[latex writer] dollar character should not be escaped in LaTeX \url{} links

[dwwalker]

In Text/Pandoc/Writers/LaTeX.hs dollar signs ($) are escaped by the following line:

'$' -> "\\$" ++ rest

This is correct for body text, where text like "$100" will be converted to the escaped form: "\$100". However, this is wrong for links that will be inside \url{} functions, because the url package performs the escaping for $ itself. Dollar signs are rare, but still valid inside URLs. Domino servers tend to rely on them in forming many URLs. For example, consider the following markdown:

<https://10.85.1.101/baz/qux.nsf/$about?OpenAbout>

This will produce the following latex:

\url{https://10.85.1.101/baz/qux.nsf/\$about?OpenAbout}

This will compile with latex without showing any errors, but the final output text will be wrong. The link text will appear like this: https://10.85.1.101/baz/qux.nsf/\protect\T1\textdollarabout?OpenAbout

Proposed Change

Add the not isUrl condition to the dollar character, the same as is done for underscores, hyphens and others. Change line 209 as follows:

--- a/src/Text/Pandoc/Writers/LaTeX.hs
+++ b/src/Text/Pandoc/Writers/LaTeX.hs
@@ -206,7 +206,7 @@ stringToLaTeX  ctx (x:xs) = do
        '€' -> "\\euro{}" ++ rest
        '{' -> "\\{" ++ rest
        '}' -> "\\}" ++ rest
-       '$' -> "\\$" ++ rest
+       '$' | not isUrl -> "\\$" ++ rest
        '%' -> "\\%" ++ rest
        '&' -> "\\&" ++ rest
        '_' | not isUrl -> "\\_" ++ rest

This change has been tested with pandoc 1.13.3. and produces the desired output for URL links when converting to LaTeX.

[jgm]

Looks good to me. If it's convenient to submit a pull
request with this change, that would be helpful.

+++ dwwalker [Jan 29 15 23:06 ]:

In Text/Pandoc/Writers/LaTeX.hs dollar signs ($) are escaped by the
following line:

'$' -> "$" ++ rest

This is correct for body text, where text like "$100" will be converted
to the escaped form: "$100". However, this is wrong for links that
will be inside \url{} functions, because the url package performs the
escaping for $ itself. Dollar signs are rare, but still valid inside
URLs. Domino servers tend to rely on them in forming many URLs. For
example, consider the following markdown:

https://10.85.1.101/baz/qux.nsf/$about?OpenAbout

This will produce the following latex:

\url{https://10.85.1.101/baz/qux.nsf/\$about?OpenAbout}

This will compile with latex without showing any errors, but the final
output text will be wrong. The link text will appear like this:
https://10.85.1.101/baz/qux.nsf/\protect\T1\textdollarabout?OpenAbout

Proposed Change

Add the not isUrl condition to the dollar character, the same as is
done for underscores, hyphens and others. Change line 209 as follows:

--- a/src/Text/Pandoc/Writers/LaTeX.hs
+++ b/src/Text/Pandoc/Writers/LaTeX.hs
@@ -206,7 +206,7 @@ stringToLaTeX ctx (x:xs) = do
'€' -> "\euro{}" ++ rest
'{' -> "{" ++ rest
'}' -> "}" ++ rest

•   '$' -> "\$" ++ rest
  

•   '$' | not isUrl -> "\\$" ++ rest
  

  '%' -> "%" ++ rest
  '&' -> "&" ++ rest
  '_' | not isUrl -> "_" ++ rest

  This change has been tested with pandoc 1.13.3. and produces the
  desired output for URL links when converting to LaTeX.

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  Reply to this email directly or [1]view it on GitHub.

References

1. [latex writer] dollar character should not be escaped in LaTeX \url{} links #1913