merge upstream

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

diff --git a/compiler/parser/Lexer.x b/compiler/parser/Lexer.x
index 43a4004..c9b2e1c 100644 (file)
--- a/compiler/parser/Lexer.x
+++ b/compiler/parser/Lexer.x
@@ -56,6 +56,7 @@ module Lexer (
    getLexState, popLexState, pushLexState,
    extension, bangPatEnabled, datatypeContextsEnabled,
    addWarning,
+   incrBracketDepth, decrBracketDepth, getParserBrakDepth,
    lexTokenStream
   ) where
 
@@ -326,6 +327,15 @@ $tab+         { warn Opt_WarnTabs (text "Warning: Tab character") }
 }
 
 <0> {
+  "<[" / { ifExtension hetMetEnabled `alexAndPred` notFollowedBySymbol }
+                                       { special ITopenBrak }
+  "]>" / { ifExtension hetMetEnabled }  { special ITcloseBrak }
+  "~~" / { ifExtension hetMetEnabled }  { special ITescape }
+  "%%" / { ifExtension hetMetEnabled }  { special ITdoublePercent }
+  "~~$" / { ifExtension hetMetEnabled }  { special ITescapeDollar }
+}
+
+<0> {
   \? @varid / { ifExtension ipEnabled }        { skip_one_varid ITdupipvarid }
 }
 
@@ -569,6 +579,13 @@ data Token
   | ITLarrowtail               --  -<<
   | ITRarrowtail               --  >>-
 
+  -- Heterogeneous Metaprogramming extension
+  | ITopenBrak                 --  <[
+  | ITcloseBrak                        --  ]>
+  | ITescape                   --  ~~
+  | ITescapeDollar             --  ~~$
+  | ITdoublePercent             --  %%
+
   | ITunknown String           -- Used when the lexer can't make sense of it
   | ITeof                      -- end of file token
 
@@ -1530,7 +1547,8 @@ data PState = PState {
         alr_expecting_ocurly :: Maybe ALRLayout,
         -- Have we just had the '}' for a let block? If so, than an 'in'
         -- token doesn't need to close anything:
-        alr_justClosedExplicitLetBlock :: Bool
+        alr_justClosedExplicitLetBlock :: Bool,
+        code_type_bracket_depth :: Int
      }
        -- last_loc and last_len are used when generating error messages,
        -- and in pushCurrentContext only.  Sigh, if only Happy passed the
@@ -1597,6 +1615,13 @@ setExts f = P $ \s -> POk s{ extsBitmap = f (extsBitmap s) } ()
 setSrcLoc :: RealSrcLoc -> P ()
 setSrcLoc new_loc = P $ \s -> POk s{loc=new_loc} ()
 
+incrBracketDepth :: P ()
+incrBracketDepth = P $ \s -> POk (s{code_type_bracket_depth = (code_type_bracket_depth s)+1}) ()
+decrBracketDepth :: P ()
+decrBracketDepth = P $ \s -> POk (s{code_type_bracket_depth = (code_type_bracket_depth s)-1}) ()
+getParserBrakDepth :: P Int
+getParserBrakDepth = P $ \s -> POk s (code_type_bracket_depth s)
+
 getSrcLoc :: P RealSrcLoc
 getSrcLoc = P $ \s@(PState{ loc=loc }) -> POk s loc
 
@@ -1807,6 +1832,8 @@ relaxedLayoutBit :: Int
 relaxedLayoutBit = 24
 nondecreasingIndentationBit :: Int
 nondecreasingIndentationBit = 25
+hetMetBit :: Int
+hetMetBit = 31
 
 always :: Int -> Bool
 always           _     = True
@@ -1814,6 +1841,8 @@ parrEnabled :: Int -> Bool
 parrEnabled      flags = testBit flags parrBit
 arrowsEnabled :: Int -> Bool
 arrowsEnabled    flags = testBit flags arrowsBit
+hetMetEnabled :: Int -> Bool
+hetMetEnabled    flags = testBit flags hetMetBit
 thEnabled :: Int -> Bool
 thEnabled        flags = testBit flags thBit
 ipEnabled :: Int -> Bool
@@ -1875,12 +1904,14 @@ mkPState flags buf loc =
       alr_last_loc = alrInitialLoc (fsLit "<no file>"),
       alr_context = [],
       alr_expecting_ocurly = Nothing,
-      alr_justClosedExplicitLetBlock = False
+      alr_justClosedExplicitLetBlock = False,
+      code_type_bracket_depth = 0
     }
     where
       bitmap =     ffiBit            `setBitIf` xopt Opt_ForeignFunctionInterface flags
                .|. parrBit           `setBitIf` xopt Opt_ParallelArrays  flags
                .|. arrowsBit         `setBitIf` xopt Opt_Arrows          flags
+              .|. hetMetBit         `setBitIf` xopt Opt_ModalTypes      flags
                .|. thBit             `setBitIf` xopt Opt_TemplateHaskell flags
                .|. qqBit             `setBitIf` xopt Opt_QuasiQuotes     flags
                .|. ipBit             `setBitIf` xopt Opt_ImplicitParams  flags