (ITocurly, _, Just _) ->
+ do setAlrExpectingOCurly Nothing
+ setNextToken t
+ lexTokenAlr
+ -}
+ (_, ALRLayout _ col : ls, Just expectingOCurly)
+ | (thisCol > col) ||
+ (thisCol == col &&
+ isNonDecreasingIntentation expectingOCurly) ->
+ do setAlrExpectingOCurly Nothing
+ setALRContext (ALRLayout expectingOCurly thisCol : context)
+ setNextToken t
+ return (L thisLoc ITocurly)
+ | otherwise ->
+ do setAlrExpectingOCurly Nothing
+ setPendingImplicitTokens [L lastLoc ITccurly]
+ setNextToken t
+ return (L lastLoc ITocurly)
+ (_, _, Just expectingOCurly) ->
+ do setAlrExpectingOCurly Nothing
+ setALRContext (ALRLayout expectingOCurly thisCol : context)
+ setNextToken t
+ return (L thisLoc ITocurly)
+ -- We do the [] cases earlier than in the spec, as we
+ -- have an actual EOF token
+ (ITeof, ALRLayout _ _ : ls, _) ->
+ do setALRContext ls
+ setNextToken t
+ return (L thisLoc ITccurly)
+ (ITeof, _, _) ->
+ return t
+ -- the other ITeof case omitted; general case below covers it
+ (ITin, ALRLayout ALRLayoutLet _ : ls, _)
+ | newLine ->
+ do setPendingImplicitTokens [t]
+ setALRContext ls
+ return (L thisLoc ITccurly)
+ (_, ALRLayout _ col : ls, _)
+ | newLine && thisCol == col ->
+ do setNextToken t
+ return (L thisLoc ITsemi)
+ | newLine && thisCol < col ->
+ do setALRContext ls
+ setNextToken t
+ -- Note that we use lastLoc, as we may need to close
+ -- more layouts, or give a semicolon
+ return (L lastLoc ITccurly)
+ (u, _, _)
+ | isALRopen u ->
+ do setALRContext (ALRNoLayout (containsCommas u) : context)
+ return t
+ (u, _, _)
+ | isALRclose u ->
+ case context of
+ ALRLayout _ _ : ls ->
+ do setALRContext ls
+ setNextToken t
+ return (L thisLoc ITccurly)
+ ALRNoLayout _ : ls ->
+ do setALRContext ls
+ return t
+ [] ->
+ -- XXX This is an error in John's code, but
+ -- it looks reachable to me at first glance
+ return t
+ (ITin, ALRLayout ALRLayoutLet _ : ls, _) ->
+ do setALRContext ls
+ setPendingImplicitTokens [t]
+ return (L thisLoc ITccurly)
+ (ITin, ALRLayout _ _ : ls, _) ->
+ do setALRContext ls
+ setNextToken t
+ return (L thisLoc ITccurly)
+ -- the other ITin case omitted; general case below covers it
+ (ITcomma, ALRLayout _ _ : ls, _)
+ | topNoLayoutContainsCommas ls ->
+ do setALRContext ls
+ setNextToken t
+ return (L thisLoc ITccurly)
+ (ITwhere, ALRLayout ALRLayoutDo _ : ls, _) ->
+ do setALRContext ls
+ setPendingImplicitTokens [t]
+ return (L thisLoc ITccurly)
+ -- the other ITwhere case omitted; general case below covers it
+ (_, _, _) -> return t
+
+isALRopen :: Token -> Bool
+isALRopen ITcase = True
+isALRopen ITif = True
+isALRopen IToparen = True
+isALRopen ITobrack = True
+isALRopen ITocurly = True
+-- GHC Extensions:
+isALRopen IToubxparen = True
+isALRopen _ = False
+
+isALRclose :: Token -> Bool
+isALRclose ITof = True
+isALRclose ITthen = True
+isALRclose ITcparen = True
+isALRclose ITcbrack = True
+isALRclose ITccurly = True
+-- GHC Extensions:
+isALRclose ITcubxparen = True
+isALRclose _ = False
+
+isNonDecreasingIntentation :: ALRLayout -> Bool
+isNonDecreasingIntentation ALRLayoutDo = True
+isNonDecreasingIntentation _ = False
+
+containsCommas :: Token -> Bool
+containsCommas IToparen = True
+containsCommas ITobrack = True
+-- John doesn't have {} as containing commas, but records contain them,
+-- which caused a problem parsing Cabal's Distribution.Simple.InstallDirs
+-- (defaultInstallDirs).
+containsCommas ITocurly = True
+-- GHC Extensions:
+containsCommas IToubxparen = True
+containsCommas _ = False
+
+topNoLayoutContainsCommas :: [ALRContext] -> Bool
+topNoLayoutContainsCommas [] = False
+topNoLayoutContainsCommas (ALRLayout _ _ : ls) = topNoLayoutContainsCommas ls
+topNoLayoutContainsCommas (ALRNoLayout b : _) = b
+
lexToken :: P (Located Token)
lexToken = do
inp@(AI loc1 _ buf) <- getInput
"noinline" -> "notinline"
"specialise" -> "specialize"
"constructorlike" -> "conlike"
- otherwise -> prag'
+ _ -> prag'
canon_ws s = unwords (map canonical (words s))
}
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