Org-mode: How to render latex inside ~code~

Question

This seems a catch-22: I want to render code in an org-mode export (html or latex pdf) where the snippet below done as a ~code block

> (cons 1 nil) \to (1)

actually renders \to as a proper right arrow (yields). Of course if I do the snippet as inline latex

$> (cons 1 nil) \to (1)$

I get the properly rendered right arrow, but now it's not in the sans mono code font. What can I do to have my cake and eat it too?

Answer 1

I would use one of the following:

~> (cons 1 nil)~ \to ~(1)~

~> (cons 1 nil) → (1)~

Answer 2

From org mode manual:

You can make words bold, /italic/, underlined, ‘=verbatim=’ and ‘~code~’, and, if you must, ‘+strike-through+’. Text in the code and verbatim string is not processed for Org mode specific syntax, it is exported verbatim.

Indeed ~> (cons 1 nil) \to (1)~ is exported as LaTeX \texttt{> (cons 1 nil) \textbackslash{}to (1)}.

But this does suggest a workaround for LaTeX: use an export filter to undo the conversion of \ to \textbackslash{}.

(defun my-latex-filter-allow-latex-in-code (text backend info)
  "Undo backslash escaping"
  (when (org-export-derived-backend-p backend 'latex)
    (replace-regexp-in-string "textbackslash{}" "" text)))

(add-to-list 'org-export-filter-code-functions
         #'my-latex-filter-allow-latex-in-code)

The export filter can be extended for handling html as well. Here's a first draft handling only \to:

(defun my-filter-allow-latex-in-code (text backend info)
  "Allow LaTeX symbols in code"
  (cond 
   ((org-export-derived-backend-p backend 'latex)
    (replace-regexp-in-string "textbackslash{}" "" text))
   ((org-export-derived-backend-p backend 'html)
    ;; either extend this or find the html export function doing these conversions
    (replace-regexp-in-string "\\\\to" "→" text))))

(add-to-list 'org-export-filter-code-functions
         #'my-filter-allow-latex-in-code)