Implement -XRecursiveDo

[ghc-hetmet.git] / compiler / parser / Lexer.x

diff --git a/compiler/parser/Lexer.x b/compiler/parser/Lexer.x
index e008456..11810a6 100644 (file)
--- a/compiler/parser/Lexer.x
+++ b/compiler/parser/Lexer.x
@@ -614,7 +614,7 @@ reservedWordsFM = listToUFM $
        ( "_scc_",      ITscc,          0 ),            -- ToDo: remove
 
        ( "forall",     ITforall,        bit tvBit),
-       ( "mdo",        ITmdo,           bit glaExtsBit),
+       ( "mdo",        ITmdo,           bit recursiveDoBit),
        ( "family",     ITfamily,        bit tyFamBit),
 
        ( "foreign",    ITforeign,       bit ffiBit),
@@ -1518,7 +1518,8 @@ bangPatBit = 8    -- Tells the parser to understand bang-patterns
 tyFamBit   = 9 -- indexed type families: 'family' keyword and kind sigs
 haddockBit = 10 -- Lex and parse Haddock comments
 magicHashBit = 11 -- # in both functions and operators
-kindSigsBit = 12 -- # in both functions and operators
+kindSigsBit = 12 -- Kind signatures on type variables
+recursiveDoBit = 13 -- mdo
 
 glaExtsEnabled, ffiEnabled, parrEnabled :: Int -> Bool
 glaExtsEnabled   flags = testBit flags glaExtsBit
@@ -1533,6 +1534,7 @@ tyFamEnabled     flags = testBit flags tyFamBit
 haddockEnabled   flags = testBit flags haddockBit
 magicHashEnabled flags = testBit flags magicHashBit
 kindSigsEnabled  flags = testBit flags kindSigsBit
+recursiveDoEnabled flags = testBit flags recursiveDoBit
 
 -- PState for parsing options pragmas
 --
@@ -1586,6 +1588,7 @@ mkPState buf loc 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
       --
       setBitIf :: Int -> Bool -> Int
       b `setBitIf` cond | cond      = bit b