From e4cca4cf67af31ce574ef2871d08f0719d4a50a5 Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Wed, 4 Sep 2019 09:24:42 -0700
Subject: [PATCH] Roff readers: better parsing of groups.

We now allow groups where the closing `\\}` isn't at the
beginning of a line.

Closes #5410.
---
 src/Text/Pandoc/Readers/Roff.hs | 14 +++++---------
 test/Tests/Readers/Man.hs       |  2 +-
 test/command/5410.md            |  7 +++++++
 3 files changed, 13 insertions(+), 10 deletions(-)
 create mode 100644 test/command/5410.md

diff --git a/src/Text/Pandoc/Readers/Roff.hs b/src/Text/Pandoc/Readers/Roff.hs
index 3ed7f05a6..18535353e 100644
--- a/src/Text/Pandoc/Readers/Roff.hs
+++ b/src/Text/Pandoc/Readers/Roff.hs
@@ -33,7 +33,7 @@ import Control.Monad.Except (throwError)
 import Text.Pandoc.Class
        (getResourcePath, readFileFromDirs, PandocMonad(..), report)
 import Data.Char (isLower, toLower, toUpper, chr,
-                  isAscii, isAlphaNum, isSpace)
+                  isAscii, isAlphaNum)
 import Data.Default (Default)
 import qualified Data.Map as M
 import Data.List (intercalate)
@@ -130,7 +130,7 @@ type RoffLexer m = ParserT [Char] RoffState m
 --
 
 eofline :: Stream s m Char => ParsecT s u m ()
-eofline = void newline <|> eof
+eofline = void newline <|> eof <|> () <$ lookAhead (string "\\}")
 
 spacetab :: Stream s m Char => ParsecT s u m Char
 spacetab = char ' ' <|> char '\t'
@@ -144,7 +144,7 @@ combiningAccentsMap =
   M.fromList $ map (\(x,y) -> (y,x)) combiningAccents
 
 escape :: PandocMonad m => RoffLexer m [LinePart]
-escape = do
+escape = try $ do
   backslash
   escapeGlyph <|> escapeNormal
 
@@ -193,7 +193,7 @@ readUnicodeChar _ = Nothing
 
 escapeNormal :: PandocMonad m => RoffLexer m [LinePart]
 escapeNormal = do
-  c <- anyChar
+  c <- noneOf "{}"
   optional expandString
   case c of
     ' ' -> return [RoffStr " "]
@@ -256,9 +256,7 @@ escapeNormal = do
     'w' -> escIgnore 'w' [quoteArg]
     'x' -> escIgnore 'x' [quoteArg]
     'z' -> escIgnore 'z' [count 1 anyChar]
-    '{' -> return mempty
     '|' -> return [RoffStr "\x2006"] --1/6 em space
-    '}' -> return mempty
     '~' -> return [RoffStr "\160"] -- nonbreaking space
     '\\' -> do
       mode <- roffMode <$> getState
@@ -350,7 +348,7 @@ lexMacro = do
   guard $ sourceColumn pos == 1 || afterConditional st
   char '.' <|> char '\''
   skipMany spacetab
-  macroName <- many (satisfy (not . isSpace))
+  macroName <- many (satisfy isAlphaNum)
   case macroName of
     "nop" -> return mempty
     "ie"  -> lexConditional "ie"
@@ -361,8 +359,6 @@ lexMacro = do
        args <- lexArgs
        case macroName of
          ""     -> return mempty
-         "\\\"" -> return mempty
-         "\\#"  -> return mempty
          "TS"   -> lexTable pos
          "de"   -> lexMacroDef args
          "de1"  -> lexMacroDef args
diff --git a/test/Tests/Readers/Man.hs b/test/Tests/Readers/Man.hs
index 8c5d428e5..c3d2582ca 100644
--- a/test/Tests/Readers/Man.hs
+++ b/test/Tests/Readers/Man.hs
@@ -74,7 +74,7 @@ tests = [
       =?> para (text "hi " <> emph (text "there " <> strong (text "bold")) <>
                                    text " ok")
     , "skip" =:
-      "a\\%\\{\\}\\\n\\:b\\0"
+      "a\\%\\\n\\:b\\0"
       =?> (para $ str "ab\8199")
     , "replace" =:
       "\\-\\ \\\\\\[lq]\\[rq]\\[em]\\[en]\\*(lq\\*(rq"
diff --git a/test/command/5410.md b/test/command/5410.md
new file mode 100644
index 000000000..fee90a1a4
--- /dev/null
+++ b/test/command/5410.md
@@ -0,0 +1,7 @@
+```
+% pandoc -f man -t native
+.ie n \{\
+'br\}
+^D
+[Para [LineBreak]]
+```