Remove code that is dead, as we require __GLASGOW_HASKELL__ >= 504

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

diff --git a/compiler/parser/Lexer.x b/compiler/parser/Lexer.x
index 856c298..d9a0fb0 100644 (file)
--- a/compiler/parser/Lexer.x
+++ b/compiler/parser/Lexer.x
@@ -25,6 +25,7 @@ module Lexer (
    Token(..), lexer, pragState, mkPState, PState(..),
    P(..), ParseResult(..), getSrcLoc, 
    failLocMsgP, failSpanMsgP, srcParseFail,
+   getMessages,
    popContext, pushCurrentContext, setLastToken, setSrcLoc,
    getLexState, popLexState, pushLexState,
    extension, glaExtsEnabled, bangPatEnabled
@@ -32,7 +33,8 @@ module Lexer (
 
 #include "HsVersions.h"
 
-import ErrUtils                ( Message )
+import Bag
+import ErrUtils
 import Outputable
 import StringBuffer
 import FastString
@@ -43,6 +45,7 @@ import DynFlags
 import Ctype
 import Util            ( maybePrefixMatch, readRational )
 
+import Control.Monad
 import Data.Bits
 import Data.Char       ( chr, isSpace )
 import Data.Ratio
@@ -56,8 +59,9 @@ import Compat.Unicode ( GeneralCategory(..), generalCategory, isPrint, isUpper )
 }
 
 $unispace    = \x05
-$whitechar   = [\ \t\n\r\f\v\xa0 $unispace]
+$whitechar   = [\ \n\r\f\v\xa0 $unispace]
 $white_no_nl = $whitechar # \n
+$tab         = \t
 
 $ascdigit  = 0-9
 $unidigit  = \x03
@@ -108,6 +112,7 @@ haskell :-
 
 -- everywhere: skip whitespace and comments
 $white_no_nl+                          ;
+$tab+         { warn Opt_WarnTabs (text "Tab character") }
 
 -- Everywhere: deal with nested comments.  We explicitly rule out
 -- pragmas, "{-#", so that we don't accidentally treat them as comments.
@@ -374,11 +379,6 @@ $white_no_nl+                              ;
 }
 
 {
--- work around bug in Alex 2.0
-#if __GLASGOW_HASKELL__ < 503
-unsafeAt arr i = arr ! i
-#endif
-
 -- -----------------------------------------------------------------------------
 -- The token type
 
@@ -389,9 +389,9 @@ data Token
   | ITdata
   | ITdefault
   | ITderiving
+  | ITderive
   | ITdo
   | ITelse
-  | ITfor
   | IThiding
   | ITif
   | ITimport
@@ -422,7 +422,6 @@ data Token
   | ITccallconv
   | ITdotnet
   | ITmdo
-  | ITiso
   | ITfamily
 
        -- Pragmas
@@ -544,7 +543,7 @@ isSpecial :: Token -> Bool
 -- not as a keyword.
 isSpecial ITas         = True
 isSpecial IThiding     = True
-isSpecial ITfor        = True
+isSpecial ITderive     = True
 isSpecial ITqualified  = True
 isSpecial ITforall     = True
 isSpecial ITexport     = True
@@ -556,7 +555,6 @@ isSpecial ITunsafe          = True
 isSpecial ITccallconv   = True
 isSpecial ITstdcallconv = True
 isSpecial ITmdo                = True
-isSpecial ITiso                = True
 isSpecial ITfamily     = True
 isSpecial _             = False
 
@@ -576,9 +574,9 @@ reservedWordsFM = listToUFM $
        ( "data",       ITdata,         0 ),     
        ( "default",    ITdefault,      0 ),  
        ( "deriving",   ITderiving,     0 ), 
+       ( "derive",     ITderive,       0 ), 
        ( "do",         ITdo,           0 ),       
        ( "else",       ITelse,         0 ),     
-       ( "for",        ITfor,          0 ),
        ( "hiding",     IThiding,       0 ),
        ( "if",         ITif,           0 ),       
        ( "import",     ITimport,       0 ),   
@@ -643,13 +641,12 @@ reservedSymsFM = listToUFM $
        ,(">>-",        ITRarrowtail,   bit arrowsBit)
 
 #if __GLASGOW_HASKELL__ >= 605
-       ,("λ", ITlam,          bit glaExtsBit)
        ,("∷",   ITdcolon,       bit glaExtsBit)
        ,("⇒",   ITdarrow,    bit glaExtsBit)
        ,("∀",        ITforall,       bit glaExtsBit)
        ,("→",   ITrarrow,    bit glaExtsBit)
        ,("←",   ITlarrow,    bit glaExtsBit)
-       ,("⋯",        ITdotdot,       bit glaExtsBit)
+       ,("?",  ITdotdot,       bit glaExtsBit)
         -- 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).
@@ -1301,6 +1298,14 @@ getCharOrFail =  do
        Just (c,i)  -> do setInput i; return c
 
 -- -----------------------------------------------------------------------------
+-- Warnings
+
+warn :: DynFlag -> SDoc -> Action
+warn option warning span _buf _len = do
+    addWarning option (mkWarnMsg span alwaysQualify warning)
+    lexToken
+
+-- -----------------------------------------------------------------------------
 -- The Parse Monad
 
 data LayoutContext
@@ -1318,6 +1323,8 @@ data ParseResult a
 
 data PState = PState { 
        buffer     :: StringBuffer,
+    dflags     :: DynFlags,
+    messages   :: Messages,
         last_loc   :: SrcSpan, -- pos of previous token
         last_offs  :: !Int,    -- offset of the previous token from the
                                -- beginning of  the current line.
@@ -1502,6 +1509,10 @@ pragState :: StringBuffer -> SrcLoc -> PState
 pragState buf loc  = 
   PState {
       buffer         = buf,
+      messages      = emptyMessages,
+      -- XXX defaultDynFlags is not right, but we don't have a real
+      -- dflags handy
+      dflags        = defaultDynFlags,
       last_loc      = mkSrcSpan loc loc,
       last_offs     = 0,
       last_len      = 0,
@@ -1519,6 +1530,8 @@ mkPState :: StringBuffer -> SrcLoc -> DynFlags -> PState
 mkPState buf loc flags  = 
   PState {
       buffer         = buf,
+      dflags        = flags,
+      messages      = emptyMessages,
       last_loc      = mkSrcSpan loc loc,
       last_offs     = 0,
       last_len      = 0,
@@ -1545,6 +1558,15 @@ mkPState buf loc flags  =
       b `setBitIf` cond | cond      = bit b
                        | otherwise = 0
 
+addWarning :: DynFlag -> WarnMsg -> P ()
+addWarning option w
+ = P $ \s@PState{messages=(ws,es), dflags=d} ->
+       let ws' = if dopt option d then ws `snocBag` w else ws
+       in POk s{messages=(ws', es)} ()
+
+getMessages :: PState -> Messages
+getMessages PState{messages=ms} = ms
+
 getContext :: P [LayoutContext]
 getContext = P $ \s@PState{context=ctx} -> POk s ctx