Implement -XRecursiveDo

diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index 26948e1..b033bf3 100644 (file)
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -189,6 +189,7 @@ data DynFlag
    | Opt_KindSignatures
    | Opt_ParallelListComp
    | Opt_GeneralizedNewtypeDeriving
    | Opt_KindSignatures
    | Opt_ParallelListComp
    | Opt_GeneralizedNewtypeDeriving

+   | Opt_RecursiveDo

 
    -- optimisation opts
    | Opt_Strictness
 
    -- optimisation opts
    | Opt_Strictness

@@ -1106,6 +1107,7 @@ xFlags = [
   ( "FFI",                             Opt_FFI ),  -- ...and also `-fffi'
   ( "ForeignFunctionInterface",                Opt_FFI ),
 
   ( "FFI",                             Opt_FFI ),  -- ...and also `-fffi'
   ( "ForeignFunctionInterface",                Opt_FFI ),
 

+  ( "RecursiveDo",                      Opt_RecursiveDo ),

   ( "Arrows",                          Opt_Arrows ), -- arrow syntax
   ( "Parr",                            Opt_PArr ),
 
   ( "Arrows",                          Opt_Arrows ), -- arrow syntax
   ( "Parr",                            Opt_PArr ),
 

@@ -1149,6 +1151,7 @@ glasgowExtsFlags = [ Opt_GlasgowExts
                   , Opt_ScopedTypeVariables
            , Opt_MultiParamTypeClasses
                   , Opt_MagicHash
                   , Opt_ScopedTypeVariables
            , Opt_MultiParamTypeClasses
                   , Opt_MagicHash

+           , Opt_RecursiveDo

            , Opt_ParallelListComp
            , Opt_EmptyDataDecls
            , Opt_KindSignatures
            , Opt_ParallelListComp
            , Opt_EmptyDataDecls
            , Opt_KindSignatures

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),
        ( "_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),
        ( "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
 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
 
 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
 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
 --
 
 -- 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
               .|. 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
       --
       setBitIf :: Int -> Bool -> Int
       b `setBitIf` cond | cond      = bit b