From 7163a044a4f9673e38f99c29f2886d42336c283e Mon Sep 17 00:00:00 2001
From: fiddlosopher <fiddlosopher@788f1e2b-df1e-0410-8736-df70ead52e1b>
Date: Mon, 12 Oct 2009 03:40:47 +0000
Subject: [PATCH] Fix inline math parser so that \$ is allowed in math.

Resolves Issue #169.

git-svn-id: https://pandoc.googlecode.com/svn/trunk@1609 788f1e2b-df1e-0410-8736-df70ead52e1b
---
 src/Text/Pandoc/Readers/Markdown.hs | 11 ++++++++---
 tests/markdown-reader-more.native   |  4 +++-
 tests/markdown-reader-more.txt      |  4 ++++
 3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/src/Text/Pandoc/Readers/Markdown.hs b/src/Text/Pandoc/Readers/Markdown.hs
index 80bc53966..d03a1123f 100644
--- a/src/Text/Pandoc/Readers/Markdown.hs
+++ b/src/Text/Pandoc/Readers/Markdown.hs
@@ -45,7 +45,7 @@ import Text.Pandoc.Readers.HTML ( rawHtmlBlock, anyHtmlBlockTag,
                                   htmlBlockElement, unsanitaryURI )
 import Text.Pandoc.CharacterReferences ( decodeCharacterReferences )
 import Text.ParserCombinators.Parsec
-import Control.Monad (when)
+import Control.Monad (when, liftM)
 
 -- | Read markdown from an input string and return a Pandoc document.
 readMarkdown :: ParserState -- ^ Parser state, including options for parser
@@ -897,8 +897,13 @@ code = try $ do
   return $ Code $ removeLeadingTrailingSpace $ concat result
 
 mathWord :: GenParser Char st [Char]
-mathWord = many1 ((noneOf " \t\n\\$") <|>
-                  (try (char '\\') >>~ notFollowedBy (char '$')))
+mathWord = liftM concat $ many1 mathChunk
+
+mathChunk :: GenParser Char st [Char]
+mathChunk = do char '\\'
+               c <- anyChar
+               return ['\\',c]
+        <|> many1 (noneOf " \t\n\\$")
 
 math :: GenParser Char ParserState Inline
 math = (mathDisplay >>= return . Math DisplayMath)
diff --git a/tests/markdown-reader-more.native b/tests/markdown-reader-more.native
index 3160f0cd3..995991a17 100644
--- a/tests/markdown-reader-more.native
+++ b/tests/markdown-reader-more.native
@@ -13,5 +13,7 @@ Pandoc (Meta [] [] "")
 , HorizontalRule
 , Header 2 [Str "Raw",Space,Str "HTML",Space,Str "before",Space,Str "header"]
 , Plain [HtmlInline "<a>",HtmlInline "</a>"]
-, Header 3 [Str "my",Space,Str "header"] ]
+, Header 3 [Str "my",Space,Str "header"]
+, Header 2 [Str "$",Space,Str "in",Space,Str "math"]
+, Para [Math InlineMath "\\$2 + \\$3"] ]
 
diff --git a/tests/markdown-reader-more.txt b/tests/markdown-reader-more.txt
index d2315046f..a7d64dde9 100644
--- a/tests/markdown-reader-more.txt
+++ b/tests/markdown-reader-more.txt
@@ -47,3 +47,7 @@
 
 ### my header
 
+## $ in math
+
+$\$2 + \$3$
+