From e752669e50815b0c1bef62fc5b1de95c33317f89 Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Thu, 31 Jan 2019 22:50:51 -0800
Subject: LaTeX reader: don't let `\egroup` match `{`.

`braced` now actually requires nested braces.
Otherwise some legitimate command and environment
definitions can break (see test/command/tex-group.md).
---
 src/Text/Pandoc/Readers/LaTeX/Parsing.hs |  6 +++---
 test/command/tex-group.md                | 12 ++++++++++++
 2 files changed, 15 insertions(+), 3 deletions(-)
 create mode 100644 test/command/tex-group.md

diff --git a/src/Text/Pandoc/Readers/LaTeX/Parsing.hs b/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
index 9437c23d9..a2dd61aee 100644
--- a/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
+++ b/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
@@ -612,19 +612,19 @@ braced' :: PandocMonad m => LP m Tok -> Int -> LP m [Tok]
 braced' getTok n =
   handleEgroup <|> handleBgroup <|> handleOther
   where handleEgroup = do
-          t <- egroup
+          t <- symbol '}'
           if n == 1
              then return []
              else (t:) <$> braced' getTok (n - 1)
         handleBgroup = do
-          t <- bgroup
+          t <- symbol '{'
           (t:) <$> braced' getTok (n + 1)
         handleOther = do
           t <- getTok
           (t:) <$> braced' getTok n
 
 braced :: PandocMonad m => LP m [Tok]
-braced = bgroup *> braced' anyTok 1
+braced = symbol '{' *> braced' anyTok 1
 
 -- URLs require special handling, because they can contain %
 -- characters.  So we retonenize comments as we go...
diff --git a/test/command/tex-group.md b/test/command/tex-group.md
new file mode 100644
index 000000000..277b32142
--- /dev/null
+++ b/test/command/tex-group.md
@@ -0,0 +1,12 @@
+```
+% pandoc -f latex -t html
+\newenvironment{foo}%
+{\emph\bgroup}%
+{\egroup}
+
+\begin{foo}
+hi
+\end{foo}
+^D
+<p><em>hi</em></p>
+```
-- 
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