Tweak alternative layout rule

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

diff --git a/compiler/parser/Lexer.x b/compiler/parser/Lexer.x
index 85d4d12..00926bd 100644 (file)
--- a/compiler/parser/Lexer.x
+++ b/compiler/parser/Lexer.x
@@ -31,15 +31,15 @@
 --       qualified varids.
 
 {
-{-# OPTIONS -Wwarn -w #-}
--- The above -Wwarn 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 #-}
 
@@ -1998,6 +1998,15 @@ alternativeLayoutRuleToken t
                     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]
@@ -2014,7 +2023,8 @@ alternativeLayoutRuleToken t
                         f ls' = ([], ls')
                     case f ls of
                         (t' : ts, ls') ->
-                            do setPendingImplicitTokens ts
+                            do setALRContext ls'
+                               setPendingImplicitTokens ts
                                setNextToken t
                                return t'
                         _ -> panic "Layout rule: [] when considering newline"
@@ -2055,13 +2065,6 @@ alternativeLayoutRuleToken t
                     setPendingImplicitTokens [t]
                     return (L thisLoc ITccurly)
              -- the other ITwhere case omitted; general case below covers it
-             -- The first [] case comes before the general case, as we
-             -- have an actual EOF token
-             (ITeof, ALRLayout _ _ : ls, _) ->
-                 do setALRContext ls
-                    setNextToken t
-                    return (L thisLoc ITccurly)
-             -- the other ITeof case omitted; general case below covers it
              (_, _, _) -> return t
 
 isALRopen :: Token -> Bool
@@ -2070,6 +2073,8 @@ isALRopen ITif     = True
 isALRopen IToparen = True
 isALRopen ITobrack = True
 isALRopen ITocurly = True
+-- GHC Extensions:
+isALRopen IToubxparen = True
 isALRopen _        = False
 
 isALRclose :: Token -> Bool
@@ -2078,11 +2083,15 @@ isALRclose ITthen   = True
 isALRclose ITcparen = True
 isALRclose ITcbrack = True
 isALRclose ITccurly = True
+-- GHC Extensions:
+isALRclose ITcubxparen = True
 isALRclose _        = False
 
 containsCommas :: Token -> Bool
 containsCommas IToparen = True
 containsCommas ITobrack = True
+-- GHC Extensions:
+containsCommas IToubxparen = True
 containsCommas _        = False
 
 topNoLayoutContainsCommas :: [ALRContext] -> Bool