Markdown writer: improved escaping.

`<` should not be escaped as `\<`, for compatibility with
original Markdown.  We now escape `<` and `>` with entities.
Also, we now backslash-escape square brackets.

Closes #2086.

1 files changed, 3 insertions, 2 deletions

diff --git a/src/Text/Pandoc/Writers/Markdown.hs b/src/Text/Pandoc/Writers/Markdown.hs
index dee4d56a4..ef87a8603 100644
--- a/src/Text/Pandoc/Writers/Markdown.hs
+++ b/src/Text/Pandoc/Writers/Markdown.hs
@@ -246,7 +246,8 @@ noteToMarkdown opts num blocks = do
 -- | Escape special characters for Markdown.
 escapeString :: WriterOptions -> String -> String
 escapeString opts = escapeStringUsing markdownEscapes
-  where markdownEscapes = backslashEscapes specialChars
+  where markdownEscapes = ('<', "&lt;") : ('>', "&gt;") :
+                          backslashEscapes specialChars
         specialChars =
                 (if isEnabled Ext_superscript opts
                     then ('^':)
@@ -257,7 +258,7 @@ escapeString opts = escapeStringUsing markdownEscapes
                 (if isEnabled Ext_tex_math_dollars opts
                     then ('$':)
                     else id) $
-                "\\`*_<>#"
+                "\\`*_[]#"
 
 -- | Construct table of contents from list of header blocks.
 tableOfContents :: WriterOptions -> [Block] -> Doc