From: Ian Lynagh <igloo@earth.li>
Date: Wed, 24 Nov 2010 20:59:57 +0000 (+0000)
Subject: Add another GHC layout rule relaxation to RelaxedLayout
X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=commitdiff_plain;h=04a12a3d4ee3eb098b1fed40195b27095a31c5ec

Add another GHC layout rule relaxation to RelaxedLayout
---

diff --git a/compiler/parser/Lexer.x b/compiler/parser/Lexer.x
index e52880b..823fc6d 100644
--- a/compiler/parser/Lexer.x
+++ b/compiler/parser/Lexer.x
@@ -211,7 +211,7 @@ $tab+         { warn Opt_WarnTabs (text "Warning: Tab character") }
 -- context if the curly brace is missing.
 -- Careful! This stuff is quite delicate.
 <layout, layout_do> {
-  \{ / { notFollowedBy '-' }		{ pop_and open_brace }
+  \{ / { notFollowedBy '-' }		{ hopefully_open_brace }
 	-- we might encounter {-# here, but {- has been handled already
   \n					;
   ^\# (line)?				{ begin line_prag1 }
@@ -757,6 +757,19 @@ pop :: Action
 pop _span _buf _len = do _ <- popLexState
                          lexToken
 
+hopefully_open_brace :: Action
+hopefully_open_brace span buf len
+ = do relaxed <- extension relaxedLayout
+      ctx <- getContext
+      (AI l _) <- getInput
+      let offset = srcLocCol l
+          isOK = relaxed ||
+                 case ctx of
+                 Layout prev_off : _ -> prev_off < offset
+                 _                   -> True
+      if isOK then pop_and open_brace span buf len
+              else failSpanMsgP span (text "Missing block")
+
 pop_and :: Action -> Action
 pop_and act span buf len = do _ <- popLexState
                               act span buf len