Noweb references in sh blocks breaks the syntax highlighting

Question

I use noweb references inside sh code blocks, for example:

#+begin_src sh
  echo "test"
  <<some-ref>>
  echo "test"
#+end_src

But this causes syntax highlighting to be broken because << gets interpreted as here document by the sh syntax highlighter and rest of the document (line 3 for the example above) becomes non-highlighted.

How can I fix this?

Answer 1

You can define the delimiters babel use for noweb references, by setting org-babel-noweb-wrap-start and org-babel-noweb-wrap-start.

For instance, in org mode document where I dabble in bash, I insert at the bottom of the file:

* COMMENT Local Variables
# Local Variables:
# org-babel-noweb-wrap-start: "«"
# org-babel-noweb-wrap-end: "»"
# End:

The syntax to refer to noweb now is:

#+begin_src sh :noweb yes
«ze_bloc_to_include»
#+end_src

I like to use « and » characters, because they are very similar to << and >>, but you can choose other combination.

The drawback of this solution : it changes for the whole buffer, not only a single block. Otherwise, pretty great all around.

Answer 2

I liked @Dreammm's idea of using the « and » characters but didn't like having to declare file local variables.

I also did not want to always use « and ».

I just overwrote the org-babel-noweb-wrap function so now I can use either << and >> or « and ».

(defun org-babel-noweb-wrap (&optional regexp)
  "Return regexp matching a Noweb reference.

Match any reference, or only those matching REGEXP, if non-nil.

When matching, reference is stored in match group 1."
  (rx-to-string
   `(and (or "<<" "«")
           (group
            (not (or " " "\t" "\n"))
            (? (*? any) (not (or " " "\t" "\n"))))
           (or ">>" "»"))))